Hello,
We are experiencing performances problem with a quad Xeon MP and
PostgreSQL 7.4 for a year now. Our context switch rate is not so high
but the load of the server is blocked to 4 even on very high load and
we have 60% cpu idle even in this case. Our database fits in RAM and
we don't have any
Guillaume Smet wrote:
Hello,
We are experiencing performances problem with a quad Xeon MP and
PostgreSQL 7.4 for a year now.
I had a similar issue with a client the other week.
Our context switch rate is not so high
but the load of the server is blocked to 4 even on very high load and
we ha
On Wed, 2006-03-15 at 21:05 -0500, Tom Lane wrote:
> So we need a more accurate estimate for the boundary case.
Agreed.
> > Using 1.0e-10 isn't very useful... the selectivity for a range should
> > never be less than the selectivity for an equality, so we should simply
> > put in a test against o
Richard,
> You should be seeing context-switching jump dramatically if it's the
> "classic" multi-Xeon problem. There's a point at which it seems to just
> escalate without a corresponding jump in activity.
No we don't have this problem of very high context switching in our
case even when the dat
Hi Guillaume,
I had a similar issue last summer. Could you please provide details
about your XEON MP server and some statistics (context-switches/load/CPU
usage)?
I tried different servers (x86) with different results. I saw a
difference between XEON MP w/ and w/o EMT64. The memory bandwidth
Guillaume Smet wrote:
Richard,
You should be seeing context-switching jump dramatically if it's the
"classic" multi-Xeon problem. There's a point at which it seems to just
escalate without a corresponding jump in activity.
No we don't have this problem of very high context switching in our
ca
On 3/16/06, Richard Huxton wrote:
> Very strange.
Sure. I can't find any logical explanation for that but it is the
behaviour we have for more than a year now (the site was migrated from
Oracle to PostgreSQL on january 2005).
We check iostat, vmstat and so on without any hint on why we have this
Sven,
On 3/16/06, Sven Geisler <[EMAIL PROTECTED]> wrote:
> What version of XEON MP does your server have?
The server is a dell 6650 from end of 2004 with 4 xeon mp 2.2 and 2MB
cache per proc.
Here are the information from Dell:
4x PROCESSOR, 80532, 2.2GHZ, 2MB cache, 400Mhz, SOCKET F
8x DUAL IN
On 3/16/06, Sven Geisler <[EMAIL PROTECTED]> wrote:
> Hi Guillaume,
>
> I had a similar issue last summer. Could you please provide details
> about your XEON MP server and some statistics (context-switches/load/CPU
> usage)?
I forgot the statistics:
CPU load usually from 1 to 4.
CPU usage < 40% fo
"Guillaume Smet" <[EMAIL PROTECTED]> writes:
> Here is a top output I had on november 17 when the server completely
> hangs (several minutes for each page of the website) and it is typical
> of this server behaviour:
> 17:08:41 up 19 days, 15:16, 1 user, load average: 4.03, 4.26, 4.36
> 288 proc
Hi Guillaume,
Guillaume Smet schrieb:
The server is a dell 6650 from end of 2004 with 4 xeon mp 2.2 and 2MB
cache per proc.
Here are the information from Dell:
4x PROCESSOR, 80532, 2.2GHZ, 2MB cache, 400Mhz, SOCKET F
8x DUAL IN-LINE MEMORY MODULE, 512MB, 266MHz
You should provide det
Simon Riggs <[EMAIL PROTECTED]> writes:
> Trying to get the information in the wrong place would be very
> expensive, I agree. But preparing that information when we have access
> to it and passing it through the plan would be much cheaper.
Where would that be?
> The operator and the opclass are
On 3/16/06, Sven Geisler <[EMAIL PROTECTED]> wrote:
> Did you compare 7.4 on a 4-way with 8.1 on a 2-way?
I know there are too many parameters changing between the two servers
but I can't really change anything before tuesday. On tuesday, we will
be able to compare both servers with the same softw
On 3/16/06, Tom Lane <[EMAIL PROTECTED]> wrote:
> Can you try strace'ing some of the backend processes while the system is
> behaving like this? I suspect what you'll find is a whole lot of
> delaying select() calls due to high contention for spinlocks ...
Tom,
I think we can try to do it.
You
"Guillaume Smet" <[EMAIL PROTECTED]> writes:
> You mean strace -p pid with pid on some of the postgres process not on
> the postmaster itself, does you?
Right, pick a couple that are accumulating CPU time.
> Do we need other options?
strace will generate a *whole lot* of output to stderr. I usu
Hi Guillaume,
Guillaume Smet schrieb:
How much faster is the XEON DP?
Well, on high load, PostgreSQL scales well on the DP (load at 40,
queries slower but still performing well) and is awfully slow on the
MP box.
I know what you mean with awfully slow.
I think, your application is facing con
On 3/16/06, Tom Lane <[EMAIL PROTECTED]> wrote:
> What we want to find out is if there's a lot of select()s and/or
> semop()s shown in the result. Ideally there wouldn't be any, but
> I fear that's not what you'll find.
OK, I'll try to do it on monday before our upgrade then see what
happens with
Kevin,
please, could you post other settings from your postgresql.conf?
interested in:
bgwriter_delay
shared_buffers
checkpoint_segments
checkpoint_timeout
wal_buffers
On Wed, 15 Mar 2006 13:43:45 -0600
"Kevin Grittner" <[EMAIL PROTECTED]> wrote:
> We were seeing clusters of query timeouts wi
PostgreSQL tuned to the max and still too slow? Database too big to
fit into memory? Here's the solution! http://www.superssd.com/
products/tera-ramsan/
Anyone purchasing one will be expected to post benchmarks! :)
--
Jim C. Nasby, Sr. Engineering Consultant [EMAIL PROTECTED]
Pervasive So
Jim Nasby wrote:
PostgreSQL tuned to the max and still too slow? Database too big to
fit into memory? Here's the solution!
http://www.superssd.com/products/tera-ramsan/
Anyone purchasing one will be expected to post benchmarks! :)
And give us one :)
--
Jim C. Nasby, Sr. Engineering Consulta
On Thu, 2006-03-16 at 10:57 -0500, Tom Lane wrote:
> Simon Riggs <[EMAIL PROTECTED]> writes:
> > Trying to get the information in the wrong place would be very
> > expensive, I agree. But preparing that information when we have access
> > to it and passing it through the plan would be much cheaper.
Simon Riggs wrote:
> [BTW how do you add new indexes to system tables? I want to add one to
> pg_inherits but not sure where to look.]
See src/include/catalog/indexing.h -- I don't remember if there's
anything else that needs modification.
--
Alvaro Herrerahttp:/
On Thu, 2006-03-16 at 15:41 -0400, Alvaro Herrera wrote:
> Simon Riggs wrote:
>
> > [BTW how do you add new indexes to system tables? I want to add one to
> > pg_inherits but not sure where to look.]
>
> See src/include/catalog/indexing.h -- I don't remember if there's
> anything else that needs
Simon Riggs <[EMAIL PROTECTED]> writes:
> I was thinking that we would fill out the OpExpr with different
> opclasses for each plan, so each one sees a different story. (I was
> thinking there was a clauselist for each plan; if not, there could be.)
This is backwards: there isn't a plan yet. If t
On Thu, 2006-03-16 at 14:45 -0500, Tom Lane wrote:
> Simon Riggs <[EMAIL PROTECTED]> writes:
> > [BTW how do you add new indexes to system tables? I want to add one to
> > pg_inherits but not sure where to look.]
>
> src/include/catalog/indexing.h
>
> Offhand I think adding a new entry is all you
Hi
I have a performance problem when traversing a table in index order with
multiple columns including a date column in date reverse order. Below
follows a simplified description of the table, the index and the
associated query
\d prcdedit
prcdedit_prcd | character(20) |
prc
The US Dept of Homeland Security has at least two =10=TB SSDs.
Rumor is they are being used for Carnivore or an offshoot/descendent of
Carnivore.
Good luck getting them to give you benchmark data.
You need >deep< pockets to afford >= 1TB of SSD.
(...and as the example shows, perhaps more money
On 3/16/06, Jim Nasby <[EMAIL PROTECTED]> wrote:
> PostgreSQL tuned to the max and still too slow? Database too big to
> fit into memory? Here's the solution! http://www.superssd.com/
> products/tera-ramsan/
>
> Anyone purchasing one will be expected to post benchmarks! :)
Pricing is tight-lipped,
explain analyze
select distinct eventmain.incidentid, eventmain.entrydate,
eventgeo.long, eventgeo.lat, eventgeo.geox, eventgeo.geoy
from eventmain, eventgeo
where
eventmain.incidentid = eventgeo.incidentid and
( long > -104.998027962962 and long < -104.985957781349 ) and
( lat > 39.707
Dan Harris wrote:
explain analyze
doh.. sorry to reply to my own post. But I messed up copying some
of the fields into the select statement that you'll see in the "Sort
Key" section of the analyze results. The mistake was mine. Everything
else is "normal" between the query and the plan
>>> On Thu, Mar 16, 2006 at 12:15 pm, in message
<[EMAIL PROTECTED]>, Evgeny Gridasov
<[EMAIL PROTECTED]> wrote:
>
> please, could you post other settings from your postgresql.conf?
Everything in postgresql.conf which is not commented out:
listen_addresses = '*' # what IP interface(s)
Jim,
> PostgreSQL tuned to the max and still too slow? Database too big to
> fit into memory? Here's the solution! http://www.superssd.com/
> products/tera-ramsan/
With a single 3 Gbyte/second infiniband connection to the device?
You'd be better off with 4 x $10K servers that do 800MB/s from dis
Jim,
On 3/16/06 10:44 PM, "Luke Lonergan" <[EMAIL PROTECTED]> wrote:
> Plus - need more speed? Add 12 more servers, and you'd run at 12.8GB/s and
> have 96TB of disk to work with, and you'd *still* spend less on HW and SW
> than the SSD.
And I forgot to mention that with these 16 servers you'd
Luke,
> With a single 3 Gbyte/second infiniband connection to the device?
Hey, take it easy! Jim's post was tongue-in-cheek.
--
Josh Berkus
Aglio Database Solutions
San Francisco
---(end of broadcast)---
TIP 5: don't forget to increase your fre
> I have a performance problem when traversing a table in index order with
> multiple columns including a date column in date reverse order. Below
> follows a simplified description of the table, the index and the
> associated query
>
> \d prcdedit
> prcdedit_prcd | character(20)
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