Have you done "ANALYZE"? That might help.
Also...try to arrange your joins based on record count (both high-to-low and
low-to-high) and see what difference it makes.
Since you have only one WHERE clause I'm guessing having project_ids as the
first join makes sense.
Michael D. Black
Senior Scientist
NG Information Systems
Advanced Analytics Directorate
From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Puneet Kishor [punk.k...@gmail.com]
Sent: Tuesday, September 27, 2011 5:46 PM
To: General Discussion of SQLite Database
Subject: EXT :[sqlite] speeding up FTS4
I have
CREATE TABLE uris (
uri_id INTEGER PRIMARY KEY,
uri TEXT,
uri_content TEXT,
downloaded_on DATETIME DEFAULT CURRENT_TIMESTAMP,
feed_history_id INTEGER
);
with 46608 rows
CREATE TABLE feed_history (
feed_history_id INTEGER PRIMARY KEY,
feed_id INTEGER,
scanned_on DATETIME DEFAULT CURRENT_TIMESTAMP
);
with 3276 rows
CREATE TABLE feeds (feed_id INTEGER PRIMARY KEY, feed_uri TEXT, project_id
INTEGER);
with 79 rows
CREATE TABLE projects (project_id INTEGER PRIMARY KEY, project_name TEXT);
with 3 rows
CREATE INDEX idx_uris_downloaded_on ON uris (downloaded_on);
CREATE VIRTUAL TABLE fts_uri USING fts4 (uri_id, uri_content);
The database file is about 27 GB.
The following query takes (CPU Time: user 23.952698 sys 73.188765) returning
46608 rows
SELECT u.uri_id uri_id, u.uri uri, u.downloaded_on,
Snippet(fts_uri, '<span class="hilite">', '</span>', '…', -1,
64) snippet
FROM fts_uri f
JOIN uris u ON f.uri_id = u.uri_id
JOIN feed_history fh ON u.feed_history_id = fh.feed_history_id
JOIN feeds f ON fh.feed_id = f.feed_id
JOIN projects p ON f.project_id = p.project_id
WHERE p.project_id = 3
AND Datetime(u.downloaded_on) >= Datetime(p.project_start)
AND fts_uri MATCH 'education,school'
ORDER BY u.uri_id, downloaded_on DESC;
The EXPLAIN QUERY PLAN for the above query tells me
0|0|0|SCAN TABLE fts_uri AS f VIRTUAL TABLE INDEX 4: (~0 rows)
0|1|1|SEARCH TABLE uris AS u USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)
0|2|2|SEARCH TABLE feed_history AS fh USING INTEGER PRIMARY KEY (rowid=?)
(~1 rows)
0|3|3|SEARCH TABLE feeds AS f USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)
0|4|4|SEARCH TABLE projects AS p USING INTEGER PRIMARY KEY (rowid=?) (~1
rows)
0|0|0|USE TEMP B-TREE FOR ORDER BY
Is there anything I can do to speed this up?
--
Puneet Kishor
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