Hi all,

Do someone already had some problem with performances using a pentium
D (64 bits) and postgres 8.2.3 on a redhat enterprise update 2 ?
I did the install from sources and nothing change... I have a RAID 0
for data and 3Gb of RAM and my inserts rate is quite low, 8333 inserts/
sec (lower than on my laptop which is 10526 inserts/sec).
I suspect a problem with the CPU because using gkrellm, the use of 1
CPU is always quite low... Is it normal ?

Many thanks for your help,


Joël

I suspect the difference is your disk subsystem. IDE disks (in your laptop
I assume) quite often (almost always!!) ignore fsync calls and return as
soon as the data gets to the disk cache, not the physical disk. SCSI disks
are almost always more correct, and wait until the data gets to the physical
disk before they return from an fsync call.

I hope this helps.

Regards,

Ben
"hatman" <joel.winteregg@gmail.com> wrote in message
news:1172678294.544317.195100@t69g2000cwt.googlegr oups.com...
Hi all,

Do someone already had some problem with performances using a pentium
D (64 bits) and postgres 8.2.3 on a redhat enterprise update 2 ?
I did the install from sources and nothing change... I have a RAID 0
for data and 3Gb of RAM and my inserts rate is quite low, 8333 inserts/
sec (lower than on my laptop which is 10526 inserts/sec).
I suspect a problem with the CPU because using gkrellm, the use of 1
CPU is always quite low... Is it normal ?

Many thanks for your help,


Joël

Hi Ben,

Thanks for you answer.

I was thinking about CPU speed bottleneck because one of the CPU load
was always quite low on the server (Pentium D, dual core) and on the
other hand, the CPU load on my laptop was always very high. After some
more testing (using a threaded client software which does the same
inserts using 10 parallel connections), i was able to have the other
CPU arround 90% too :-)
Then the INSERT speed reached 18'181 inserts/sec !!

So now i'm wondering if i reached the disk limit or again the CPU
limit... Anyway, thanks a lot for your advice, i didn't know this
difference between fsync implementation on SCSI and IDE !

Joël

On Mar 1, 12:00 pm, "Ben Trewern" <ben.trew...@mowlem.com> wrote:
> I suspect the difference is your disk subsystem. IDE disks (in your laptop
> I assume) quite often (almost always!!) ignore fsync calls and return as
> soon as the data gets to the disk cache, not the physical disk. SCSI disks
> are almost always more correct, and wait until the data gets to the physical
> disk before they return from an fsync call.
>
> I hope this helps.
>
> Regards,
>
> Ben"hatman" <joel.winter...@gmail.com> wrote in message
>
> news:1172678294.544317.195100@t69g2000cwt.googlegr oups.com...
> Hi all,
>
> Do someone already had some problem with performances using a pentium
> D (64 bits) and postgres 8.2.3 on a redhat enterprise update 2 ?
> I did the install from sources and nothing change... I have a RAID 0
> for data and 3Gb of RAM and my inserts rate is quite low, 8333 inserts/
> sec (lower than on my laptop which is 10526 inserts/sec).
> I suspect a problem with the CPU because using gkrellm, the use of 1
> CPU is always quite low... Is it normal ?
>
> Many thanks for your help,
>
> Joël