| Lists: | pgsql-bugs |
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| From: | "vikas" <vikas(dot)dubey(at)newgen(dot)co(dot)in> |
|---|---|
| To: | pgsql-bugs(at)postgresql(dot)org |
| Subject: | BUG #4690: an select query is not using the index |
| Date: | 2009-03-04 10:15:49 |
| Message-ID: | 200903041015.n24AFnhk092105@wwwmaster.postgresql.org |
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| Lists: | pgsql-bugs |
The following bug has been logged online:
Bug reference: 4690
Logged by: vikas
Email address: vikas(dot)dubey(at)newgen(dot)co(dot)in
PostgreSQL version: PostgreSQL 7.3
Operating system: i686-pc-linux-gnu
Description: an select query is not using the index
Details:
hi
there is a table PDBFolder whose one column is Parentfolderindex on which an
index 'idx_folder_parentfolderindex' is created.
when i execute the following query
Select ParentFolderIndex From PDBFolder Where ParentFolderIndex In (
Select FolderId From FolderTree Where Leaf = 1::int4 )
it takes approximately 10 minutes and when i see the query execution plan of
this query it shows sequence scan on pdbfolder(which contain 50,000 rows).
can you suggest there is any way to use index idx_folder_parentfolderindex
in above query
regards
Vikas Dubey
| From: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
|---|---|
| To: | vikas <vikas(dot)dubey(at)newgen(dot)co(dot)in> |
| Cc: | pgsql-bugs(at)postgresql(dot)org |
| Subject: | Re: BUG #4690: an select query is not using the index |
| Date: | 2009-03-04 10:51:05 |
| Message-ID: | 49AE5D19.60206@gmx.net |
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vikas wrote:
> The following bug has been logged online:
>
> Bug reference: 4690
> Logged by: vikas
> Email address: vikas(dot)dubey(at)newgen(dot)co(dot)in
> PostgreSQL version: PostgreSQL 7.3
Time to upgrade.
> Operating system: i686-pc-linux-gnu
> Description: an select query is not using the index
> Details:
>
> hi
>
> there is a table PDBFolder whose one column is Parentfolderindex on which an
> index 'idx_folder_parentfolderindex' is created.
More details please.
| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
| Cc: | vikas <vikas(dot)dubey(at)newgen(dot)co(dot)in>, pgsql-bugs(at)postgresql(dot)org |
| Subject: | Re: BUG #4690: an select query is not using the index |
| Date: | 2009-03-04 16:49:17 |
| Message-ID: | 3212.1236185357@sss.pgh.pa.us |
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| Lists: | pgsql-bugs |
Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> vikas wrote:
>> PostgreSQL version: PostgreSQL 7.3
> Time to upgrade.
Indeed. 7.4 was the first release that had even an inkling of how to
optimize IN (sub-SELECT) clauses.
regards, tom lane