[mythtv-commits] Ticket #9792: Deadlocked scheduler

[MythTV]

#9792: Deadlocked scheduler
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 Reporter:  warped <warpme@…>      |          Owner:
     Type:  Bug Report - General   |         Status:  new
 Priority:  minor                  |      Milestone:  unknown
Component:  MythTV - General       |        Version:  Trunk Head
 Severity:  medium                 |     Resolution:
 Keywords:                         |  Ticket locked:  0
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Comment (by warped <warpme@…>):

 Daniel,[[BR]]
 I'm running on ArchLinux (in fact I'm using Arch as base for my own
 distro). In context of fixes Arch is rolling release distro - so sys is
 usually more fresh than other distros. Average delay between upstream and
 arch packagers is week or two.[[BR]]
 Last pkg sync between my distro and arch pkg base was at 20110513 - so I
 would say OS is latest greatest.[[BR]]
 As I understand deadlock is in mysql libraries (so not in myth code). Is
 this mean issue is in OS ?. If so - shame on Arch (other than that - it is
 really great distro for appliances).[[BR]]
 I started to drill in DB optimization and currently I'm experimenting with
 query_caching strategies.[[BR]]
 Now I'm testing "Do not cache results in or retrieve results from the
 query cache". 24h so far OK[[BR]]
 "Cache all cacheable query results except for those that begin with SELECT
 SQL_NO_CACHE"[[BR]]
 and "Cache results only for cacheable queries that begin with SELECT
 SQL_CACHE" both gave deadlocks within hours.[[BR]]

 In past I wasn't use mysqltuner.pl - but I had tuned DB settings from some
 posts in users-mailing list. I just checked  - my tunings were touching
 caching strategy. It was set to "Cache all cacheable query results except
 for those that begin with SELECT SQL_NO_CACHE". If current tests with "Do
 not cache results in or retrieve results from the query cache" will
 finalize OK - it will probably mean that for some reason MySql 5.1.11,
 5.1.12 & 5.5.12 (only those I tested) can't use caching with MythTV  on
 Archlinux....[[BR]]
 Daniel - btw thx for Your time helping to deal with issue probably not
 related to myth !

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Ticket URL: <http://code.mythtv.org/trac/ticket/9792#comment:6>
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