Jan Wieck wrote: > Zeugswetter Andreas SB SD wrote: > > >> > One problem with O_SYNC would be, that the OS does not group writes any > >> > more. So the code would need to eighter do it's own sorting and grouping > >> > (256k) or use aio, or you won't be able to get the maximum out of the disks. > >> > >> Or just run multiple writer processes, which I believe is Oracle's > >> solution. > > > > That does not help, since for O_SYNC the OS'es (those I know) do not group those > > writes together. Oracle allows more than one writer to busy more than one > > disk(subsystem) and circumvent other per process limitations (mainly on platforms > > without AIO). > > Yes, I think the best way would be to let the background process write a > bunch of pages, then fsync() the files written to. If one tends to have > many dirty buffers to the same file, this will group them together and > the OS can optimize that. If one really has completely random access, > then there is nothing to group.
Agreed. This might force enough stuff out to disk the checkpoint/sync() would be OK. Jan, have you tested this? -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
