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Displaying posts with tag: bugs (reset)
Fun with Bugs #10 - recently reported bugs affecting MySQL 5.6.12

MySQL 5.6.12 is available to community for more than a week already, so people started to test and use it. And, no wonder, new bug reports started to appear. Let's concentrate on them in this issue.

I'd like to start with a funny one.  Bug #69413 had scared some of my Facebook readers to death, as we see kernel mutex mentioned clearly in the release notes for 5.6.12. What, kernel mutex comes back again? No, it's just a result of null merge and, probably, copy/paste from the release notes for 5.5.32.

It seems recent bug reports for 5.6.12 are mostly related to small details that may not be of any importance to a typical user. For example, …

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Fun with Bugs #9 - MySQL 5.6.12, quick review

So, it seems we have MySQL 5.6.12 released officially. We have great Changes in MySQL 5.6.12 page already widely shared and people already blogging about a feature implemented by my dear friend Sinisa.

Quick scroll over changes shows 130+ bugs fixed and it will surely take time to understand the impact of all these fixes. We have 2 months for this till next release, so eventually we'll find out what's good in MySQL 5.6.12 and should we immediately switch to it from all other older 5.x.y versions.

But we have to start with something, and I'd like to start with bugs that I've mentioned in …

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MySQL 5.6 Experiences - .mylogin.cnf and mysql_config_editor

Having  basic ideas of how I am going to describe new features explained, I can proceed with some real (and I hope useful) content. As I read this page about new features from top to bottom, let's start with security improvements...

.mylogin.cnf and mysql_config_editor  Details:

  • you can store authentication credentials encrypted in an option file named .mylogin.cnf (in user's home directory or in %APPDATA%\MySQL on Windows)
  • password is no longer stored in plain text (like in .my.cnf) and still is not exposed in the command lines...
  • you have to use mysql_config_editor utility to create the .mylogin.cnf file
  • but if …
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More details on "MySQL 5.6 Experiences" coming soon...

I've already shared my presentation few hours before I made it during PLMCE 2013, back on April 24. The idea behind the presentation was simple (and I think that any MySQL user who is planning to upgrade to MySQL 5.6.x in production should do something like this): let's read the "What Is New in MySQL 5.6" manual page and check new features one by one.

This is what I am going to do with the content of that manual page in the upcoming blog posts (and what was done as background work for the presentation):

  • Remove extra details and add references to each major feature
  • For every feature description add extra references (articles …
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Fun with Bugs #8 - what's wrong with Oracle's way of handling public MySQL bugs database

Many people seem unhappy with the way Oracle develops MySQL. I am not one of them. I think very few really important things are missing and in this post I'd like to concentrate on one of them: having internal and public bugs databases not in sync in too many cases.

Let me quote myself to explain where problem starts:

"Now the most important thing you should know about MySQL bugs processing the way it is done now in Oracle. When bug is "Verified" and(!) considered serious enough, it is copied to the Oracle internal bugs database and further processing, including status changes etc, is done there. All further comments to the public bug report are then copied to internal bug report automatically, but no comments or status changes in internal bug report are copied to public bug in any other way …

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MySQL bug 69179 – INFORMATION_SCHEMA.PARTITIONS causes query plan changes

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 …

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Fun with bugs #7, still mostly about 5.6.11

It looks like now Oracle will release new 5.6.x every 2 months, so while I'd happily write about bugs fixed in 5.6.12 we still have to wait for the official release to happen. I am too impatient to wait for 5.6.12, so let me write this post of a classical kind - just a summary of my MySQL bugs' related posts on Facebook since the previous one.

I have to start with replication-related bugs in 5.6.11 pointed out by Giuseppe Maxia:

  • Bug #69095 -  replication fails with GTID enabled and master changes from SBR to RBR. This bug is "Verified" since April 30, but got no public comments since that. …
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Fun with Bugs #6 - MySQL 5.6.11

Last time I had written about bugs here it was a beginning of February, and hardly somebody could imagine that we were going to have 2 more months of winter, 2 more months to wait for next MySQL 5.6 GA release or that in 2 months and two weeks I'll be speaking about MySQL in public for 50 minutes based on my own presentation, and speaking about bugs (surely)...

In any case, MySQL 5.6.11 looks promising and had got a lot of bugs fixes (check at least this nice post by Todd Farmer). Time for me to get back to bugs I've mentioned in the previous …

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MySQL: Every detail matters

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 …

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Granting privileges may break replication in MySQL 5.6.10

MySQL lets database administrators define access rights on many levels – from the ability to run global commands down to access to individual columns. Some rights can be applied to many different objects, such as for example SELECT or UPDATE, which can be granted globally or restricted only to certain databases or tables, while others are only meant for one specific purpose. An example of the latter could be FILE privilege, which permits user to interact with the file system from inside a database instance. It only makes sense as the global right and not anywhere else.

As any other activity that produces changes, GRANT statements are replicated to MySQL slaves. Regardless of the binary log format setting, such events are always logged in STATEMENT format. It is likely because the command needs to handle more than just updating the contents of a few system tables, so such design allows each slave to fully execute the changes within their …

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