Filip Rembia*kowski<plk.zuber@xxxxxxxxx> wrote: > 2011/1/19 Charles.Hou <givemeegn@xxxxxxxxx>: >> " select * from mybook" SQL command also increase the XID ? > > Yes. Single SELECT is a transaction. Hence, it needs a transaction > ID. No, not in recent versions of PostgreSQL. There's virtual transaction ID, too; which is all that's needed unless the transaction writes something. Also, as a fine point, if you use explicit database transactions (with BEGIN or START TRANSACTION) then you normally get one XID for the entire transaction, unless you use SAVEPOINTs. -Kevin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
