nbeweb=> EXPLAIN select count(*) from onp_web_index;
QUERY PLAN
-----------------------------------------------------------------------------
Hi all.
I have a problem with a table which only has 298 rows in it. A select count(*)
takes forever and CTRL-C also takes a long time canceling the query. There
are only 298 rows in the table when count(*) returns. How come it takes such
a long time counting only 298 rows? Here is EXPLAIN ANALYZE:
nbeweb=> EXPLAIN ANALYZE select count(*) from onp_web_index;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------
Aggregate (cost=205759.52..205759.52 rows=1 width=0) (actual
time=179748.910..179748.913 rows=1 loops=1)
-> Seq Scan on onp_web_index (cost=0.00..205455.41 rows=121641 width=0)
(actual time=179735.956..179747.821 rows=298 loops=1)
Total runtime: 179748.993 ms
(3 rows)
Here is the schema:
nbeweb=> \d onp_web_index;
Table "public.onp_web_index"
Column | Type | Modifiers
-------------+-------------------+---------------------------------------------------------------
id | integer | not null default
nextval('public.onp_web_index_id_seq'::text)
starturl_id | integer | not null
lang_id | integer | not null
url_host | character varying | not null
url_path | character varying | not null
title | character varying | not null
content | tsvector | not null
plain_text | character varying | not null
Indexes:
"onp_web_index_pkey" primary key, btree (id)
"onp_web_index_url_host_key" unique, btree (url_host, url_path)
"onp_web_index_idx" gist (content)
Foreign-key constraints:
"$2" FOREIGN KEY (lang_id) REFERENCES code(id)
"$1" FOREIGN KEY (starturl_id) REFERENCES onp_web_index_starturl(id) ON
DELETE CASCADE
Any hints on how I can "fix" this lousy performance?
--
Andreas Joseph Krogh <[EMAIL PROTECTED]>
Senior Software Developer / Manager
gpg public_key: http://dev.officenet.no/~andreak/public_key.asc
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