Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp> writes:
> [ use a global sync instead of fsync ]
> 1. Does sync really wait for the completion of data be written on to
> disk?
Linux is *alone* among Unix platforms in waiting; every other
implementation of sync() returns as soon as the last dirty buffer
is scheduled to be written.
> 2. Are we suffered any performance penalty from sync?
A global sync at the completion of every xact would be disastrous for
the performance of anything else on the system.
> However, in most cases the system is dedicated for only PostgreSQL,
"Most cases"? Do you have any evidence for that?
regards, tom lane