Manfred Koizar wrote: > One more argument for pg_subtrans being visible to all backends: If > an UPDATE is about to change a tuple touched by another active > transaction, it waits for the other transaction to commit or abort. > We must always wait for the main transaction, not the subtrans.
This issue kills the idea that we can get away with providing lookup to the other backends _only_ while we are twiddling the clog bits. Other transactions are going to need to know if the XID they see on the tuple is owned by an active backend. This means we have to provide child/master xid lookup during the transaction, meaning we may as well use pg_clog or separate file, especially if we can get autovacuum for 7.4. It kills the idea that somehow locking would work. -- 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 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html
