Greg Smith <gsmith@xxxxxxxxxxxxx> writes: > Quoting from Lewine's "POSIX Programmer's Guide": > "After a write() to a regular file has successfully returned, any > successful read() from each byte position in the file that was modified by > that write() will return the data that was written by the write()...a > similar requirement applies to multiple write operations to the same file > position" Yeah, I imagine this is what the OP is thinking of. But note that what it describes is the behavior of concurrent write() and read() calls within a normally-functioning system. I see nothing there that constrains the order in which writes hit physical disk, nor (to put it another way) that promises anything much about the state of the filesystem after a crash. As you stated, PG is largely independent of these issues anyway. As long as the filesystem honors its spec-required contract that it won't claim fsync() is complete before all the referenced data is safely on persistent store, we are OK. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
