Re: [PATCHES] Bitmapscan changes

Wow, nice!

Can you tell us:
- how big is the table
- cardinality of the column
- how big is the index in each case
- how much memory on the machine
- query and explain analyze

Thanks!

- Luke

Msg is shrt cuz m on ma treo

-----Original Message-----
From: Grzegorz Jaskiewicz [mailto:gj(at)pointblue(dot)com(dot)pl]
Sent: Saturday, March 17, 2007 05:16 PM Eastern Standard Time
To: Joshua D.Drake
Cc: Heikki Linnakangas; PostgreSQL-development Hackers
Subject: Re: [HACKERS] [PATCHES] Bitmapscan changes

This is on dual ultra 2 sparc. with ultrawide 320 scsi drives. 512MB
ram.
I had to drop size of DB, because the DB drive is 4GB (I do welecome
bigger drives as donation, if someone asks - UWscsi 320).

here are my results. With only 4.2 patch (no maintain cluster order
v5 patch). If the v5 patch was needed, please tell me - I am going
rerun it with.

hope it is usefull.

Repeat 3 times to ensure repeatable results.
Timing is on.
select_with_normal_index
--------------------------
100000
(1 row)

Time: 1727891.334 ms
select_with_normal_index
--------------------------
100000
(1 row)

Time: 1325561.252 ms
select_with_normal_index
--------------------------
100000
(1 row)

Time: 1348530.100 ms
Timing is off.
And now run the same tests with clustered index
Timing is on.
select_with_clustered_index
-----------------------------
100000
(1 row)

Time: 870246.856 ms
select_with_clustered_index
-----------------------------
100000
(1 row)

Time: 477089.456 ms
select_with_clustered_index
-----------------------------
100000
(1 row)

Time: 381880.965 ms
Timing is off.

---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match