From: | Szymon Guz <mabewlun(at)gmail(dot)com> |
---|---|
To: | Tadipathri Raghu <traghu(dot)dba(at)gmail(dot)com> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: Optimizer showing wrong rows in plan |
Date: | 2010-03-28 07:29:46 |
Message-ID: | e4edc9361003280029v7174f84bo72d073aced772206@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-performance |
2010/3/28 Tadipathri Raghu <traghu(dot)dba(at)gmail(dot)com>
> Hi Guz,
>
> Thank you for the prompt reply.
>
>
>> No, the optimizer is not retrieving anything, it just assumes that there
>> are 2400 rows because that is the number of rows that exists in the
>> statictics for this table. The optimizer just tries to find the best plan
>> and to optimize the query plan for execution taking into consideration all
>> information that can be found for this table (it also looks in the
>> statistics information about rows from this table).
>
>
> So, whats it assuming here as rows(2400). Could you explain this.
>
>
>
It is assuming that there are 2400 rows in this table. Probably you've
deleted some rows from the table leaving just one.
regards
Szymon Guz
From | Date | Subject | |
---|---|---|---|
Next Message | Tadipathri Raghu | 2010-03-28 07:33:48 | Re: Optimizer showing wrong rows in plan |
Previous Message | Tadipathri Raghu | 2010-03-28 07:11:07 | Re: Optimizer showing wrong rows in plan |