On 10/04/10 20:49, Josh Berkus wrote: >> The other major bottleneck they ran into was a kernel one: reading from >> the heap file requires a couple lseek operations, and Linux acquires a >> mutex on the inode to do that. The proper place to fix this is >> certainly in the kernel but it may be possible to work around in >> Postgres. > > Or we could complain to Kernel.org. They've been fairly responsive in > the past. Too bad this didn't get posted earlier; I just got back from > LinuxCon. > > So you know someone who can speak technically to this issue? I can put > them in touch with the Linux geeks in charge of that part of the kernel > code. Hmmm... lseek? As in "lseek() then read() or write()" idiom? It AFAIK cannot be fixed since you're modifying the global "strean position" variable and something has got to lock that. OTOH, pread() / pwrite() don't have to do that. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
