Hi, On Thu, 28 Feb 2002 at 16:10, Tom Lane wrote:
> > -> Index Scan using foo2_pkey on foo2 > > (cost=0.00..10387.79 rows=352072 width=4) > > (actual time=0.26..174.32 rows=38432 loops=1) > > The actual rows read from this indexscan seem to be many fewer than > the number of rows in the table. What are the ranges of the id > values in tables foo and bar? I'm wondering if the merge could have > stopped far short of the end of the foo table; if so, *that* is the > effect that we are failing to model accurately. Good guess :) max=# SELECT 'bar' AS tablename, min(ref2foo), max(ref2foo), count(ref2foo) FROM bar UNION SELECT 'foo', min(id), max(id), count(id) from foo; tablename | min | max | count -----------+----------+----------+-------- bar | 10000010 | 10049999 | 38431 foo | 10000010 | 10423442 | 352072 (2 rows) I'll tell my colleague (it's his test database, after all) that he should take more realistic test data before complaining about bad performance... cu Reinhard ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]