How do you defrag a table?

How do you defrag a table?

How to Optimize MySQL Tables and Defragment to Recover Space

1. Identify Tables for Optimization. The first step is to identify whether you have fragmentation on your MySQL database.
2. Defrag using OPTIMIZE TABLE command.
3. Defrag using mysqlcheck command.
4. Defrag All Tables or All Databases.
5. After Optimization.

How do I defrag a table in SQL?

There are two main ways to defragment a Heap Table:

1. Create a Clustered Index and then drop it.
2. Use the ALTER TABLE command to rebuild the Heap. This REBUILD option is available in SQL Server 2008 onwards. It can be done with online option in enterprise edition. Alter table TableName rebuild.

What is table fragmentation in MySQL?

Fragmentation means that the physical ordering of the index pages on the disk is not close to the index ordering of the records on the pages, or that there are many unused pages in the 64-page blocks that were allocated to the index. One symptom of fragmentation is that a table takes more space than it “should” take.

How can I defrag a table in MySQL?

Another way to perform a defragmentation operation is to use mysqldump to dump the table to a text file, drop the table, and reload it from the dump file.

Which is the best way to defragment a table?

For more information, see Section 14.13, “InnoDB and Online DDL” . Another way to perform a defragmentation operation is to use mysqldump to dump the table to a text file, drop the table, and reload it from the dump file.

What does fragmentation mean in a table MySQL?

Fragmentation means that the physical ordering of the index pages on the disk is not close to the index ordering of the records on the pages, or that there are many unused pages in the 64-page blocks that were allocated to the index.

Which is a symptom of fragmentation in InnoDB?

One symptom of fragmentation is that a table takes more space than it “should” take. How much that is exactly, is difficult to determine. All InnoDB data and indexes are stored in B-trees , and their fill factor may vary from 50% to 100%.