Planet MySQL Planet MySQL: Meta Deutsch Español Français Italiano 日本語 Русский Português 中文
Showing entries 1 to 10 of 158 10 Older Entries

Displaying posts with tag: primary (reset)

MySQL 5.7 InnoDB Versus the Thread Sanitizer
+1 Vote Up -0Vote Down

InnoDB and the Thread Sanitizer do not work well together in MySQL 5.7.  There are hundreds of possible data races reported by the Thread Sanitizer in the InnoDB code for the simplest case of initializing the MySQL server and shutting it down.  Luckily, most of these data races are benign.  The problem of finding an interesting data race in the InnoDB software is similar to finding …

  [Read more...]
MySQL 5.7 Performance Schema Versus the Thread Sanitizer
+0 Vote Up -0Vote Down

This blog continues the investigation into possible data races in the MySQL server reported by the Thread Sanitizer.  The previous blog investigated several possible data races that were detected when the MySQL server is initialized.  This blog investigates three data races in the performance schema that are reported when the MySQL server is shut down.  The …

  [Read more...]
MySQL 5.7 Initialization Versus the Thread Sanitizer
+0 Vote Up -0Vote Down

The MySQL server is a large multi-threaded program primarily written in the C++ programming language.  Unfortunately,  data races and deadlocks in concurrent C++ programs are common.  Fortunately, the Thread Sanitizer can be used to find data races and deadlocks.  MySQL 5.7 does not support the Thread Sanitizer, but is is easy to …

  [Read more...]
Uninitialized data problem in the LZMA compressor used by TokuFT
+0 Vote Up -0Vote Down

The LZMA algorithm implemented by the xz compression software package is one of the compression algorithms used by TokuDB for MySQL and TokuMX for MongoDB. …

  [Read more...]
MySQL 5.7 Versus the Address Sanitizer
+1 Vote Up -0Vote Down

MySQL 5.7 supports the Address Sanitizer, which checks for several memory related software errors including memory leaks.  It is really nice to see support for the Address Sanitizer built into MySQL.  Unfortunately, when running the mysql tests included in MySQL 5.7.9, the Address Sanitizer reports several memory leaks, which causes some of  the tests to fail.  Here are some of the …

  [Read more...]
Advanced MySQL Server Auditing
+0 Vote Up -0Vote Down



We remember when we first started auditing MySQL servers, there were very few tools available.  In one of our early big gigs, we were battling serious performance issues for a client.  At the time, tuning-primer.sh was about the only tool available that could be used to diagnose performance bottlenecks.  Fortunately, with a lot of manual interpolation of the raw data it presented, we were able to find the issue with the server and suggest how to resolve them.  For that we are very thankful.  It was a first step in analyzing MySQL status variables, minimizing the number of formulas to learn and calculate by hand.  Obviously …

  [Read more...]
TokuBackup Versus the Sanitizers
+1 Vote Up -0Vote Down

Percona recently open sourced TokuBackup, a library that may be used to take a snapshot of a set of files while these files are being changed by a running application like MySQL or MongoDB.  Making TokuBackup open source allows a larger set of users to improve and extend the software.  This blog describes how the Address Sanitizer and Thread Sanitizer found bugs in the TokuBackup …

  [Read more...]
Remove a Galera (Percona Cluster) Node During Backup
+0 Vote Up -0Vote Down

With Galera (Percona Cluster or MariaDB Cluster), it is sometimes advisable to not route traffic to a node during a backup due to the node already being under a heavier load.  In these situations, it may be wise to not route traffic there until the backup is complete.

Since the default /usr/bin/clustercheck script did not have the option of doing this, we created a modified version.  The below script looks for the presence of the xtrabackup tool running in the process list.  If it is found, the clustercheck script returns the appropriate exit code (502) which signals the load balancer to not route traffic its way.  The …

  [Read more...]
Personal Summary of the Percona Live Amsterdam 2015 Conference
+2 Vote Up -0Vote Down

Last week, 21-23 September, it took place the European MySQL Conference, or “Data performance Conference” as this year’s subtitle was “MySQL. NoSQL. Data in the cloud.”. This year, it changed its location from London to Amsterdam and, as most people I talked to agreed, the change was for good. As every year, Percona was the company organizing …

  [Read more...]
MySQL Health Check Script
+0 Vote Up -0Vote Down

Ever get called out for a MySQL issue only to realize that there was no issue?  It was a false alarm from the monitor.  We sure have and it’s frustrating, especially at 3:00 or 4:00 in the morning!

Many DBAs work in an environment where there is some sort of first level support that gets assigned tickets first.  Unfortunately, many of the times these groups are, shall we say, less than skilled in MySQL.  As a result, they quickly escalate the ticket onto the primary on-call DBA, even when there is really nothing wrong.

Much of the time, there are multiple types of MySQL topology in these environments: standalone, galera cluster, …

  [Read more...]
Showing entries 1 to 10 of 158 10 Older Entries

Planet MySQL © 1995, 2016, Oracle Corporation and/or its affiliates   Legal Policies | Your Privacy Rights | Terms of Use

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.