MySQL/Galera release 0.6 shipped out today.

MySQL/Galera is synchronous multi-master clustering solution for innodb storage engine, offering un-compromised performance and thanks to certification based replication model, scalability even with write intensive work loads.

We have tested MySQL/Galera 0.6 with a number of benchmarks. Here is a summary of sysbench oltp benchmark run on clusters of 1-4 nodes of Amazon EC2 large instances: sysbench results Scalability is remarkable here and many other benchmarks show similar performance gain.

The 0.6 release adds following new features over the earlier Demo-2 release:

• Merged with MySQL 5.1.33
• Full DDL replication using "total order isolation" mode
• Workaround for drupal issue #282555. The fix is simply about retrying the …

For a bit more info, what about various storage engines over MySQL releases. Have they changed much? Here we’re looking at the storage/X/ directory for code, so for some engines this excludes the handler that interfaces with the MySQL Server.

You can view the data on the spreadsheet.

So Jonas pointed out that the NDB kernel hasn’t changed too much in size over releases. Let’s have a look:

In fact, the size went down slightly from 4.1 to 5.0. In this, 6.4 and 7.0 are the same thing but appear twice for completeness.

You can see the raw results in the spreadsheet here.

Giuseppe Maxia spoke at the May 2009 Boston MySQL User Group about MySQL 5.4 and what it can do, the new performance features, etc.

Sorry for the (relatively) short notice, but I will be talking at Sun’s CommunityOne conference in San Francisco on June 1st.

I’ll be talking about, and demonstrating, the DTrace probes we have put into MySQL in a joint presentation with Robert Lor who will be doing the same for Postgres.

CommunityOne West Badge

Our presentation is on the Monday afternoon.

Check out the CommunityOne West Conference Site for more details and registration.

One of the hot mutexes in InnoDB is the buffer pool mutex.
Among other things this mutex protects the page hash where
pages reside when they are in the cache.

There is already a number of variants of how to split out
this mutex. Here follows a short description of the various
approaches.

1) Google v3 approach
Ben Hardy at Google took the approach of using an array of
mutexes (64 mutexes) and this mutex only protects the
actual read, insert and delete from the page hash table.
This has the consequence of a very simple patch, it means
also that when the block has been locked one has to check
that the owner of the block hasn't changed since we didn't
protect the block between the read of the hash and the
locking of the block, thus someone is capable of coming in
between and grabbing the block for another page before we
get to lock the …

For whatever reason, let’s look at “Total Physical Source Lines of Code” from a recent mysql-6.0 tree (and PBXT from PBXT source repo):

See the spreadsheet here.

Raw data:

Blackhole        336
CSV             1143
Archive         2960
MyISAM         34019
PBXT           41732
Maria          69019
InnoDB         82557
…

The MySQL Query Analyzer ("Quan") is designed to save development time on query coding and tuning by expanding on all of the good things found in the Slow Query Log, SHOW PROCESSLIST; EXPLAIN plan, and 5.1 profiler all with no dependence of any of these atomic things. To this end, we integrated Quan into the Enterprise Monitor so developers can monitor security, performance, availability AND all of their queries across all their MySQL servers from a single, consolidated view.

The MySQL manual for str_to_date states:
If str contains an illegal date, time, or datetime value, STR_TO_DATE() returns NULL. An
illegal value also produces a warning.

Surely "I'm_not_a_valid_date" is not a valid date, time or datetime value.

mysql> select str_to_date("I'm_not_a_valid_date","I'm_not_a_valid_date");
+------------------------------------------------------------+
| str_to_date("I'm_not_a_valid_date","I'm_not_a_valid_date") |
+------------------------------------------------------------+
| 0000-00-00                                                 |
+------------------------------------------------------------+
1 row in set (0.00 sec)

The problem here is that values in the format string which are not preceded by the percent sign (%) are treated as constant characters which must match the input string exactly. Normally these characters are used as delimiters. For example, …

My colleague Lenz might have forgotten to post before he disappeared on a well-deserved vacation but we've enabled Russian as a choice in PlanetMySQL. Feel free to start submitting your Russian language blogs.

Russian Language PlanetMySQL: http://ru.planet.mysql.com
New feed submissions: http://ru.planet.mysql.com/new

We haven't completely translated all the strings yet (that's my fault, I need to stringify the vote stuff) but we're getting there!

(EDIT: LenZ is not on vacation... in fact he is at PHPDay2009 in Verona, Italy... sorry LenZ)