[EMAIL PROTECTED] ("Harpreet Dhaliwal") writes:
> I was just wondering if Vacuum Db in postgresql is somehow superior
> to the ones that we have in other RDBMS.The thing that is more akin to VACUUM, in Oracle's case, is the rollback segment. In Oracle, Rollback segments are areas in your database which are used to temporarily save the previous values when some updates are going on. In the case of Oracle, if a transaction rolls back, it has to go and do some work to clean up after the dead transaction. This is not *exactly* like PostgreSQL's notion of vacuuming, but that's the nearest equivalent that Oracle has. The Oracle InnoDB product also has the notion of rollback segments; if you use InnoDB tables with MySQL, the rollback functionality has much the same behaviour as Oracle. Note that in the case of PostgreSQL, the MVCC behaviour (which requires VACUUMing) has the merit that COMMIT and ROLLBACK both have near-zero costs; in either case, the cost is merely to mark the transaction as either committed or failed. Data doesn't have to be touched at time of COMMIT/ROLLBACK; any costs that need to be paid are deferred to VACUUM time. -- select 'cbbrowne' || '@' || 'acm.org'; http://www3.sympatico.ca/cbbrowne/postgresql.html "For be a man's intellectual superiority what it will, it can never assume the practical, available supremacy over other men, without the aid of some sort of external arts and entrenchments, always, in themselves, more or less paltry and base. This it is, that forever keeps God's true princes of the Empire from the world's hustings; and leaves the highest honors that this air can give, to those men who become famous more through their infinite inferiority to the choice hidden handful of the Divine Inert, than through their undoubted superiority over the dead level of the mass." --Moby Dick, Ch 33 ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
