From: Steinar H. Gunderson <sesse@debian.org>
Date: Sun, 30 Jul 2006 13:52:33 +0000 (+0200)
Subject: When inserting multiple images at the same time, we could deadlock -- inserting
X-Git-Url: https://git.sesse.net/?p=pr0n;a=commitdiff_plain;h=d1b49fa6c2fd1b3d449dc938f0731c0426636c02;hp=d1b49fa6c2fd1b3d449dc938f0731c0426636c02

When inserting multiple images at the same time, we could deadlock -- inserting
new rows into images would (due to the foreign key constraint) lock the corresponding
row in event using a shared lock, then the update (due to last_picture) would
upgrade the lock to exclusive, causing a deadlock later. To fix this, we move
last_picture into its own table; we could also lock it explicitly earlier, but
that would stall other transactions (and they can run for 10-15 seconds or so,
or perhaps even longer) so it is not desirable.
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