Artem Russakovskii's programming and technology blog

• Tom Hanlon of MySQL presents
• Benchmarking tools
  • mysqlslap (with MySQL 5.1)
  • sql-bench
  • supersmack – Jeremy Zawodny's tool
  • Apache Bench (combined with some sample PHP scripts)
  • MySQL's benchmark() function
  • mybench
  • WAST
  • JMeter
• sql-bench
  • pros
    • ubiquitous
    • long history of use
  • cons
    • single thread
    • Perl
    • not always real-life test cases (create 10k tables?)
  • list of tests follows
• supersmack
  • configurable, flexible
  • 1000 queries, 50 users
    • super-smack -d mysql select-key-smack 50 1000
  • can modify queries to be closer to what your own application uses
  • pros
    • benches concurrent connections
    • well documented
  • cons
    • test language sucks
• Apache Bench
  • webserver benchmarking tool
  • point to a webserver, utilizes concurrent users
  • siege, httperf, httpload are similar
  • 404 errors deliver really quickly, so make sure to check for those
• benchmark()
  • tests

…

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Updated: April 24th, 2008

Unfortunately I didn't find any available seats to take notes for this but this morning a very interesting keynote took place. Representatives from 7 large companies mentioned in the title gathered on stage and answered various questions by MySQL's Kaj Arno.

These questions included things like "how many MySQL servers do you have", "how many DBAs", etc. It was a lot of fun, hopefully someone (Sheeri) will edit and post the video soon.

Keith has a nice summary of everything that went on together with the numbers here.

Update: Venu has even better notes here….

• Paul McCullagh presents
• BLOB

• invented by Jim Starkey
• Basic Large OBject
• Binary Large OBject
• photos, films, mp4 files, pdfs, etc

• mysql client send buffer -> receive buffer on the server (max_allowed_packet)
• streaming a BLOB

• continuous data stream
• stream BLOB data directly in and out of the database
• store BLOBs of any size (>4GB) in the database
• create a scalable back-end that can handle any throughput and storage requirements. Wouldn't need to know in advance how big the database will get
• provide an open system that can be used by all engines
• provide extensions for BLOB streaming to existing MySQL clients

• referential integrity (no invalid references), can take a lot of

…

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• Jay Pipes, Tobias Asplund
• Finding out the number of rows that would have been returned (MyISAM and InnoDB)

• SQL_CALC_FOUND_ROWS and FOUND_ROWS()
• COUNT(*)
• MEMORY table
• if query cache is on, then it makes no difference
• if it's off

• Memory MyISAM is fastest
• FOUND_ROWS() is slightly slower than count(*)

• SELECT … WHERE a UNION SELECT … WHERE b
  vs
  SELECT … WHERE a AND b
• index_merge wins

• composite index is faster
• of course, multiple indexes are more flexible than composite index

• …

• query cache

…

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• Phil Hilderbrand of thePlatform for Media, Inc presents
• classic partitioning

• old school – union in the archive tables
• auto partitioning and partition pruning
• great for data warehousing
• query performance improved
• maintenance is clearly improved

• often id driven access vs date driven access
• 1 big clients could be 80% of the whole database, so there's a difficulty selecting partitioning schemes

• reducing seek and scan set sizes
• improving inserts/updates durations
• making maintenance easier

• Robert Hodges from Continuent presents
• About Continuent

• leading provider of open source database availability and scaling solutions

• uni/cluster – multi-master database clustering that replicates data across multiple databases and load balances reads
• uses "database virtualization"

• protection from db and site failures
• continuous operation during upgrades

• Brewer's conjecture

• DDL support
• inconsistent reads between replicas
• deadlocks
• sequences
• non-deterministic SQL

• data replication

• where are updates processed? master/master vs master/slave
• when are updates replicated? sync vs async

• views – who is active, who is crashed, do

…

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• Suicide

• having no backups
• depending on slaves for backup
• keeping backups on same SAN
• having a single DBA – Frank didn't like this one at all
• not keeping binlogs

• how much time?
• uncompressed backup ready to mount?
• separate network for recovery?

• first problem: backup was highly compressed (tar.gz)
• uncompressing took hours
• so keep uncompressed backups (at least last N days)
• it should be mountable, rather than transferable

• row by row recovery (get the range of ids)
• custom scripts
• may not be able to use primary key
• foreign key based retrieval faster
• lose 4 seconds for each crashed record

…

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Updated: April 17th, 2008

I had a chance to visit the Kickfire booth after the keynotes and before the first presentation. They gave me a kicking t-shirt, followed by a presentation on the newly announced Kickfire appliance (now in beta, shipping in Fall 2008). Here are some notes I jotted down:

• von Neumann bottleneck
• SQL chip (SQC), packs the power of 10s of conventional CPUs
• Query parallelization on the chip
• On-chip memory – 64GB. No registers – no von Neumann bottleneck
• Beats the performance of a given 3 server, 32 CPU, 130TB box (1TB of actual data – space is used for distributing IO)
• SQC uses column-store, compression, intelligent indexing
• SQL Chip, PCI connection, plugs into a Linux server
  • SQL execution
  • Memory management
  • Loader

…

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• Baron Schwartz presents
• only works for SELECTs
• nobody dares admit if they've never seen EXPLAIN
• MySQL actually executes the query
• at each JOIN, instead of executing the query, it fills the EXPLAIN result set
• everything is a JOIN (even SELECT 1)
• Columns in EXPLAIN

• id: which SELECT the row belongs to
• select_type

• simple
• subquery
• derived
• union
• union result

• join
• range
• …

• Robin Schumacher
• gives overview of MySQL products
• MySQL Enterprise
• MySQL 5.1 announced
  • table/index partitioning -> great for data warehouses, range, cache, key, list, composite, subpartitioning. Partition pruning. Response time greatly improved with proper partitioning.
  • row-based/hybrid replication -> safer and smarter
  • disk-based cluster -> supports bigger DBs
  • built-in job scheduler -> simplified task management
  • problem SQL identification -> easier troubleshooting. Dynamic query tracing is now available, no need to trace things in slow query logs.
  • faster full-text search -> 500% increase in some cases
  • 5.1.24RC available for the conference
• MySQL 6.0
  • Falcon engine – transactional engine
  • new backup (version 1.0) -> cross engine, non-blocking, to replace mysqldump
• Falcon
  • planned default transactional storage engine. Q4 GA (general availability).
  • not InnoDB replacement
  • most

…

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• Speaker: Mikael Ronstrom, PhD, the creator of the Cluster engine
• Explains the cluster structure
• Aspects of performance
  • Response times
  • Throughput
  • Low variation of response times
• Improving performance
  • use low level API (NDB API), expensive, hard
  • use new features in MySQL Cluster Carrier Grade Edition 6.3 (currently 6.3.13), more on this later
  • proper partitioning of tables, minimize communication
  • use of hardware
• NDB API is a C++ record access API
  • supports sending parallel record operations within the same transaction or in different transactions
  • asynchronous and synchronous
  • NDB kernel is programmed entirely asynchronously
• Looking at performance
  • Fire synchronous insert transactions – 10x TCP/IP time cost
  • Five inserts in one synchronous transaction – 2x TCP/IP time cost
  • Five asynchronous insert transactions – 2x TCP/IP

…

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Were there too many "my"'s in that title? Anyway… this week's MySQL conference is promising to be really busy and exciting. I can't wait to finally be there and experience it in all its glory. Thanks to the O'Reilly personal conference planner and scheduler and the advice of my fellow conference goers, I was able to easily (not really) pick out the speeches I am most interested in attending.

Here goes (my pass doesn't include Monday 🙁 ):

Tuesday

8:30am Tuesday, 04/15/2008

State of MySQL

Keynote Ballroom E

Mårten Mickos (MySQL)

In his annual State of MySQL keynote, Marten discusses the current and future role of MySQL in the modern online world. The presentation also covers the …

Updated: July 8th, 2009

Today I was asked a question about defining custom extensions for vim syntax highlighting such that, for example, vim would know that example.lmx is actually of type xml and apply xml syntax highlighting to it. I know vim already automatically does it not just based on extension but by looking for certain strings inside the text, like <?xml but what if my file doesn't have such strings?

After digging around I found the solution. Add the following to ~/.vimrc (the vim configuration file):

1
2
3

syntax on
filetype on
au BufNewFile,BufRead *.lmx set filetype=xml

After applying it, my .lmx file is highlighted:

Same principle works, for instance, for mysql dumps …

As half of the world population already knows, the MySQL conference is coming in less than 3 weeks. Since this event only happens once a year, lasts only 4 days, and costs more than a Russian mail-order bride, I'd really like to get the most out of it. Considering that the schedule is completely packed, with 8 (!!) events going on in parallel, I imagine things can get a little frantic. Additionally, I've never been to a conference of such size before and I'm not sure what to expect.

So… I'm contemplating:

• printing out the event schedule and drawing a zig-zagging "map" of exactly where I'll be jumping to next, once the previous presentation ends. I'm actually wondering

…

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Updated: January 4th, 2009

Here are some quick links for now: http://blogs.mysql.com/kaj/2008/05/23/mysql-clusters-improved-release-model/, http://johanandersson.blogspot.com/2008/05/mysql-cluster-62-officially-released.html, http://blogs.sun.com/theaquarium/entry/improved_release_model_for_mysql.

This article contains my notes and detailed instructions on setting up a MySQL cluster. After reading it, you should have a good understanding of what a MySQL cluster is capable of, how and why it works, and how to set one of these bad boys up. Note that I'm primarily a developer, with an interest in systems administration but I think that every developer should be able to understand and set up a MySQL cluster, at least to …