Pavan Deolasee wrote: > One of the improvements of HOT is to truncate a DEAD tuple to its > line pointer. A DEAD tuple could be an old version of an updated > tuple or a deleted tuple. When a tuple is truncated, the space used > by the line pointer can not be reused (until the index entries are removed). > But the space used by the actual tuple can be reused for a later update, > after > the page is defragmented. Note that this defragmentation can happen > outside of a VACUUM. > > This gives us an ability to run VACUUM less frequently on a table. We > still need to run VACUUM to remove the line pointer bloat, but may be less > frequently for the given percentage of bloat. IMHO this should have a > positive > effect on performance atleast in an IO bound scenario.
I have updated the release note item title to mention DELETE as well: Heap-Only Tuples (<acronym>HOT</>) accelerate space reuse for most <command>UPDATE</>s and <command>DELETE</>s -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://postgres.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend