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Displaying posts with tag: speculations (reset)
Fun with Bugs #57 - On MySQL Bug Reports I am Subscribed to, Part I

I've decided to stop reviewing MySQL Release Notes in this series, but it does not mean that I am not interested in MySQL bugs any more. At the moment I am subscribed to 91 active MySQL bugs reported by other MySQL users, and in this blog post I am going to present 15 of them, the most recently reported ones. I'd really want to see them fixed or at least properly processed as soon as possible.

In some cases I am going to add my speculations on how the bug had better be handled, or maybe highlight some important details about it. It is not my job any more to process/"verify" any community bug reports for any kind of MySQL, but I did that for many years and I've spent more than 5 years "on the other side", being a member of Community, so in some cases I let myself to share some strong opinion on what may be done …

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Fun with Bugs #56 - On Some Public Bugs Fixed in MySQL 5.7.20

While MySQL 8.0.x hardly has much impact on my regular work, recent MySQL 5.7.20 release is something to check carefully. MySQL 5.7 is widely used in production, as a base for Percona Server 5.7, some features may be merged into MariaDB 10.x etc. So, here is my review of some community reported bugs that were fixed in recently released MySQL 5.7.20, based on the release notes.

Usually I start with InnoDB bug fixes, but in 5.7.20 several related fixes were made only to bugs reported internally. So, this time I have to start with partitioning:

  • Bug #86255 - First one to write about, and the bug report is …
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MySQL Support Engineer's Chronicles, Issue #8

This week is special and full of anniversaries for me. This week 5 years ago I left Oracle behind and joined Percona... Same week 5 years ago I had written something about MySQL in this blog for the first time in my life. 5 years ago I've created my Facebook account that I actively (ab)use for discussing work-related issues. So, to summarize, it's a five years anniversary of my coming out as a MySQL Entomologist, somebody who writes and speaks about MySQL and bugs in MySQL in public! These 5 years were mostly awesome.

I decided to celebrate with yet another post in this relatively new series and summarize in short what interesting things I studied, …

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Fun with Bugs #55 - On Some Public Bugs Fixed in MySQL 8.0.2

I do not care much about MySQL 8.0.x at the moment, as it's far from being GA and is work in progress. It is not yet used by customers whom I have to support. But I know about many interesting changes and improvements there that, eventually, are going to influence all main forks and kinds of MySQL. So, it would not be wise to ignore MySQL 8.0.c entirely even for me.

For this post I decided to briefly check what community reported bugs were fixed in the recent release, 8.0.2, based on release notes. For me it's a measure of community interest in MySQL 8.0.x and Oracle's interest in further working with MySQL Community. I ended up with the following, short enough list of bug fixes in the categories I usually care about (InnoDB, partitioning, replication and optimizer):

  • The very first InnoDB bug mentioned in …
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More on Studying MySQL Hashes in gdb, and How P_S Code May Help

I have to get back to the topic of checking user variables in gdb to clarify few more details. In his comment Shane Bester kindly noted that calling functions defined in MySQL code is not going to work when core dump is studied. So, I ended up with a need to check what does the my_hash_element() function I've used really do, to be ready to repeat that step by step manually. Surely I could skip that and use Python and Shane himself did, but structures of HASH type are widely used in MySQL, so I'd better know how to investigate them manually than blindly use existing code.

Quick search with grep for …

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Fun with Bugs #54 - On Some Bugs Fixed in MySQL 5.7.19

More than 3 months after 5.7.18 we' ve got MySQL 5.7.19 released recently. This is my quick review of the release notes with interesting fixed bug (reported in public) highlighted in the areas I am usually interested in.

Let's start with InnoDB. The following bug fixes attracted my attention:

  • Bug #85043 is still private. You know how much I hate those. At least we can see it was about the fact that "The server allocated memory unnecessarily for an operation that rebuilt the table." Let's hope this is no longer the case.
  • Bug …
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Fun with Bugs #53 - On Some Percona Software Bugs I've Reported

So far in this series I had written only/mostly about MySQL server bugs. Does it mean that there are no unique or interesting bugs in other MySQL-related software or MySQL forks and projects that use MySQL code?

Surely no, it doesn't. So, today I'd like to present a short list of currently active (that is, new or probably not yet resolved) bugs that I had reported for Percona's software at Launchpad over the years I use it. The list is based on this link, but I excluded minor reports and those that probably are just forgotten, while the problem is fixed long time ago.

Let me start with bugs in XtraBackup, the tool that plays a key role in most MySQL environments that are not using Oracle's Enterprise …

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MySQL Support Engineer's Chronicles, Issue #7

This week in Support was busy enough for me. Among other things I had to study all possible reasons (other than obvious query cache impact) for queries hanging in "query end" status and noted Bug #80652 related to binlog group commit and fixed in MySQL 5.7.17+ and 8.0.1+ only. The case I had to review was related to Galera though, and I suggest you to note that "query end" may be related to Galera replication stall. Studying this path further soon brought lp:1197771 - "Cluster stalls while distributing transaction" to my attention again, so I asked about proper status for it on Facebook. As it happens way too often recently, I've got few 'Likes" but no further comments, neither …

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My First Steps with MariaDB ColumnStore

This is a "Howto" kind of post, and some speculations and historical references aside, it will show you how to build MariaDB ColumnStore (current version 1.0.9) from GitHub source, how to install and configure it for basic usage, as well as how to resolve some minor problems you may get in the process. Keep reading and eventually you'll get the real Howto below :)

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I try not to care about any software issues besides good old MySQL, InnoDB storage engine internals, query optimization and some MyRocks or a little bit of …

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Fun with Bugs #52 - On Some Bugs Fixed in MySQL 5.7.18

I had not reviewed MySQL 5.7 release notes for quite a some time in this series. Last time I checked it was MySQL 5.7.15. So, as soon as I noted new release, 5.7.18, I decided to check the release notes for any interesting fixed bug (reported by Community users in public) in the areas I am interested in: InnoDB, replication, optimizer and few others.

Note that recently most of the bugs fixed are internal only, found by Oracle engineers that never cared (or are not allowed, who knows) to report them in public, so this blog post is not even remotely a full review of what's fixed in MySQL 5.7.18 and is not a replacement for reading the detailed …

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