Re: Allowing WAL fsync to be done via O_SYNC

Alfred Perlstein <bright(at)wintelcom(dot)net> writes:
>> Just by making a thread call libc changes personality to use thread
>> safe routines (I.E. add mutex locking). Use one thread feature, get
>> the whole set...which may not be that bad.

> Actually it can be pretty bad. Locked bus cycles needed for mutex
> operations are very, very expensive, not something you want to do
> unless you really really need to do it.

It'd be interesting to try to get some numbers about the actual cost
of using a thread-aware libc, on platforms where there's a difference.
Shouldn't be that hard to build a postgres executable with the proper
library and run some benchmarks ... anyone care to try?

regards, tom lane