What is table definition cache?
This parameter shows the number of table definitions (SHOW CREATE TABLE \G) that can be stored. This is to speed up opening of tables and only one entry per table. You should consider increasing this parameter if you have large number of tables (>400) in your DB instance.
What is table open cache?
table_open_cache indicates the maximum number of tables the server can keep open in any one table cache instance. Ideally, you’d like this set so as to re-open a table as infrequently as possible.
How do I increase table definition cache in MySQL?
You can check whether you need to increase the table cache by checking the Opened_tables status variable. 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.
What is table cache in MySQL?
The table_cache variable controls the amount of memory available for the table cache, and thus the total number of tables MySQL can hold open at any given time. For busy servers with many databases and tables, this value should be increased so that MySQL can serve all requests reliably.
How do I cache a table in MySQL?
If you use InnoDB, MySQL will automatically cache the table for you, and create hash-indexes for often used parts of the index. I suggest you increase the amount of memory MySQL has at its disposal and it should take care of your problems all by itself. By default MySQL is setup to conserve space, not to run fast.
What is Performance_schema?
The MySQL Performance Schema is a feature for monitoring MySQL Server execution at a low level. The Performance Schema has these characteristics: The Performance Schema provides a way to inspect internal execution of the server at runtime. Performance Schema events are specific to a given instance of the MySQL Server.
What is query cache size in MySQL?
The query_cache_limit value determines the maximum size of individual query results that can be cached. The default value is 1,048,576 bytes and this is equivalent to 1MB. MySQL does not handle cached data in one big chunk; instead it is handled in blocks.
What is MySQL Opened_tables?
Opened_tables – number of tables that have been opened since startup. Let’s come to my questions: Question #1: Eventhough Mysql states Open_tables show number of “tables” that are open at the moment, I’ve read in the past that it’s not actually the number of tables opened, but the number of table file descriptors.
Does MySQL use cache?
The MySQL query cache is a global one shared among the sessions. It caches the select query along with the result set, which enables the identical selects to execute faster as the data fetches from the in memory.
What is Innodb_buffer_pool_instances?
The innodb_buffer_pool_instances divides the InnoDB buffer pool in a number of regions. For systems with buffer pools in the multi-gigabyte range, dividing the buffer pool into separate instances can improve concurrency, by reducing contention as different threads read and write to cached pages.
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