The option with
T1: A B C and T2 A D (to avoid the updates)
works very well with a simple query
Insert into T2 (A, D)
select A, functionToGetD from T1 left join T2 on T1.A = T2.A
where T2.A is null
The above gives me the new records for those where D was not filled yet.
Since they are all
Thanks again everyone for the excellent suggestions.
I looked into IO::Reactor, but after a few hours of fiddling decided I was
getting the kind of performance I wanted from using a slightly more than
modest number of threads and decided(due to dev timelines) to come back to
patching the SNMP
I am running PostgreSQL 8.0.x on Solaris 10 AMD64. My Tablesize for this
test is about 80G. When I run a query on a column which is not indexed, I
get a full table scan query and that's what I am testing right now. (I am
artificially creating that scenario to improve that corner
Merlin Moncure [EMAIL PROTECTED] writes:
One thing that might interest you is that the penalty in 8.1 for
stats_command_string=true in this type of access pattern is very high: I
was experimenting to see if the new cpu efficiency gave me enough of a
budget to start using this. This more than
On Sun, 2005-08-21 at 16:13 -0400, Ron wrote:
At 10:54 AM 8/21/2005, Jeremiah Jahn wrote:
On Sat, 2005-08-20 at 21:32 -0500, John A Meinel wrote:
Well, since you can get a read of the RAID at 150MB/s, that means that
it is actual I/O speed. It may not be cached in RAM.
PERC4eDC-PCI Express, 128MB Cache, 2-External Channels
Looks like they are using the LSI Logic MegaRAID SCSI 320-2E
controller. IIUC, you have 2 of these, each with 2 external channels?
A lot of people have mentioned Dell's versions of the LSI cards can be
WAY slower than the
Jignesh Shah [EMAIL PROTECTED] writes:
Running a script (available on my blog) I find the following top 5 functions
where it spends most time during a 10 second run of the script
It's pretty risky to draw conclusions from only 10 seconds' worth of
gprof data --- that's only 1000 samples total
On 8/22/05 8:41 AM, Tom Lane [EMAIL PROTECTED] wrote:
MemoryContextSwitchTo and LockBuffer itself takes 15% of the total time of
the query. I was expecting read to be the slowest part (biggest component)
but it was way down in the 0.4% level.
You do know that gprof counts only CPU
That seems quite peculiar; AFAICS the pgstat code shouldn't be any
slower than before. At first I thought it might be because we'd
increased PGSTAT_ACTIVITY_SIZE, but actually that happened before
8.0 release, so it shouldn't be a factor in this comparison.
Just FYI the last time I looked at
Also is there any way to optimize LockBuffer?
Yes, test on 8.1. The buffer manager was re-written for 8.1. You should
see a decrease in both LockBuffer and context switch activity.
Aglio Database Solutions
Like I mentioned I am using DTrace on Solaris 10 x64 and not gprof.
DTrace is not based on sampling but actual entry/exit point. Ofcourse my 10
second profile is just a sample that I can assure you is representative of
the query since it is a very simple query that does simple table
Jignesh Shah wrote:
Now the question is why there are so many calls to MemoryContextSwitchTo
in a single SELECT query command? Can it be minimized?
I agree with Tom -- if profiling indicates that MemoryContextSwitchTo()
is the bottleneck, I would be suspicious that your profiling setup is
On Tue, Aug 16, 2005 at 09:29:32AM +0200, Sebastian Hennebrueder wrote:
I would like to test the performance of my Java/PostgreSQL applications
especially when making full text searches.
For this I am looking for a database with 50 to 300 MB having text fields.
e.g. A table with
RRS (http://rrs.decibel.org) might be of use in this case.
On Tue, Aug 16, 2005 at 01:59:53PM -0400, Alex Turner wrote:
Are you calculating aggregates, and if so, how are you doing it (I ask
the question from experience of a similar application where I found
that my aggregating PGPLSQL
I am looking for the latest pgbench and documentation.
If someone know where I can locate them it would save a lot of search time.
TPC-C Benchmarks Sybase
Rio de Janeiro, RJ, Brazil 22031-010
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