Using MySQL Sandbox I can install multiple instances of MySQL. It is not uncommon for me to run 5 or 6 instances at once, and in some occasions, I get to have even 10 of them. It is usually not a problem. But today I had an issue while testing MariaDB, for which I needed 5 instances, and I the installation failed after the 4th one. To make sure that the host could run that many servers, I tried installing 10 instances of MySQL 5.6 and 5.7. All at once, for a grand total of 20 instances:

$ make_multiple_sandbox --how_many_nodes=10 5.6.14
installing node 1
installing node 2
installing node 3
installing node 4
installing node 5
installing node 6
installing node 7
installing node 8
installing node 9
installing node 10
group directory installed in $HOME/sandboxes/multi_msb_5_6_14
$ make_multiple_sandbox --how_many_nodes=10 5.7.4 …

Oracle engineers suppose to open new bugs in its internal bug database until they think opening them in public one makes sense.

Example of such a case is Bug #68415 "resolveip and mysqlaccess still use gethostbyaddr"

Reason for making it public is that it describes behavior, which was introduced into the tools resolveip and mysqlaccess without intention and they now still can work with NetBIOS name, different or not existent in DNS while MySQL server cannot.

Interesting fact that such NetBIOS names were not ever officially supported, but they worked until deprecated function gethostbyaddr was replaced with recommended to use …

Over the past few years, we’ve seen MySQL technology advance in leaps and bounds, especially when it comes to scalability. But by focusing on the internals of the storage engine for so long, MySQL has fallen behind regarding support for advanced SQL features.

SQLite, another popular open-source SQL database, just released version 3.8.3, including support for recursive SQL queries using the WITH RECURSIVE syntax, in compliance with SQL:1999.

Why is this significant? It means that MySQL is now the only widely-used SQL implementation that does not support recursive queries. Fifteen years after it was defined in the SQL standard, almost every other SQL database of note has supported this feature:

• …

I was really pleased to see the announcement by Oracle MySQL yum repositories that they have now produced a yum repository from where the MySQL RPMs they provide can be downloaded. This makes keeping up to date much easier. Many companies setup internal yum repositories with the software they need as then updating servers is much easier and can be done with a simple command. For many people at home that means you set this up once and don’t need to check for updates and do manual downloads, but can do a quick yum update xxxx and you get the latest version. Great!  This new yum repository only covers RHEL6 did not include RHEL5 which is not yet end of life and still used by me and probably quite a lot of other people. I filed bug#70773 to ask for RHEL5 support to be …

In this post I wanted to highlight

percona.com/bugs/<tool>

 , for example: percona.com/bugs/pt-stalk.  This only works for Percona Toolkit.  We often advise people to check a tool’s current bugs, but we don’t always say how.

The official link for Percona Toolkit bugs on Launchpad is https://bugs.launchpad.net/percona-toolkit/+bugs, but then you still have search from there.  So this quick link is a lot easier if, for example, pt-stalk fails to parse df with NFS …

I checked some updates to Shard-Query into SVN. Partitioning support has been extended for MySQL 5.6+ to ALL partitioning types.

This includes all previously unsupported types including RANGE LIST/COLUMNS partitioned tables that are partitioned over more than one column, and HASH/KEY/LINEAR variants as well. Shard-Query now exclusively uses the PARTITION hint for partition elimination instead of WHERE clauses in MySQL 5.6. For 5.5 and previous versions, support remains limited to LIST,RANGE, and LIST/RANGE COLUMNS over a single column.

The old mysql interface DAL has been replaced completely by the PDO DAL.

There is no major difference for end users except that you have to check that the return of the query() method is an object with the is_object() function instead of checking that it is a resource with the is_resource() function. I updated bin/run_query, which is the example application.

I …

Matt Lord already announced this change, but I am so happy, so want to repeat. MySQL Community Bugs Database Team introduced new button "Affects Me". After you click this button, counter, assigned to each of bug reports, will increase by one. This means we: MySQL Support and Engineering, - will see how many users are affected by the bug.

Why is this important? We have always considered community input as we prioritize bug fixes, and this is one more point of reference for us. Before this change we only had a counter for support customers which increased when they opened a support request, complaining they are affected by a bug. But our customers are smart and not always open support request when hit a bug: sometimes they simply implement workaround. Or there could be other circumstances when they don't …

My MySQL bugs is a list I recently created and intend to keep up to date with issues I have seen.

Shard-Query examines INFORMATION_SCHEMA.PARTITIONS to determine if a table is partitioned.  When a table is partitioned, Shard-Query creates multiple background queries, each limited to a single partition.  Unfortunately, it seems that examining INFORMATION_SCHEMA.PARTITIONS causes query plans to change after the view is accessed.

I have reported bug 69179 to MySQL AB  Oracle Corporation(old habits die hard).

Be careful: If you have automated tools (like schema management GUI tools) then make sure they don’t examine INFORMATION_SCHEMA.PARTITIONS or you may get bad plans until you analyze your tables or restart the database, even if using persistent stats.

I can only get the bug to happen when a WHERE clause is issued that limits access to a single partition.  It may be that the per partition statistics …

Some bugs can have a high impact if it causes data corruption, security issues or simply causes MySQL to crash. But what about small bugs and small usability issues?

This entry from the MySQL 5.6.8 release notes is an interesting one:
InnoDB: On startup, MySQL would not start if there was a mismatch between the value of the innodb_log_file_size configuration option and the actual size of the ib_logfile* files that make up the redo log. This behavior required manually removing the redo log files after changing the value of innodb_log_file_size. The fix causes MySQL to write all …