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  1. MariaDB Server
  2. MDEV-5541

every subsequent DROP TABLE is slower

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 10.0.7
    • Fix Version/s: 10.0.8
    • Component/s: None
    • Labels:
    • Environment:
      Debian GNU/Linux 7: 3.2.38-vs2.3.2.16-beng #1 SMP Tue Feb 12 10:48:52 GMT 2013 x86_64 GNU/Linux

      Default config with increased innodb buffer size to 20GB and file per table turned on.

      Description

      Each test CREATEs and DROPs 1024 tables. I've checked that CREATE time is constant, while DROP time increases every time it is invoked.

      while true; do time perl -e 'print "CREATE TABLE foo (id int) Engine=InnoDB; DROP TABLE foo;\n" for 1..1024' | mysql test; done
       
      real	0m2.351s
      user	0m0.020s
      sys	0m0.040s
       
      real	0m2.340s
      user	0m0.010s
      sys	0m0.060s
       
      real	0m2.458s
      user	0m0.030s
      sys	0m0.050s
       
      real	0m2.657s
      user	0m0.030s
      sys	0m0.040s
       
      real	0m2.914s
      user	0m0.020s
      sys	0m0.040s
       
      real	0m3.262s
      user	0m0.020s
      sys	0m0.050s
       
      real	0m3.702s
      user	0m0.020s
      sys	0m0.040s
       
      real	0m4.187s
      user	0m0.030s
      sys	0m0.040s
       
      real	0m4.552s
      user	0m0.040s
      sys	0m0.030s
       
      real	0m4.966s
      user	0m0.020s
      sys	0m0.050s
       
      real	0m5.327s
      user	0m0.050s
      sys	0m0.030s
       
      real	0m5.669s
      user	0m0.000s
      sys	0m0.080s
       
      real	0m6.017s
      user	0m0.010s
      sys	0m0.070s
       
      real	0m6.322s
      user	0m0.030s
      sys	0m0.050s
       
      real	0m6.659s
      user	0m0.020s
      sys	0m0.070s
       
      real	0m6.872s
      user	0m0.020s
      sys	0m0.050s

      DROP time becomes stable when database instance is using maximum allowed amount of RAM. In my case test time can raise from 2.3 second to over 1 minute.

      I've checked MariaDB 5.5.34 and PerconaDB 5.6 and they are not affected by this issue - DROP time is constant despite of amount of used RAM.

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            • Assignee:
              Unassigned
              Reporter:
              bbkr Pawel Pabian (Inactive)
            • Votes:
              1 Vote for this issue
              Watchers:
              4 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved: