[mythtv-users] [mythtv-commits] Ticket #7604: Very slow query when delete recording (was Re: Very slow mythfrontend, mysql at 100%)

[GXL.nl]

Michael T. Dean said the following on 19/11/09 20:33:
> On 11/19/2009 02:09 PM, GXL.nl wrote:
>> I have the same thing, also made a bug report (#7604) for it since it 
>> only happens since I upgraded to 0.22 (and from Ubuntu 8.04 to 9.1).
>>
>> I have enabled the slow-query-log from MySQL and it shows the 
>> following query as being slow (13 secs):
>>
>>
> <scheduler query>
>> I dug in a little deeper and when I run this query direclt from mysql 
>> (phpmyadmin) it takes 13 secs but if I remove the two fields from 
>> oldrecstatus it only takes 3 secs. For this test I have disabled the 
>> cache with SQL_NO_CACHE and I have only removed the two fields 
>> (oldrecstatus.recstatus, oldrecstatus.reactivate) but have kept the 
>> JOIN on that table.
>>
>> Anyone have an idea? 
> 
> GXL, I'm assuming you're the person who submitted ticket #7604, right?  
> Are you seeing any issues or negative effects or UI slowness or anything?
> 
> That query does take time.  13s could be normal or may indicate a 
> problem on your system--depending on a lot of different factors.  But, 
> the UI should be completely disconnected from the scheduler query's 
> execution, so it shouldn't affect anything even if it is running slow.
> 
> Also, can you please provide the (complete) output of:
> 
> mythbackend --version
> 
> Please describe symptions--what do you see besides just a query being 
> reported in the slow-query log?
> 
> Thanks,
> Mike
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> 
Hi Mike,

Yes it was me who entered that ticket and I was about to write a mail to the list as (you?) suggested in that ticket when I 
saw Ronald having the same issue.

The frontend hangs on the confirmation message. So when I select a recording to delete and I press `Yes Delete` that window 
will be shown for about 15-20 secs. It might not sound as a long time but 20 sec waiting is a long time :) That is the only 
thing noticable (but I havent really used this version yet).

Since I wanted to find out what was keeping the system busy I saw that mysql was at 100% at that time so I enabled the 
slow-query-log.

$ mythbackend --version
Please include all output in bug reports.
MythTV Version   : 22594
MythTV Branch    : branches/release-0-22-fixes
Network Protocol : 50
Library API      : 0.22.20091023-1
QT Version       : 4.5.2
Options compiled in:
  linux profile using_oss using_alsa using_pulse using_jack using_backend using_dvb using_firewire using_frontend 
using_glx_proc_addr_arb using_hdhomerun using_hdpvr using_iptv using_ivtv using_joystick_menu using_libfftw3 using_lirc 
using_mheg using_opengl_video using_opengl_vsync using_qtwebkit using_v4l using_x11 using_xrandr using_xv using_xvmc 
using_xvmc_vld using_xvmcw using_bindings_perl using_bindings_python using_opengl using_vdpau using_ffmpeg_threads 
using_libavc_5_3 using_live using_mheg

If you need more info, please let me know


Nijn