Hi,

If a MyISAM table is not in the table_open_cache, it will be opened by the query that needs the table.  To increase the chances of the table being in the table_open_cache, increase the size to 4000 for a start (1/10 of your current open files). 

Be careful though.  Increasing the table_open_cache increases the amount of time it takes to search the table cache, as the search is linear through the structure that holds the table_cache.  It also increases the time for a flush tables operation.

Also increase table_definition_cache.  This value is hash backed, so the performance impact of increasing it is minimal.  I would increase it to 40000 since you have 40000 open files.

These value changes can be made online.  

On Tue, Apr 21, 2015 at 9:14 AM, Honza Horak <hhorak@redhat.com> wrote:
On 04/21/2015 05:07 PM, Justin Swanhart wrote:
Hi,

Are you using MyISAM or InnoDB?  What are the values of
table_open_cache, table_definition_cache and innodb_open_files?

 It is a mixture of MyISAM and InnoDB, but we got complaints especially about the MyISAM tables.

Options table_open_cache, table_definition_cache have default values, so 400, innodb_open_files is changed to 128.

Honza

--justin

On Tue, Apr 21, 2015 at 6:26 AM, Honza Horak <hhorak@redhat.com
 <mailto:hhorak@redhat.com>> wrote:

    Hey, with limited experiences with mariadb deployments, I'm
    wondering how many open files by the mysqld daemon is still sane
    (expected).

    We have a customer that reports hundreds of thousands of open files
    with 600 connections (thread_pool_max_threads is used). Those
    processes seem rather stalled, but files in the datadir are often
    opened 40.000 times.

    Is it even possible that one file is opened several times during
    processing one query? Or does it mean there are ~40.000 queries running?

    Version of MariaDB: 5.5.40

    Honza

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