On Wed, 24 Apr 2002, Bruce Momjian wrote: > We expect the file system to do re-aheads during a sequential scan. > This will not happen if someone else is also reading buffers from that > table in another place.
Right. The essential difficulties are, as I see it: 1. Not all systems do readahead. 2. Even systems that do do it cannot always reliably detect that they need to. 3. Even when the read-ahead does occur, you're still doing more syscalls, and thus more expensive kernel/userland transitions, than you have to. Has anybody considered writing a storage manager that uses raw partitions and deals with its own buffer caching? This has the potential to be a lot more efficient, since the database server knows much more about its workload than the operating system can guess. cjs -- Curt Sampson <[EMAIL PROTECTED]> +81 90 7737 2974 http://www.netbsd.org Don't you know, in this new Dark Age, we're all light. --XTC ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org