On Wed, 2008-09-17 at 16:25 -0400, Alvaro Herrera wrote: > We've been profiling a large system (8 CPUs, 64 GB of memory, some > dozens of disks) which seems rather more swamped than it should. Part > of the problem seems to come from CleanupTempFiles, the second entry in > oprofile output.
I'm glad you've observed this also. I saw it about two years ago but wasn't able to convince anyone else it existed at the time. > I can see two simple ways to solve this problem. One is to create a > second array that keeps pointers to the temp files in VfdCache. Then, > on CleanupTempFiles we scan that array instead of VfdCache directly. > > The second one is to use a separate VfdCache for temp files, but this > seems much more involved, requiring touch almost all of fd.c. > > Of course, perhaps there's another solution which involves rethinking > fd.c in a more thorough fashion, but I'm not sure how right offhand. Simple solution is to have a state variable so you can see whether a backend has created an temp files in this transaction. Most don't, so I think the above two solutions are overkill. If we created any, scan for them, if not, don't. Just a simple boolean state, just as we have for AtEOXact_RelationCache(). -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
