On Thu, 28 Nov 2002 21:46:09 -0500, Tom Lane <[EMAIL PROTECTED]> wrote: >Manfred suggested a separate log file ("pg_subclog" or some such) but >I really don't see any operational advantage to that. You still end up >with 4 bytes per transaction, you're just assuming that putting them >in a different file makes it better. I don't see how.
There are two points: 1) If your site/instance/application/whatever... does not use nested transactions or does use them only occasionally, you don't have to pay the additional I/O cost. 2) If we update a subtransaction's pg_clog bits as soon as the status of the main transaction is known, pg_subtrans is only visited once per subtransaction, while pg_clog has to be looked up once per tuple. Things might look different however, if we wrap every command into a subtransaction... Servus Manfred ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html