Re: Index ot being used

Bruno Wolff III wrote:
> On Sun, Jun 12, 2005 at 23:42:05 -0400,
> Madison Kelly <linux(at)alteeve(dot)com> wrote:
>
>>As you probably saw in my last reply, I went back to the old index and
>>tried the query you and Tom Lane recommended. Should this not have
>>caught the index?
>
>
> Probably, but there might be some other reason the planner thought it
> was better to not use it. Using indexes is not always faster.
>
> It would help to see your latest definition of the table and indexes,
> the exact query you used and explain analyze output.
>

Okay, here's what I have at the moment:

tle-bu=> \d file_info_7 Table
"public.file_info_7"
Column | Type | Modifiers
----------------------+----------------------+-----------------------------------------
file_group_name | text |
file_group_uid | bigint | not null
file_mod_time | bigint | not null
file_name | text | not null
file_parent_dir | text | not null
file_perm | text | not null
file_size | bigint | not null
file_type | character varying(2) | not null default
'f'::character varying
file_user_name | text |
file_user_uid | bigint | not null
file_backup | boolean | not null default true
file_display | boolean | not null default false
file_restore_display | boolean | not null default false
file_restore | boolean | not null default false
Indexes:
"file_info_7_display_idx" btree (file_parent_dir, file_name)

tle-bu=> \d file_info_7_display_idx
Index "public.file_info_7_display_idx"
Column | Type
-----------------+------
file_parent_dir | text
file_name | text
btree, for table "public.file_info_7"

tle-bu=> EXPLAIN ANALYZE SELECT file_name, file_parent_dir, file_display
FROM file_info_7 WHERE file_type='d' ORDER BY file_parent_dir ASC,
file_name ASC;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Sort (cost=15091.53..15165.29 rows=29502 width=114) (actual
time=12834.933..12955.136 rows=25795 loops=1)
Sort Key: file_parent_dir, file_name
-> Seq Scan on file_info_7 (cost=0.00..11762.44 rows=29502
width=114) (actual time=0.244..2533.388 rows=25795 loops=1)
Filter: ((file_type)::text = 'd'::text)
Total runtime: 13042.421 ms
(5 rows)

Since my last post I went back to a query closer to what I actually
want. What is most important to me is that 'file_parent_dir, file_name,
file_display' are returned and that the results are sorted by
'file_parent_dir, file_name' and the results are restricted to where
'file_info='d''.

Basically what I am trying to do is display a directory tree in a
file browser. I had this working before but it was far, far too slow
once the number of directories to display got much higher than 1,000.
That is what 'file_display' is, by the way.

Again, thank you!

Madison

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Madison Kelly (Digimer)
TLE-BU, The Linux Experience; Back Up
http://tle-bu.thelinuxexperience.com
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