Dec 01, 2015 |
MySQL
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:
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ERROR 1808 (HY000): Schema mismatch (Table flags don't match, server table has 0x10 and the meta-data file has 0x1) |
After some research, I found that there is a similar bug reported to MySQL for this issue (https://bugs.mysql.com/bug.php?id=76142), but […]
Apr 09, 2015 |
MySQL, Percona Live
Recently, 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 […]
Mar 20, 2014 |
Insight for DBAs, MySQL, Percona Software
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? From […]
Feb 26, 2014 |
MySQL, Percona Services, Percona Software
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 rebuild […]
Jan 24, 2014 |
Insight for DBAs, MySQL, Percona Services
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 and […]
Sep 25, 2013 |
Insight for DBAs, MySQL, Percona Software
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 […]
Aug 12, 2013 |
MySQL, Percona Software
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 […]
Jun 26, 2013 |
Insight for DBAs, MySQL, Percona Software
One very interesting feature, “Compact Backup,” is introduced in Percona XtraBackup 2.1. You can run “compact backups” with the –compact option, which is very useful for those who have limited disk space to keep the MySQL database backup. Now let’s first understand how it works. When we are using –compact option with Innobackupex, it will omit the […]
