Re: _bt_check_unique checks every row in table when doing update??

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mats Lofkvist <mal@algonet.se>
Cc: pgsql-bugs@postgresql.org
Date: 2002-09-09T20:21:50Z
Lists: pgsql-bugs
Mats Lofkvist <mal@algonet.se> writes:
> But when doing ~1000 updates (i.e. setting val0 and val1 with
> a where on an existing key0/key1/key2 triplet), I get this which
> seems very strange to me:

I suppose you repeatedly updated the same row 1000 times?  That creates
an O(N^2) behavior because the dead tuples have to be rechecked again
and again.

7.3 will be smarter about this.

			regards, tom lane