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Showing entries 1 to 10 of 14 4 Older Entries

Displaying posts with tag: regression (reset)

Testing the Fastest Way to Import a Table into MySQL (and some interesting 5.7 performance results)
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As I mentioned on my last post, where I compared the default configurations options in 5.6 and 5.7, I have been doing some testing for a particular load in several versions of MySQL. What I have been checking is different ways to load a CSV file (the same file I used for testing the compression tools) into MySQL. For those seasoned MySQL DBAs and programmers, you …

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MySQL 5.5.40 Overview and Highlights
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MySQL 5.5.40 was recently released (it is the latest MySQL 5.5, is GA), and is available for download here:

http://dev.mysql.com/downloads/mysql/5.5.html

This release, similar to the last 5.5 release, is mostly uneventful.

There were 0 “Functionality Added or Changed” bugs this time, and 18 bugs overall fixed.

Out of the 18 bugs, most seemed rather minor or obscure, but there are 3 I think are worth noting (all 3 are InnoDB-related, regressions, and serious if you encounter them, so best to be aware of them):

  • InnoDB: An …
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Fun with Bugs #28 - regression bugs in MySQL 5.6
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2013 was a great year for MySQL Community. New MySQL 5.6 GA release with its increased throughput, scalability and new features as well as more interaction and cooperation with MySQL Community from Oracle side brought us a lot of new perspectives and good feelings over the year.

Unfortunately new MySQL 5.6 GA release also reminded about old and well known problem with new MySQL versions. They all introduce new regression bugs. MySQL 5.6 had not become an exception.

Note that according to good old tradition (that I hope will be …



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

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Fun with Bugs #19 - waiting for MySQL 5.6.13 and some real fun?
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I feel like MySQL 5.6.12 was released ages ago, while in reality it was on June 3, less than 2 months ago. No wonder I feel so, after writing several posts about bugs fixed and not fixed in it... Anyway, we still have to wait for MySQL 5.6.13 for a week or even two probably and in the meantime I decided to write new post for this series based on good old idea of making a digest of my recent bugs-related posts at Facebook. I know, it's boring and annoying (same as waiting for the release of 5.6.13).

Let's start with …

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Fun with Bugs #15 - Recent News and Hawthorne Effect Studies
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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 …

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Fun with Bugs #14 - InnoDB in MySQL 5.6
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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  - …




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Fun with Bugs #11 - Top 10 Optimizer Regression Bugs in MySQL 5.6
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I've got a question from colleague last night on what bugs should users take into account if they plan to upgrade to MySQL 5.6 now. Simple answer is: it depends. If one of the new features or scalability improvements are really important, then bugs in other features or clearly identified problematic use cases may be just ignored or avoided.

But to be on a safe side users should at least check if they are (or may be) affected by a known regression bugs, when new version is slower or produce wrong results or crashes in cases that worked without problems before.

List of bugs in MySQL 5.6 that can be formally …



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Serious XFS Performance Regression in Linux Kernel 2.6.32-279
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I'm not the only one to have noticed this, but I spent a sufficient amount of time banging my head against a wall finding this out that I thought it important to make more people aware of this.

While trying to validate new database hardware we were seeing some serious performance issues in production.  Most MySQL benchmarks using sysbench or pt-playback couldn't reproduce it, but a simple sysbench 16 threaded filio test on the mysql partition showed about 1/3 the throughput we would expect.   The fact that much of the hardware was new as well as the OS we were using made tracking down the cause difficult (changing …

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Nasty InnoDB regression in MySQL 5.5.25
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We just ran into a nasty InnoDB bug that only seems to exist in MySQL 5.5.25:

An InnoDB update that modifies a rows primary key can trigger some recursive behavior that creates new rows until all disk space is exceeded. This does not affect all primary key updates in general but only gets triggered when a few other conditions are also met, so you're not too likely to run into it, but if you do your mysqld server will waste a lot of IO bandwidth and storage space on this and will usually eventually run out of disk space.

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Showing entries 1 to 10 of 14 4 Older Entries

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