On Mon, 2007-03-19 at 10:51 +0000, Heikki Linnakangas wrote: > Pavan Deolasee wrote: > > Heikki Linnakangas wrote: > > > Pavan Deolasee wrote: > > > We would only need the extra byte in HOT-updated tuples. > > Alternatively, we could use the bits we have free in infomask2. There's > > currently 5 bits free, using just 2 or 3 of those would get us quite > > far. Or just one, which would be the Tom's suggestion of only using HOT > > for tables with a single index. > > > > > > > We've already used three of those, two for tracking HEAP_ONLY > > and HOT_UPDATED tuples and one for tracking fragmented tuple. > > HEAP_ONLY_TUPLE would go away in favor of the per-index bits. So we have > bits available for three indexes.
ISTM that we are getting very close to a great idea here. I was unwilling to compromise to have HOT if only one index existed, but IMHO allowing HOT with <= 3 indexes is an acceptable compromise for this release. (We can always use vertical partitioning techniques to allow additional access paths to be added to the same table - I'd be very happy to document that with worked examples, if requried). I trust that we will think of ways of extending that limit in later releases. -- Simon Riggs EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
