Automatic Partition Maintenance in MySQL and MariaDB: Part 3

Geoff Montee MariaDB , MySQL , Partitioning 3 Comments

Casinolistings free slots

These principles likewise acted as a easy way to comprehend other people online have similar dream similar to mine to know many more on the subject of this condition. They go out of their way to point out that this may be a working feature, and thus work is now labor, should not the classroom, and should be cared as a result! Congress also wants to raise prices on consumers, or least some of them.

Biggest online casino in the world

Check out our blog entries on the latest news and developments regarding sleep disorders. If they reall do perform, people will demand more of them and the politics will change. The plan, lambasted by union groups, may not get off the ground.

Zen spin casino

All the pieces else by means of three unbelievable matches. Our food was delicious, we had prime rib with lobster tail and some veggies. He represented northumberland in the legislative assembly of lower canada from 1814 to 1824 and from 1827 to 1830. My last name and initials?

Free online slots demo

Online studying has made taking your college diploma so much easier because you can easily earn your current degree through the comfort of your home and when you finish working! The eskimo talk 19 48 29 november 2010 utc incubate. My family members always say that i am wasting my time here at web, but i know i am getting know-how all the time by reading such nice content. Almost always there is going to be some wagering requirements on your end!

Cafe roulette

In this conversation, we discuss having a baby during coronavirus, the impact of the economic shock to comedians, and what has been going on inside ny fire houses over the last few months. Normally banking institutions and banking institutions are able to provide change costs that can be better than all those open to men and women. Then his diplomatic cover was blown in a sensational book, exposing his real career to his kids and, more dangerously, to the entire world.

Genting malaysia online casino

New drugs in the medical war against cancer and cardiovascular disease are now available or on the way. Michigan, the big 10 champion, will meet the university of southern california, the pac 10 leader, in the rose bowl football game on new year's day. The protesters were demanding closure of clark, subic bay naval base and four other smaller u. When these opinions and expectations about your partner differ now and then in real life, it can either leave you ecstatic or depressed.

Best mobile roulette

However, cheers rang out from the few people on the streets and from apartment balconies. Please follow our links to find all the information that makes this the best online casino! I do not even understand how i ended up right here, however i believed this post was great.

Roulette predictor online

This post is in fact a fastidious one it assists new internet users, who are wishing in favor of blogging. I just had a chance to look at the second contest problem posted by sklansky. Jost plans, on bnmswiek trr.

Poker ace 88

Among the children, over 6,500 premature deaths from any cause were recorded and among these, almost 300 had obese mothers when they were born. He begins with the 1992-93 season. Deering was front and center.

27 wins slot

Some people do not even have to go to a casino to access a slot machine. Thanks, i have recently been looking for information about this subject for ages and yours is the best i have found out so far. Although it's not likely to spark a giddy citizenry into launching fireworks, approval by saturday of all 13 spending bills would be a political coup for both parties.

Best international sports betting sites

It was directed by alastair reid. Nigeria number one betting website has its own old mobile site. This compares with pounds 144.

Joo casino 20 free

Your stamping room is shaping up well and i know chiltern you will be glad when it is finished. You are able to brew yummy gourmet coffee every morning with new filtered normal water. They were very professional with keeping communications open about my order, so that i was satisfied when i received my hair, and i am over the moon. During the charging process, the amount of acid content in the electrolyte increases and that makes the electrolyte as stronger.

Free online video poker

This collection of photographs consist of 2 postcards, 5 small photographic prints related to sigurd hagen. That he loved me enough to send his son to this earth to be the mediator for me to god. Collinsville is bringing back their popular hometown christmas variety show for a third year this december.

Fiesta casino

Suction denture brush model nc the suction denture brush, model nc, is a denture brush with a suction base designed for use by people with limited manual dexterity or use of only one hand. Michael keith spell, 25, of parachute, colorado, was sentenced following a hearing before state district judge richard simonton in sidney. Encontraremos la forma de realizar el pago y hacerte llegar los libros que buscas.

Safest sports betting sites

8576 ft m cite gnis id 793308 name wiles peak willow mountain coord 46 19 16 n 113 54 15 w display inline name willow mountain el. The amount of listings and website views is much smaller on flipkey compared to airbnb. Only after a couple weeks did i find out my account is cancelled and i was able to successfully request my money.

Betonline poker tournaments

Call comcast and have them remote reset the box. Professional style, clay filled casino chips. 2 bryan avenue 0.

Bookie gambling

I sing in a choir inpeakhealth. I have observed that in the world of today, video games include the latest rage with children of all ages. A investigate down from corporation formal, task masterly clothing is at assault unembellished, unprogressive, and household, if a lilliputian more slacken when it comes exyth. Check out the list below and explore the casinos with the latest, best no deposit and deposit casino bonuses uk players can get!

Spin palace bonus

His old friend roberts, who turned fbi informant after his conviction in the philadelphia killings, leaked the bombing plans, tarrants said. Left handed people are in their right mind. Faf du plessis, shane watson, and ms dhoni are all greats whose time has come. Casino game gold fish casino slots casino play.

Wizard of oz free spins

The ion and electron temperatures affect casino online in australia its growth in opposite manner and the electron temperature causes this instability to grow! Play with the dogs and do laundry - the joys of life,. Relationships on main hassle-free tips for free ukraine to craigslist backpage personals new? When you first friend someone, focus on making a personal comment that weaves connection?

Mandarin palace casino free spins

Orders will be processing at a slower rate due to the ongoing coronavirus outbreak. Real wonderful information can be found on web blog. Just couldn't go back to sleep. The goal is to give you a devotional thought to carry you through the day along with a quick idea for.

Real mobile casino

Get the top wireless buzzer alarm currently in stock and currently on sale now. I truly enjoy studying on this web site, it contains wonderful content. There is a continuation of the ball in order to fight with the champion. Thus, the best combine the two and offer free spins without requiring you to make a deposit.

Thunderbolt casino free spins

Just like in combat, every action taken or not taken changes the shape of things, the way things are going to play out? My very own feet keep on being warm and comfortable devoid of across heater. Move readily without any trouble.

Acr online poker

Priorities in this function include improving school and student housing infrastructure, and providing bursaries for tertiary students from poor and working-class families. Commerce college ctg notice board long way home ryan innes! If you want to save money on traveling, be accommodating when you are reserving your airfare. The women of begajah still comb their hair each morning after bathing, but no longer for profit!

Poker kiu

Once obtained admins generally do not want give it up. I would like to express some appreciation to you just for bailing me out of this type of problem? You managed to hit the nail upon the top and defined out the entire thing with no need side-effects , other folks could take a signal.

Casino1 club

My husband and i got so more than happy john could deal with his researching from the ideas he received in your blog. Hi, its pleasant article concerning media print, we all be familiar with media is a wonderful source of facts. However 1 of your main advantages in meeting a licensed tarot representative is by which because these businesses have been practicing just for some precious time they were often intuitive and therefore can gone through more to make the handmade cards with a lot of insight? Additionally, they change tremendously from brand name to manufacturer.

Pokerclub now

And few democrats are expected to object when mr. In his judgment, justice allsop found that woolworths had entered each of the agreements with the substantial purpose of substantially lessening competition in local packaged takeaway liquor markets in campbelltown, tweed heads and arncliffe. Gander whitening gels are applied onto the tooth surface with a small brush. J'aurais du rester couchée a matin?

Agent spins

The project is part of broader efforts by. Will fish continue in the future to be regarded as a healthy foodstuff, or at least one which is safe to eat. For this reason the following tips are present. Your special commitment to getting the message across ended up being pretty productive and has without exception enabled those just like me to attain their desired goals.

Adda52 office

Reversible and adjustable for use on either side of the bed, this rail secures to the bed frame and mattress with the included safety strap! The coaching course will cancel the additional bonuses after this period expires! Even better, he had no walks for the first time in 10 starts this year.

Coral bingo

Each race was held over a distance of 1500 m swim 40 km cycle 10 km run an olympic distance triathlon. There were a few glitches in the online learning platform, but those arose from the changeover to a better system. Green nike windbreaker on the hunt.

Freaky vegas casino

The range of games that 24vip casino offers includes more than 200 slots, including 3d games, bonus round, video slots, i-slots and classic 3-lane slots. Comments and questions should be directed to the omb reviewer listed below by august 2, 2006. Yeu e, goldberg df, mah fs, beckman ka, luchs ji, solomon jd, white de, gupta pk.

247 poker free game

Furthermore effortlessly-cleanable clothing decrease the total level of clothes a visitor needs to get together, they can give a comfortable security world wide web in the case of unexpected setbacks. Marijuana oil has actually already marked a new period in which guy ceased to fear what is unknown, and started to discover what our forefathers had already discovered and use the significant potential, at first look, a little bizarre relationships, associated mainly with pathology. Delete source provided indicates all rights reserved so licence is false unless permission is provided. I'll bookmark your website and take the feeds also.

Slots 7 casino no deposit bonus

Hyundai motors announced production would resume tuesday at the company's assembly plant at ulsan, an industrial city on the southeast coast. These include the river spirit casino resort, retail development on riverside parkway, and the revitalization of riverwalk. He wanted to create all this detail. How yon celebrating cherish alongside paying it forward.

Edge roulette

She moves in with the guy and his family, who are some type of royalty and i think he's a vampire. Admin dari pihak site judi bola on-line cash asli terbaik ini memiliki layanan 24 jam non-stop, dalam mana setiap player boleh menghubungi servis purchaser suport setiap waktu serta berpedoman medium chatting apa tertentu yang berada di dalam site penting situs judi bola online itu. Acne in testosterone zone 5 htp and 20mg lexapro.

Win river resort casino

Use these recommendations while traveling so you could have a terrific time. See the latest deals and special offers? 12 link is not on the monitorlist?

Treasures of troy free slots

Its rng software is being examined by a third-get together to ensure equity in every recreation. Thank you for your comment ray? I will make sure to bookmark your blog and will often come back in the foreseeable future.

Apollo casino

I have linked to your free maps portion! Choose prior to the very first menstrual stage was not really right. 11 décembre 2020 at 0 h 45 min. Html 2 afd statistics find sources colombo international school this is a copy and paste job which had produced an article on a school which reads as an advertisement.

Even money blackjack

Talk with your enter in to abbreviation away from what you can do to succour be established some of the crushing potty of her. But the new lime doser, placed on stocketts run in the patuxent river, is a new design that doesn't rely on a computer. He roped in two employees for a game of ping-pong and positioned another group right by the bar.

Bgo casino 20 free spins

Thanks to modern innovation, the resulting option is tidy, complimentary of heavy metals and unneeded waxes, naturally present in the plant, and the drawn liquid has a typical, oily consistency. Home security system project using iot. The podcast also shares stories over six episodes with six influential inspiring female founders, creatives, entertainers, thought leaders and activists. My extensive internet lookup has at the end been recognized with extremely good strategies to share with my family and friends.

888 casino free bet

Ya hazme caso o dejame ir! Such games have been designed to give the most realistic experience possible! The family would like to thank the skilled doctors and nurses at saint francis hospital, the staff of the ouachita dialysis center, and the family physician, dr. There was always laugh when he came?

Website casino online

It surpasses the word free to skip the middle! You understood my vision and went above and beyond like always. They know that some cannot make it to london very easily. Cbd oil vape charlotte web cbd oil.

Learnwpt

The ph difference may not be meaningful, in spite of that, since the protein may be denatured. They might cover items including misplaced luggage or vacation cancellation. 21 -21 68 -1.

888 casino bonus

All i know from previous experience based on fact not assumptions was that by they time they capped membership for another program the level of profit on recommended trades dropped due to the amount of people all cashing at once. Both bills would enable commercial banks and insurance companies as well as farm credit system banks to pool farm loans and sell them as securities on the so-called farmer mac market, just as home mortgages are sold on a secondary market. To purchase the cannon assets, is controlled by interpart s. 5 bgcolor ccffcc 29 align left kang chil gu align left flagioc kor 2002 winter 101?

Blackjack browser

The start of the first qualifying round shall be regarded as the start of the competition during the olympic games. A windy day is not the day for thatching. Director of the castro district. Come back each week and see the latest online casinos and casino bonuses available to play on.

Reddit nba betting

She came to understand so many things, not to mentiin how it is like to possess an incredible teaching spirit to have the mediocre ines just graddp certain complex topics. Php and disposition trails that are unencumbered to advantage, and even if in search safeness reasons multifarious intent their gates at evening, some bear special nighttime programs for exploring nocturnal animals that are usefulness checking out. Excursion operators, car hire organizations, vehicle hire firms along with other agencies are trying to find progressive methods to let tourists live green.

Perfect gems slot

As many as 250,000 spectators watched, and gambled on, chariot races in rome's circus maximus. To jen and the whole family i'm so sorry for your loss my heart goes out to you and your family! I moved down mostly by making hands and i was never down more.

Jumba bet free spins online casino

2002182vendor name fujiko n packing material co. You locate the best money saving deals on viagra online beyond just the best price on generic viagra. Dill, a university of maine extension specialist in pest management.

888 poker restricted countries

I had an issue with the bath tube and the technician was available in a minute and mended the issue in a couple of minutes. In general, ewallets such as neteller and skrill are preferable for depositing such small amounts. Hillcountries talk 09 53 27 november 2010 utc after i pointed out the author of the article has contributed to tamil tiger websites is a baseless allegation and should be ignored by the closing admin? Here is what a typical journey via camonster will seem like should you resolve to join the positioning.

True fortune casino free spins

So, online video slots machine no download and some of them can be very tasty indeed. Customer accounts are automatically activated and provided with data from the cpdb when a customer from one casino property first visits an affiliated casino property? In a nonendemic area, the awareness of the pathologist to the possibility of casino online in nj this disease will exclude a neoplasm and facilitate prompt antihelminthic treatment. I'm on business alpha male xl free trial the key struggle is persuading residents that the exchanges will be available, despite highly publicized attacks from leaders in austin, she says.

Play las vegas slots

Assessment of the watershed will support stakeholders in development of a watershed management plan. Thanks for sharing i have enjoyed every piece of your content. Working with airports is undoubtedly an unfortunate demand for a lot modern journey.

Fruit party slot demo

I hit some black ice at online roulette veilig about 80mph last march and i could not have responded as poker online judi uang asli fast as the computer did to keep my truck on it s lid in the ditch. In between the two time periods, the boulders were submerged, the scientists say. Last month, the sec established september 26th as the new kickoff for its 2020 football season due to the covid-19 pandemic.

Piggy riches megaways review

We also proposed that apm entities and eligible clinicians can submit other payer arrangements for cms to determine whether they are aligned other payer medical home models and other payer advanced apms, as applicable, through the eligible clinician initiated process. It promises capable and expert satisfaction of its own duty, carries out the building and construction of each object following the dreams of the client, watching the concept of an specific method. Nervous just thinking abt it. Patients can navigate using strictly spatial information and specific details of landmarks such as house number or door color!

Betsson welcome bonus

Buenos aires, argentina - south american nations hope to see the fruits of economic austerity programs they imposed in 1990. Japan is seen as the leader in what the industry calls quick product turnaround time, usually three years or less. As a yearly tradition, players can bask in a completely white los santos as snow will fall for the next few days.

Vegas poker online

This is often the quickest and most effective way to resolve concerns. Parking for the event will be free and tickets will be sold on the premises. No download required and no spammy popup ads.

Lucky creek 100 no deposit bonus 2020

Prob the best at home sketch. They provide their customers an individualized relocating strategy and offer a group of rigorously taught moving experts that are prepared to manage every portion of the technique. Intraoperatively, as the integrity of the cartilage of the proximal pole of the scaphoid was observed, dorsal vascularized distal radius graft was performed using the 1, 2 intercompartmental supraretinacular artery. In addition, igt has joined the united nations global compact, the largest corporate responsibility initiative in the world for the development, implementation, and disclosure of responsible corporate policies and practices.

Play caribbean poker online free

Continuing strong opposition from israel's supporters in congress has forced the administration in recent days to discuss a compromise that might include dropping the maverick missiles. Slimvirgin talk contribs 15 37 2 december 2010 utc i m thinking of using the school library journal and voya reviews under the editorial reviews tab here. I believe that the focus should remain on finding ayla. Betting extra win initially installation tryst dec.

Space wins slots

With weeden out recovering from a sprained thumb, hoyer made just his second nfl start in week 3 and led the browns to consecutive wins, directing clutch fourth-quarter drives and throwing clinching touchdown passes in both games. Check with the danes, though? I tried to get new thermocouple from local plumbing supply store.

Crystal slots

Us origdiff user coibot editsummary id 25038919 lang ca wikidomain w namespace pagename maggie grace username 95. Iran has allowed husbands to prevent their wives from working, placed restrictions on women's mobility and limited their work in the judicial sector, the report said. Depart all pointless belongings in your own home!

Nitrogen sports betting

When figuring out getting a great look on your ft whenever you go on the plane journey, remember that you may be most cozy in boots that move away from very easily. Visitor badges must be worn at all times in the building. The menu bar is packed with a range of links and features, including sports betting, live in-play betting, online casino, live casino, bonuses and promotions, and results.

Euro palace casino mobile

Its publication comes just months after nobel prize-winning author guenter grass wrote a hugely popular book about the wilhelm gustloff, a boat on which 9,000 german civilians were killed when it was torpedoed by a soviet submarine in 1945. Opened in, the facility has martins ferry played host to thousands of events, with cornwall over 2, , people crossing our threshold. A standard person, after taking doses of medicinal cannabis and accomplishing the appropriate state of cannabinoids in the blood, can delight in increased resistance, lowered susceptibility to cancer, delayed aging and decreased risk of stroke or cardiac arrest? Peradventure you forever wanted to mark in sooner than a for nothing, but your ancient henchman was against the idea.

Twin win slot machine

The internal epa study on environmental risks, first reported in the new york times, is based on subjective judgments by 75 top agency staff members. Do you know who made the game owzat? You can choose between sports, casino and table games?

Southgate casino las vegas

You can save a map and then add locations to it. More challenging more does not necessarily mean worse. In games you dont understand well try to decide how easy it is to make the nuts. This leads to a higher house edge compared to european roulette.

Online betting new customer offers

Part of this preparation is to ensure schs has an adequate emergency water supply for all students. Wayne lockett, aerospace engineer, airframe branch, anm-120s, faa, seattle aircraft certification office, 1601 lind avenue, sw. But amex president kenneth leibler says the reporting discrepancies make it difficult to compare the two markets.

Blackjack red dead 2 online

Any tips to help my luck? Heavy weekend rains in brazil and northern argentina helped improve the soybean crops there and bring a negative mood to soybean trading, said gidel. Most online casinos are bullshit.

Blackjack dealer soft 17

Myrle fuller talk 15 41 1 december 2010 utc note this debate has been included in the list of american football related deletion discussions. If you love the great outside the house, nature, and the smell of outdoors, practically nothing will make you happy over a good camping outdoors getaway. Indeed, many pool bets were made between friends or colleagues rather than through official sports betting platforms. That is why we are here.

Slots that pay real money

Mr jean-claude juncker, luxembourg's finance minister, said shorter working hours would send a 'negative, defeatist signal' to europe's workers. I just could not go away your site prior to suggesting that i extremely loved the usual info a person supply on your guests. They may be used to a variety of different ways and are fantastic for on the go. Punters have time to choose from us, decimal and malaysian odds to have a best experience.

Card roulette

Carol guzy of the washington post was named newspaper photographer of the year friday, with magnum's eugene richards winning the top magazine award in the 47th annual pictures of the year competition! As we are limited in what we can do in the interior until the asbestos is removed, we have begun tackling the exterior at the main floor rim joist. Dmk's second health meter has been knocked off completely. His clever sense of humor and infectious laugh were appreciated by many.

Free spins no deposit fishing frenzy

Probable coadjutor foods can extension testosterone in men? Here is a list of the films that john houseman produced or acted in during a stage, screen and radio career that spanned 60 years. It keeps your details hidden from the recipient of your funds so you never have your sensitive card information given out to an unknown third party?

888 casino get 88 free

If they do it s easy enough to grab the list using awb from whatlinkshere and generate a bulleted list. The final state of the index is printed. 90 align center 23 align center colspan 7 eliminated align center 45 erik arambula monterrey individual align center 60. Next meeting is july 16 th at the winery.

Free spins on cash bandits 2

Marijuana oil has already marked a brand-new era in which guy stopped to fear what is unknown, and began to rediscover what our forefathers had already observed and utilize the substantial potential, in the beginning glimpse, a little strange relationships, associated primarily with pathology? The german reich party had five members during the first west german legislature starting in 1949? I'm going to take a note of your website and keep checking for. Save more when you book direct.

Casino leo vegas

Car hire from a1 travel? Meanwhile, william evancho, former head of alcoa's steamship division, was bored with his job in the new kensington lab. Without further ado, let us get started with our comprehensive review of 21 casino. Just make sure you follow the rules of every particular activity or facility.

32red free bet

4 million people in harris county, which includes houston, voted in person and by mail during the early voting period ending friday, out of a total of 2. Salah eka kampiun pada th. The audio footage yesterday afternoon i shared in the whatsapp group cupumaniak. The 30 world book night u.

Ipoker network sites

Since 2012, which shows how confident people are in using the u! Our hope is to make this ride a seasonal event to enjoy nature at its finest. Before you book any getaway by airplane, investigation various airlines very first.

Wsop poker chips

Need help writing a essay77. I am truly sorry to have learned of the passing of patrick o'brian. 29ho9809 s 12 100 74 115 -.

Mini roulette online casino

That came after the average had already failed to move beyond its 1101. Professor kolb says the original study, titled friday the 13th, part vii, was published tongue-in-cheek. And he has some very creative ways of doing this.

Planet 7 casino $100 no deposit bonus codes 2020

After receiving your first two cards, you have up to four options. With a rugged housing, ip42 protection and they guarantee unique performances. Yours list the following is an archived discussion concerning one or more categories. Antonius could log on and play from his home in monaco, gus hansen from scandinavia, and others could play from wherever they were in the world at the time.

Rise of olympus free slot

However i don't think you lost a lot of value here, but still value is value. Honolulu, hi the 13 th largest city in the nation in the middle of the pacific ocean where president barack obama once called home is a bastion of culture and art, be it in their museums and concert halls to the urban hubs which have been embraced by the hollywood television and film communities. Anyway stay up the excellent high quality writing, it is rare to see a great blog like this one nowadays. And 40 per cent of all hangover remedies are sold in the four weeks around christmas.

Betway casino slots

An aisle chair provides you with better accessibility baggage safe-keeping, bath rooms, air travel employees, in addition to stop you from getting compressed on sides. The median value of the ctr ratio is around 9 percent. 3 forms in the blackfoot data set, grouped by category.

Free casino video games

But even as the colonial union moves toward peace, it becomes increasingly clear that some would prefer other, more dangerous paths. If you or someone you know has a gambling problem, call 800. So very sorry for your loss, jack was such a wonderful man and his beautiful soul will be missed on this earth.

Casino extreme

At this time, it seems like wordpress is the preferred blogging platform available right now. Personally, if all web owners and bloggers made good content material as you did, the web will probably be much more useful than ever before. Not only will it place them hectic and from trouble, it will likely be enjoyable for them as well.

Real slot

Entity to finance its activities without additional subordinated financial support from other parties. He was a resident of washington but had taught at yale university since 1989. That is definitely a great good quality. Your thoughts really clarified all our queries.

Tiger 777 casino

Make the easiest day for ron at school and help him with correct answers brighton. By joining this affiliate program and receiving and using links to the merchant website, you are confirming that you have read this agreement and that you agree to be bound by the terms and conditions contained in this agreement. How do i connect up to this group in australia!

22bet online login

Marijuana oil has already marked a brand-new era in which male stopped to fear what is unknown, and started to discover what our forefathers had currently discovered and utilize the significant capacity, at first glimpse, a little strange relationships, associated generally with pathology. April sales comparisons for stores open more than a year declined virtually across the board. Spend some time and never let all of the numerous preparations you need to make, detract out of your enjoyment.

Ladbrokes football betting odds

I kept on nodding while they went on speaking and speaking and speaking! Claim welcome offer at wildz casino? Replaceability national geographic is a copyrighted publication for which by nature no free images exist.

Yabby casino no deposit bonus

You must take part in a contest for among the best blog sites on the web. If you pack increase your camp out web site to look home, leave several logs plus some kindling for the next camping outdoors class which comes along. You literally have superb article material. A court has decided no trial will be held in belgium on the 1987 zeebrugge ferry disaster that killed 193 people because the ship and all its victims were british, officials said thursday.

Galfond

Profibrotic gene expression after treatment with pln-1474. Supreme court justice thurgood marshall refused to continue a delay requested by the defense, which claimed a second trial would violate the defendants' right to avoid double jeopardy. When someone votes, the tip will be highlighted in that color in your. You can definitely tell the difference between medium format images and 35mm images on instagram.

Classic slots online

It is especially essential that you ask about any invisible costs which might be tacked onto your monthly bill in the event the areas are affordable! The amendments in this update are intended to render more detailed implementation guidance with the expectation to reduce the degree of judgement necessary to comply with topic 606. Detection of flux emergence, splitting, merging, and cancellation of network fields.

Gold country casino

Most of the boys ended up passionate to read them and already have undoubtedly been loving those things. Best betting bonus uk ie extensions. Record levels of failures are projected and the insurance fund overseen by the fdic will soon run dry unless action is taken by congress. When data and processing power of your cellphone is restricted, utilizing an app instead of a website can potentially assist the user friendliness.

Planet 7 no deposit bonus free spins

The patrol commander will notify the public of specific enforcement times by marine radio safety broadcast. Apabila dijumlahkan ala kesemestaan, anton honifar menelanjangi makin dari 5 tips menjumpai memimpin hadiah seru ini. Excellent issues altogether, you just won a logo new reader.

Play roulette wheel

2 wide receiver in green bay. A total of dollars 473m would be arranged through various bilateral agencies from france, sweden, finland, japan as well as the asian development bank. Handbasins at big bathroom shop. Expenditure estimates for these hospitalizations are the last part of the study.

888 roulette free

Daniel negreanu, one of the most accomplished poker players of all-time, will have to find another bank at which to stash his winnings. No parece falso y te hace tan satisfecho como una cita caliente. Melainkan mungkinan wajib memadai tau mengenai rules dan terhitung berjenis-jenis makna yang tersedia di sementara tontonannya.

Slot hunter free spins

We developed a mobile accessories manufacturers union with our really- shut factories and also we owned the firm shares each various other to make sure that dealers could place orders for different mobile devices products in an easier method without the unnecessary price by trading companies. University of dallas senior pitcher chris schierhorn of anchorage earned his third win of the season yesterday in texas after a remarkable relief appearance against centenary of louisiana. Motshegwa said there are many cases of harassment and violence in the workplace reported, however, due to the many gaps in legal protections regarding workplace harassment and violence, workers are not fully protected.

Jackpot city 150 free spins

Gross increases - current period tax positions. You can go to a museum of excellent works of art anywhere in the country however in boston you can in fact visit a museum dedicated to bad art work. At the other extreme, super monopoly money is a highly volatile slot, so you may have to wait a while to land a win, but prizes can be bigger.

3d roulette game free online

Tabletten bei ms, tabletten auflosen und deutschland kaufen, au. Nevada gambling is legal and forms a critical economic state pillar. Sincerely, george nedder boston, ma.

Best video poker odds

Drawing lottery games vs slot machine odds. The article describes the bomb being left with a note that told of the detonation mechanisms and how they would be triggered. Manley and i happen to be saving to buy a new guide on this topic and your article has made us all to save our own money. The refrigerators use up lots of cash to finish up the debris refrigerator repair and dust.

Passe roulette

Can you buy chloramphenicol over the counter. When i purchased a brand-new cooktop, refrigerator and also dish washer for my kitchen, i requested a discount and also got it. Thousands of popular first names commonly used by speakers in italy.

Old fruit machines for sale

Haga men have checked purses and bags at the door of movie theaters for bombs! Mysql -u root -p create the wordpress database. Arlo home security cameras are providing their full support features to its users as they are considered among the topmost cameras in terms of protection and security. Legal proceedings and regulatory actions.

Spartan king slot

61 19 32 19 thu nov 25 2010 user anthony meenagh user talk contribs on page omagh diff undo overlap username overlaps with pagename anthony meenagh omagh 26. Nowadays fans of this kind of gambling can scarcely visit the gambling halls. Back in boston, they knew the housing and the schools and had the commute memorized.

Casino 25 free spins

Anderlecht appear to be the team that everyone else in belgium appears to hate, success, of course, breeds jealousy and a record 33 belgian titles and 5 european trophies play no small part in that. Finally, we will review some of the trends affecting production and operations management. Outliers in this plot may indicate samples where, for some reason, the common relationship between the two variables of interest does not hold. Huawei p smart fundas amazon.

Pragmatic sweet bonanza

This will also answer your other question regarding the waiting for withdrawals! We explore what the future holds for his replacement and which ceos now rank as our favorites. Is cbd legal in florida. Bosch provides components and systems for automating, connecting, and electrifying the shuttles?

Lucky tree slot machine

Howrah 2011 election summary 1977 2006 in the 2006 2001 1996 and 1991 state assembly elections rabindra ghosh of forward bloc won the uluberia south assembly seat defeating his nearest rivals pulak roy of trinamool congress in 2006 bani kumar singha of trinamool congress in 2001 pulak roy of congress in 1996 and amar banerjee of congress in 1991. Fry was also a member of the usa eagles for the 2011 rugby world cup in new zealand where he started against australia. Most likely you could write following article content relating to this article.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Automatically Dropping Old Partitions in MySQL and MariaDB: Part 2

Geoff Montee MariaDB , MySQL , Partitioning 3 Comments

In a previous blog post , I showed how a DBA could configure MySQL or MariaDB to automatically drop old partitions. Some readers provided some feedback on some issues that they’ve run into while doing similar operations. Specifically:

  1. It can sometimes help to maintain an empty first partition when partitioning by dates, since partition pruning cannot always eliminate the first partition. Sometimes this can happen due to optimizer bugs, and other times this can happen because the optimizer cannot exclude invalid dates in DATE and DATETIME fields.
  2. ALTER TABLE ... DROP PARTITION operations can take a while, and they can block queries in the meantime, so sleeping between operations to allow some other queries to execute can sometimes be beneficial.
  3. It is also generally beneficial to automatically add new partitions.

In this blog post, I will discuss the first two items. I may discuss the third item in a future blog post.

Partitioned table definition

Our partitioned table is going to have a couple changes:

  • It will contain an empty first partition called p_first .
  • The last partition will be renamed from p_default to p_future , since that makes more sense.

Here is our new definition:

DROP TABLE IF EXISTS db1.quarterly_report_status;

CREATE TABLE db1.quarterly_report_status (
   report_id INT NOT NULL,
   report_status VARCHAR(20) NOT NULL,
   report_updated TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB
PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated) ) (
   PARTITION p_first VALUES LESS THAN ( UNIX_TIMESTAMP('2016-10-01 00:00:00')),
   PARTITION p201610 VALUES LESS THAN ( UNIX_TIMESTAMP('2016-11-01 00:00:00')),
   PARTITION p201611 VALUES LESS THAN ( UNIX_TIMESTAMP('2016-12-01 00:00:00')),
   PARTITION p201612 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-01-01 00:00:00')),
   PARTITION p201701 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-02-01 00:00:00')),
   PARTITION p201702 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-03-01 00:00:00')),
   PARTITION p201703 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-04-01 00:00:00')),
   PARTITION p201704 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-05-01 00:00:00')),
   PARTITION p201705 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-06-01 00:00:00')),
   PARTITION p201706 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-07-01 00:00:00')),
   PARTITION p201707 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-08-01 00:00:00')),
   PARTITION p201708 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-09-01 00:00:00')),
   PARTITION p_future VALUES LESS THAN (MAXVALUE)
);

Stored procedure definition

Our stored procedure is also going to have a couple changes:

  • It takes a new parameter called p_seconds_to_sleep that controls how many seconds the server sleeps between ALTER TABLE ... DROP PARTITION operations.
  • After all old partitions are dropped, it will reorganize the empty first partition to fill the gap in the range left by the dropped ones.

Here is the new code (with comments inline):

DROP PROCEDURE IF EXISTS db1.drop_old_partitions;

DELIMITER $$
CREATE PROCEDURE db1.drop_old_partitions(p_schema varchar(64), p_table varchar(64), p_months_to_keep int, p_seconds_to_sleep int)
   LANGUAGE SQL
   NOT DETERMINISTIC
   SQL SECURITY INVOKER
BEGIN  
   DECLARE done INT DEFAULT FALSE;
   DECLARE current_partition_name varchar(64);
   -- We'll use this cursor later to get
   -- the list of partitions to drop.
   -- @last_partition_name_to_keep will be
   -- set later.
   DECLARE cur1 CURSOR FOR 
   SELECT partition_name 
   FROM information_schema.partitions 
   WHERE TABLE_SCHEMA = p_schema 
   AND TABLE_NAME = p_table 
   AND PARTITION_NAME != 'p_first'
   AND PARTITION_NAME != 'p_future'
   AND PARTITION_NAME < @last_partition_name_to_keep;
   DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
   
   -- Now we get the last month of data that we want to keep
   -- by subtracting p_months_to_keep from the current date.
   -- Note that it will actually keep p_months_to_keep+1 partitions,
   -- since the current month is not complete.
   SET @date = CURDATE();
   SET @months_to_keep = p_months_to_keep;   
   SET @q = 'SELECT DATE_SUB(?, INTERVAL ? MONTH) INTO @last_month_to_keep';
   PREPARE st FROM @q;
   EXECUTE st USING @date, @months_to_keep;
   DEALLOCATE PREPARE st;
   
   -- Then we format the last month in the same format used
   -- in our partition names.
   SET @q = 'SELECT DATE_FORMAT(@last_month_to_keep, ''%Y%m'') INTO @formatted_last_month_to_keep';
   PREPARE st FROM @q;
   EXECUTE st;
   DEALLOCATE PREPARE st;
   
   -- And then we use the formatted date to build the name of the
   -- last partition that we want to keep. This partition name is
   -- assigned to @last_partition_name_to_keep, which is used in
   -- the cursor declared at the start of the procedure.
   SET @q = 'SELECT CONCAT(''p'', @formatted_last_month_to_keep) INTO @last_partition_name_to_keep';
   PREPARE st FROM @q;
   EXECUTE st;
   DEALLOCATE PREPARE st;
   
   SELECT CONCAT('Dropping all partitions before: ', @last_partition_name_to_keep);
   
   SET @first = TRUE;
   
   -- And then we loop through all partitions returned by the cursor,
   -- and those partitions are dropped.
   OPEN cur1;

   read_loop: LOOP
      FETCH cur1 INTO current_partition_name;
   
      IF done THEN
         LEAVE read_loop;
      END IF;
     
     IF ! @first AND p_seconds_to_sleep > 0 THEN
        SELECT CONCAT('Sleeping for ', p_seconds_to_sleep, ' seconds');
        SELECT SLEEP(p_seconds_to_sleep);
     END IF;

      SELECT CONCAT('Dropping partition: ', current_partition_name);
   
      -- First we build the ALTER TABLE query.
      SET @schema = p_schema;
      SET @table = p_table;
      SET @partition = current_partition_name;
      SET @q = 'SELECT CONCAT(''ALTER TABLE '', @schema, ''.'', @table, '' DROP PARTITION '', @partition) INTO @query';
      PREPARE st FROM @q;
      EXECUTE st;
      DEALLOCATE PREPARE st;
      
      -- And then we prepare and execute the ALTER TABLE query.
      PREPARE st FROM @query;
      EXECUTE st;
      DEALLOCATE PREPARE st;
     
      SET @first = FALSE;
   END LOOP;
   
   -- If no partitions were dropped, then we can also skip this.
   IF ! @first THEN
      -- Then we need to get the date of the new first partition.
	  -- We need the date in UNIX timestamp format.
      SET @q = 'SELECT DATE_FORMAT(@last_month_to_keep, ''%Y-%m-01 00:00:00'') INTO @new_first_partition_date';
      PREPARE st FROM @q;
      EXECUTE st;
      DEALLOCATE PREPARE st;     
      SELECT UNIX_TIMESTAMP(@new_first_partition_date) INTO @new_first_partition_ts;
     
     -- We also need to get the date of the second partition
      -- since the second partition is also needed for REORGANIZE PARTITION.
      SET @q = 'SELECT DATE_ADD(@new_first_partition_date, INTERVAL 1 MONTH) INTO @second_partition_date';
      PREPARE st FROM @q;
      EXECUTE st;
      DEALLOCATE PREPARE st;
      SELECT UNIX_TIMESTAMP(@second_partition_date) INTO @second_partition_ts;
  
      SELECT CONCAT('Reorganizing first and second partitions. first partition date = ', @new_first_partition_date, ', second partition date = ', @second_partition_date);
   
      -- Then we build the ALTER TABLE query.
      SET @schema = p_schema;
      SET @table = p_table;
      SET @q = 'SELECT CONCAT(''ALTER TABLE '', @schema, ''.'', @table, '' REORGANIZE PARTITION p_first, '', @last_partition_name_to_keep, '' INTO ( PARTITION p_first VALUES LESS THAN ( '', @new_first_partition_ts, '' ), PARTITION '', @last_partition_name_to_keep, '' VALUES LESS THAN ( '', @second_partition_ts, '' ) ) '') INTO @query';
      PREPARE st FROM @q;
      EXECUTE st;
      DEALLOCATE PREPARE st;
     
      -- And then we prepare and execute the ALTER TABLE query.
      PREPARE st FROM @query;
      EXECUTE st;
      DEALLOCATE PREPARE st;
   END IF;
END$$
DELIMITER ;

Let’s try running the new procedure:

MariaDB [db1]> SHOW CREATE TABLE db1.quarterly_report_status\G
*************************** 1. row ***************************
       Table: quarterly_report_status
Create Table: CREATE TABLE `quarterly_report_status` (
  `report_id` int(11) NOT NULL,
  `report_status` varchar(20) NOT NULL,
  `report_updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated))
(PARTITION p_first VALUES LESS THAN (1475294400) ENGINE = InnoDB,
 PARTITION p201610 VALUES LESS THAN (1477972800) ENGINE = InnoDB,
 PARTITION p201611 VALUES LESS THAN (1480568400) ENGINE = InnoDB,
 PARTITION p201612 VALUES LESS THAN (1483246800) ENGINE = InnoDB,
 PARTITION p201701 VALUES LESS THAN (1485925200) ENGINE = InnoDB,
 PARTITION p201702 VALUES LESS THAN (1488344400) ENGINE = InnoDB,
 PARTITION p201703 VALUES LESS THAN (1491019200) ENGINE = InnoDB,
 PARTITION p201704 VALUES LESS THAN (1493611200) ENGINE = InnoDB,
 PARTITION p201705 VALUES LESS THAN (1496289600) ENGINE = InnoDB,
 PARTITION p201706 VALUES LESS THAN (1498881600) ENGINE = InnoDB,
 PARTITION p201707 VALUES LESS THAN (1501560000) ENGINE = InnoDB,
 PARTITION p201708 VALUES LESS THAN (1504238400) ENGINE = InnoDB,
 PARTITION p_future VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.00 sec)

MariaDB [db1]> CALL db1.drop_old_partitions('db1', 'quarterly_report_status', 6, 5);
+--------------------------------------------------------------------------+
| CONCAT('Dropping all partitions before: ', @last_partition_name_to_keep) |
+--------------------------------------------------------------------------+
| Dropping all partitions before: p201702                                  |
+--------------------------------------------------------------------------+
1 row in set (0.00 sec)

+--------------------------------------------------------+
| CONCAT('Dropping partition: ', current_partition_name) |
+--------------------------------------------------------+
| Dropping partition: p201610                            |
+--------------------------------------------------------+
1 row in set (0.00 sec)

+---------------------------------------------------------+
| CONCAT('Sleeping for ', p_seconds_to_sleep, ' seconds') |
+---------------------------------------------------------+
| Sleeping for 5 seconds                                  |
+---------------------------------------------------------+
1 row in set (0.02 sec)

+---------------------------+
| SLEEP(p_seconds_to_sleep) |
+---------------------------+
|                         0 |
+---------------------------+
1 row in set (5.02 sec)

+--------------------------------------------------------+
| CONCAT('Dropping partition: ', current_partition_name) |
+--------------------------------------------------------+
| Dropping partition: p201611                            |
+--------------------------------------------------------+
1 row in set (5.02 sec)

+---------------------------------------------------------+
| CONCAT('Sleeping for ', p_seconds_to_sleep, ' seconds') |
+---------------------------------------------------------+
| Sleeping for 5 seconds                                  |
+---------------------------------------------------------+
1 row in set (5.03 sec)

+---------------------------+
| SLEEP(p_seconds_to_sleep) |
+---------------------------+
|                         0 |
+---------------------------+
1 row in set (10.03 sec)

+--------------------------------------------------------+
| CONCAT('Dropping partition: ', current_partition_name) |
+--------------------------------------------------------+
| Dropping partition: p201612                            |
+--------------------------------------------------------+
1 row in set (10.03 sec)

+---------------------------------------------------------+
| CONCAT('Sleeping for ', p_seconds_to_sleep, ' seconds') |
+---------------------------------------------------------+
| Sleeping for 5 seconds                                  |
+---------------------------------------------------------+
1 row in set (10.05 sec)

+---------------------------+
| SLEEP(p_seconds_to_sleep) |
+---------------------------+
|                         0 |
+---------------------------+
1 row in set (15.05 sec)

+--------------------------------------------------------+
| CONCAT('Dropping partition: ', current_partition_name) |
+--------------------------------------------------------+
| Dropping partition: p201701                            |
+--------------------------------------------------------+
1 row in set (15.05 sec)

+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
| CONCAT('Reorganizing first and second partitions. first partition date = ', @new_first_partition_date, ', second partition date = ', @second_partition_date) |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Reorganizing first and second partitions. first partition date = 2017-02-01 00:00:00, second partition date = 2017-03-01 00:00:00                            |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (15.06 sec)

Query OK, 0 rows affected (15.11 sec)

MariaDB [db1]> SHOW CREATE TABLE db1.quarterly_report_status\G
*************************** 1. row ***************************
       Table: quarterly_report_status
Create Table: CREATE TABLE `quarterly_report_status` (
  `report_id` int(11) NOT NULL,
  `report_status` varchar(20) NOT NULL,
  `report_updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated))
(PARTITION p_first VALUES LESS THAN (1485925200) ENGINE = InnoDB,
 PARTITION p201702 VALUES LESS THAN (1488344400) ENGINE = InnoDB,
 PARTITION p201703 VALUES LESS THAN (1491019200) ENGINE = InnoDB,
 PARTITION p201704 VALUES LESS THAN (1493611200) ENGINE = InnoDB,
 PARTITION p201705 VALUES LESS THAN (1496289600) ENGINE = InnoDB,
 PARTITION p201706 VALUES LESS THAN (1498881600) ENGINE = InnoDB,
 PARTITION p201707 VALUES LESS THAN (1501560000) ENGINE = InnoDB,
 PARTITION p201708 VALUES LESS THAN (1504238400) ENGINE = InnoDB,
 PARTITION p_future VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.00 sec)

We can see that our changes seem to be working as expected. In addition to old partitions being dropped, we can also see that p_first ‘s date range was updated.

Event definition

Our event definition only needs one minor change: the addition of the new parameter for our stored procedure. This is fairly straight forward. If we want it to sleep for 5 seconds between operations, then the new definition would be:

DROP EVENT db1.monthly_drop_old_partitions_event;

CREATE EVENT db1.monthly_drop_old_partitions_event
   ON SCHEDULE
   EVERY 1 MONTH
   STARTS NOW()
DO
   CALL db1.drop_old_partitions('db1', 'quarterly_report_status', 6, 5);

Conclusion

I enjoy the challenge of writing interesting stored procedures like this, so I will probably eventually write a stored procedure that will also automatically add new partitions. In the mean time, I would love to hear if anyone else can think of any other improvements.

Note: You can find part 3 of this blog series here .

Automatically Dropping Old Partitions in MySQL and MariaDB

Geoff Montee MariaDB , MySQL , Partitioning 10 Comments

A MariaDB Support customer recently asked how they could automatically drop old partitions after 6 months. MariaDB and MySQL do not have a mechanism to do this automatically out-of-the-box, but it is not too difficult to create a custom stored procedure and an event to call the procedure on the desired schedule. In this blog post, I will show one way to do that.

Partitioned table definition

For this demonstration, I’ll use a table definition based on one from MySQL’s documentation on range partitioning , with some minor changes:

DROP TABLE IF EXISTS db1.quarterly_report_status;

CREATE TABLE db1.quarterly_report_status (
   report_id INT NOT NULL,
   report_status VARCHAR(20) NOT NULL,
   report_updated TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB
PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated) ) (
   PARTITION p201610 VALUES LESS THAN ( UNIX_TIMESTAMP('2016-11-01 00:00:00')),
   PARTITION p201611 VALUES LESS THAN ( UNIX_TIMESTAMP('2016-12-01 00:00:00')),
   PARTITION p201612 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-01-01 00:00:00')),
   PARTITION p201701 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-02-01 00:00:00')),
   PARTITION p201702 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-03-01 00:00:00')),
   PARTITION p201703 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-04-01 00:00:00')),
   PARTITION p201704 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-05-01 00:00:00')),
   PARTITION p201705 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-06-01 00:00:00')),
   PARTITION p201706 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-07-01 00:00:00')),
   PARTITION p201707 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-08-01 00:00:00')),
   PARTITION p201708 VALUES LESS THAN ( UNIX_TIMESTAMP('2017-09-01 00:00:00')),
   PARTITION p_default VALUES LESS THAN (MAXVALUE)
);

The most significant change is that the partition naming scheme is based on the date. This will allow us to more easily determine which partitions to remove.

Stored procedure definition

The stored procedure itself contains some comments that explain what it does, so I will let the code speak for itself, for the most part:

DROP PROCEDURE IF EXISTS db1.drop_old_partitions;

DELIMITER $$
CREATE PROCEDURE db1.drop_old_partitions(p_schema varchar(64), p_table varchar(64), p_months_to_keep int)
   LANGUAGE SQL
   NOT DETERMINISTIC
   SQL SECURITY INVOKER
BEGIN  
   DECLARE done INT DEFAULT FALSE;
   DECLARE current_partition_name varchar(64);
   -- We'll use this cursor later to get
   -- the list of partitions to drop.
   -- @last_partition_name_to_keep will be
   -- set later.
   DECLARE cur1 CURSOR FOR 
   SELECT partition_name 
   FROM information_schema.partitions 
   WHERE TABLE_SCHEMA = p_schema 
   AND TABLE_NAME = p_table 
   AND PARTITION_NAME != 'p_default' 
   AND PARTITION_NAME < @last_partition_name_to_keep;
   DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
   
   -- Now we get the last month of data that we want to keep
   -- by subtracting p_months_to_keep from the current date.
   -- Note that it will actually keep p_months_to_keep+1 partitions,
   -- since the current month is not complete.
   SET @date = CURDATE();
   SET @months_to_keep = p_months_to_keep;   
   SET @q = 'SELECT DATE_SUB(?, INTERVAL ? MONTH) INTO @last_month_to_keep';
   PREPARE st FROM @q;
   EXECUTE st USING @date, @months_to_keep;
   DEALLOCATE PREPARE st;
   
   -- Then we format the last month in the same format used
   -- in our partition names.
   SET @q = 'SELECT DATE_FORMAT(@last_month_to_keep, ''%Y%m'') INTO @formatted_last_month_to_keep';
   PREPARE st FROM @q;
   EXECUTE st;
   DEALLOCATE PREPARE st;
   
   -- And then we use the formatted date to build the name of the
   -- last partition that we want to keep. This partition name is
   -- assigned to @last_partition_name_to_keep, which is used in
   -- the cursor declared at the start of the procedure.
   SET @q = 'SELECT CONCAT(''p'', @formatted_last_month_to_keep) INTO @last_partition_name_to_keep';
   PREPARE st FROM @q;
   EXECUTE st;
   DEALLOCATE PREPARE st;
   
   SELECT CONCAT('Dropping all partitions before: ', @last_partition_name_to_keep);
   
   -- And then we loop through all partitions returned by the cursor,
   -- and those partitions are dropped.
   OPEN cur1;

   read_loop: LOOP
      FETCH cur1 INTO current_partition_name;
   
      IF done THEN
         LEAVE read_loop;
      END IF;

      SELECT CONCAT('Dropping partition: ', current_partition_name);
   
      -- First we build the ALTER TABLE query.
      SET @schema = p_schema;
      SET @table = p_table;
      SET @partition = current_partition_name;
      SET @q = 'SELECT CONCAT(''ALTER TABLE '', @schema, ''.'', @table, '' DROP PARTITION '', @partition) INTO @query';
      PREPARE st FROM @q;
      EXECUTE st;
      DEALLOCATE PREPARE st;
      
      -- And then we prepare and execute the ALTER TABLE query.
      PREPARE st FROM @query;
      EXECUTE st;
      DEALLOCATE PREPARE st;
   END LOOP;
END$$
DELIMITER ;

Let's try running the procedure as a test:

MariaDB [(none)]> SHOW CREATE TABLE db1.quarterly_report_status;
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table                   | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| quarterly_report_status | CREATE TABLE `quarterly_report_status` (
  `report_id` int(11) NOT NULL,
  `report_status` varchar(20) NOT NULL,
  `report_updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated))
(PARTITION p201610 VALUES LESS THAN (1477972800) ENGINE = InnoDB,
 PARTITION p201611 VALUES LESS THAN (1480568400) ENGINE = InnoDB,
 PARTITION p201612 VALUES LESS THAN (1483246800) ENGINE = InnoDB,
 PARTITION p201701 VALUES LESS THAN (1485925200) ENGINE = InnoDB,
 PARTITION p201702 VALUES LESS THAN (1488344400) ENGINE = InnoDB,
 PARTITION p201703 VALUES LESS THAN (1491019200) ENGINE = InnoDB,
 PARTITION p201704 VALUES LESS THAN (1493611200) ENGINE = InnoDB,
 PARTITION p201705 VALUES LESS THAN (1496289600) ENGINE = InnoDB,
 PARTITION p201706 VALUES LESS THAN (1498881600) ENGINE = InnoDB,
 PARTITION p201707 VALUES LESS THAN (1501560000) ENGINE = InnoDB,
 PARTITION p201708 VALUES LESS THAN (1504238400) ENGINE = InnoDB,
 PARTITION p_default VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */ |
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

MariaDB [(none)]> CALL db1.drop_old_partitions('db1', 'quarterly_report_status', 6);
+--------------------------------------------------------------------------+
| CONCAT('Dropping all partitions before: ', @last_partition_name_to_keep) |
+--------------------------------------------------------------------------+
| Dropping all partitions before: p201702                                  |
+--------------------------------------------------------------------------+
1 row in set (0.00 sec)

+--------------------------------------------------------+
| CONCAT('Dropping partition: ', current_partition_name) |
+--------------------------------------------------------+
| Dropping partition: p201610                            |
+--------------------------------------------------------+
1 row in set (0.00 sec)

+--------------------------------------------------------+
| CONCAT('Dropping partition: ', current_partition_name) |
+--------------------------------------------------------+
| Dropping partition: p201611                            |
+--------------------------------------------------------+
1 row in set (0.01 sec)

+--------------------------------------------------------+
| CONCAT('Dropping partition: ', current_partition_name) |
+--------------------------------------------------------+
| Dropping partition: p201612                            |
+--------------------------------------------------------+
1 row in set (0.04 sec)

+--------------------------------------------------------+
| CONCAT('Dropping partition: ', current_partition_name) |
+--------------------------------------------------------+
| Dropping partition: p201701                            |
+--------------------------------------------------------+
1 row in set (0.05 sec)

Query OK, 0 rows affected (0.07 sec)

MariaDB [(none)]> SHOW CREATE TABLE db1.quarterly_report_status;
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table                   | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| quarterly_report_status | CREATE TABLE `quarterly_report_status` (
  `report_id` int(11) NOT NULL,
  `report_status` varchar(20) NOT NULL,
  `report_updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated))
(PARTITION p201702 VALUES LESS THAN (1488344400) ENGINE = InnoDB,
 PARTITION p201703 VALUES LESS THAN (1491019200) ENGINE = InnoDB,
 PARTITION p201704 VALUES LESS THAN (1493611200) ENGINE = InnoDB,
 PARTITION p201705 VALUES LESS THAN (1496289600) ENGINE = InnoDB,
 PARTITION p201706 VALUES LESS THAN (1498881600) ENGINE = InnoDB,
 PARTITION p201707 VALUES LESS THAN (1501560000) ENGINE = InnoDB,
 PARTITION p201708 VALUES LESS THAN (1504238400) ENGINE = InnoDB,
 PARTITION p_default VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */ |
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

As you can see from the above output, several partitions were dropped.

Event definition

We want our stored procedure to run automatically every month, so we can use an event to do that.
Before testing the event, we need to do two things:

  • We need to recreate the table with the original definition, so that it has all of the original partitions.
  • We need to ensure that event_scheduler=ON is set, and if not, we need to set it.
MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'event_scheduler';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| event_scheduler | OFF   |
+-----------------+-------+
1 row in set (0.00 sec)

MariaDB [(none)]> SET GLOBAL event_scheduler=ON;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'event_scheduler';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| event_scheduler | ON    |
+-----------------+-------+
1 row in set (0.00 sec)

And then we can run the following:

CREATE EVENT db1.monthly_drop_old_partitions_event
   ON SCHEDULE
   EVERY 1 MONTH
   STARTS NOW()
DO
   CALL db1.drop_old_partitions('db1', 'quarterly_report_status', 6);

Since we specified STARTS NOW() , the event ran immediately. We can confirm this by looking at the table definition again:

MariaDB [(none)]> SHOW CREATE TABLE db1.quarterly_report_status;
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table                   | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| quarterly_report_status | CREATE TABLE `quarterly_report_status` (
  `report_id` int(11) NOT NULL,
  `report_status` varchar(20) NOT NULL,
  `report_updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated))
(PARTITION p201702 VALUES LESS THAN (1488344400) ENGINE = InnoDB,
 PARTITION p201703 VALUES LESS THAN (1491019200) ENGINE = InnoDB,
 PARTITION p201704 VALUES LESS THAN (1493611200) ENGINE = InnoDB,
 PARTITION p201705 VALUES LESS THAN (1496289600) ENGINE = InnoDB,
 PARTITION p201706 VALUES LESS THAN (1498881600) ENGINE = InnoDB,
 PARTITION p201707 VALUES LESS THAN (1501560000) ENGINE = InnoDB,
 PARTITION p201708 VALUES LESS THAN (1504238400) ENGINE = InnoDB,
 PARTITION p_default VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */ |
+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Conclusion

Thanks to the flexibility of stored procedures and events, it is relatively easy to automatically drop old partitions in MySQL and MariaDB. Has anyone else implemented something like this?

Note: You can find part 2 of this blog series here .

Using the MariaDB Audit Plugin with MySQL

Geoff Montee MariaDB , MySQL , Security 8 Comments

The MariaDB audit plugin is an audit plugin that is bundled with MariaDB server. However, even though it is bundled with MariaDB, the plugin is actually compatible with MySQL as well. In this blog post, I will describe how to install the plugin with MySQL.

Install the plugin

Unfortunately, neither MariaDB Corporation nor MariaDB Foundation currently distribute a standalone binary for the MariaDB audit plugin. That means that if you want to use this plugin with MySQL, you will have to obtain the plugin from a MariaDB server package. We can check this table to determine what version of MariaDB server that we should use. The table says that the latest version of the plugin is 1.4.0, and that this version is present in MariaDB 10.1.11. The latest release of MariaDB 10.1 is currently 10.1.19, so let’s just grab that, since that should also have the plugin:

$ wget https://downloads.mariadb.org/interstitial/mariadb-10.1.19/bintar-linux-x86_64/mariadb-10.1.19-linux-x86_64.tar.gz

Let’s extract the tarball and copy the plugin library from the tarball’s plugin directory to MySQL’s plugin directory:

$ tar -xzf mariadb-10.1.19-linux-x86_64.tar.gz
$ ls -l mariadb-10.1.19-linux-x86_64/lib/plugin/ | grep "audit"
-rwxr-xr-x 1 ec2-user ec2-user 176024 Nov 4 09:37 server_audit.so
$ sudo install mariadb-10.1.19-linux-x86_64/lib/plugin/server_audit.so /usr/lib64/mysql/plugin/

Now that the plugin library is in MySQL’s plugin directory, we can tell MySQL to install it:

$ mysql -u root
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.6.30-log MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> INSTALL PLUGIN server_audit SONAME 'server_audit.so';
Query OK, 0 rows affected (0.02 sec)

Configure the plugin

Now that the plugin is installed, we can configure it. For example, if we want to log all 6 event types, but we want to exclude the user named root , then we could add the following to MySQL’s configuration file:

server_audit_logging=ON
server_audit_events=connect,query,table,query_ddl,query_dml,query_dcl
server_audit_excl_users=root

And then restart the server:

$ sudo systemctl restart mysqld

At that point, audit logging will be enabled!

For more information on configuring MariaDB’s audit plugin, see this documentation page .

Has anyone used the MariaDB audit plugin with MySQL?

Importing InnoDB Partitions in MySQL 5.6 and MariaDB 10.0/10.1

Geoff Montee MariaDB , MySQL 4 Comments

Transportable tablespaces for InnoDB tables is a very useful feature added in MySQL 5.6 and MariaDB 10.0. With this new feature, an InnoDB table’s tablespace file can be copied from one server to another, as long as the table uses a file-per-table tablespace .

Unfortunately, the initial transportable tablespace feature in MySQL 5.6 and MariaDB 10.0 does not support partitioned tables. Support for partitioned tables was added in MySQL 5.7 . MDEV-10568 has been submitted to request that this feature be ported to MariaDB, so hopefully that does happen at some point. However, having this feature in some future new version doesn’t help you much if you wanted to use this feature in the older versions of MySQL or MariaDB.

The good news is that there is a workaround that allows you to use transportable tablespaces in MySQL 5.6 and MariaDB 10.0/10.1/10.2 to copy partitioned tables from one server to another. In this blog post, I will describe how to do so. This process can be a bit tedious, so I would recommend writing a script to automate it.

Test data

In this post, I’ll use the following test table to demonstrate how this works:

CREATE TABLE employees (
id INT NOT NULL,
fname VARCHAR(30),
lname VARCHAR(30),
store_id INT NOT NULL
)
PARTITION BY RANGE (store_id) (
PARTITION p0 VALUES LESS THAN (6),
PARTITION p1 VALUES LESS THAN (11),
PARTITION p2 VALUES LESS THAN (16),
PARTITION p3 VALUES LESS THAN MAXVALUE
);
INSERT INTO employees VALUES
(1, 'Geoff', 'Montee', 1),
(2, 'Chris', 'Calendar', 6),
(3, 'Kyle', 'Joiner', 11),
(4, 'Will', 'Fong', 16);

Export table files from original server

The process to export the partitioned table’s tablespaces from the original server is almost identical to the process for non-partitioned tables.

The first step, is to execute the following FLUSH command on the table:

MariaDB [db1]> FLUSH TABLES employees FOR EXPORT;
Query OK, 0 rows affected (0.00 sec)

After executing the above command, leave the session open, so that the tables are locked.

Next, you should see some .ibd and .cfg files for the table in the database’s data directory:

$ sudo ls -l /var/lib/mysql/db1/
total 428
-rw-rw---- 1 mysql mysql 827 Dec 5 16:08 employees.frm
-rw-rw---- 1 mysql mysql 48 Dec 5 16:08 employees.par
-rw-rw---- 1 mysql mysql 579 Dec 5 18:47 employees#P#p0.cfg
-rw-r----- 1 mysql mysql 98304 Dec 5 16:43 employees#P#p0.ibd
-rw-rw---- 1 mysql mysql 579 Dec 5 18:47 employees#P#p1.cfg
-rw-rw---- 1 mysql mysql 98304 Dec 5 16:08 employees#P#p1.ibd
-rw-rw---- 1 mysql mysql 579 Dec 5 18:47 employees#P#p2.cfg
-rw-rw---- 1 mysql mysql 98304 Dec 5 16:08 employees#P#p2.ibd
-rw-rw---- 1 mysql mysql 579 Dec 5 18:47 employees#P#p3.cfg
-rw-rw---- 1 mysql mysql 98304 Dec 5 16:08 employees#P#p3.ibd

Copy these files somewhere safe:

$ mkdir /tmp/backup
$ cp /var/lib/mysql/db1/employees*ibd /tmp/backup/
$ cp /var/lib/mysql/db1/employees*cfg /tmp/backup/
$ ls -l /tmp/backup/
total 400
-rw-r----- 1 root root 579 Dec 5 18:52 employees#P#p0.cfg
-rw-r----- 1 root root 98304 Dec 5 18:52 employees#P#p0.ibd
-rw-r----- 1 root root 579 Dec 5 18:52 employees#P#p1.cfg
-rw-r----- 1 root root 98304 Dec 5 18:52 employees#P#p1.ibd
-rw-r----- 1 root root 579 Dec 5 18:52 employees#P#p2.cfg
-rw-r----- 1 root root 98304 Dec 5 18:52 employees#P#p2.ibd
-rw-r----- 1 root root 579 Dec 5 18:52 employees#P#p3.cfg
-rw-r----- 1 root root 98304 Dec 5 18:52 employees#P#p3.ibd

Now that the files are copied, you can unlock the tables in the session that you still have open:

MariaDB [db1]> UNLOCK TABLES;
Query OK, 0 rows affected (0.00 sec)

Import table files on new server

Now that we have the .ibd and .cfg files of the partitions, the first step would be to place them somewhere where they will be accessible on your new server.

Then, if it does not already exist, create an empty copy of the partitioned table:

MariaDB [newdb]> CREATE TABLE employees (
-> id INT NOT NULL,
-> fname VARCHAR(30),
-> lname VARCHAR(30),
-> store_id INT NOT NULL
-> )
-> PARTITION BY RANGE (store_id) (
-> PARTITION p0 VALUES LESS THAN (6),
-> PARTITION p1 VALUES LESS THAN (11),
-> PARTITION p2 VALUES LESS THAN (16),
-> PARTITION p3 VALUES LESS THAN MAXVALUE
-> );
Query OK, 0 rows affected (0.06 sec)

Now we need an empty non-partitioned table that has the same structure as our partitioned table to serve as a placeholder. We can create that with the following query:

MariaDB [newdb]> CREATE TABLE placeholder AS SELECT * FROM employees WHERE NULL;
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0

The above query gets us a non-partitioned table with the original structure that has 0 rows:

MariaDB [newdb]> SHOW CREATE TABLE placeholder;
+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| placeholder | CREATE TABLE `placeholder` (
`id` int(11) NOT NULL,
`fname` varchar(30) DEFAULT NULL,
`lname` varchar(30) DEFAULT NULL,
`store_id` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

MariaDB [newdb]> SELECT * FROM placeholder;
Empty set (0.00 sec)

After this point is where the process can get a little tedious if your table has a lot of partitions. For each partition, we need to do the following:

Discard our placeholder table’s tablespace:

MariaDB [newdb]> ALTER TABLE placeholder DISCARD TABLESPACE;
Query OK, 0 rows affected (0.00 sec)

Copy the .ibd and .cfg files for the partition to the database’s data directory, but rename these files such that they are named for the placeholder table:

$ cp /tmp/backup/employees#P#p0.cfg /var/lib/mysql/newdb/placeholder.cfg
$ cp /tmp/backup/employees#P#p0.ibd /var/lib/mysql/newdb/placeholder.ibd
$ chown mysql:mysql /var/lib/mysql/newdb/placeholder.*

Import the tablespace for the placeholder table:

MariaDB [newdb]> ALTER TABLE placeholder IMPORT TABLESPACE;
Query OK, 0 rows affected (0.04 sec)

The placeholder table now contains the data of p0 from the original partitioned table:

MariaDB [newdb]> SELECT * FROM placeholder;
+----+-------+--------+----------+
| id | fname | lname | store_id |
+----+-------+--------+----------+
| 1 | Geoff | Montee | 1 |
+----+-------+--------+----------+
1 row in set (0.00 sec)

Now exchange partition p0 in our partitioned table with the tablespace of our placeholder table:

MariaDB [newdb]> ALTER TABLE employees EXCHANGE PARTITION p0 WITH TABLE placeholder;
Query OK, 0 rows affected (0.02 sec)

Now our partitioned table on the new server has the real contents of partition p0 :

MariaDB [newdb]> SELECT * FROM employees;
+----+-------+--------+----------+
| id | fname | lname | store_id |
+----+-------+--------+----------+
| 1 | Geoff | Montee | 1 |
+----+-------+--------+----------+
1 row in set (0.00 sec)

If we repeat the above process for partitions p1 , p2 , and p3 , then our partitioned table on the new server will have all of the contents of the table from the original server:

MariaDB [newdb]> SELECT * FROM employees;
+----+-------+----------+----------+
| id | fname | lname | store_id |
+----+-------+----------+----------+
| 1 | Geoff | Montee | 1 |
| 2 | Chris | Calendar | 6 |
| 3 | Kyle | Joiner | 11 |
| 4 | Will | Fong | 16 |
+----+-------+----------+----------+
4 rows in set (0.00 sec)

Has anyone successfully used a process like this in the past?

Emulating Sequences in MySQL and MariaDB

Geoff Montee MariaDB , MySQL 8 Comments

Sequences are objects defined by the SQL standard that are used to create monotonically increasing sequences of numeric values. Whenever nextval is called on a sequence object, it generates and returns the next number in the sequence. For MySQL and MariaDB users, this might sound similar to MySQL’s AUTO_INCREMENT columns , but there are some differences:

  • Sequences are defined by the SQL Standard. AUTO_INCREMENT columns are not in the standard, but are a MySQL extension.
  • Sequences are their own objects with their own state, which means that multiple columns in multiple tables could all use numbers from the same sequence. In contrast, MySQL’s AUTO_INCREMENT feature is tied to a specific column in a specific table, so multiple columns in multiple tables cannot directly use the same AUTO_INCREMENT pool.

MySQL and MariaDB do not yet support SQL Standard sequences. If you would like MariaDB to support sequences, you may want to consider voting for this feature request .

Users who have migrated to MySQL or MariaDB from other databases might find this feature to be a strange omission, considering that many other databases do support sequences, including:

Despite the fact that MySQL and MariaDB don’t yet support sequences, it is fairly easy to emulate SQL standard sequences in MySQL and MariaDB using an AUTO_INCREMENT column and functions. In this blog post, I’ll describe how to do that using MariaDB 10.1.

Emulating sequences in MariaDB

The first step needed to create our emulated sequence is to create a table that keeps track of the sequence values:

CREATE TABLE sequence_values (
id INT AUTO_INCREMENT PRIMARY KEY,
thread_id INT NOT NULL,
created DATETIME DEFAULT CURRENT_TIMESTAMP
);

The second step is to create a function that generates and returns the next value in the sequence:

DELIMITER //

CREATE FUNCTION `sequence_nextval`()
RETURNS INT
NOT DETERMINISTIC
MODIFIES SQL DATA
BEGIN

DECLARE nextval int;

INSERT INTO sequence_values (thread_id) VALUES (CONNECTION_ID());
SELECT last_insert_id() INTO nextval;

RETURN nextval;

END//

DELIMITER ;

Finally, let’s create a table that we want to use the sequence with:

CREATE TABLE sequence_test_a (
seq int NOT NULL PRIMARY KEY,
str varchar(50)
);

For users who are used to databases with real standard sequence support, it might be tempting to define the table in the following way instead:

CREATE TABLE sequence_test_a (
seq int NOT NULL PRIMARY KEY DEFAULT sequence_nextval(),
str varchar(50)
);

Unfortunately, MariaDB 10.1 does not support setting a DEFAULT value to a stored function. However, this will be supported in MariaDB 10.2 . ( Edit: I’ve been told that new MariaDB 10.2 feature will not include support for stored functions as DEFAULT values. However, you can still use triggers, as mentioned in the comments by Frederico.)

One of the benefits of sequences is that they can be used across multiple tables, so let’s create a second table that will use the sequence as well:

CREATE TABLE sequence_test_b (
seq int NOT NULL PRIMARY KEY,
str varchar(50)
);

Now let’s insert some data into the tables:

MariaDB [db1]> INSERT INTO sequence_test_a VALUES (sequence_nextval(), 'a_str1');
Query OK, 1 row affected (0.00 sec)

MariaDB [db1]> INSERT INTO sequence_test_a VALUES (sequence_nextval(), 'a_str2');
Query OK, 1 row affected (0.01 sec)

MariaDB [db1]> INSERT INTO sequence_test_b VALUES (sequence_nextval(), 'b_str1');
Query OK, 1 row affected (0.00 sec)

MariaDB [db1]> INSERT INTO sequence_test_b VALUES (sequence_nextval(), 'b_str2');
Query OK, 1 row affected (0.00 sec)

MariaDB [db1]> INSERT INTO sequence_test_a VALUES (sequence_nextval(), 'a_str3');
Query OK, 1 row affected (0.00 sec)

What are the contents of these tables now?

MariaDB [db1]> SELECT * FROM sequence_test_a;
+-----+--------+
| seq | str |
+-----+--------+
| 1 | a_str1 |
| 2 | a_str2 |
| 5 | a_str3 |
+-----+--------+
3 rows in set (0.00 sec)

MariaDB [db1]> SELECT * FROM sequence_test_b;
+-----+--------+
| seq | str |
+-----+--------+
| 3 | b_str1 |
| 4 | b_str2 |
+-----+--------+
2 rows in set (0.00 sec)

As you can see from the above output, the seq column in each table was populated with monotonically increasing values in the order in which the rows were inserted, so our sequence appears to be working properly.

I should also note that the sequence_values table will grow over time:

MariaDB [db1]> SELECT * FROM sequence_values;
+----+-----------+---------------------+
| id | thread_id | created |
+----+-----------+---------------------+
| 1 | 3 | 2016-08-18 14:09:49 |
| 2 | 3 | 2016-08-18 14:09:50 |
| 3 | 3 | 2016-08-18 14:09:58 |
| 4 | 3 | 2016-08-18 14:10:22 |
| 5 | 3 | 2016-08-18 14:10:23 |
+----+-----------+---------------------+
5 rows in set (0.00 sec)

If you do not need to keep track of when a sequence was generated, you could create an event or cron job to periodically prune old events.

Has anyone else created their own sequence implementation in MySQL or MariaDB?

Bitwise operators with BINARY fields in MySQL and MariaDB

Geoff Montee MariaDB , MySQL Leave a Comment

A MariaDB support customer recently upgraded to MariaDB 10.1, and they noticed that some of their queries using bitwise operators started to return warnings, which they thought was strange because they produced no warnings in MariaDB 10.0. These particular queries used bitwise operators on BINARY(N) fields.

For example, their table was similar to this:

CREATE TABLE item_flags (
item_id int(11) NOT NULL,
flags binary(2) NOT NULL DEFAULT '\0\0',
PRIMARY KEY (`item_id`)
);

And their query was similar to this:

SELECT item_id, flags
FROM item_flags
WHERE (flags & 4) = 4;

Let’s see what happens when we actually execute this query:

MariaDB [db1]> CREATE TABLE item_flags (
-> item_id int(11) NOT NULL,
-> flags binary(2) NOT NULL DEFAULT '\0\0',
-> PRIMARY KEY (`item_id`)
-> );
Query OK, 0 rows affected (0.01 sec)

MariaDB [db1]> INSERT INTO item_flags VALUES (1, 1), (2, 2), (3, 3), (4, 4);
Query OK, 4 rows affected (0.01 sec)
Records: 4 Duplicates: 0 Warnings: 0

MariaDB [db1]> SELECT item_id, flags
-> FROM item_flags
-> WHERE (flags & 4) = 4;
+---------+-------+
| item_id | flags |
+---------+-------+
| 4 | 4 |
+---------+-------+
1 row in set, 4 warnings (0.00 sec)

As we can see from the above output, it looks like MariaDB gave us a warning for each row that the query examined. Let’s look at those warnings:

MariaDB [db1]> SHOW WARNINGS;
+---------+------+--------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------+
| Warning | 1292 | Truncated incorrect INTEGER value: '1\x00' |
| Warning | 1292 | Truncated incorrect INTEGER value: '2\x00' |
| Warning | 1292 | Truncated incorrect INTEGER value: '3\x00' |
| Warning | 1292 | Truncated incorrect INTEGER value: '4\x00' |
+---------+------+--------------------------------------------+
4 rows in set (0.00 sec)

The warnings show us two things:

  • When each row was inserted, the flags column was treated as a binary string that was right-padded with the null character. From the MySQL documentation :

    The BINARY and VARBINARY types are similar to CHAR and VARCHAR, except that they contain binary strings rather than nonbinary strings. That is, they contain byte strings rather than character strings. This means that they have no character set, and sorting and comparison are based on the numeric values of the bytes in the values.

    …snip…

    When BINARY values are stored, they are right-padded with the pad value to the specified length. The pad value is 0x00 (the zero byte). Values are right-padded with 0x00 on insert, and no trailing bytes are removed on select. All bytes are significant in comparisons, including ORDER BY and DISTINCT operations. 0x00 bytes and spaces are different in comparisons, with 0x00 < space.

  • That string value is then being converted to an INTEGER . This is because bitwise operators in MySQL and MariaDB operate on integers. From the MySQL documentation :

    Bit functions and operators comprise BIT_COUNT(), BIT_AND(), BIT_OR(), BIT_XOR(), &, |, ^, ~, <>. (The BIT_AND(), BIT_OR(), and BIT_XOR() functions are aggregate functions described at Section 13.20.1, “Aggregate (GROUP BY) Function Descriptions”.) Currently, bit functions and operators require BIGINT (64-bit integer) arguments and return BIGINT values, so they have a maximum range of 64 bits. Arguments of other types are converted to BIGINT and truncation might occur.

  • It would probably be an improvement if the flags column’s data type were tinyint instead of BINARY(2) , so that this conversion step could be avoided.

    However, it sounds like bitwise operators will work directly on BINARY(N) fields in MySQL 8.0. From the MySQL documentation again:

    A planned extension for MySQL 8.0 is to change this cast-to-BIGINT behavior: Bit functions and operators will permit binary string type arguments (BINARY, VARBINARY, and the BLOB types), enabling them to take arguments and produce return values larger than 64 bits. Consequently, bit operations on binary arguments in MySQL 5.7 might produce different results in MySQL 8.0. To provide advance notice about this potential change in behavior, the server produces warnings as of MySQL 5.7.11 for bit operations for which binary arguments will not be converted to integer in MySQL 8.0. These warnings afford an opportunity to rewrite affected statements. To explicitly produce MySQL 5.7 behavior in a way that will not change after an upgrade to 8.0, cast bit-operation binary arguments to convert them to integer.

    This sounds like it would be a nice improvement. In MySQL 8.0, it sounds like the above SQL could be rewritten like this:

    MariaDB [db1]> CREATE TABLE item_flags (
    -> item_id int(11) NOT NULL,
    -> flags binary(2) NOT NULL DEFAULT x'00',
    -> PRIMARY KEY (`item_id`)
    -> );
    Query OK, 0 rows affected (0.01 sec)

    MariaDB [db1]> INSERT INTO item_flags VALUES (1, x'01'), (2, x'02'), (3, x'03'), (4, x'04');
    Query OK, 4 rows affected (0.00 sec)
    Records: 4 Duplicates: 0 Warnings: 0

    MariaDB [db1]> SELECT item_id, flags
    -> FROM item_flags
    -> WHERE (flags & x'04') = x'04';
    +---------+-------+
    | item_id | flags |
    +---------+-------+
    | 1 | |
    | 2 | |
    | 3 | |
    | 4 | |
    +---------+-------+
    4 rows in set, 9 warnings (0.00 sec)

    MariaDB [db1]> SHOW WARNINGS;
    +---------+------+-----------------------------------------------+
    | Level | Code | Message |
    +---------+------+-----------------------------------------------+
    | Warning | 1292 | Truncated incorrect INTEGER value: '\x01\x00' |
    | Warning | 1292 | Truncated incorrect INTEGER value: '\x04' |
    | Warning | 1292 | Truncated incorrect DOUBLE value: '\x04' |
    | Warning | 1292 | Truncated incorrect INTEGER value: '\x02\x00' |
    | Warning | 1292 | Truncated incorrect INTEGER value: '\x04' |
    | Warning | 1292 | Truncated incorrect INTEGER value: '\x03\x00' |
    | Warning | 1292 | Truncated incorrect INTEGER value: '\x04' |
    | Warning | 1292 | Truncated incorrect INTEGER value: '\x04\x00' |
    | Warning | 1292 | Truncated incorrect INTEGER value: '\x04' |
    +---------+------+-----------------------------------------------+
    9 rows in set (0.00 sec)

    If it isn’t completely obvious from the above output, this SQL doesn’t currently work the way some might expect it to in MariaDB 10.1, since the BINARY(N) field has to be converted to bigint to make use of the bitwise-and ( & ) operator.

    I submitted a feature request to have BINARY(N) support for bitwise operators implemented in MariaDB . If this feature sounds important to you, you may want to consider voting for it to express your interest.

DDL Failures in MariaDB Galera Cluster

Geoff Montee DDL , Galera Cluster , MariaDB , MySQL Leave a Comment

A MariaDB support customer recently asked me what would happen if a Data Definition Language (DDL) statement failed to complete on one or more nodes in MariaDB Galera Cluster. In this blog post, I will demonstrate what would happen.

The demonstration below was performed on a 2-node cluster running MariaDB 10.1 , but other Galera Cluster distributions should work similarly.

Schema Upgrades in Galera Cluster

Schema upgrades and DDL in Galera Cluster are handled a bit differently than in a standalone MariaDB or MySQL server.

Transactions in Galera Cluster are replicated in a “virtually synchronous” manner. This means that unless a particular node is desynchronized from the cluster, all replicated tables need to have identical (or at least compatible) definitions on all nodes. If a node tries to replicate data for a particular table and if some nodes have incompatible definitions for that table, those nodes will not be able to apply the transactions to their copy of the table. This also means that incompatible schema upgrades should happen on all nodes at the same time.

Galera Cluster provides two methods of applying schema upgrades, and you can switch between them using the wsrep_OSU_method option. One method, Total Order Isolation (TOI), can be used to apply incompatible changes in a slow, but safe way. The other method, Rolling Schema Upgrade (RSU), can be used to apply backward-compatible changes in a faster way. These are described in more detail in the Galera Cluster documentation page about Schema Upgrades .

But since DDL is treated specially in Galera Cluster, what happens if some DDL fails to complete successfully on one or more nodes?

A DDL Failure in TOI Mode

First, lets look at what happens when DDL fails in TOI mode. Let’s make sure that TOI mode is currently set:

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'wsrep_osu_method';
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| wsrep_osu_method | TOI |
+------------------+-------+
1 row in set (0.00 sec)

It is, so let’s create a table by executing the following on one node:

MariaDB [db1]> CREATE TABLE tab (
-> id int PRIMARY KEY,
-> str varchar(50)
-> ) ENGINE=InnoDB;
Query OK, 0 rows affected (0.03 sec)

Let’s make sure that this table exists on both nodes.

Node 1:

MariaDB [db1]> SHOW CREATE TABLE tab;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| tab | CREATE TABLE `tab` (
`id` int(11) NOT NULL,
`str` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Node 2:

MariaDB [db1]> SHOW CREATE TABLE tab;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| tab | CREATE TABLE `tab` (
`id` int(11) NOT NULL,
`str` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

We want to see DDL fail, so lets do some setup for that by making one node have a slightly different definition of the table. We can do so by running some DDL in RSU mode:

MariaDB [db1]> SET wsrep_osu_method='RSU';
Query OK, 0 rows affected (0.00 sec)

MariaDB [db1]> ALTER TABLE tab ADD COLUMN num int DEFAULT NULL;
Query OK, 0 rows affected (0.02 sec)
Records: 0 Duplicates: 0 Warnings: 0

Do the two nodes have the same definition of the table now?

Node 1:

MariaDB [db1]> SHOW CREATE TABLE tab;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tab | CREATE TABLE `tab` (
`id` int(11) NOT NULL,
`str` varchar(50) DEFAULT NULL,
`num` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Node 2:

MariaDB [db1]> SHOW CREATE TABLE tab;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| tab | CREATE TABLE `tab` (
`id` int(11) NOT NULL,
`str` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

They now have different definitions, so let’s execute some DDL on node 1 that will fail on node 2. We also need to set wsrep_OSU_method back to TOI.

MariaDB [db1]> SET wsrep_osu_method='TOI';
Query OK, 0 rows affected (0.00 sec)

MariaDB [db1]> ALTER TABLE tab MODIFY COLUMN num bigint DEFAULT NULL;
Query OK, 0 rows affected (0.04 sec)
Records: 0 Duplicates: 0 Warnings: 0

Since node 2 does not have the num column, this DDL should fail on that node. Lets look at the definition of the table on both nodes now:

Node 1:

MariaDB [db1]> SHOW CREATE TABLE tab;
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tab | CREATE TABLE `tab` (
`id` int(11) NOT NULL,
`str` varchar(50) DEFAULT NULL,
`num` bigint(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Node 2:

MariaDB [db1]> SHOW CREATE TABLE tab;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| tab | CREATE TABLE `tab` (
`id` int(11) NOT NULL,
`str` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

The DDL obviously failed on node 2, but it doesn’t look like anything happened. Lets look at node 2’s error log:

2016-07-28 14:42:48 140579533392640 [ERROR] Slave SQL: Error ‘Unknown column ‘num’ in ‘tab” on query. Default database: ‘db1’. Query: ‘ALTER TABLE tab MODIFY COLUMN num bigint DEFAULT NULL’, Internal MariaDB error code: 1054
2016-07-28 14:42:48 140579533392640 [Warning] WSREP: RBR event 1 Query apply warning: 1, 3
2016-07-28 14:42:48 140579533392640 [Warning] WSREP: Ignoring error for TO isolated action: source: d25d604b-54f0-11e6-a77e-f681b74c50f4 version: 3 local: 0 state: APPLYING flags: 65 conn_id: 5 trx_id: -1 seqnos (l: 7, g: 3, s: 2, d: 2, ts: 1017404963701)

Node 2 just ignored the error!

Now what actually happens when we try to insert something into the num field?

Node 1:

MariaDB [db1]> INSERT INTO tab (id, str, num) VALUES (1, 'str1', 1);
Query OK, 1 row affected (0.01 sec)

MariaDB [db1]> SELECT * FROM db1.tab;
+----+------+------+
| id | str | num |
+----+------+------+
| 1 | str1 | 1 |
+----+------+------+
1 row in set (0.00 sec)

Node 2:

MariaDB [db1]> SELECT * FROM tab;
+----+------+
| id | str |
+----+------+
| 1 | str1 |
+----+------+
1 row in set (0.00 sec)

The extra column at the end of the list is just ignored! This is because Galera Cluster follows many of the same compatibility rules as standard MySQL replication, and an extra column at the end of the list is considered a valid difference in standard MySQL replication .

But lets see what happens if the difference is invalid.

Node 1:

MariaDB [db1]> SET wsrep_osu_method='RSU';
Query OK, 0 rows affected (0.00 sec)

MariaDB [db1]> ALTER TABLE tab DROP COLUMN num;
Query OK, 0 rows affected (0.02 sec)
Records: 0 Duplicates: 0 Warnings: 0

MariaDB [db1]> ALTER TABLE tab ADD COLUMN num int DEFAULT NULL AFTER id;
Query OK, 0 rows affected (0.03 sec)
Records: 0 Duplicates: 0 Warnings: 0

MariaDB [db1]> SHOW CREATE TABLE tab;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tab | CREATE TABLE `tab` (
`id` int(11) NOT NULL,
`num` int(11) DEFAULT NULL,
`str` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Node 2:

MariaDB [db1]> SHOW CREATE TABLE tab;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
| tab | CREATE TABLE `tab` (
`id` int(11) NOT NULL,
`str` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

And now let’s try to insert some data:

Node 1:

MariaDB [db1]> INSERT INTO tab (id, num, str) VALUES (2, 1, 'str2');
Query OK, 1 row affected (0.00 sec)

MariaDB [db1]> SELECT * FROM db1.tab;
+----+------+------+
| id | num | str |
+----+------+------+
| 1 | NULL | str1 |
| 2 | 1 | str2 |
+----+------+------+
2 rows in set (0.00 sec)

Node 2:

MariaDB [db1]> SELECT * FROM tab;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 5
Current database: db1

+----+------+------+
| id | num | str |
+----+------+------+
| 1 | NULL | str1 |
| 2 | 1 | str2 |
+----+------+------+
2 rows in set (0.00 sec)

You might notice two weird things here:

  • Our client was disconnected from node 2.
  • Node 2 has the num column now.

That’s weird! Let’s look at node 2’s error log. What do we see?

First, we can see that it tried to apply the transaction 4 times:

2016-07-28 14:55:34 140579533392640 [ERROR] Slave SQL: Column 1 of table ‘db1.tab’ cannot be converted from type ‘int’ to type ‘varchar(50)’, Internal MariaDB error code: 1677
2016-07-28 14:55:34 140579533392640 [Warning] WSREP: RBR event 2 Write_rows_v1 apply warning: 3, 5
2016-07-28 14:55:34 140579533392640 [Warning] WSREP: Failed to apply app buffer: seqno: 5, status: 1
at galera/src/trx_handle.cpp:apply():351
Retrying 2th time
2016-07-28 14:55:34 140579533392640 [ERROR] Slave SQL: Column 1 of table ‘db1.tab’ cannot be converted from type ‘int’ to type ‘varchar(50)’, Internal MariaDB error code: 1677
2016-07-28 14:55:34 140579533392640 [Warning] WSREP: RBR event 2 Write_rows_v1 apply warning: 3, 5
2016-07-28 14:55:34 140579533392640 [Warning] WSREP: Failed to apply app buffer: seqno: 5, status: 1
at galera/src/trx_handle.cpp:apply():351
Retrying 3th time
2016-07-28 14:55:34 140579533392640 [ERROR] Slave SQL: Column 1 of table ‘db1.tab’ cannot be converted from type ‘int’ to type ‘varchar(50)’, Internal MariaDB error code: 1677
2016-07-28 14:55:34 140579533392640 [Warning] WSREP: RBR event 2 Write_rows_v1 apply warning: 3, 5
2016-07-28 14:55:34 140579533392640 [Warning] WSREP: Failed to apply app buffer: seqno: 5, status: 1
at galera/src/trx_handle.cpp:apply():351
Retrying 4th time
2016-07-28 14:55:34 140579533392640 [ERROR] Slave SQL: Column 1 of table ‘db1.tab’ cannot be converted from type ‘int’ to type ‘varchar(50)’, Internal MariaDB error code: 1677
2016-07-28 14:55:34 140579533392640 [Warning] WSREP: RBR event 2 Write_rows_v1 apply warning: 3, 5
2016-07-28 14:55:34 140579533392640 [ERROR] WSREP: Failed to apply trx: source: d25d604b-54f0-11e6-a77e-f681b74c50f4 version: 3 local: 0 state: APPLYING flags: 1 conn_id: 5 trx_id: 76646 seqnos (l: 9, g: 5, s: 4, d: 3, ts: 1783539089510)

When that failed, the failed node determined that it was inconsistent with the cluster, so it shot itself in the head :

2016-07-28 14:55:34 140579533392640 [ERROR] WSREP: Failed to apply trx 5 4 times
2016-07-28 14:55:34 140579533392640 [ERROR] WSREP: Node consistency compromized, aborting…
2016-07-28 14:55:34 140579533392640 [Note] WSREP: Closing send monitor…
2016-07-28 14:55:34 140579533392640 [Note] WSREP: Closed send monitor.
2016-07-28 14:55:34 140579533392640 [Note] WSREP: gcomm: terminating thread
2016-07-28 14:55:34 140579533392640 [Note] WSREP: gcomm: joining thread
2016-07-28 14:55:34 140579533392640 [Note] WSREP: gcomm: closing backend
…snip…
2016-07-28 14:55:35 140579533392640 [Note] WSREP: /usr/sbin/mysqld: Terminated.

And it was automatically restarted by systemd, at which point it did an SST:

2016-07-28 14:55:44 139821320411264 [Note] WSREP: Read nil XID from storage engines, skipping position init
2016-07-28 14:55:44 139821320411264 [Note] WSREP: wsrep_load(): loading provider library ‘/usr/lib64/galera/libgalera_smm.so’
2016-07-28 14:55:44 139821320411264 [Note] WSREP: wsrep_load(): Galera 25.3.15(r3578) by Codership Oy loaded successfully.
2016-07-28 14:55:44 139821320411264 [Note] WSREP: CRC-32C: using hardware acceleration.
2016-07-28 14:55:44 139821320411264 [Note] WSREP: Found saved state: 00000000-0000-0000-0000-000000000000:-1
…snip…
2016-07-28 14:55:45 139821320096512 [Note] WSREP: New cluster view: global state: d25dbeb7-54f0-11e6-bac9-c2bc3c331fb6:5, view# 4: Primary, number of nodes: 2, my index: 1, protocol version 3
2016-07-28 14:55:45 139821320096512 [Warning] WSREP: Gap in state sequence. Need state transfer.
2016-07-28 14:55:45 139821024540416 [Note] WSREP: Running: ‘wsrep_sst_rsync –role ‘joiner’ –address ‘172.31.22.174’ –datadir ‘/var/lib/mysql/’ –parent ‘2159’ –binlog ‘mariadb-bin’ ‘
2016-07-28 14:55:45 139821320096512 [Note] WSREP: Prepared SST request: rsync|172.31.22.174:4444/rsync_sst
2016-07-28 14:55:45 139821320096512 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification.
2016-07-28 14:55:45 139821320096512 [Note] WSREP: REPL Protocols: 7 (3, 2)
2016-07-28 14:55:45 139821097465600 [Note] WSREP: Service thread queue flushed.
2016-07-28 14:55:45 139821320096512 [Note] WSREP: Assign initial position for certification: 5, protocol version: 3
2016-07-28 14:55:45 139821097465600 [Note] WSREP: Service thread queue flushed.
2016-07-28 14:55:45 139821320096512 [Warning] WSREP: Failed to prepare for incremental state transfer: Local state UUID (00000000-0000-0000-0000-000000000000) does not match group state UUID (d25dbeb7-54f0-11e6-bac9-c2bc3c331fb6): 1 (Operation not permitted)
at galera/src/replicator_str.cpp:prepare_for_IST():482. IST will be unavailable.
2016-07-28 14:55:45 139821041313536 [Note] WSREP: Member 1.0 () requested state transfer from ‘*any*’. Selected 0.0 ()(SYNCED) as donor.
2016-07-28 14:55:45 139821041313536 [Note] WSREP: Shifting PRIMARY -> JOINER (TO: 5)
2016-07-28 14:55:45 139821320096512 [Note] WSREP: Requesting state transfer: success, donor: 0
2016-07-28 14:55:47 139821049706240 [Note] WSREP: (e31e0085, ‘tcp://0.0.0.0:4567’) turning message relay requesting off
2016-07-28 14:55:48 139821041313536 [Note] WSREP: 0.0 (): State transfer to 1.0 () complete.
2016-07-28 14:55:48 139821041313536 [Note] WSREP: Member 0.0 () synced with group.
WSREP_SST: [INFO] Extracting binlog files: (20160728 14:55:48.132)
mariadb-bin.000038
WSREP_SST: [INFO] Joiner cleanup. rsync PID: 2199 (20160728 14:55:48.137)
WSREP_SST: [INFO] Joiner cleanup done. (20160728 14:55:48.642)
2016-07-28 14:55:48 139821320411264 [Note] WSREP: SST complete, seqno: 5

The State Snapshot Transfer (SST) re-imaged node 2 based on an rsync transfer from node 1, so that explains why node 2 suddenly had a consistent definition of our table.

A DDL Failure in RSU Mode

We’ve seen what happens when DDL fails in TOI mode, but what happens when it fails in RSU mode? This is easy to demonstrate:

MariaDB [db1]> SET wsrep_osu_method='RSU';
Query OK, 0 rows affected (0.00 sec)

MariaDB [db1]> ALTER TABLE tab ADD COLUMN num int DEFAULT NULL;
ERROR 1060 (42S21): Duplicate column name 'num'

In RSU mode, DDL works in similar ways to how it works on a standalone MariaDB/MySQL server, so nothing catastrophic happens when DDL fails. It simply returns an error.

Conclusion

DDL can be kind of weird in Galera Cluster, but many of the quirks are in place to protect the integrity of your data.

Has anyone else noticed strange failures that can happen with DDL in Galera Cluster?

Configuring LDAP Authentication and Group Mapping With MariaDB

Geoff Montee MariaDB , MySQL , Security 3 Comments

OpenLDAP.org

Author’s note: For the most up-to-date directions on setting up LDAP authentication using PAM and user or group mapping with MariaDB, please see the relevant MariaDB documentation page .

In this blog post, I will demonstrate how to configure MariaDB to use LDAP authentication and group mapping. I have previously written blog posts about configuring PAM authentication and user mapping with MariaDB and configuring PAM authentication and group mapping with MariaDB . If you’ve read those blog posts, a lot of this information will be familiar to you. However, a big difference is that this blog post will also include instructions on setting up an LDAP server.

What do you need to follow these instructions?

  • A server running MariaDB 10.0+
  • An RHEL/CentOS 7 server to function as your LDAP server

I am not an LDAP administrator, so if anyone notices that I did anything incorrect or weird, please let me know!

What is group mapping

When I refer to group mapping in this blog post, I am referring to the ability to allow all the members of a POSIX user group to authenticate as a single MariaDB user account. A common use case it to allow all of the members of a DBA-related group to authenticate as a MariaDB superuser account.

The main benefits of this are:

  • You probably need a POSIX group for your team to control access to shared files anyway, so why not use it to simplify authentication as well?
  • Even if you have a team of 10 DBAs, you would only need to maintain one MariaDB user account for all of them to share.
  • There are no shared passwords. Even though there’s only one MariaDB user account, each DBA still uses their own LDAP password to log in.
  • LDAP is centralized, so even if you have 100 MariaDB servers, group membership only needs to be changed in one place.

In this blog post, I will be mapping the mysql-admins POSIX group to the dba MariaDB user account.

Setting up the LDAP server

If you would like to use LDAP authentication with MariaDB, it is very important that the LDAP Server is set up correctly. The steps in this section have been performed on RHEL 7, but they should be pretty similar for other Linux distributions.

Install LDAP components

First, we need to install the LDAP server and other LDAP components.

sudo yum install openldap openldap-servers openldap-clients nss-pam-ldapd

Create LDAP configuration file from template

Then we need to set up our LDAP configuration. For this, I used a template included with OpenLDAP.

sudo cp /usr/share/openldap-servers/DB_CONFIG.example /var/lib/ldap/DB_CONFIG
sudo chown ldap. /var/lib/ldap/DB_CONFIG

Start and enable service

We also want to start the slapd daemon, and make sure that it starts automatically when the system reboots. On RHEL 7, we would execute:

sudo systemctl start slapd
sudo systemctl enable slapd

Set the LDAP root password

Then let’s set the root password for the LDAP service. To do that, first we need to use the slappasswd utility to generate a password hash from a clear-text password:

slappasswd

This utility should provide a password hash that looks kind of like this: {SSHA}taDVduzRb34r8wwnhPTDLiYHqwTkHY2k

Now that we have the password hash, let’s create an ldif file to set the root password. LDAP uses ldif files to make changes to the directory.

Let’s make an ldif file to set the LDAP root password using the hash that we created above:

tee ~/olcRootPW.ldif <<EOF
dn: olcDatabase={0}config,cn=config
changetype: modify
add: olcRootPW
olcRootPW: {SSHA}taDVduzRb34r8wwnhPTDLiYHqwTkHY2k
EOF

Then we can use the ldapadd utility to execute the ldif file:

sudo ldapadd -Y EXTERNAL -H ldapi:/// -f ~/olcRootPW.ldif

Add some standard schemas

OpenLDAP comes with some standard schemas that will be needed later when we want to create POSIX users and groups in our directory. Let’s add those schemas:

sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/openldap/schema/cosine.ldif
sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/openldap/schema/nis.ldif
sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/openldap/schema/inetorgperson.ldif

Setup the directory manager

Next, let’s set up a directory manager. The directory manager is a privileged LDAP user that we will use to make changes to the directory after this step.

Let’s use the slappasswd utility to generate a password hash from a clear-text password just like we did for the root password above. Simply execute:

slappasswd

Just like it did above, this utility should provide a password hash that looks kind of like this: {SSHA}A0oN2jPVFafjxeb92VwYRwwbZMVppMam

Now that we have the password hash, let’s create an ldif file to create the directory manager:

tee ~/setupDirectoryManager.ldif <<EOF
dn: olcDatabase={1}monitor,cn=config
changetype: modify
replace: olcAccess
olcAccess: {0}to * by dn.base="gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth"
read by dn.base="cn=Manager,dc=support,dc=mariadb" read by * none

dn: olcDatabase={2}hdb,cn=config
changetype: modify
replace: olcSuffix
olcSuffix: dc=support,dc=mariadb

dn: olcDatabase={2}hdb,cn=config
changetype: modify
replace: olcRootDN
olcRootDN: cn=Manager,dc=support,dc=mariadb

dn: olcDatabase={2}hdb,cn=config
changetype: modify
add: olcRootPW
olcRootPW: {SSHA}A0oN2jPVFafjxeb92VwYRwwbZMVppMam


dn: olcDatabase={2}hdb,cn=config
changetype: modify
add: olcAccess
olcAccess: {0}to attrs=userPassword,shadowLastChange by
dn="cn=Manager,dc=support,dc=mariadb" write by anonymous auth by self write by * none
olcAccess: {1}to dn.base="" by * read
olcAccess: {2}to * by dn="cn=Manager,dc=support,dc=mariadb" write by * read
EOF

Note that I am using the dc=support,dc=mariadb domain for my directory. You can change this to whatever is relevant to you.

Now let’s run the ldif file:

sudo ldapmodify -Y EXTERNAL -H ldapi:/// -f ~/setupDirectoryManager.ldif

Setup the base domain

Now let’s create an ldif file to setup the base domain:

tee ~/setupBaseDomain.ldif <<EOF
dn: dc=support,dc=mariadb
objectClass: top
objectClass: dcObject
objectclass: organization
o: Support Team
dc: support

dn: cn=Manager,dc=support,dc=mariadb
objectClass: organizationalRole
cn: Manager
description: Directory Manager

dn: ou=People,dc=support,dc=mariadb
objectClass: organizationalUnit
ou: People


dn: ou=Group,dc=support,dc=mariadb
objectClass: organizationalUnit
ou: Group
EOF

And then run it:

ldapadd -x -D cn=Manager,dc=support,dc=mariadb -W -f ~/setupBaseDomain.ldif

Setup the POSIX group

Above, I mentioned that we would be mapping the mysql-admins POSIX group to the dba MariaDB user. Let’s create an ldif file to represent this group:

tee ~/createMySQLAdminsGroup.ldif <<EOF
dn: cn=mysql-admins,ou=Group,dc=support,dc=mariadb
objectClass: top
objectClass: posixGroup
gidNumber: 678
EOF

And then let’s run it:

ldapadd -x -D cn=Manager,dc=support,dc=mariadb -W -f ~/createMySQLAdminsGroup.ldif

Setup a POSIX user

We also need to have a POSIX user account who is a member of our POSIX group. Let’s create an ldif file for a user account named geoff .

tee ~/createGeoffUser.ldif <<EOF
dn: uid=geoff,ou=People,dc=support,dc=mariadb
objectClass: top
objectClass: account
objectClass: posixAccount
objectClass: shadowAccount
cn: geoff
uid: geoff
uidNumber: 16859
gidNumber: 100
homeDirectory: /home/geoff
loginShell: /bin/bash
gecos: geoff
userPassword: {crypt}x
shadowLastChange: -1
shadowMax: -1
shadowWarning: 0
EOF

Then let’s run it:

ldapadd -x -D cn=Manager,dc=support,dc=mariadb -W -f ~/createGeoffUser.ldif

Then set the user’s password:

ldappasswd -x -D cn=Manager,dc=support,dc=mariadb -W -S uid=geoff,ou=People,dc=support,dc=mariadb

Add the user to the group

Both the user and group exist, but the user isn’t yet a member of the group. Let’s create an ldif file to add the user to the group:

tee ~/addMySQLAdminsGroupMembers.ldif <<EOF
dn: cn=mysql-admins,ou=Group,dc=support,dc=mariadb
changetype: modify
add: memberuid
memberuid: geoff
EOF

And then run it:

ldapmodify -x -D cn=Manager,dc=support,dc=mariadb -W -f ~/addMySQLAdminsGroupMembers.ldif

Setting up the MariaDB server

Now that the LDAP server is configured, we need to setup the MariaDB server. I won’t show how to install MariaDB in this blog post, since there are already many references available for that. Here, I will only show how to get LDAP authentication and group mapping working with an existing MariaDB server.

Install LDAP and PAM libraries

First, we need to make sure that the LDAP and PAM libraries are installed:

sudo yum install openldap-clients nss-pam-ldapd pam pam-devel

Setup authentication

Now that the LDAP client and libraries are installed, we need to update the PAM configuration to use LDAP. We can use the authconfig utility for this. Be sure to replace –ldapserver and –ldapbasedn with values that are relevant for you.

sudo authconfig --enableldap \
--enableldapauth \
--ldapserver=172.31.27.223 \
--ldapbasedn="dc=support,dc=mariadb" \
--enablemkhomedir \
--update

Test new user account

Now that the server is configured to use LDAP authentication, let’s see if our user account works and if the user is a member of the proper groups.

[ec2-user@ip-172-31-22-174 ~]$ su geoff
Password:
[geoff@ip-172-31-22-174 ec2-user]$ groups
users mysql-admins

Looks great so far!

Setup the user mapping plugin

In order to use user or group mapping with MariaDB’s PAM authentication plugin, we need to install an external user mapping plugin for PAM. We can download this plugin from MariaDB’s source code repository, then build it, and then install it:

wget https://raw.githubusercontent.com/MariaDB/server/10.1/plugin/auth_pam/mapper/pam_user_map.c
gcc pam_user_map.c -shared -lpam -fPIC -o pam_user_map.so
sudo install --mode=0755 pam_user_map.so /lib64/security/

Setup the PAM policy

Let’s create a PAM policy specifically for MariaDB. Since we want to use LDAP and group mapping, we need to make sure that this policy is written to use the PAM modules for LDAP and user mapping plugins. This policy worked for me:

sudo tee /etc/pam.d/mysql <<EOF
#%PAM-1.0
auth sufficient pam_ldap.so use_first_pass
auth sufficient pam_unix.so nullok try_first_pass
auth required pam_user_map.so


account [default=bad success=ok user_unknown=ignore] pam_ldap.so
account required pam_unix.so broken_shadow
EOF

Configure the user mapping

The user mapping module looks in /etc/security/user_map.conf for its configuration file. Let’s create that file now:

sudo tee /etc/security/user_map.conf <<EOF
@mysql-admins: dba
EOF

Notice that we use the @ character to prefix group names. If we just wanted to map the geoff user, we could do this instead:

sudo tee /etc/security/user_map.conf <<EOF
geoff: dba
EOF

Create a local account for the user functioning as the proxy user

Because of the way the PAM authentication plugin for MariaDB works, we need to have a local user account for the MariaDB user functioning as the proxy user. Our proxy user is named dba , so let’s create a local user account with that name.

sudo useradd dba

Allow mysql to read /etc/shadow

Because of the way PAM authentication works, the user running the mysqld process needs to be able to read /etc/shadow . The default user that runs mysqld is usually named mysql . Let’s make sure that this user can read /etc/shadow :

sudo groupadd shadow
sudo usermod -a -G shadow mysql
sudo chown root:shadow /etc/shadow
sudo chmod g+r /etc/shadow

Setup privileges in MariaDB

Now let’s setup our privileges in MariaDB:

-- Install the plugin
INSTALL SONAME 'auth_pam';

— Create the “dba” user
CREATE USER ‘dba’@’localhost’ IDENTIFIED BY ‘strongpassword’;
GRANT ALL PRIVILEGES ON *.* TO ‘dba’@’localhost’;

— Create an anonymous catch-all user that will use the PAM plugin and the mysql PAM policy
CREATE USER ”@’localhost’ IDENTIFIED VIA pam USING ‘mysql’;


-- Allow the anonymous user to proxy as the dba user
GRANT PROXY ON 'dba'@'localhost' TO ''@'localhost';

Restart MariaDB

Since we changed the group membership of the mysql user, we have to restart mysqld to put the changes into effect:

sudo systemctl restart mariadb

Try it out

Now let’s try it out:

[ec2-user@ip-172-31-22-174 ~]$ mysql -u geoff -h localhost
[mariadb] Password:
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 7
Server version: 10.1.14-MariaDB MariaDB Server

Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.

Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the current input statement.


MariaDB [(none)]> SELECT USER(), CURRENT_USER();
+-----------------+----------------+
| USER() | CURRENT_USER() |
+-----------------+----------------+
| geoff@localhost | dba@localhost |
+-----------------+----------------+
1 row in set (0.00 sec)

Since CURRENT_USER() is showing dba@localhost , we know it worked. Awesome!

Conclusion

LDAP authentication and group mapping is very useful for users who want to consolidate account management. However, it can be a little difficult to setup and administrate. I hope this blog post helps simplify it for some!