Anyone interested in improving postgresql scaling?

Kris Kennaway kris at
Mon Feb 26 00:22:36 UTC 2007

If so, then your task is the following:

Make SYSV semaphores less dumb about process wakeups.  Currently
whenever the semaphore state changes, all processes sleeping on the
semaphore are woken, even if we only have released enough resources
for one waiting process to claim.  i.e. there is a thundering herd
wakeup situation which destroys performance at high loads.  Fixing
this will involve replacing the wakeup() calls with appropriate
amounts of wakeup_one().


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