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Displaying posts with tag: bugs (reset)
"I'm Winston Wolf, I solve problems."

My (few) readers are probably somewhat tired of boring topics of metadata locks and gdb breakpoints that I discuss a lot this year, so for this weekend I decided to concentrate on something less technical but still important to me - the way I prefer to follow while providing support for MySQL.

Before I continue, it's time to add the explicit disclaimer: the views on how support engineer should work expressed below are mine alone and not those of my current (or any previous) employer. Specific case I describe may be entirely fictional and has nothing to do with any real life customer. I love thy customers in reality... …

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New Year Wishes for Providers of MySQL Support Services

Three years ago I shared my wishes for customers of Oracle's MySQL Support Services. There I basically asked them to report any problem that they suspect to be caused by the bug in MySQL software at http://bugs.mysql.com.This year I want to share wishes mostly for myself (and other providers of MySQL Support services).

I have a job of MySQL Support Engineer for almost 10.5 years. I did it in MySQL AB, Sun, Oracle and Percona. I had enough opportunities to see all kinds of approaches, types, kinds and qualities of services. But I still have some dreams in this area that I'd like to see fulfilled for both myself as a provider of service and for customers of such a service:

  1. I wish to see MySQL Support mostly done in an asynchronous way, via …
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MySQL Bug #79497: Full text indexes and aggregate functions

Playing around with the Employees sample database and full text search on MySQL, I found a weird bug. After creating a full text targeting a column on a table, a "select distinct" query to retrieve the range of values returns an empty set. So if you initially perform the following query, the outcome comes with 7 rows: mysql> select distinct title from titles; +--------------------+ | title

Fun with Bugs #37 - Bugs fixed in MySQL 5.6.27

MySQL 5.6.27 was released on September 30 formally. Source code is also available on GitHub, and I have it compiled (some users are less lucky) and running for a couple of days already. In this post I'll comment on some bugs reported by MySQL Community that are fixed there.

I'd like to start with a couple of bugs where patches were also contributed. First of all, the fix suggested by Stewart Smith in Bug #72811, "Set NUMA mempolicy for optimum mysqld performance", helps to allocate memory in a more reasonable way on NUMA-enabled systems. Previously it was like all interleaved or nothing, now there is a way to apply this only …

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MySQL 5.7 : Playing with mysqlpump

MySQL 5.7 comes with a new backup tool, named mysqlpump, which is almost the same as mysqldump with the ability of extracting data in parallel threads.

I tried a little experiment. Using a server containing 11 databases, with a total of 300 tables and about 20 million rows (roughly ≈ 10GB,) I used both mysqldump and mysqlpump to get a backup.

mysqldump --all-databases  > dump.sql
mysqlpump --all-databases \
--add-drop-database --add-drop-table --skip-watch-progress \
--default-parallelism=10 \
--parallel-schemas=db,db1,db2 \
--parallel-schemas=db3,db4,db5 \
--parallel-schemas=db6,db7,db8 \
--parallel-schemas=db9,db10 > pump.sql

The backup with mysqldump took 3 minutes and 33 seconds. The one with mysqlpump took 2 minutes and …

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MySQL 5.7.8 : features, bugs and rumors


I’ve had a look at a preview release of MySQL 5.7.8, some time before it became available to the general public (perks and duties of an Oracle ACE) and I found a few interesting things among the release notes and the tarball itself:

  • There is a new tool named mysqlpump, which is intended as a replacement for mysqldump, with parallel processing, compression, progress watch, the long awaited ability of excluding databases or tables, and more.
  • The json functionality has been fished out from the labs and added to the main distribution.
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MYSQL Sandbox 3.0.55 and new Github replication scripts


Both MySQL and MariaDB have been busy, each introducing new features, sometimes creating the same feature, often with different syntax.

This is sometimes good for users, who have a wide choice. And sometimes it is bad, as once you are used to the deployment and syntax of one flavor, it is hard to switch to a different one. This problem is enhanced if you are dealing with an application, MySQL Sandbox, that needs to work well with all flavors.

The latest releases of MySQL Sandbox (3.0.51 to 3.0.55) have been necessary to solve minor and major troublesome points with MySQL 5.7.8 and MariaDB 10.1.

The current version (3.0.55) can install all the newest releases, including replication with MySQL 5.7.8 which suffers from a compatibility bug (better explored in a separate article). …

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Fun with Bugs #36 - Bugs fixed in MySQL 5.6.25

Two days ago Oracle had released MySQL 5.6.25, so it's time to check what bugs reported by MySQL Community are fixed there. As usual, I'll mention both a bug reporter and engineer who verified the bug. Please, pay attention to fixes in replication and partitioning - if you use these features (or queries to INFORMATION_SCHEMA with a lot of complex tables in your database), please, consider upgrading ASAP.

The following InnoDB related bugs were fixed:

  • Bug #69990 - CREATE_TIME and UPDATE_TIME are wrong for partitioned tables. Finally this bug reported by my colleague Justin Swanhart and verified by Umesh (almost …
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Beware of MySQL BLOB Corruption in Older Versions

Does your dataset consist of InnoDB tables with large BLOB data such that the data is stored in external BLOB pages? Was the dataset created in MySQL version 5.1 and below and without using the InnoDB plugin, or with InnoDB plugin but with MySQL version earlier than 5.1.55? If the answer to both the questions are "YES" then it could very well be that you have a hidden corruption lying around in your dataset.

The post Beware of MySQL BLOB Corruption in Older Versions appeared first on ovais.tariq.

Nasty MySQL Replication Bugs that Affect Upgrade to 5.6

There were two nasty MySQL replication bugs in two different 5.6 releases that would make it difficult to upgrade slaves to MySQL 5.6 while still connected to MySQL 5.5 master. The first of those bugs is MySQL bug 72610 which affects 5.6.19. Essentially this bug is triggered when the table structure on the slave is different from the table structure on the master which leads to unnecessarily large amount of RAM usage while replicating events that affect that table. The amount of RAM used would generally be more noticeable when the replicated transaction consists of thousands of RBR events. The...

The post Nasty MySQL Replication Bugs that Affect Upgrade to 5.6 appeared first on ovais.tariq.

Showing entries 31 to 40 of 150
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