Bruce Momjian wrote: > If we only prune on an update (or insert) why not just do prune every > time? I figure the prune/defrag has to be lighter than the > update/insert itself.
Pruning is a quite costly operation. You need to check the visibility of each tuple on the page, following tuple chains as you go, mark line pointers as not used or redirected, and finally memmove all the tuples to remove the gaps between them. And it needs to be WAL-logged. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
