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#1 (**permalink**) 04-11-2008, 07:54 AM

i am using version 8.0.3

if you run the following query:

select count(*) from T1 where (T1.a>10 and T1.a<20) or (T1.a>90 and T1.a
<100)

the set_baserel_size_estimate will accurately estimate the selectivity on
T1.

However, if you run

select count(*) from T1, T2 where T1.b=T2.c and (T1.a>10 and T1.a<20) or(
T1.a>90 and T1.a<100)

the selectivity estimate on T1 is always 1.0 the reason is the
re-l->baserestrictinfo is NULL for the second query in
set_baserel_size_estimates().

is this a bug?

#2 (**permalink**) 04-11-2008, 07:54 AM

uwcssa <uwcssa@gmail.com> writes:
> select count(*) from T1, T2 where T1.b=3DT2.c and (T1.a>10 and T1.a<20) or=
> (
> T1.a>90 and T1.a<100)

> the selectivity estimate on T1 is always 1.0 the reason is the
> re-l->baserestrictinfo is NULL for the second query in
> set_baserel_size_estimates().

Sure you're not looking at T2?

regards, tom lane

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postgresql bug?