Problem solved.. I set the fetchSize to a reasonable value instead of
the default of unlimited in the PreparedStatement and now the query
is . After some searching it seeems this is a common problem, would it
make sense to change the default value to something other than 0 in
the JDBC driver?
If
Vijay Moses <[EMAIL PROTECTED]> writes:
> Hi i have four sample tables ename, esal, edoj and esum
> All of them have 100 records. Im running the following
> query : select ename.eid, name, sal, doj, summary from
> ename,esal,edoj,esum where ename.eid=esal.eid and ename.eid=edoj.eid
> and ename.
[EMAIL PROTECTED] writes:
> I am interested in tablespaces--what exactly is this feature, some sort of
> organizational addition (?) and howcan I best take advantage of this?
See
http://developer.postgresql.org/docs/postgres/manage-ag-tablespaces.html
It doesn't talk a lot yet about *why* yo
Damien Dougan wrote:
Basically we have a number of tables, which are exposed as 2 public
views (say PvA and PvB). For each row in PvA, there are a number of
related rows in PvB (this number is arbitrary, which is one of the
reasons why it cant be expressed as additional columns in PvA - so we
reall
Hi i have four sample tables ename, esal, edoj and esum
All of them have 100 records. Im running the following
query : select ename.eid, name, sal, doj, summary from
ename,esal,edoj,esum where ename.eid=esal.eid and ename.eid=edoj.eid
and ename.eid=esum.eid. Its a join of all four tables which
Hi, I have downloaded the new postgresql (version 8.0 beta2) and I was
wondering what performance features I can take advantage of before I start
to dump my 3/4 terrabyte database into the new database. More
specifically
I am interested in tablespaces--what exactly is this feature, some sort of
o
Mark Cotner wrote:
Hi all,
I had a difficult time deciding which list to post
this to, so please forgive me if this list doesn't
perfectly match my questions. My decision will not
solely be based on performance, but it is the primary
concern. I would be very appreciative if you all
could comment
Hi, I have downloaded the new postgresql (version 8.0 beta2) and I was
wondering what performance features I can take advantage of before I start
to dump my 3/4 terrabyte database into the new format. More specifically
I am interested in tablespaces--what exactly is this feature, some sort of
orga
Bruce Momjian <[EMAIL PROTECTED]> writes:
> If we had a majority of queries filling more than one block we would
> be checkpointing like crazy and we don't normally get reports about
> that.
[ raised eyebrow... ] And of course the 30-second-checkpoint-warning
stuff is a useless feature that no on
Stephen Crowley <[EMAIL PROTECTED]> writes:
> On Mon, 13 Sep 2004 21:11:07 -0400, Tom Lane <[EMAIL PROTECTED]> wrote:
>> Stephen Crowley <[EMAIL PROTECTED]> writes:
>>> Does postgres cache the entire result set before it begins returning
>>> data to the client?
>>
>> The backend doesn't, but libpq
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Hash: SHA1
Tom Lane wrote:
| Gaetano Mendola <[EMAIL PROTECTED]> writes:
|
|>Now that the argument is already open, why postgres choose
|>on linux fdatasync? I'm understanding from other posts that
|>on this platform open_sync is better than fdatasync.
|
|
| AFAIR
Tom Lane wrote:
> The tests that started this thread are pretty unconvincing in my eyes,
> because they are comparing open_sync against code that fsyncs after each
> one-block write. Under those circumstances, *of course* fsync will lose
> (or at least do no better), because it's forcing the same
On Mon, 13 Sep 2004 21:11:07 -0400, Tom Lane <[EMAIL PROTECTED]> wrote:
> Stephen Crowley <[EMAIL PROTECTED]> writes:
> > Does postgres cache the entire result set before it begins returning
> > data to the client?
>
> The backend doesn't, but libpq does, and I think JDBC does too.
>
> I'd recomm
On Mon, 2004-09-13 at 20:51, Stephen Crowley wrote:
> Does postgres cache the entire result set before it begins returning
> data to the client?
Sometimes you need to be careful as to how the clients treat the data.
For example psql will resize columns width on the length (width) of the
data ret
Stephen Crowley <[EMAIL PROTECTED]> writes:
> Does postgres cache the entire result set before it begins returning
> data to the client?
The backend doesn't, but libpq does, and I think JDBC does too.
I'd recommend using a cursor so you can FETCH a reasonable number of
rows at a time.
> Also, wh
Does postgres cache the entire result set before it begins returning
data to the client?
I have a table with ~8 million rows and I am executing a query which
should return about ~800,000 rows. The problem is that as soon as I
execute the query it absolutely kills my machine and begins swapping
for
Mark,
I thought some additional comments on top of Christopher's excellent notes
might help you.
> Christopher Browne
> The world rejoiced as Mischa Sandberg
> <[EMAIL PROTECTED]> wrote:
> > Mark Cotner wrote:
> >> Requirements:
> >> Merge table definition equivalent. We use these
> >> extensiv
Gaetano Mendola <[EMAIL PROTECTED]> writes:
> Now that the argument is already open, why postgres choose
> on linux fdatasync? I'm understanding from other posts that
> on this platform open_sync is better than fdatasync.
AFAIR, we've seen *one* test from *one* person alleging that.
And it was def
Gaetano,
> Now that the argument is already open, why postgres choose
> on linux fdatasync? I'm understanding from other posts that
> on this platform open_sync is better than fdatasync.
Not necessarily. For example, here's my test results, on Linux 2.6.7,
writing to a ReiserFS mount on a Soft
Bruce Momjian wrote:
Have you seen /src/tools/fsync?
Now that the argument is already open, why postgres choose
on linux fdatasync? I'm understanding from other posts that
on this platform open_sync is better than fdatasync.
However I choose open_sync. During initdb why don't detect
this parameter
Quoting Bruce Momjian <[EMAIL PROTECTED]>:
>
> Have you seen /src/tools/fsync?
>
I have now. Thanks.
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TIP 7: don't forget to increase your free space map settings
Have you seen /src/tools/fsync?
---
[EMAIL PROTECTED] wrote:
> Hi, I'd like to help with the topic in the Subject: line. It seems to be a
> TODO item. I've reviewed some threads discussing the matter, so I hope I've
Thanks for the thanks !
Generally, when grouping stuff together, it is a good idea to have two
sorted lists, and to scan them simultaneously. I have already used this
solution several times outside of Postgres, and it worked very well (it
was with Berkeley DB and there were 3 lists to sc
Pierre-Frederic, Paul,
Thanks for your fast response (especially for the python code and
performance figure) - I'll chase this up as a solution - looks most
promising!
Cheers,
Damien
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TIP 6: Have you searched our list arch
My simple python program dumps 1653992 items in 1654000 categories in :
real3m12.029s
user1m36.720s
sys 0m2.220s
It was running on the same machine as postgresql (AthlonXP 2500).
I Ctrl-C'd it before it dumped all the database but you get an idea.
If you don't know Python and Generators
There's a very simple solution using cursors.
As an example :
create table categories ( id serial primary key, name text );
create table items ( id serial primary key, cat_id integer references
categories(id), name text );
create index items_cat_idx on items( cat_id );
insert st
On 13/09/2004 12:38 Damien Dougan wrote:
[snip]
Are there any tools/tricks/tips with regards to extracting large volumes
of data across related tables from Postgres? It doesnt have to export
into XML, we can do post-processing on the extracted data as needed -
the important thing is to keep the rel
Hi All,
I am having a performance problem extracting a large volume of data from
Postgres 7.4.2, and was wondering if there was a more cunning way to get
the data out of the DB...
This isn't a performance problem with any particular PgSQL operation,
its more a strategy for getting large volumes
A long time ago, in a galaxy far, far away, [EMAIL PROTECTED] (Mark Cotner) wrote:
> Agreed, I did some preliminary testing today and am very impressed.
> I wasn't used to running analyze after a data load, but once I did
> that everything was snappy.
Something worth observing is that this is true
See comments . . . thanks for the feedback.
'njoy,
Mark
--- Christopher Browne <[EMAIL PROTECTED]> wrote:
> The world rejoiced as Mischa Sandberg
> <[EMAIL PROTECTED]> wrote:
> > Mark Cotner wrote:
> >> Requirements:
> >> Merge table definition equivalent. We use these
> >> extensively.
>
> >
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