Parameter on FromDual GmbH

InnoDB Buffer Pool Instances is too small

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 16 Jul 2015 20:09:36 +0000

If you are using MariaDB/MySQL 5.5 and newer you should use several InnoDB Buffer Pool Instances for performance reasons.
Some rules to size InnoDB Buffer Pool instances are:

Table definition cache too small

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 15 Jul 2015 06:08:36 +0000

The number of table definitions (SHOW CREATE TABLE<br>G) that can be stored in the table definition cache (table_definition_cache). If you have a large number of tables (
> 400) in your database instance, you should consider a larger table definition cache to increase your database throughput and decrease your query latency.
The command SELECT COUNT(*) FROM information_schema.tables; shows you how many tables and thus table definitions you have. The global status Open_table_definitions is the current amount of open table definitions.

Table open cache too small

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 15 Jul 2015 06:04:36 +0000

The Table Open Cache (table_open_cache or old name table_cache) is a cache to store file handles for all threads. The actual value of cache entries can be seen with the global status of open tables (Open_tables).
Increasing table_open_cache increases the number of file descriptors (open_files_limit) that MySQL requires.
You can check whether you need to increase the Table Open Cache by checking Open_tables and Opened_tables. If the value of Opened_tables is large and you do not use FLUSH TABLES often (which just forces all tables to be closed and reopened), then you should increase the value of the table_open_cache variable.

InnoDB Flush Method has changed

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 01 Jul 2015 10:34:36 +0000

The InnoDB Flush Method has changed. This can have an impact on InnoDB write Performance.

MySQL Cluster Local Checkpoint (LCP) and Global Checkpoint (GCP)

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 29 Jul 2010 16:29:48 +0000

MySQL Cluster is mainly an in-memory database. Nevertheless it requires a good I/O system for writing various different information to disk.

Some more details about DiskSyncSize

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 29 May 2008 14:43:00 +0000

The parameter DiskSyncSize is a MySQL Cluster parameter and was added in MySQL 5.1.23.