Wednesday, 9 July 2014

MySQL Community Dinner 2014

Hello all,

I hope you're doing well. After the successful event last year it's a no brainer to arrange another community dinner when we're all together again in London this November. We had a fantastic turn-out for the meal last year, seating over 100 MySQLers in a venue whom were expecting only 60. So this year join the MySQL community again for a bite to eat and a beverage or two and discuss life, love and data.

The When
Monday, November 3rd 2014

The Where 
Masala Zone, Covent Garden

The Why
We have a vibrant community surrounding the MySQL ecosystem. Whether you want to talk about the meaning of life with Colin Charles or find out how Facebook take their logical backups even quiz Shlomi Noach about where thinks up his latest and greatest MySQL tools; why not do it with a curry and a beer?!

Other important need to knows
This is a `pay your own way` dinner. I'm sure you can appreciate that the MySQL Community is not a company or entity with an ample bank balance. However if I win the lottery between now and then I promise I'll pick up the tab for everyone ;) .

So please, please bring cash to simplify paying the cheque at the end of the evening. Last year, we found that it was optimal to pay per table.

The Menu
Whilst the chefs are fantastic at the Masala Zone, they cannot perform miracles. With over 100 MySQL community members eating and drinking it's not possible to offer an a la cart menu. I will post the set menu options and we will run a poll on which one to select. IMO the food is 2nd to the company but we can't have a hungry community.

Suggestions
If you have an opinion on something surrounding this, your community event, please let it be known in the comments.

Finally
Please register you attendance on the eventbrite page so we can handle the numbers. https://www.eventbrite.co.uk/e/mysql-community-dinner-14-tickets-12220960221

I am looking forward to seeing you all again.

Andrew

Tuesday, 12 November 2013

Percona Live in 30 seconds

I'm on the train home from London. Stalled at a signal waiting to move on. Here are some thoughts/facts/findings from my past 2.5 days.

- Walking from Waterloo to Kensington can be done. It's not a bad thing after a 3 hour train journey.
- Pubs in London also close at 10.30pm on a Sunday
- Don't trust the wifi near the guy with a pelicase on his shoulder
- Belgians are good peoples that love Indian food.
- Book 60 and 112 will come
- Double Decker buses go the long way around
- The MySQL community is alive
- It matters not what branch/fork you use, free beer/food/bus/OOS unites all
- MariaDB 10 soon. Stay tuned.
- "Peter in a Box" tipped as a hot favourite gift this Christmas.
- Using AWS? Spread yourself across AZ, Regions.
- System security is generally overlooked
- setenforce 1 (learn how to use selinux)
- Sysbench is not as understood as I understand. Lua.
- Henrik will not resist a MySQL conference invite :D
- Common_schema to become part of the server (one day, Shlomi!)
- Galera, PXC remains a hot topic with more and more production installs
- Fractal trees don't lose their leaves in the fall
- Unix load still misunderstood by many. See > 1, check what the CPU and IO is actually doing
- Backups are pretty important, RDBA sets the standard for backup ref. architecture. Mydumper wts.
- Oracle Engineers now available at PL events
- PerconaLive++
- The Crazy Italian guy is still crazy

Now there you have it, you missed a lot if you didn't make it this year!

Wednesday, 23 October 2013

MySQL Community Dinner

Dear Community,

it is my pleasure to announce that there will be a community dinner on the evening of Monday the 11th of November in London coinciding with the Percona Live Conference. In the same spirit as the community dinner in Santa Clara, the event will be `pay your own way` so it's important to bring some cash on the evening so that splitting the bill is as painless as possible.

The venue is Masala Zone in Earl's Court, which is a short walk from the Millenium Gloucester. For anyone that would like to walk over we will meet in the foyer of the hotel at ~7pm and walk over. 

Please make your way over to our eventbrite page to register your attendance so that we can give the guys at Masala Zone good notice of how many to expect.

The link above will take you to the Masala Zone site where you can see what's on the menu. 

http://www.eventbrite.co.uk/event/8935216473

Please let me know if you've got any questions in the comments.

Looking forward to seeing you there!

Monday, 14 October 2013

MySQL Replication Filters: replicate-ignore-table & ON DELETE CASCADE

It's no secret that you shouldn't rely on replication filtering. Recently a customer asked if an `ON DELETE CASCADE` would still affect the data on a slave if the table was being ignored through replication filtering. It was one of those occasions that I couldn't give a confident answer without a quick test but alas the gut was right and the obvious answer is yes, "ON DELETE|UPDATE CASCADE" will change data even if you replicate using replication filters.

I tested using RBR and SBR. If anything I was questioning the behaviour of RBR here but it turns out to be consistent with SBR. I had a master-slave setup already deployed for some other testing so it was easy to implement the FKs needed for this. The dataset is the trusty world db available from dev.mysql.com and I needed to change the constraints on the table to match the conditions proposed.

Master

mysql> ALTER TABLE City DROP FOREIGN KEY City_ibfk_1;
Query OK, 5000 rows affected (0.06 sec)
Records: 5000 Duplicates: 0 Warnings: 0

mysql> ALTER TABLE City ADD CONSTRAINT `city_ibfk_1` FOREIGN KEY (`CountryCode`) REFERENCES `Country` (`Code`)
ON DELETE CASCADE;
Query OK, 5000 rows affected (0.06 sec)
Records: 5000 Duplicates: 0 Warnings: 0

mysql> SELECT COUNT(*) FROM City WHERE CountryCode = 'UKR';
+----------+
| COUNT(*) |
+----------+
| 57 |
+----------+
1 row in set (0.00 sec)

Slave

mysql> SELECT COUNT(*) FROM City WHERE CountryCode = 'UKR';
+----------+
| COUNT(*) |
+----------+
| 57 |
+----------+
1 row in set (0.00 sec)

So our row counts match. I'll update the my.cnf file for the replication filtering.

Slave

cat /etc/my.cnf
...
replicate-ignore-table = "world.City"
...

Restart MySQL on the slave and check the status;
mysql> SHOW SLAVE STATUS\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.0.101
Master_User: repl
Master_Port: 3306
...
Replicate_Ignore_Table: world.City
...
1 row in set (0.00 sec)

Filter exists, lets test it. Update a row on the master and compare the values between the instances;

Master

mysql> UPDATE City SET population=90000 WHERE ID = 3482;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0

mysql> SELECT * FROM City WHERE ID = 3482;
+------+------------+-------------+---------------+------------+
| id | Name | CountryCode | District | Population |
+------+------------+-------------+---------------+------------+
| 3482 | Mukatševe | UKR | Taka-Karpatia | 90000 |
+------+------------+-------------+---------------+------------+
1 row in set (0.00 sec)

Checking the slave we can see that it remains the old value;

Slave

mysql> SELECT * FROM City WHERE ID = 3482;
+------+------------+-------------+---------------+------------+
| ID | Name | CountryCode | District | Population |
+------+------------+-------------+---------------+------------+
| 3482 | Mukatševe | UKR | Taka-Karpatia | 89000 |
+------+------------+-------------+---------------+------------+
1 row in set (0.00 sec)

Now if we delete the parent record in the Country table we can see that the CASCADE affects the 'ignored' table on the Slave too.

Master

mysql> DELETE FROM Country WHERE Code = 'UKR';
Query OK, 1 row affected (0.00 sec)

mysql> SELECT COUNT(*) FROM City WHERE CountryCode = 'UKR';
+----------+
| COUNT(*) |
+----------+
| 0 |
+----------+
1 row in set (0.00 sec)

Slave

mysql> SELECT COUNT(*) FROM City WHERE CountryCode = 'UKR';
+----------+
| COUNT(*) |
+----------+
| 0 |
+----------+
1 row in set (0.00 sec)

If you're running with FK Constraints with ON DELETE|UPDATE CASCADE and replication filtering on your slaves you might not have the data you think you have.

Tuesday, 8 October 2013

Bristol MySQL Meetup

The next Bristol (and surrounding areas) MySQL meetup will take place on Thursday 10th of October in Bristol (currently) scheduled for 7.00pm at the Watershed. I say currently because it might be moved if we can find a quieter place. I personally found the Watershed pretty noisy. The topic of the night will be tools. We'll have a 50,000ft overview of some of the tools and then make some time for some demos. According to the RSVP list there's a nice mix of Dev and Ops so there should be a mixture of experience and hopefully some inspirational use cases for tools being used in the wild. Right this moment the agenda of tools will be some from the following;
  • pt-toolkit
  • openark-toolkit
  • Oracle's MySQL Utilities
  • Xtrabackup
  • Mydumper
  • Common_schema
  • AOT
To give you guys and girls further incentive to attend the meetup, we have some swag to unload. There will be some Pythian and Percona t-shirts, some Oracle/MySQL usb drives & stickers and a ticket to Percona Live London to unburden myself of. I'd like to pass out some swag for participation over chance so make sure to bring a tasty question or story about how you use DBA/Dev tools. The Percona Live UK ticket is a very kind donation from Percona, so a HUGE `thank you` goes to Kortney and Tom for arranging that for us. The caveat to bagging swag/ticket: it's limited to attendees only and there will be a photo of the proud owners posted on the meetup page (with you permission of course). We will also have a discount code made available for anyone looking to attend PLUK. Follow the latest news for Percona Live London using the #perconalive hashtag or via Percona.com. Please post any questions or suggestions for Thursday night topic/venue.

Saturday, 31 August 2013

PLUK Attendees: Show of hands

It will soon be November and we'll be queuing up to register for the Percona Live conference once again. I spoke with some of this year's Percona Live London committee we all agreed that it would be great to arrange a community dinner if there was a community interest. In the past years of the PLUK conference there has not been a community event to attend in order to discuss sessions and make new friends. I for one love the `Pythian-arranged Community Dinner` at Pedro's that occurs annually in Santa Clara during the Percona Live Conference. I know that there are many attendees that do London and CA each year and wager that they'd agree that it's a great event. So lets have it... please r.s.v.p here and if the numbers are good enough we'll schedule something the evening of the tutorials. Please let me know of your interest in the comments below. Thanks :D

Saturday, 17 August 2013

Bristol MySQL Meetup & Holland Part II

So just a quick note to express how great it felt to get the first MySQL Meetup in the UK's Bristol done. We had great enthusiastic attendees bringing their own curiosity about the product. We spent a couple of hours in conversation about a broad range of MySQL related topics. Amongst the points discussed were; MySQL Connect, Percona Live London, InnoDB vs. MyISAM, replication, query tuning and Ben gave a demo on pt-query-digest and pt-visual-explain. Although we touched many aspects it was really a primer for what we would like to achieve going forward. We're planning content and dates for the next meetup so keep an eye on the meetup page. I want to express that all comers are welcome whether you're fantastically experienced or a curious noob there's place for you. The group has already made many friends such as TomD from Percona, Stoker from Oracle and Marco from Pythian. They've all donated some sought after swag and we're thinking of fun ways to reward it to our group members.

Holland Part II


Since I penned the first part of the Holland Framework article series I've been immensely busy but things are beginning to slow down. I'll find some time to complete that series for anyone sitting on the edge of their seat awaiting the sequel as this next part was the driver for my blog post. The company I'm working with are currently using Holland in production to make file-per-table mysqldump backups using holland and whilst I would always recommend a mixed backup set (logical and physical) I'm not satisfied in the DR plan using only mysqldump so there's more Holland framework in my immediate future.

That is all from me for now. Hope you have a great weekend.