On Tue, 15 Feb 2005, Magnus Hagander wrote:
Run:
hdparm -I /dev/hda
If you get a line like:
Commands/features:
Enabled Supported:
* READ BUFFER cmd
* WRITE BUFFER cmd
* Host Protected Area feature set
* Look-ahead
* Write cache
...
(last line is what matters here)
you have write cacheing enabled.
Thanks. Ok, really I have it enabled (fortunately :)
To turn it of, run
hdparm -W0 /dev/hda
Done. Now it is disabled.
Not sure if you need to reboot, I don'tt hink so. Then re-run the
benchmark on linux.
No, under Linux reboot makes nothing (it is completely dynamical system).
Now I have
/usr/local/pgsql/bin:14>pgbench -c 1 -t 500
starting vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 1
number of transactions per client: 500
number of transactions actually processed: 500/500
tps = 89.528064 (including connections establishing)
tps = 89.560730 (excluding connections establishing)
It is about 9 times slower. But again 4 times faster then under Windows.
After
[EMAIL PROTECTED]:/e# hdparm -W1 /dev/hda
/dev/hda:
setting drive write-caching to 1 (on)
/usr/local/pgsql/bin:24>pgbench -c 1 -t 500
starting vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 1
number of transactions per client: 500
number of transactions actually processed: 500/500
tps = 846.189777 (including connections establishing)
tps = 849.481986 (excluding connections establishing)
Regards,
E.R.
_________________________________________________________________________
Evgeny Rodichev Sternberg Astronomical Institute
email: [EMAIL PROTECTED] Moscow State University
Phone: 007 (095) 939 2383
Fax: 007 (095) 932 8841 http://www.sai.msu.su/~er
---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
