On Sat, Nov 13, 2010 at 07:53, Craig Ringer <craig@xxxxxxxxxxxxxxxxxxxxx> wrote: > Oracle's MVCC approach has its own costs. Like Pg's, those costs increase > with update/delete frequency. Instead of table bloat, Oracle suffers from > redo log growth (or redo log size management issues). Instead of increased > table scan costs from dead rows, Oracle suffers from random I/O costs as it > looks up the out-of-line redo log for old rows. Instead of long-running > writer transactions causing table bloat, Oracle can have problems with > long-running reader transactions aborting when the redo log runs out of > space. Another advantage of Oracle's approach seems that they need much less tuple-level overhead. IMO the 23-byte tuple overhead is a much bigger drawback in Postgres than table fragmentation. Regards, Marti -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
