Re: hash aggregation

On Thu, Oct 11, 2012 at 8:15 AM, Korisk <Korisk(at)yandex(dot)ru> wrote:
> What's your seq_page_cost and random_page_cost?
> hashes=# SELECT name, setting, reset_val FROM pg_settings WHERE setting <> reset_val;
> name | setting | reset_val
> -------------------------+----------------+-----------
> archive_command | (disabled) |
> enable_bitmapscan | off | on
> enable_indexscan | off | on
> enable_seqscan | off | on
> log_file_mode | 0600 | 384
> random_page_cost | 0.1 | 4
> seq_page_cost | 0.1 | 1
> transaction_isolation | read committed | default
> unix_socket_permissions | 0777 | 511

Could you please try to set *_page_cost to 1 and then EXPLAIN ANALYZE it again?

> -> Index Only Scan Backward using hashcheck_name_idx on public.hashcheck
> (cost=10000000000.00..10000398674.92 rows=25986792 width=32)
> (actual time=0.104..3785.767 rows=25990002 loops=1)

I am just guessing but it might probably be some kind of a precision
bug, and I would like to check this.

> (9 rows)
>
> Postgresql 9.2.1 was configured and built with default settings.
>
> Thank you.

--
Sergey Konoplev

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