Partition

Before I forget it and have to search again here a short note about how to rename a MySQL Partition:

My dream:

ALTER TABLE history RENAME PARTITION p2015_kw10 INTO p2015_kw09;

In reality:

ALTER TABLE history
REORGANIZE PARTITION p2015_kw10 INTO (
PARTITION p2015_kw09 VALUES LESS THAN (UNIX_TIMESTAMP('2015-03-02 00:00:00'))
);

Caution: REORGANIZE PARTITION causes a full copy of the whole partition!

Hint: I assume it would be very easy for MySQL or MariaDB to make this DDL command an in-place …

Introduction

Recently a customer claimed that his queries were slow some times and sometimes they were fast.

First idea: Flipping query execution plan caused by InnoDB could be skipped because it affected mainly MyISAM tables.

Second idea: Caching effects by either the file system cache caching MyISAM data or the MyISAM key buffer caching MyISAM indexes were examined: File system cache was huge and MyISAM key buffer was only used up to 25%.

I was a bit puzzled…

Then we checked the table_open_cache …

Table of Contents

• Reasons to Upgrade MariaDB or MySQL
• How to Upgrade to MariaDB or MySQL
• MariaDB and MySQL Reserved Keywords
• MariaDB and MySQL Problems we hit in real life
  • Upgrade MySQL 4.1 to MySQL 5.1
  • Upgrade MySQL 4.1 to MySQL 5.6
  • Upgrade MySQL 5.0 to MySQL 5.1
  • Upgrade MySQL 5.0 to MySQL 5.6
  • Upgrade MySQL 5.0 to MariaDB 10.3
  • Upgrade MySQL 5.1 to MySQL 5.5
  • Upgrade MySQL 5.5 to MySQL 5.6
  • Upgrade MySQL 5.6 to MySQL 5.7
  • Upgrade MySQL 5.7.12 to MySQL 5.7.21
  • Upgrade MySQL 5.7 to MySQL 8.0
  • Upgrade MariaDB 5.5 …

Following question came up recently: What happens if you drop or add a partition of an existing already partitioned table with ALTER TABLE? Will it be copied or will just the single partition be dropped and added? How are the index(es) rebuild after such a drop/add?

In the MySQL documentation were not to many details mentioned:

ALTER TABLE … ADD PARTITION creates no temporary table except for MySQL Cluster.
…
ADD or DROP operations for RANGE or LIST partitions are immediate operations or …