Re: weired behavior... after pg_resetxlog-> dump->initdb-->reload.

Dear Tom,

It does.

rt2=# explain SELECT name from users_sample group by name having
count(*) > 1 ;
+-----------------------------------------------------------------------+
| QUERY PLAN |
+-----------------------------------------------------------------------+
| HashAggregate (cost=25.00..26.00 rows=200 width=78) |
| Filter: (count(*) > 1) |
| -> Seq Scan on users_sample (cost=0.00..20.00 rows=1000 width=78) |
+-----------------------------------------------------------------------+
(3 rows)

Time: 375.619 ms
rt2=# explain analyze SELECT name from users_sample group by name having
count(*) > 1 ;
+------------------------------------------------------------------------------------------------------------------------+
| QUERY
PLAN |
+------------------------------------------------------------------------------------------------------------------------+
| HashAggregate (cost=25.00..26.00 rows=200 width=78) (actual
time=567.981..567.981 rows=0 loops=1) |
| Filter: (count(*) >
1)
|
| -> Seq Scan on users_sample (cost=0.00..20.00 rows=1000 width=78)
(actual time=0.046..160.706 rows=100489 loops=1) |
| Total runtime: 577.212
ms
|
+------------------------------------------------------------------------------------------------------------------------+
(4 rows)

Tom Lane wrote:

>Rajesh Kumar Mallah <mallah(at)trade-india(dot)com> writes:
>
>
>>here is something which was the original problem
>>and is replicable.
>>
>>
>
>Hm. Does EXPLAIN show that the GROUP BY query is using hash
>aggregation? Does its behavior change if you turn off enable_hashagg?
>
> regards, tom lane
>
>
>