Recently, I was working on a MySQL support ticket where a customer was facing an issue while transporting tablespace from MySQL 5.6 to MySQL 5.7.
After closely reviewing the situation, I saw that while importing tablespace they were getting errors such as:
Shell
ERROR 1808 (HY000): Schema mismatch (Table flags don’t match, server table has 0x10 and the meta-data file has 0x1)
1
ERROR […]
Read moreRecently, I was working on one of the issue related to locks and deadlocks with InnoDB tables and I found very interesting details about how InnoDB locks and deadlocks works with or without index for different Isolation levels.
Here, I would like to describe a small test case about how SELECT ..FOR UPDATE (with and without limit) behave […]
Working as a Percona Support Engineer, every day we are seeing lots of issues related to MySQL replication. One very common issue is slave lagging. There are many reasons for slave lag but one common reason is that queries are taking more time on slave then master. How to check and log those long-running queries? […]
Read more
While working on a recent support issue as a Percona Support Engineer, I got one question from a customer asking how to monitor ALTER TABLE progress. Actually, for MySQL 5.5 and prior versions, it’s quite difficult to ALTER the table in a running production environment especially for large tables (with millions of records). Because it will […]
Read more
There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory usage for MySQL. As a Percona support engineer, I’m seeing many issues regularly related to heavy server loads – OR OOM killer got invoked […]
Read more
Editor’s Note: This post was written for MySQL 5.1/5.5 and that the default for innodb_file_per_table was turned ON in 5.6 and the behaviors/process noted below may not be necessary for someone running 5.6/5.7.
When innodb_file_per_table is OFF and all data is going to be stored in ibdata files. If you drop some tables and delete […]
Percona Toolkit’s pt-archiver is one of the best utilities to archive the records from large tables to another tables or files. One interesting thing is that pt-archiver is a read-write tool. It deletes data from the source by default, so after archiving you don’t need to delete it separately.
As it is done by default, you […]
