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Uday VaraganiThis post was originally published in October 2018 and was updated in March 2023. pt-query-digest is one of the most commonly used tools for query auditing in MySQL. By default, pt-query-digest reports the top ten queries consuming the most amount of time inside MySQL. A query that takes more time than the set threshold for […]
A couple of weeks ago, one of our customers reached us asking about the WARNING messages in their MySQL error log. After a while, there were a few more requests from some other customers asking whether to worry about these messages or not. In this post, I am going to write about the condition at […]
Foreign key related issues are very common when dealing with DDL changes in MySQL using Percona toolkit. In this blog post, I will explain how the tool (pt-online-schema-change) handles foreign key constraints when executing a DDL change. First of all, I would like to explain why foreign keys have to be handled at all before […]
Recently, I received a support request where the customer wanted to convert an INTEGER column to BIGINT on two tables. These tables are related by a foreign key, and it is a 3 node PXC cluster. These tables are 20GB and 82 GB in size and DDL’s on such tables in a production environment is […]