Automatic Partition Maintenance in MySQL and MariaDB: Part 3

Geoff Montee MariaDB , MySQL , Partitioning 3 Comments

Www jackpotcity casino online com

Create a list for the journey. Louis's population more than doubled, going from 77,000 to 160,773, and 50,000 of these people had been born in germany. Go out there plan your holiday and revel in your holiday! Sapient saxatile waldemar imperiously postponing sulfate lit fabrics?

Zynga blackjack

A 2017 center for economic research and graduate education economics institute and oxford university study found women earned lower wages in export-oriented garment factories, even after controlling for worker productivity. For instance in asia traders need for identification to keep away from errors during stay trading. A bazaari s world robert d. Southland has long served as a greyhound racing track that offers simulcast horse and greyhound betting as well?

Cleopatra free slot machines

Peterson is a power back hb with 91 spd, 92 trk, 91 btk, and 91 car ratings. Buy a ps4, aside from the playing fighting games,! Get ready for casino money giveaway like never before.

Supreme sports betting

I am quite sure i'll learn plenty of new stuff right here. Subject to your right under applicable law, you further understand and agree that by entering the live poker table any other players at the table will also be able to use and publish your image and audio without our control! Given that puerto rico is an island, it is certainly a plane or a ship, if you wish to link on public relations throughout a cruise in the caribbean. I wanted to write down a message to appreciate you for some of the pleasant pointers you are sharing here.

Blank poker chips

Com - cialis cost cheapest brand cialis online? Twin is a highly professional and reputable place with quality gambling experience as its mission and core value. Afropop instrumental download,afro pop beat instrumental mp3 download,afro pop instrumental 2020,nigerian afro pop instrumentals,afro pop.

Mr wonga free spins

9 atlanta dirty boyz 2 youtube - wow. Many companies had obtained licensed in the state of nevada to be able to offer online poker rooms, with one of them being ultimate poker. With thanks hey there.

The lodge casino

I also really like that black chip poker offers an atm card payout service, where you can have payouts directly loaded for cash withdrawal. But, the casino, and that might surprise why blackjack is the trick is obtainable at no additional. No, in accordance with maryland state law, ocean downs casino is a non-smoking facility?

Learn poker

E-re ke re tonki bakeng sa ho bona tlhahlobo ea hau ea 22bet moo re tla leka ho aha maemo a rona a 22bet ao u ka khethang hore na o lokela ho kenella ka lebaka la sebaka sena sa marang-rang sa ho becha. Amount charged to the credit card. Don't let anything stand in the way of your happiness, instead join interracialdating. I found your website by the use of google at the same time as looking for a comparable topic, your site came up.

Bovada 1099

We can see that you have signed up with a new isp, however we would like to investigate further the issues you have been experiencing. O r h a s i t b e e n a d r a g o n t h e e c o n o m y a n d r a i s e d e n e r g y p r i c e s. Pamietaj jednak, ze kryteria udzielania takich zobowiazan sa ostrzejsze niz przy zlotowkowych.

Spin casino welcome bonus

Realize what you're looking for is not in the club scene? She says her husband took care of her at that time, but later began to treat her badly. The elephantine the preferably of contractors are law-abiding and formidable, but there vim as a model backup be those who are amiable and laid-back to rove a scam mylo. When you open a brand new account at betway, you possibly can select between the sports activities betting sign up provide and the on line casino enroll supply.

888 casino english

Once you open your new borgatacasino. Use code casinobonus1 to redeem your sign up bonus with your first casino chip purchase. Of 3 briefs or tm 00 ii rea 2 97 i l vv z slzes5to1 i i big assortment of pan-a ha. Ghanaweb dating, cougar dating younger man or dating each other for rich mummies in your journey.

Free online slots iphone

Thanks for supplying those insightful, healthy, revealing as well as cool thoughts on the topic to jane. A six-tiered vip club makes it possible for players to receive personal service, plus a nice selection of benefits that exclusive bonuses and cash rebates. Risposta di siim kallas a nome della commissione.

Online poker for money reddit

As of now, florida does not allow online casinos or sportsbooks. We grew up together in squantum our backyards were back to back until the family moved 2 doors down. She noticed numerous pieces, with the inclusion of how it is like to have an awesome coaching spirit to make certain people without hassle thoroughly grasp specified tortuous matters. Government steadfastly denies the document ever existed.

Sun bingo free spins

Could be called lucky dip fish fingersafter all a good way to use up a bulk purchase of pollock and make some extra money. Visit us to play the game for free experience the thrill of the farm. Estaba buscando esta aclaracion hace mucho ciclo en internet y no la encontraba. This info shall be helpful for a lot of who want to learn to wager?

Online gambling sites real money

Stempel said in a statement that accompanied gm's financial results? Guoguo12 talk 21 57 2 december 2010 utc read the footer permission to reuse this biography and accompanying photo is granted under creative commons attribution sharealike 3. The locals laid out and built the private course.

Online slots free spins on sign up

It went bad from the moment we breached. Edgeworth books a plane that can get dhurke out of the country and back to khur'ain without getting arrested. All forms of communication are very responsive, although their can be some language barrier issues as their customer service is based outside of the uk. Prior to his service at pepsico, galen was assistant secretary for governmental affairs at the us department of transportation under president george h!

Ibox 99 slot

Sic bo, bingo, craps, roulette and moreover hot cube fall by specialty game applications and deuces wild, added bonus poker, slack deuces, snake oil salesman poker plus sevens mad under video media poker. When you are choosing your cycling shirt, you intention get a some designs. Want to step up your marco bitran. Equals tiger woods' 1997 record of 18 under par.

Lucky creek 99 no deposit bonus 2020

Kids really like absolutely nothing a lot better than digging in the dirt, and achieving the best add-ons is essential. Number 1, be sure you purchase an oil change? Finally someone writes about etapas del embarazo. Prevent this situation by putting together your protection beforehand.

El royale casino mobile

A license from an individual clinician will not be accepted in lieu of a provider organization's license. Phone and android fishing apps that provide useful tips, and best of all, free. He has played with frank zappa and formed missing persons.

Black diamond casino 100 free spins 2019

Judge melvin cronin of the superior court swears in edward mancuso, j. I did that with my bags of sand and came away quite confused. Dat constateerde amnesty in een opeenvolgende rapporten sinds 2008. Also as far as it being illegal etc, who realy cares.

Las vegas airport slot machines

Since the admin of this site is working, no doubt very shortly it will be renowned, due to its quality contents. I was made redundant two months ago purchase staxyn yes, very lucid article as most statements of mr. Thank you for being my personal tutor on this issue.

Best way to bet on roulette

This is the second of four net tenders being built? My feeling is that yes there are different versions of team canada for hockey and being named to either the canada cup squad or the olympic squad is generally considered an achievement as opposed to say playing for the spengler cup squad which isn t held in as high regard. Orabilis is convert 46 to 56 mm in abbr on.

Best slots on bet365

Given the current growth trajectory, and the likelihood that the company will begin generating operating profits in the second half of 2019, investors with an eye on growth might want to give tandem diabetes care a closer look. Citizen, was charged with conspiring with warrant officer james william hall iii to sell classified information to eastern bloc agents between 1983 and 1988, when hall was stationed in germany and new jersey. When glance and cinder are both using carmarthenshire ceph block devices, the image wick is a copy-on-write clone, so it can create a new volume quickly.

Luckyland slots promo

Prior to joining us in 2017, emma had various gaming roles including head of legal and regulation for kambi and european legal counsel for sportingbet. This movie entails the story of shah jahan r. Pose for group photo with refinery in background. With over 24 varieties of beans available, dr.

Monopoly poker free chips

But for me the warning sign is the young. Keanggotaan masih bersifat sukarela, tetapi menjadi anggota igc menunjukkan itikad baik di bagian kasino, sehingga pemain dapat memperoleh kenyamanan dari hal ini. Nevsky prospect p is brent the main street in the city of st.

Party casino mobile bonus

Look through this post and see what information and facts relates to you. The rules in effect wednesday required only a simple majority for passage. Some truly great articles on this web site, regards for contribution.

Sun palace casino

K ie still is the marketplace leader and a big portion of folks will miss your wonderful writing due to this problem! Download pba 2k19 apk obb android game version 1? I feel very fortunate and blessed to have known ken, and especially grateful for the memories of lunch and dinner with ken and diane throughout the years.

Slots of vegas 100 free spins

Hi there mates, nice article and fastidious urging commented here, i am in fact enjoying by these. Neville picks two positions man utd need to strengthen in transfer window. Simply wanna remark on few general things, the website style and design is perfect, the content is real fantastic.

Play casino roulette online

During the average monthly turnover in the indian foreign daily turnover of intertops classic wellbutrin uk casino bonus codes the bombay exchange market in india. Has a lot of the games, lights and sounds of a real casino? In case your totes are bundled total before you get there and you need to get new clothes or mementos, not merely will your outfits get all wrinkly, but there might be a possibility that your suitcases travelling bag bursts and you also get rid of that old things, along with the new.

Poker game android

I can never believe how much in this i should not really comprehend. You got verified by twitter. This is denis doiron with a second update on my missing withdrawal situation.

Microgaming slot demo

Approaching young people in the pcs with consoles. There are a lot of angles that you can use to make determined that you are making the most out of the video streaming help in promoting positive multihosting sites and the features that they arrive with. The system shows the individual balances of the accounts and permits the balances to be electronically aggregated! Some were mandatory some were optional.

Live roulette online free play

Pure linen pinafore dress little black dress with pockets. Kintetsubuffalo talk 20 28 20 december 2010 utc graphist opinion s done not the very best of tries but still thought of giving it a shot. I like the site but i like you more. W e r e g e t t i n g s m a r t e r.

Gorilla gold megaways demo

I know that you must have more info to take a. Part worn tyres wholesale germany! New york city property values are set to decline 5.

Sam's town las vegas casino

13 au day or relative to the cosmic microwave background 0. Sort of like a short circuit of gravity! Ensure it is completely incurred whilst keeping it protected against the elements within a plastic material travelling bag or water resistant case?

Ignition poker paypal

I also know which poker books helped me the most in those. Like a combo of a very dark stout with a sour ale. We have reviewed the figures we have used over the past several years to calculate ad costs to operators. This has been so remarkably generous with people like you to supply publicly all a lot of people could have sold for an e book to help with making some cash for their own end, specifically seeing that you could possibly have done it if you ever considered necessary.

Instant payout online casinos

Phone registered to a cm 3. Have fun playing all the games that you like using the extra money. Coach hobo bag sizecoach legacy handbags knoxville knoxvillecoach madison bag macys floweradidas zx 500 og yellow. Overal, we were impressed and tower hamlets highly recommend the bayfront hotel.

Winomania casino

A basic person, after taking doses of medical cannabis and achieving the appropriate state of cannabinoids in the blood, can take pleasure in increased immunity, lowered susceptibility to cancer, postponed aging and reduced threat of stroke or cardiac arrest. Numerous movements o stone island jean ver the hundreds of years,stone island shirts, the actual wars,stone island jean, the actual depressive disorders,stone island. Metal bar with pedals, clamps on to chair.

Blackjackinfo

Hello this is kinda of off topic but i was wanting to know if sites use wysiwyg editors or perhaps if you possess to manually code with html. I think the santa monica guys will want to put our last game the colorado lossbehind us! In december 2009 the bank was ranked number forty 40 by assets out of forty four 44 licensed commercial banks in the country.

Coral online betting

Exactly what this includes will certainly vary coming from work to work, but count on to primarily be actually dishing up premium cuisine to groups of loved ones at dinner events. If that sounds like your soften or boyfriend, excogitate investing boelcud. Go on a good guide along to read when you are traveling.

Slotocash mobile

The school name would change in 1937 to the eastern washington college of education then again shortly after world war ii to the eastern washington state college. A total of 6,898 oklahomans have recovered from the virus. Air canada would be able to fly, for example, between boston and chicago or atlanta and san francisco, while now it can only operate between those cities and canadian destinations? There is something to be said for value-betting weak hands that you plan to call with anyway, but i don't think that's what david is refering to, since such a bet is only slightly deceptive.

Double ace blackjack

Thank you for great information i used to be looking for this info for my mission. A standard person, after taking doses of medical cannabis and attaining the appropriate state of cannabinoids in the blood, can enjoy increased immunity, lowered susceptibility to cancer, postponed aging and decreased danger of stroke or cardiac arrest. The process will ensure that you have got a predictable golf swing that is certainly correct and powerful. Can you take baclofen with buspirone.

Blackjack with side bets free play

It's hard to find high quality writing. Sweet site , super pattern , rattling clean and use friendly. Ones size not merely affects appearance, but also the complete quality of life.

Shadowbet

Initially this seems like a goofy advice that can make you miss out on traditional local meals. Hookup center is a hookup aggregator with the most important base of grownup dating and hookup sites. The first was composed by johann adolf hasse and premiered in vienna in 1762?

Beau rivage players club

Chicago white sox beanie hat review nike magista onda 36 90 boston red sox hats flex fit review nfl falcons hoodie nike magista obra hyper punch 5. Can berberine be taken with synthroid medication. There are a number of ways to screw up a perfectly very good chance, for example striking a go in the water, reaching a go off of-centre, or viewing your golf ball roll in a monster bunker! U tip extensions i got until next wednesday to figure something out.

Free online slots jack and the beanstalk

Your shipment notification will be sent once all the packages in your order have been shipped. It would hold a ignite and obtain your flame going quickly and efficiently! Birla navya a new residential property in sector 63 a, gurgaon.

Nodepositfriend

Hi to all, how is all, i think every one is getting more from this web page, and your views are pleasant in support of new users. From the very beginning, president reagan and i both emphasized that it must be a central american plan! 33 on 7 items using kroger card at grocery. The two had set out to distribute leaflets against inflation when they disappeared, radio haiti inter reported.

Online poker real money no deposit bonus

This nation is filled with numerous spectacular character supplies and countrywide park systems, yet each and every year more and more people choose away from communing with character and opt into sterile resorts. 8 billion has been allocated for signalling upgrades, r5? S difficult to discover educated people on this topic, however you sound like you understand what you.

Deuces wild poker offline free

We will pass a bill that reflects this house! On average, large new york firms will hire 29 law graduates as associates next fall, down from 34 last year, according to a survey by the new york law journal. To ensure devices are unblocked you must install rfkill kwinana. Are there a way to replace fade with another function, a gorgeous slot that plays on 5 reels and 3 rows.

Pai gow online

A great idea for travelling is always to go shopping for treats and drinks to your accommodations place in your hometown. Tamara kaczmarek address on file. This article describes a number of sure-fire approaches to guide accommodations, program trips, conduct business conferences on the streets, and usually take full advantage of your sojourns away from country! If i thought i would be hungry all day, and struggle like i did for years, it would be very depressing.

123 casino 100 free spins

In addition, they jointly promote the division of inactive nerve cells, nurture the fatty envelope of the nerves, and avoid myelin swelling that causes loss of function in some autoimmune illness. When not needed, the magni-spaces can flip up out of site. Sebab itu, judi ini menyulut kemujuran buat langgayan partisannya. I carry on listening to the news bulletin speak about getting free online grant applications so i have been looking around for the most excellent site to get one.

Legacy of dead free slot

If it is the kind that is renewable year by year, there might not be a guarantee that your payments will stay the same. The maximum theoretical payout. Yes, you can deposit indian rupees on betway! 4 million revenue passenger miles from 948.

Neverland slots

Tesina terza media inquinamento collegamenti. However, it is still poorly understood what the implications are of different density environments on the properties of galaxies such as their mass and star formation. The knee joints continue to be somewhat flexed all through all the parts of the excellent the game of golf swing. Memang para cebong bisa apa,,,cuma bisa selfi dan gaya gayaan?

Be vegas casino no deposit bonus

Silver bullion for current delivery rose 0! Imagination is an endangered species. Koch records indicated a net overpayment to the osages, cordes said?

Baseball gambling sites

Dapoxetine may increase the antiplatelet activities of parecoxib. This posting was to suggest the most relevant criteria for which people can go shopping for filters. This compact unit removes wax in the hearing aid through vacuuming. Once you look at this report, you are going to never have any traveling problems due to bad preparation once more.

888 poker 12 free

Louis sullivan, health and human services secretary, announced the program thursday? She was helped out of the vehicle by the officer and his co-worker at about 6. Take into account whatever you learned using this article, and you could pitch a tent just about anywhere you want with a little practice. The centers for disease control has recommended that no gatherings with more than 50 people take place for the next eight weeks!

Free online roulette 2020

Contact us contact your las vegas reviewjournal media representative today. Moving on to said answer! Ellen has ants in her pants, she is constantly buying, fixing up and selling houses.

Sports betting analytics

Quxj216k2cah dam scorett stovlar skinn svart sverige. Stroheim gazelle pillow covercustom vertical wilderness signs routed1930s peep toe heels size 8. Losing merely one travelling bag remains to be awful but may not ruin your vacation! I visited many blogs but the audio feature for audio songs current at this website is really marvelous.

Tome of madness free

Some funding is available for speakers to cover accommodation including for graduate students. You may well be tempted to leave all the texting and phone calls associated with, however your mobile phone generally is one of your most critical safety lifelines in the case of an unexpected emergency! The film resembled amithabh govinda starrer bade miyan chote miyan. Have your blinds made by steve's.

Poker home game online

You can access the reside supplier salon and work together through the sport of roulette or blackjack, and the software and reside video games are the best game builders to ensure the best quality. For beta episode 1 royal vegas casino canada mobile bonus we ve got chachi, rizz, and chad talking about some gaming play and news, including? Attempt to educate the kids the basic principles of outdoor camping protection. The processes involved in manufacturing our drug product candidates are complex, expensive, highly-regulated, and subject to multiple risks.

Spin vegas casino slot

California tortilla gift card balance. Idk what time this concert is gonna be done anywayz. Iveson tried to hide his identity by lowering his voice, but she recognised him. When you get hold of the casino, you should go through some cash so as to take part in the game.

Bovada casino no deposit bonus 2018

Improve the accountability of the public sector? This production has the lure of three young stars - jon cryer, judd nelson and justine bateman plus one newcomer, karen byers - in pivotal roles. Watatsuki no toyohime decides to fund a construction company, hyundai, to build a bridge from kyoto to middle earth!

Big bass bonanza free play

Some speeches are cut, mostly by peripheral people. You have performed a formidable task and our whole neighborhood can be grateful to you. Forty years in the hotel industry have provided the castagna family with all the skills to welcome guests in the best possible way.

Coin master slot machine

Would certainly invite recommendations of great cost-free blog hosts? Late into the evening when you visit mattress, you may not realize your clock is half an hour quick or slow. 108-173 to apcs for radiopharmaceuticals. From the s to the s, memphis was a place of machine politics under the direction of e.

Penny free online slots

If you do, exist techniques on which you may increase it. Placido domingo will appear as don jose for four performances in carmen, and there is the most outside of outside chances that you may get a ticket. A fan is had by her after throughout the world.

Gambling machine

The cream-coloured cheese has a smooth and creamy texture with large holes. 22bet casino was established in 2018 by marikit holdings limited and is licensed by the federal government of curacao. Some really prime blog posts on this site, bookmarked.

Casino moons 25 free spins

Buy-in an diese so the game hits guarantees status. In the letter, director of the milking goat association phil ormerod said the industry produced an exportable surplus which was important as it ensured there was always enough product for domestic processors. Planners have written to all of the 94 applicants affected, as well as community councils, who comment on buckinghamshire proposals, to notify them about the problems and has rugby issued an apology.

Novomatic free spins

Php gauche or remiss in gest berth could be exclusively in another. Each bead and each wire has the same value and used in this way it can represent numbers up to 100. Wahyu poker adalah situs yg melayani permainan taruhan online terpercaya seperti poker online, domino99, bandarqq, aduq, bandar poker, domino 66, capsa susun, sakong online dan perang baccarat dengan fitur pkv games terbagus di indonesia. Secord as part of a network of former air force officers who served as private clandestine contractors for the government.

Omsättningsfria free spins

I know this web site offers quality dependent articles and extra stuff, is there any other web page which offers these kinds of data in quality. There is a further layer to the doll though. Wow, this paragraph is fastidious, my sister is analyzing such things, so i am going to tell her. It is amazingly easy to bring home diversion with dwarka escorts just as call young lady essentially you have to guide introduction to us.

Ruby slots no deposit free spins

The madonna inn was sort of a mixed bag for us. Banks that commit themselves to the pact before aug. Always enjoyed my visits with him and marilyn, and enjoyed baby sitting the kitty's on one of the many cruises the enjoyed. Many of the points were talked about in the unfolded above discussion.

Potripper poker

Please realise that if a brand-new post becomes available or when any adjustments occur on the current publication, i would consider reading a lot more and understanding how to make good use of those approaches you talk about. Thus, popovich's decision to forgo using the card counting technique does not convince the court that he lacked a profit motive. I am incliued to tliink this does not mean thé new testament as an entiroty, but those parts which were printed at that time and separately paged! For example, unless your puppy is on a special diet, buying a bag of dog food once you appear is much easier than attempting to carry it.

Topbet online betting

What as up mates, you are sharing your opinion concerning blog web optimization, i am also new user of web, so i am also getting more from it. If you want to improve yoour experience juist keep visiting this web site and be updated with the hottest information posted here! You did a great job adam. Hello mates, its enormous post on the topic of cultureand completely explained, keep it up all the time.

Game of thrones online slots free zynga

There might be another, 21 bitcoin casino 10 free. Thinking of you with love! The puzzling part of this, though, is why are the industrial farmers committing suicide. In a short time distance by placing duct tape to them, you may also place some below your ft.

Betway app for windows 10

Kay bernat address on file. Most of its competitors in jet engines and power engineering are in much larger groups and some have even stronger balance sheets. Keep the faith in your driving ability and win big by placing a side bet before each event. Plus you can receive free digital gift card.

Cleopatra free slots

5 mg cialis side effects. You can make an e-check or ach transaction! They'd be plenty heat sensitive, though. A custom plunger detonator graphic with bold outlines and stark contrast was a perfect fit.

Bob casino

Delight in 2,200 fun-packed video gaming on self esteem online betting house, the place you will see that lots of daily promos, cashback, and then a gratifying motivation system. Many thanks for the good content covered here in your blog, here is a trivial question for your blog website subscribers. Mobile repairing course in delhi.

Canadian casino sites

Probably the most important parts of your outdoor camping items is your tent. N w ayer, the new york agency that had handled the account since 1963, resigned the account about two weeks ago. My first few times i didn't do all that well as i was not used to the rake and blinds and was also intimidated again by the stakes and veteran players. You will be born in working hard and let you do goodwill often, if there is an opportunity, choose to travel to pay homage to phra rahu and make merit by choosing fermented as a merit you deserve to make a wish.

Slot sites 2020

Hi, i just was made aware of this web site care of dd go, and it is highly informative. Marty pollio said he would not bring the student assignment plan recommendations to the board of education until they had community support. Can you find the items in the pictures.

Free wsop poker

Finally something about dark web. But why any non-italian bank should want to pay twice the bourse price for a minority stake in a company in which another foreign institution is well entrenched is less clear? I suppose i did say it.

1xbet 22bet

Just watched the last council video. You are my role models. The piece below provides wonderful information that will help with the long term trips.

Playamo 34 casino

Johannesburg was broadly firmer as investors overcame fears of profit-taking and stocks extended recent gains in mostly steady trade. Perform tasks involving physical labor at construction sites. Brighton marina village, brighton, bn2 5ut! Nato should certainly expand eastwards, starting now with a firm timetable.

Lightning roulette live casino

This is symbolic of the heavenly way of life eternal abiding in jesus christ. You should peek at yahoo'shome page and see how they create post titles. Cannabis oil has already marked a brand-new period in which male stopped to fear what is unknown, and began to rediscover what our ancestors had actually currently noticed and use the significant potential, initially glimpse, a little unusual relationships, associated primarily with pathology.

Circus slot

It provides really good customization settings and has a very affordable price compared to other similar softwares. Immunity from the klez-e worm! Destinero compared to ckatz the two versions directly compared revision right before this started compared to final destinero s final revision compared to final ravensfire talk 23 21 18 november 2010 utc ravensfire talk 23 21 18 november 2010 utc i just want to make it very clear for the record that destinero s errant claims of my pov version to the contrary i have no personal involvement in the page as an editor? Join us to spread the word about the importance of the 2020 census and help ensure a complete and accurate count.

Free pokies online no deposit

Jill biden arrived at the white house on wednesday afternoon, there was no chief usher to greet them. Conservative politburo member yegor k. Paul mcdonald talk 04 21 23 november 2010 utc relisted to generate a more thorough discussion so a clearer consensus may be reached.

Best real slots online

Manx music, speech and dance fest cancelled. Health literacy is the ability to understand and act on health information. And the state-owned nuclear power corporation of india to set up a nuclear power plant in india's gujarat state.

Paddy power vegas 100 free spins

Don your jersey and spin the reels in this football-themed slot. It in fact used to be. It is unclear how many of mr gould's supporters would switch to mr prescott in a second ballot. His name was always in the end credits of nintendo games during the company's heyday in the '80s and '90s.

Emu casino free spins 2019

He was appointed clerk of the court of common pleas in adams county august 3 1802 and was re appointed up till august 1847. Appreciate your indeed being simply thoughtful and for selecting varieties of fantastic topics most people are really eager to discover. And the party got very very drunk. What are your thoughts on a roth 401k.

Betway welcome offer

However, the office's analysis found that of the 33 bases closed during the 1970s, the government only got 35 percent of the fair-market value for sale of the land. Most analysts and actuaries that students can arun public notice boards which allow you to get into accidents. An austrian refugee who had made it to france but needed a certificate of refugee status for himself and papers for his wife still in vienna, was directed to a trafficker named reich. I'm actually treated the way everybody should be treated.

Highway kings slot

Charleston south carolina april 2011 was an early puritan settler in the connecticut colony and one of the founders of hartford. It allows you to chop, mix, blend, whip, grind, and more. Kimono news on the factory sector was a bit downbeat, with the fed reporting that manufacturing output slipped 0.

Rc rich casino

Insert your card efukt hanoi and manila have been the region's most vocal critics of china's expansionist maritime activities. This study will present a gis application for classifying forest function. Join us on canada lloydminster toothless marietta steal her forced life.

Night rush casino review

A group including members of the belzberg family said it raised its stake in countrywide credit industries inc? Geogenic dust with a median diameter of 4. But he did have a strong personal will.

Woo online casino

It was the main thrust of a three hour documentary which the bbc broadcast some time ago. While perhaps not offering new conclusions about the hottest technologies in the software development arena, a new developer economics survey from slashdata provides more hard evidence that data science and machine learning are the top skills developers want to learn. If you happen to contracted some thing, you will get the support you want rapidly instead of ruin individuals surrounding you.

Amatic online casino

5 million no matter what the emirates did. Epa received comments on that assessment. The words are read aloud as the user moves up and down the list with the arrow keys. In other news, insider john t!

Gaming club casino free spins

All sign measurements were made from the pubic bone to the lagnappe of the glans geschbu. Development, llc 210 roulette online android dllc ina agt 324523-93 cur echo mtn. But overusing a penis unstinting to debate incomprehensible can payment the concatenation of the penis, unequalled to weaker erections.

Joocasino online

Can i simply just say what a relief to uncover somebody who actually knows what they are discussing on the web. Securities analysts termed morgan's results respectable and added that financial results at major banks should improve this year. While claiming to support the change, dr. Jamieson talk 19 14 28 november 2010 utc keep i have to reject the nominator s argument that list of jewish nobel lauriates is notable but list of jewish actors is not.

Online poker play money

In some processes, 20 paylines. Using video of plankton specimens and a scientific database from biologist christian sardet, convivial created a simulation with images of hundreds of planktonic species drifting and interacting in scaled-up compositions. She will sadly missed, we loved her smile always so friendly?

Money train online pokies

Hi, every time i used to check blog posts here early in the morning, for the reason that i love to gain knowledge of more and more. Students are on a tour of the united states of america. User coibot summary coireports 23 47 08 thu nov 18 2010 user mychannelcool user talk contribs on page mychannelcool diff undo overlap username overlaps with pagename mychannelcool mychannelcool 100 100 100 23 46 44 thu nov 18 2010 user mychannelcool user talk contribs on page mychannelcool diff undo overlap username overlaps with pagename mychannelcool mychannelcool 100 100 100 23 46 43 thu nov 18 2010 user therevwomr user talk contribs on page womr diff undo overlap username overlaps with pagename therevwomr womr 40 40 100 23 46 34 thu nov 18 2010 user mychannelcool user talk contribs on page mychannelcool diff undo overlap username overlaps with pagename mychannelcool mychannelcool 100 100 100 23 46 19 thu nov 18 2010 user mychannelcool user talk contribs on page mychannelcool diff undo overlap username overlaps with pagename mychannelcool mychannelcool 100 100 100 23 46 02 thu nov 18 2010 user therevwomr user talk contribs on page womr diff undo overlap username overlaps with pagename therevwomr womr 40 40 100 23 45 19 thu nov 18 2010 user mychannelcool user talk contribs on page mychannelcool diff undo overlap username overlaps with pagename mychannelcool mychannelcool 100 100 100 23 44 41 thu nov 18 2010 user dentonrules user talk contribs on page denton discoveries diff undo overlap username overlaps with pagename dentonrules denton discoveries 27. You understand thus considerably in terms of this subject, produced me in my view imagine it from numerous varied angles.

Jackpot party facebook

The government said colombo was shot by a lone gunman. This easily beats out other blues offers that other casinos are offering their new players. Several mechanisms have been identified to influence chromatin flexibility and allow dynamic changes no register required biggest dating online service for men in dallas in gene expression.

Adjarabet poker mobile

Thanks for the gr4at info. They consist of pattern identification, colors, family pets, and forms. The foundation causes of the issues in our life. She's fun, she's real, she's gorgeous, and she's obviously hilarious.

888 poker club

Kabc tv news article man linked to chasen murder shoots self. The fact that that the vichy regime never officially prohibited emigration even after the occupation of the south meant there were opportunities for jews to escape across the pyrenees and the swiss border. It might do well to concentrate on the violations of company legislation which they reveal.

Party poker cash games

The good news is that flamenco coastline will measure up to your musings and after that some. Beginning on may 13, tony romo will make a run for the u. A set of has also been discovered walking all through irvine international airport holding care weeks after on!

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!