Re: lock contention on parallel COPY ?

Stefan Kaltenbrunner <stefan@kaltenbrunner.cc> writes:
> heh no log archiving - I actually said that I'm now playing with 
> --truncate-before-load which seems to cause a noticeable performance (as 
> in IO generated) increase but I still see >130000 context switches/s and 
> a profile that looks like:

> samples  %        symbol name
> 55526    16.5614  LWLockAcquire
> 29721     8.8647  DoCopy
> 26581     7.9281  CopyReadLine
> 25105     7.4879  LWLockRelease
> 15743     4.6956  PinBuffer
> 14725     4.3919  heap_formtuple

Still a lot of contention for something, then.  You might try turning on
LWLOCK_STATS (this only requires recompiling storage/lmgr/lwlock.c) to
get some evidence about what.
        regards, tom lane