On 7/7/05, Bruce Momjian <pgman@candle.pha.pa.us> wrote: > One idea would be to just tie its behavior directly to fsync and remove > the option completely (that was the original TODO), or we can adjust it > so it doesn't have the same risks as fsync, or the same lack of failure > reporting as fsync.
I wonder about one thing -- how much impact has the underlying filesystem? I mean, the problem with "partial writes" to pages is how to handle a situation when the machine looses power and we are not sure if the write was completed or not. But then again, imagine the data is on a filesystem with data journaling (like ext3 with data=journal). There, to my understanding, the data is first written into journal prior to be written to disk drive. Assuming the drive looses power during the process, I guess there would be two possible situations: 1) the modification was committed to journal completely, so we can replay the journal and we are sure the 8kb block is fine. (*) 2) the modification in the journal is not complete. It has not been fully committed to the filesystem journal. And we are safe to assume that drive has an old data. (*) I am not sure if it is true for 8kb-blocks, and of course, I haven't got good knowledge about ext3's journalling and its atomicity... Assuming above are true, it would be interesting to see how ext3 with data=journal and partial writes competes with ext3 data=someother without it. I don't have extensive knowledge with journalling internals, but I thought I would mention it, so people with wider knowledge could put their input here. Regards, Dawid ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings