Tag - pt-table-checksum

Caveats With pt-table-checksum Using Row-Based Replication, and Replication Filters

pt-table-checksum row based replication caveat

As per the documentation, pt-table-checksum is a tool to perform online replication consistency checks by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master.
The master and each slave insert checksums into the percona.checksums table, and these are later compared for differences. It’s fairly obvious that […]

Read more

How to Handle pt-table-checksum Errors

pt-table-checksum Errors

In this blog post, we’ll look at how to approach pt-table-checksum errors.
pt-table-checksum is one of the most popular tools in Percona Toolkit, and it is widely used to identify data differences between masters and slaves. Therefore, as Percona Support Engineers we have customers often asking questions related to the pt-table-checksum errors and warnings produced. […]

Read more

MySQL replication primer with pt-table-checksum / pt-table-sync, part 2

pt-online-schema-change

This is the second and last tutorial blog post on how to use pt-table-checksum / pt-table-sync tools for MySQL replication.
In the first post, I showed you how to use the
pt-table-checksum  /
pt-table-sync  tools in a typical MySQL replication setup. In this post, we’ll discuss MySQL replication for more advanced topologies. I will show you how to […]

Read more

MySQL replication primer with pt-table-checksum and pt-table-sync

MySQL replication is a process that allows you to easily maintain multiple copies of MySQL data by having them copied automatically from a master to a slave database.
It’s essential to make sure the slave servers have the same set of data as the master to ensure data is consistent within the replication stream. MySQL […]

Read more

Keep your MySQL data in sync when using Tungsten Replicator

MySQL replication isn’t perfect and sometimes our data gets out of sync, either by a failure in replication or human intervention. We are all familiar with Percona Toolkit’s pt-table-checksum and pt-table-sync to help us check and fix data inconsistencies – but imagine the following scenario where we mix regular replication with the Tungsten Replicator:

We […]

Read more

Checking table definition consistency with mysqldiff

Data inconsistencies in replication environments are a pretty common. There are lots of posts that explain how to fix those using pt-table-checksum and pt-table-sync. Usually we only care about the data but from time to time we receive this question in support:
How can I check the table definition consistency between servers?
Replication also allow us […]

Read more

5 free handy tools for monitoring and managing MySQL replication

MySQL Replication is very simple to set up. In this post I’ll discuss its importance and five handy tools for monitoring and managing MySQL replication.
What is MySQL Replication? It’s the process of copying the (real-time events) data from one master instance to another slave instance and maintaining the redundant consistent data in a different […]

Read more

Percona Toolkit 2.2.13 is now available

Percona is pleased to announce the availability of Percona Toolkit 2.2.13.  Released January 26, 2015. Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or complex for DBAs to perform manually. Percona Toolkit, like all Percona software, is free and open source.
This release is […]

Read more

Data inconsistencies on MySQL replicas: Beyond pt-table-checksum

Percona Toolkit’s pt-table-checksum is a great tool to find data inconsistencies between a MySQL master and its replicas. However it is sometimes not enough to know that there are inconsistencies and let pt-table-sync fix the issue: you may want to know which exact rows are different to identify the statements that created the inconsistency. […]

Read more

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 […]

Read more