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From:Reindl Harald Date:June 13 2013 11:19am
Subject:Re: open files in mysqld 5.1.53
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Am 13.06.2013 12:07, schrieb Hartmut Holzgraefe:
> this combined with file-per-table engines like MyISAM or ARCHIVE (maybe with InnoDB
> with innodb-file-per-table
> being active, too?) may well lead
> to a lot of file handles being used, and this again combined with the table_cache
> keeping opened tables (and the
> related files) open for later
> reuse can lead to a lot of file handles being used and kept in use ...
> FLUSH TABLES may help here by at least releasing those handles that are
> just kept open by the table cache ...

it is a simple calculation but the handling is wrong

4861x32 = 155552
471206 / 155552 = 3
each table has 3 files on disk (frm, myd, myi)

however - i do not buy the logic that every of the
32 cached threads had accessed ANY of the 4861
tables - impossible, there are databases from
websites which have very low traffic and so
it is unlikely that in 3 days avery thread has
accessed every table on the machine
______________________________

[root@localhost:~]$ lsof | grep mysqld | wc -l
471206

nobody but oracle knows why there are so much file handles
and this is MySQL 5.5.32

[--] Data in MyISAM tables: 481M (Tables: 4861)
[OK] Highest usage of available connections: 6% (32/500)
[OK] Thread cache hit rate: 99% (32 created / 425K connections)


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Thread
open files in mysqld 5.1.53walter harms12 Jun
  • Re: open files in mysqld 5.1.53Reindl Harald12 Jun
  • Re: open files in mysqld 5.1.53Manuel Arostegui12 Jun
    • Re: open files in mysqld 5.1.53walter harms13 Jun
      • Re: open files in mysqld 5.1.53Hartmut Holzgraefe13 Jun
        • Re: open files in mysqld 5.1.53walter harms13 Jun
        • Re: open files in mysqld 5.1.53Reindl Harald13 Jun