| From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Elliott Groszek <elliott(dot)groszek(at)navy(dot)mil>, pgsql-bugs(at)postgresql(dot)org |
| Subject: | Re: BUG #5755: Query Optimzer Bug |
| Date: | 2010-11-17 18:37:42 |
| Message-ID: | 4CE420F6.7070003@enterprisedb.com |
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| Lists: | pgsql-bugs |
On 17.11.2010 18:05, Tom Lane wrote:
> "Elliott Groszek"<elliott(dot)groszek(at)navy(dot)mil> writes:
>> The following SQL statements produce different query plans even though
>> "phone" is not reference in the SQL!
>
>> explain update customer set login_name =
>> (select "NESSOuserName" from person,phone
>> where person.cac_cert=customer.cac_cert);
>
>> explain update customer set login_name =
>> (select "NESSOuserName" from person
>> where person.cac_cert=customer.cac_cert);
>
> That's not a bug.
Particularly, note that they produce different results if "phone" table
is empty.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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