Search Results for: big or small table

When (and how) to move an InnoDB table outside the shared tablespace

In my last post, “A closer look at the MySQL ibdata1 disk space issue and big tables,” I looked at the growing ibdata1 problem under the perspective of having big tables residing inside the so-called shared tablespace. In the particular case that motivated that post, we had a customer running out of disk space in his […]

How to recover table structure from InnoDB dictionary

To recover a dropped or corrupt table with Percona Data Recovery Tool for InnoDB you need two things: media with records(ibdata1, *.ibd, disk image, etc.) and a table structure. Indeed, there is no information about the table structure in an InnoDB page. Normally we either recover the structure from .frm files or take it from […]

Understanding the maximum number of columns in a MySQL table

This post was initially going to be two sets of polls: “What is the maximum number of columns in MySQL?” and “What is the minimum maximum number of columns in MySQL?”. Before you read on, ponder those questions and come up with your own answers… and see if you’re right or can prove me wrong! […]

Drop table performance

There have been recent discussions about DROP TABLE performance in InnoDB. (You can refer to Peter’s post and these bug reports: and It may not sound that serious, but if your workload often uses DROP TABLE and you have a big buffer pool, it may be a significant issue. This can get […]

Lost innodb tables, xfs and binary grep

Before I start a story about the data recovery case I worked on yesterday, here’s a quick tip – having a database backup does not mean you can restore from it. Always verify your backup can be used to restore the database! If not automatically, do this manually, at least once a month. No, seriously […]

Using VIEW to reduce number of tables used

Many Open Source software solutions use database per user (or set of tables per user) which starts to cause problems if it is used on massive scale (blog hosting, forum hosting etc), resulting of hundreds of thousands if not millions of tables per server which can become really inefficient. It is especially inefficient with Innodb […]