On 17-Nov-05, at 2:50 PM, Alex Turner wrote:
Just pick up a SCSI drive and a consumer ATA drive.
Feel their weight.
You don't have to look inside to tell the difference.
At one point stereo manufacturers put weights in the case just to
make them heavier.
The older ones weighed more and
On 18-Nov-05, at 1:07 AM, Luke Lonergan wrote:
Greg,
On 11/17/05 9:17 PM, Greg Stark [EMAIL PROTECTED] wrote:
Ok, a more productive point: it's not really the size of the
database that
controls whether you're I/O bound or CPU bound. It's the available
I/O
bandwidth versus your CPU
Dave Cramer wrote:
On 18-Nov-05, at 1:07 AM, Luke Lonergan wrote:
Postgres + Any x86 CPU from 2.4GHz up to Opteron 280 is CPU bound after
110MB/s of I/O. This is true of Postgres 7.4, 8.0 and 8.1.
A $1,000 system with one CPU and two SATA disks in a software RAID0 will
perform exactly the
Luke Lonergan wrote:
Alan,
On 11/18/05 5:41 AM, Alan Stange [EMAIL PROTECTED] wrote:
That's interesting, as I occasionally see more than 110MB/s of
postgresql IO on our system. I'm using a 32KB block size, which has
been a huge win in performance for our usage patterns. 300GB database
Title: Re: [PERFORM] Hardware/OS recommendations for large databases (
Dave,
On 11/18/05 5:00 AM, Dave Cramer [EMAIL PROTECTED] wrote:
Now there's an interesting line drawn in the sand. I presume you have
numbers to back this up ?
This should draw some interesting posts.
Part 2: The
While I agree with you in principle that pg becomes CPU bound
relatively easily compared to other DB products (at ~110-120MBps
according to a recent thread), there's a bit of hyperbole in your post.
a. There's a big difference between the worst performing 1C x86 ISA
CPU available and the best
Title: Re: [PERFORM] Hardware/OS recommendations for large databases (
Dave,
On 11/18/05 5:00 AM, Dave Cramer [EMAIL PROTECTED] wrote:
Now there's an interesting line drawn in the sand. I presume you have
numbers to back this up ?
This should draw some interesting posts.
OK, here we
On 18-Nov-05, at 8:30 AM, Luke Lonergan wrote: Richard, On 11/18/05 5:22 AM, "Richard Huxton" dev@archonet.com wrote: Well, I'm prepared to swap Luke *TWO* $1000 systems for one $80,000 system if he's got one going :-) Finally, a game worth playing! Except it’s backward – I’ll show you 80
On Nov 18, 2005, at 10:13 AM, Luke Lonergan wrote:Still, there is a CPU limit here – this is not I/O bound, it is CPU limited as evidenced by the sensitivity to readahead settings. If the filesystem could do 1GB/s, you wouldn’t go any faster than 244MB/s.Yeah, and mysql would probably be faster
On Nov 18, 2005, at 1:07 AM, Luke Lonergan wrote:
A $1,000 system with one CPU and two SATA disks in a software RAID0
will
perform exactly the same as a $80,000 system with 8 dual core CPUs
and the
world's best SCSI RAID hardware on a large database for decision
support
(what the poster
Alan,
On 11/18/05 5:41 AM, Alan Stange [EMAIL PROTECTED] wrote:
That's interesting, as I occasionally see more than 110MB/s of
postgresql IO on our system. I'm using a 32KB block size, which has
been a huge win in performance for our usage patterns. 300GB database
with a lot of
Richard Huxton wrote:
Dave Cramer wrote:
On 18-Nov-05, at 1:07 AM, Luke Lonergan wrote:
Postgres + Any x86 CPU from 2.4GHz up to Opteron 280 is CPU bound
after
110MB/s of I/O. This is true of Postgres 7.4, 8.0 and 8.1.
A $1,000 system with one CPU and two SATA disks in a software RAID0
Title: Re: [PERFORM] Hardware/OS recommendations for large databases (
Richard,
On 11/18/05 5:22 AM, Richard Huxton dev@archonet.com wrote:
Well, I'm prepared to swap Luke *TWO* $1000 systems for one $80,000
system if he's got one going :-)
Finally, a game worth playing!
Except its backward
Luke Lonergan wrote:
Alan,
On 11/18/05 8:13 AM, Alan Stange [EMAIL PROTECTED] wrote:
I told you in my initial post that I was observing numbers in
excess of
what you claiming, but you seemed to think I didn't know how to
measure
an IO rate.
Prove me wrong, post your data.
Alex,
On 11/18/05 8:28 AM, Alex Turner [EMAIL PROTECTED] wrote:
Ok - so I ran the same test on my system and get a total speed of
113MB/sec.
Why is this? Why is the system so limited to around just
110MB/sec? I
tuned read ahead up a bit, and my results improve a
bit..
OK! Now we're on the
Bill,
On 11/18/05 7:55 AM, Bill McGonigle [EMAIL PROTECTED] wrote:
There is some truth to it. For an app I'm currently running (full-text
search using tsearch2 on ~100MB of data) on:
Do you mean 100GB? Sounds like you are more like a decision support
/warehousing application.
Dev
Ok - so I ran the same test on my system and get a total speed of
113MB/sec. Why is this? Why is the system so limited to around just
110MB/sec? I tuned read ahead up a bit, and my results improve a
bit..
Alex
On 11/18/05, Luke Lonergan [EMAIL PROTECTED] wrote:
Dave,
On 11/18/05 5:00
Luke Lonergan wrote:
Alan,
On 11/18/05 9:31 AM, Alan Stange [EMAIL PROTECTED] wrote:
Here's the output from one iteration of iostat -k 60 while the box is
doing a select count(1) on a 238GB table.
avg-cpu: %user %nice%sys %iowait %idle
0.990.00 17.97 32.40
Alan,
On 11/18/05 10:30 AM, Alan Stange [EMAIL PROTECTED] wrote:
Actually, this was dual cpu and there was other activity during the full
minute, but it was on other file devices, which I didn't include in the
above output. Given that, and given what I see on the box now I'd
raise the 20%
Alan Stange [EMAIL PROTECTED] writes:
Luke Lonergan wrote:
Alan,
On 11/18/05 9:31 AM, Alan Stange [EMAIL PROTECTED] wrote:
Here's the output from one iteration of iostat -k 60 while the box is
doing a select count(1) on a 238GB table.
avg-cpu: %user %nice%sys %iowait
Greg,
On 11/18/05 11:07 AM, Greg Stark [EMAIL PROTECTED] wrote:
That said, 130MB/s is nothing to sneeze at, that's maxing out two high end
drives and quite respectable for a 3-disk stripe set, even reasonable for a
4-disk stripe set. If you're using 5 or more disks in RAID-0 or RAID 1+0 and
Luke Lonergan wrote:
opterons from Sun that we got some time ago. I think the 130MB/s is
slow given the hardware, but it's acceptable. I'm not too price
sensitive; I care much more about reliability, uptime, etc.
I don't know what the system cost. It was part of block of dual
Then I
Greg Stark wrote:
Alan Stange [EMAIL PROTECTED] writes:
Luke Lonergan wrote:
Alan,
On 11/18/05 9:31 AM, Alan Stange [EMAIL PROTECTED] wrote:
Here's the output from one iteration of iostat -k 60 while the box is
doing a select count(1) on a 238GB table.
avg-cpu: %user
Title: Re: [PERFORM] Hardware/OS recommendations for large databases (
Vivek,
On 11/18/05 8:07 AM, Vivek Khera [EMAIL PROTECTED] wrote:
On Nov 18, 2005, at 10:13 AM, Luke Lonergan wrote:
Still, there is a CPU limit here this is not I/O bound, it is CPU limited as evidenced by the
Luke,Interesting numbers. I'm a little concerned about the use of blockdev —setra 16384. If I understand this correctly it assumes that the table is contiguous on the disk does it not ?DaveOn 18-Nov-05, at 10:13 AM, Luke Lonergan wrote: Dave, On 11/18/05 5:00 AM, "Dave Cramer" [EMAIL PROTECTED]
Breaking the ~120MBps pg IO ceiling by any means
is an important result. Particularly when you
get a ~2x improvement. I'm curious how far we
can get using simple approaches like this.
At 10:13 AM 11/18/2005, Luke Lonergan wrote:
Dave,
On 11/18/05 5:00 AM, Dave Cramer [EMAIL PROTECTED]
Steve Wampler wrote:
Is the performance behavior that we're experiencing a known
problem with 7.2 that has been addressed in 7.4? Or will the
upgrade fix other problems while leaving this one?
I'm pretty sure that in versions earlier than 7.4, IN clauses that use a
subquery will always use
Hi,
I am trying to use Explain Analyze to trace a slow SQL statement called from
JDBC.
The SQL statement with the parameters taked 11 seconds. When I run a explain
analyze from psql, it takes 50 ms with a reasonable explain plan. However
when I try to run an explain analyze from JDBC with the
We have a large DB
with partitioned tables in postgres. We have had trouble with a
ORDER/LIMIT type query. The order and limit are not pushed down to the
sub-tables
CREATE TABLE base
(
foo int
);
CREATE TABLE
bar_0
extra int
) INHERITS
(base);
ALTER TABLE bar ADD
PRIMARY KEY
Luke Lonergan wrote:
(mass snippage)
time psql -c select count(*) from ivp.bigtable1 dgtestdb
[EMAIL PROTECTED] IVP]$ cat sysout3
count
--
8000
(1 row)
real1m9.875s
user0m0.000s
sys 0m0.004s
[EMAIL PROTECTED] IVP]$
Mark,
On 11/18/05 3:46 PM, Mark Kirkwood [EMAIL PROTECTED] wrote:
If you alter this to involve more complex joins (e.g 4. way star) and
(maybe add a small number of concurrent executors too) - is it still the
case?
4-way star, same result, that's part of my point. With Bizgres MPP, the
Virag Saksena [EMAIL PROTECTED] writes:
ERROR: no value found for parameter 1
Here is sample code which causes this exception ...
pst=prodconn.prepareStatement(explain analyze select count(*) from
jam_heaprel r where heap_id = ? and parentaddr = ?);
I don't think EXPLAIN can take
Title: Re: [PERFORM] Hardware/OS recommendations for large databases (
Mark,
On 11/18/05 3:46 PM, Mark Kirkwood [EMAIL PROTECTED] wrote:
If you alter this to involve more complex joins (e.g 4. way star) and
(maybe add a small number of concurrent executors too) - is it still the
case?
I may
Luke Lonergan wrote:
Mark,
On 11/18/05 3:46 PM, Mark Kirkwood [EMAIL PROTECTED] wrote:
If you alter this to involve more complex joins (e.g 4. way star) and
(maybe add a small number of concurrent executors too) - is it still the
case?
I may not have listened to you - are you
Hi,
We want to create a database for each one of our departments, but we only
want to have one instance of postgresql running. There are about 10-20
departments. I can easily use createdb to create these databases. However,
what is the max number of database I can create before
On Nov 19, 2005, at 12:24 , anon permutation wrote:
However, what is the max number of database I can create before
performance goes down?
Assuming each database is performing well alone, how would putting
10-20 of them together in one instance affect postgres?
In terms of getting a new
On 11/18/05, anon permutation [EMAIL PROTECTED] wrote:
Hi,
We want to create a database for each one of our departments, but we only
want to have one instance of postgresql running. There are about 10-20
departments. I can easily use createdb to create these databases. However,
After of
37 matches
Mail list logo
