Search Results for: mysql get error message

SELinux and the MySQL init script

I recently worked with a customer who had a weird issue: when their MySQL server was started (Percona Server 5.5), if they try to run service mysql start a second time, the init script was not able to detect that an instance was already running. As a result, it tried to start a second instance […]

New PERFORMANCE_SCHEMA defaults in MySQL 5.7.7

I thought it was worth a moment to reiterate on the new Performance Schema related defaults that MySQL 5.7.7 brings to the table, for various reasons. For one, most of you might have noticed that profiling was marked as deprecated in MySQL 5.6.7. So it is expected that you invest into learning more about Performance […]

Worrying about the ‘InnoDB: detected cycle in LRU for buffer pool (…)’ message?

If you use Percona Server 5.5 and you have configured it to use multiple buffer pool instances than sooner or later you’ll see the following lines on the server’s error log and chances are you’ll be worried about them:

Worry not as this is mostly harmless. It’s becoming a February tradition for me (Fernando) […]

Diagnosing SST errors with Percona XtraDB Cluster for MySQL

State Snapshot Transfer (SST) is used in Percona XtraDB Cluster (PXC) when a new node joins the cluster or to resync a failed node if Incremental State Transfer (IST) is no longer available. SST is triggered automatically but there is no magic: If it is not configured properly, it will not work and new nodes […]

Recover orphaned InnoDB partition tablespaces in MySQL

A few months back, Michael wrote about reconnecting orphaned *.ibd files using MySQL 5.6. I will show you the same procedure, this time for partitioned tables. An InnoDB partition is also a self-contained tablespace in itself so you can use the same method described in the previous post. To begin with, I have an example […]

How to avoid hash collisions when using MySQL’s CRC32 function

Percona Toolkit’s  pt-table-checksum performs an online replication consistency check by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master – and the tool pt-table-sync synchronizes data efficiently between MySQL tables. The tools by default use the CRC32. Other good choices include MD5 and SHA1. If you have installed the FNV_64 user-defined function, pt-table-sync will […]

Percona XtraBackup 2.2.5 now available (free MySQL hot backup software)

Percona is glad to announce the release of Percona XtraBackup 2.2.5 on October 2, 2014. Downloads are available from our download site here and Percona Software Repositories. Percona XtraBackup enables MySQL backups without blocking user queries, making it ideal for companies with large data sets and mission-critical applications that cannot tolerate long periods of downtime. […]

Reducer.sh – A powerful MySQL test-case simplification/reducer tool

Let me start by saying a big “thank you” to the staff at Oracle for deciding to open source reducer.sh. It’s a tool I developed whilst I was working for them several years ago. Its sole purpose is to do one thing – but do it good: test-case simplification. So, let’s say some customer just […]

A schema change inconsistency with Galera Cluster for MySQL

I recently worked on a case where one node of a Galera cluster had its schema desynchronized with the other nodes. And that was although Total Order Isolation method was in effect to perform the schema changes. Let’s see what happened. Background For those of you who are not familiar with how Galera can perform […]