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Displaying posts with tag: bugs (reset)
Fun with Bugs #24 - PERFORMANCE_SCHEMA

It seems that one of my session proposals is accepted for Percona Live London 2013, so I have to prepare myself to speak about PERFORMANCE_SCHEMA new features and problems in MySQL 5.6. Bugs are going to be discussed, among other things. Let's check current active bugs (and some "Not a bug"s) related to PERFORMANCE_SCHEMA in this issue.

I'd like to start with Bug #68514 that got some attention this week again, in despite of its "Not a bug" formal status. Detailed instrumentation comes with a cost, and to reduce high CPU cost (reported as Bug #67736 by Domas at 5.6 RC stage) it was decided to allocate memory in bigger batches. It seems notable (I'd say unexpectedly high) amount …

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It's all about bugs fixed: MySQL 5.6.14

Most of MySQL gurus and famous users are probably in San Francisco now, getting ready for fun at MySQL Connect. Part of that fun should come from the announcement of great new MySQL 5.6.14 release (that somewhat silently happened yesterday).

I am sitting at home though and I've seen at best 3 sunny days in September. The rest of the time it rains, so hardly I can do anything more funny and useful than review of MySQL bug reports even during my weekend. Let me try to tell you what MySQL 5.6.14 is really about and what you should expect from it based on the list of bugs fixed. Please, do not blame me if my summary would be different from the upcoming keynotes at MySQL Connect. It rains here...


I'll use good old approach of checking my older posts about bugs in MySQL 5.6.13 and comparing it to the …

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New Shard-Query features checked into SVN

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 …

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MySQL Bugs Verification - Is It Really Simple?

While it was explained already by Sveta and others what does it really mean to "Verify" (or "Confirm", in Launchpad/Percona's terms) a bug in MySQL software, and why this step in a bug's life cycle is important, we still often read complains about too much time taken to verify the bug even with a clearly repeatable test case that can be just copy/pasted, like Bug #69985 or notably more serious Bug #69990. Moreover, I often make comments of this kind myself...

So, it seems there is still a need …

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Fun with Bugs #22 - Some Bug Reports You Should Not Miss

Yet another user installed MySQL 5.5.32 yesterday and got a system that can not start... It's really easy to help in this case - just downgrade back to 5.5.31 or upgrade to 5.5.33 if you can. Why problem happened during upgrade? Because of a regression bug #69623.

This case that was easily solved during a quick chat reminded me about the problem of bugs in production. Nobody expects any sane DBA to review every new bug report, but some of them should not be missed, at least when upgrading to any newer version. Regression bugs (I see 15 here reported for …

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Fun with Bugs #20 - welcome MySQL 5.6.13!

MySQL 5.6.13 is released today! Installation is in progress right now, so I had not checked anything yet personally in reality, but we have release notes to study.

I'll base my quick review on my older posts devoted to known bugs in MySQL 5.6.12 in three main areas: InnoDB, optimizer and replication. All quoted text below is taken from the release notes.

Let's start with InnoDB. From my "top 10" list I only see the following bug fixed in 5.6.13:

  • Bug #69316. "Performance; InnoDB: A code regression introduced in MySQL 5.6 negatively impacted …
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What is the problem with "To be fixed later" bug status?

Bug #69842 was actively discussed on Facebook recently. Mostly not it's technical content - people do agree that InnoDB probably needs separate doublewrite buffer(s) for every possible InnoDB page size. It's more about bugs processing approaches, so I have to say something about this.

The story was simple enough. I've mentioned this bug in my previous post and yesterday my dear friend Sinisa added some comments and set status to "To be fixed later". This had made bug reporter (who co-incidentally is a "small data engineer" at Facebook) unhappy, because (let me quote):
"...bugs can still …

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Fun with Bugs #17 - Oldies but Goldies

I've just noted the date... 8 years ago I had my first official working day as a support engineer in bugs verification team of MySQL Support at MySQL AB. Why not to celebrate this anniversary with a blog post about bugs?

So, here they are, 12 oldest bugs in MySQL software that are still just "Verified" (it should mean they are accepted, but not yet fixed):

  1. Bug #2 - MySQL Connector/J doesn't make toast. I knew that Connector/J must be the most broken MySQL software (as I hate Hibernate). Now you can see how much it is broken, and nobody cares to fix it since 2002! This is a real shame...
  2. Bug #199 - Innodb autoincrement counter is lost on restart. This great report from Peter Zaitsev is still "Verified", since 2003. It became a documented "feature" in …
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Fun with Bugs #15 - Recent News and Hawthorne Effect Studies

Let me present a quick review of new and recently verified MySQL bug reports (mostly in 5.6.12, but not only). Surely I have to start with this request that many my colleagues had already mentioned in their blogs:

Bug #69558 - Put *all* know bugs into the public bug tracking system at bugs.mysql.com. We may argue on how and when this should apply to "security" bugs, but automatic bi-directional replication (even if delayed) with Oracle internals bugs database is what I was also asking for since we were forced to use it. Click on "Affects Me" button there and let's hope that some day Oracle will publish list of bugs that affect most of community users and may even try to take this into account while making decisions.

I have good news for everybody who was following MySQL 5.6 Performance Schema overhead discussions. …

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Fun with Bugs #14 - InnoDB in MySQL 5.6

InnoDB improvements in MySQL 5.6 are well known. One of the key reasons to upgrade to MySQL 5.6 for most users is to get the benefits of improved performance, scalability, new monitoring features and fulltext indexes support in InnoDB.

Is there anything to double check before assuming that InnoDB in MySQL 5.6 is just better than any older version for any practical purposes? Let's review known public InnoDB-specific bug reports. Here is my "Top 10" list, as of MySQL 5.6.12, starting with most recent reports:

  1. Bug #69424  - maybe I miss something (I am not the only one though), but I see no way to continue using raw devices (on Linux at least) to store InnoDB data. You had working raw device in 5.5.32, then you upgrade to 5.6.12 and just can not start MySQL any more. Check this bug for the details and maybe you'll find …
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