Well, O_DIRECT has finally made it into the Linux kernel. It lets you open a file in such a way that reads and writes don't go to the buffer cache but straight to the disk. Accesses must be aligned on filesystem block boundaries.
Is there any case where PG would benefit from this? I can see it reducing memory pressure and duplication of data between PG shared buffers and the block buffer cache. OTOH, it does require that writes be batched up for decent performance, since each write has an implicit fsync() involved (just as with O_SYNC). Anyone played with this on systems that already support it (Solaris?) -Doug -- In a world of steel-eyed death, and men who are fighting to be warm, Come in, she said, I'll give you shelter from the storm. -Dylan ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org