[mythtv-commits] Ticket #13649: Excessive calls to SELECT sourceid FROM capturecard WHERE cardid = ?

[MythTV]

#13649: Excessive calls to SELECT sourceid FROM capturecard WHERE cardid = ?
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     Reporter:  bib1963               |      Owner:  (none)
         Type:  Bug Report - General  |     Status:  new
     Priority:  minor                 |  Milestone:  needs_triage
    Component:  MythTV - General      |    Version:  Unspecified
     Severity:  medium                |   Keywords:
Ticket locked:  0                     |
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 My system has 2 USB devices and set to grab the EIT data.

 If I run tcpdump on the DB port, I see around 80 calls per second to the
 above SQL. This is somewhat excessive.

 Given that few systems would have anything more than a small number of
 devices,and even /if/ a system had a huge number, my feeling that the
 result from a single call can be cached, either while the backend is
 always up, or even for a period of a few seconds, thus reducing the load.

 Perhaps not a true bug report, but could be improved.

 The following may not be true, I could have just been unlucky with my
 timing...
 This then leads onto a second problem with the EIT data. I see that as it
 is being read, it is always written to the DB. With SSDs, this put
 unnecessary wear and tear on the device. Should there not be a read first,
 and a write only if the data is different?

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Ticket URL: <https://code.mythtv.org/trac/ticket/13649>
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