On Sun, 2007-09-09 at 07:55 -0400, Bruce Momjian wrote: > Simon Riggs wrote: > > On Sat, 2007-09-08 at 23:13 -0400, Bruce Momjian wrote: > > > In summary, I feel we have the HOT mechanics down well, but the open > > > issue is _when_ to activate each operation. > > > > That has been the only open issue for months. The interplay of behaviour > > is where HOT succeeds and fails. Some behaviours sound like they will be > > good, but aren't. > > Looking at the patch, it seems defragmentation is checked every time a > heap page is pinned in heapam.c by calling heap_page_prune_defrag(). If > page free space < 1.2 * average_tuple_size the page is defragmented. It > would seem defragmentation is checked as much as possible. Seems > pruning is also as aggressive as possible.
I think the factor should be 1.0. A Setting of 1.2 will lead to twice as many defragmentation attempts when we have a fixed row length. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org
