Re: COPY locking

"Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM> writes:
> access/heap/hio.c:RelationGetBufferForRelation() uses LockPage
> (ie lmgr -> semops) to syncronize table extending.

But no semop should occur unless somebody is actually blocking on
the lock. John's trace only showed one active backend, so I figured
that there shouldn't be any blockage.

> Probably we could
> optimize this somehow, but allocation of new page in bufmgr is
> horrible and that's why we have locks in hio.c from the beginning.

See later message about eliminating lseeks --- I think we should be
able to avoid doing this lock for every single tuple, as it does now,
and only do it when we need to allocate a new page.

regards, tom lane