[Bug 819325] [NEW] update-apt-xapi starts to use 100% CPU

[Paul Sladen]

Public bug reported:

Approximately once per day, 'apt-xapian-index' starts to use 100% CPU
and disk for a minute or so.  This is noticeable because:

  (a)  fan spins up to maximum
  (b)  machine gets /very/ hot
  (c)  stops being responsive (even a caps-lock toggle check takes ~2 seconds to respond)
  (d) a window briefly flashes up and then disappears

This is sub-optimal because, a. hurts my ears for 5 minutes
during+afterwards, b. hurts my legs for 20 minutes afterwards, c. hurts
productivity for 2 minutes during and raises stress levels, d. steals
focus for a few hundred milliseconds.

The root cause of this appears a disk and CPU-intensive database batch
job.  I wonder if it would be possible to back-off slightly and not tie-
up the disk and CPU if the user is currently using the machine (a
scheduling issue admittedly, but is the database run being run as child
of a GUI process and so inheriting that priority?)

** Affects: apt-xapian-index (Ubuntu)
     Importance: Undecided
         Status: New

** Description changed:

- Approximately once per day, 'apt-xapian-index' starts to use 100% for a
- minute or so.  This is noticeable because:
+ Approximately once per day, 'apt-xapian-index' starts to use 100% CPU
+ and disk for a minute or so.  This is noticeable because:
  
-   (a)  fan spins up to maximum
-   (b)  machine gets /very/ hot
-   (c)  stops being responsive (even a caps-lock toggle check takes ~2 seconds to respond)
-   (d) a window briefly flashes up and then disappears
+   (a)  fan spins up to maximum
+   (b)  machine gets /very/ hot
+   (c)  stops being responsive (even a caps-lock toggle check takes ~2 seconds to respond)
+   (d) a window briefly flashes up and then disappears
  
  This is sub-optimal because, a. hurts my ears for 5 minutes
  during+afterwards, b. hurts my legs for 20 minutes afterwards, c. hurts
  productivity for 2 minutes during and raises stress levels, d. steals
  focus for a few hundred milliseconds.
  
  The root cause of this appears a disk and CPU-intensive database batch
  job.  I wonder if it would be possible to back-off slightly and not tie-
  up the disk and CPU if the user is currently using the machine (a
  scheduling issue admittedly, but is the database run being run as child
  of a GUI process and so inheriting that priority?)

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https://bugs.launchpad.net/bugs/819325

Title:
  update-apt-xapi starts to use 100% CPU

Status in “apt-xapian-index” package in Ubuntu:
  New

Bug description:
  Approximately once per day, 'apt-xapian-index' starts to use 100% CPU
  and disk for a minute or so.  This is noticeable because:

    (a)  fan spins up to maximum
    (b)  machine gets /very/ hot
    (c)  stops being responsive (even a caps-lock toggle check takes ~2 seconds to respond)
    (d) a window briefly flashes up and then disappears

  This is sub-optimal because, a. hurts my ears for 5 minutes
  during+afterwards, b. hurts my legs for 20 minutes afterwards, c.
  hurts productivity for 2 minutes during and raises stress levels, d.
  steals focus for a few hundred milliseconds.

  The root cause of this appears a disk and CPU-intensive database batch
  job.  I wonder if it would be possible to back-off slightly and not
  tie-up the disk and CPU if the user is currently using the machine (a
  scheduling issue admittedly, but is the database run being run as
  child of a GUI process and so inheriting that priority?)

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