Re: CREATE INDEX and HOT - revised design

Bruce Momjian wrote:
> > You don't need to scan the whole page like in the lossy bitmap mode, 
> > just all the tuples in the HOT-chain.
> > 
> > You need to somehow pass the information that multiple indexes have been 
> > used in the bitmap scan to the bitmap heapscan node, so that it knows 
> > when the extra checking is required.
> 
> That might be confusing because you are going to have some tids that are
> chains, and some that aren't.  The hard part is making sure you don't
> include the same tid twice.
> 
> Another idea is to set pg_index xid to FrozenTransactionId once the
> VACUUM happens, and if it not frozen, do something special for bitmap
> scans.

Anyway, perhaps we can leave the bitmap scan part to someone more
familiar with that part of the code, like Tom.

HOT is a huge feature, so let's keep working on it.  The patch doesn't
have to be 100% on April 1, but we certainly want to try to get as far
as we can by then.

--  Bruce Momjian  <bruce@momjian.us>          http://momjian.us EnterpriseDB
http://www.enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +