You need to show us exactly what you're doing....it's not clear....

reboot (please wait for disk to settle after login).
sqlite3 dba
.timer on
select count(id) from tab1; -- database not cached in OS or in sqlite3
select count(id) from tab1; -- this will be faster as the database is cached 
inside sqlite3
.quit
sqlite3 dba
select count(id) from tab1;   -- this should be faster than the 1st time above 
as the file is cached in the OS now
select count(id) from tab1;   -- this should be the same speed as the 2nd time 
from the previous run and should be faster than the 1st select of this run
.quit


And if you repeat this sequence for another databse you should see exactly the 
same results as the first database as they are not related at all.
sqlite3 dbb
.timer on
select count(id) from tab1;
select count(id) from tab1; -- this will be faster as the database is cached 
inside sqlite3
.quit
sqlite3 dba
select count(id) from tab1;   -- this should be faster than the 1st time above 
as the file is cached in the OS now
select count(id) from tab1;   -- this should be the same speed as the 2nd time 
from the previous run and should be faster than the 1st select of this run



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 徐 [okd...@126.com]
Sent: Monday, September 05, 2011 3:12 AM
To: sqlite-users@sqlite.org
Subject: EXT :Re: [sqlite] select speed is too slow


> For eg, the query like this: "select count(id) from tab1"  ,and the
> record number is above 100,000. If i can't restart my pc, the
> speed is quicker when i do the second query.

>>This must be because the OS cached your database file into memory.

thanks forSébastien Escudier's reply. but I am comfused that: First time
i used sqlite database A for query, and second time database B, and then the
second query speed of another database (B) is still faster.    :(
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Reply via email to