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FW: Out of swap space & memory



-----Original Message-----
From: Kevin Bartz [mailto:kb****@loyaltymatrix.com]
Sent: Monday, August 09, 2004 10:37 AM
To: 'm***@thegodshalls.com'
Subject: RE: [GENERAL] Out of swap space & memory

Thanks for your reply, Mike! Theoretically, I should need only six of the
columns, but as a means of verifying integrity, I would like to de-dup using
all the columns. For instance, if there are two rows identical everywhere
but some column outside the six, I would like to know about it so I can
report back to the data provider. Maybe there's some other way to do this
kind of check?

Kevin

-----Original Message-----
From: mike g [mailto:mi**@thegodshalls.com]
Sent: Friday, August 06, 2004 9:07 PM
To: Kevin Bartz
Subject: RE: [GENERAL] Out of swap space & memory

hmmmm, Can you determine which are rows are duplicates by examining one
column or must you examine all the columns?
On Fri, 2004-08-06 at 22:56, Kevin Bartz wrote:
Thanks for your reply, but how can I then solve the problem of duplicates?
Using your example, if one duplicate lives between rows 1 and 1,000,000 and another between rows 1,000,001 and 2,000,000, de-duping them individually
will result in the duplicate showing up twice.

Kevin

-----Original Message-----
From: mike g [mailto:mi**@thegodshalls.com]
Sent: Friday, August 06, 2004 8:52 PM
To: Kevin Bartz
Subject: RE: [GENERAL] Out of swap space & memory

Can octanenights_raw be altered? If so using the Sequence feature in
postgres you could autopopulate that column with a number starting at 1
on up to 36 million. Then your select queries could be select X from
octanenights_raw where sequence_column_name > 1 and sequence_column_name
< 1000000 etc.

Mike

On Fri, 2004-08-06 at 22:40, Kevin Bartz wrote:
Well, all I'm doing right now is using psql from the command line. A bit
unintelligent, I know, but I want to make sure things will work
appropriately before I dive into the world of query editors.

Thanks for your suggestions. My data won't need to be updated regularly. In
this case, as in all others, loading each set of data is a one-shot

process,
so I don't think I'll need to worry about truncating.

I can't think of any way to break the problem into steps, since the
duplicates may well be scattered throughout the table. If I split
octanenights into octanenights1 and octanenights2 and then de-dup each
individually, I would have to first be sure that octanenights1 does not
share a duplicate with octanenights2, or that duplicate would appear in

the
UNION ALLed version. Maybe I'm missing something?

Thanks for your kind response.

Kevin

-----Original Message-----
From: mike g [mailto:mi**@thegodshalls.com]
Sent: Friday, August 06, 2004 8:19 PM
To: Kevin Bartz
Cc: 'Manfred Koizar'; pg***********@postgresql.org
Subject: Re: [GENERAL] Out of swap space & memory

Ok,

This is a long shot but how are you executing your code? In say a
pgadminIII sql window with the below entered line after line?

If so I believe it will be treated as one transaction. With the default
settings postgres would have to keep track of everything done to be able
to rollback all the changes if it failed. I would believe that would
force it to keep track of all 56 million rows combined in memory
(probably just the oid column - I am sure the other more experienced
postgresql wizards can verify) but still that can take a lot of
resources.

If by chance you are doing it one sweep try executing it in separate
steps so the commit can be executed.

Hopefully then you won't run out of resources then.

Are you doing a drop / create say everynight to update your data? If so
perhaps using TRUNCATE octanenights might be more efficient.

If you must drop a full table perhaps a vacuum should be done
afterwards???

Mike

On Fri, 2004-08-06 at 21:32, Kevin Bartz wrote:
Mike, thanks so much for your reply. I'm sorry for not showing you my SQL.
I
didn't show it because I couldn't manage to boil it down to something
reproducible that everyone could try. But here's what it was:

drop table octanenights;
CREATE TABLE octanenights (member_id varchar(100), campaign_id

varchar(100),
catalog_type varchar(100), pushed int, delivered int, clicks int, opened int, month varchar(100), type1 int, type2 int, type3 int, type4 int,

type5 int);

copy octanenights from
'/home/kevin/octanenights/proc/uberfile/uberfile1.txt' null as '';
copy octanenights from
'/home/kevin/octanenights/proc/uberfile/uberfile2.txt' null as '';
copy octanenights from
'/home/kevin/octanenights/proc/uberfile/uberfile3.txt' null as '';

select * from octanenights limit 10;
alter table octanenights rename to octanenights_raw;

-- de-dup the table
select member_id, campaign_id, catalog_type, pushed, delivered, clicks, opened, month, type1, type2, type3, type4, type5
into octanenights
from octanenights_raw
group by member_id, campaign_id, catalog_type, pushed, delivered, clicks, opened, month, type1, type2, type3, type4, type5;

Let me tell you a little about octanenights. It's a file of about

36,000,000
rows, each describing an e-mail sent. Unfortunately, there are duplicate records scattered throughout the table, which I do not care about. One

might
suggest that I could've used uniq from the command line for this, but the data were not sorted originally and the duplicate records may be scattered anywhere in the table. The objective in the final line is to de-dup the table and place it into octanenights, leaving the original in
octanenights_raw in case I ever need to refer back to it.

MS SQL Server, with as much RAM and less clock speed, de-dups the table in
about six minutes. The de-duped version has about 26,000,000 rows. The

final
line is where Postgres gobbles up all my swap and RAM and then conks
out completely.

Am I doing something wrong? Maybe there was a better way to approach

this problem? I'd be open to suggestions of any kind, since I'm still very,

very
new to the world of optimizing Postgres.

Kevin

-----Original Message-----
From: pg*****************@postgresql.org
[mailto:pg*****************@postgresql.org] On Behalf Of Manfred Koizar Sent: Tuesday, August 03, 2004 3:04 AM
To: Kevin Bartz
Cc: pg***********@postgresql.org
Subject: Re: [GENERAL] Out of swap space & memory

On Mon, 2 Aug 2004 20:08:45 -0700, "Kevin Bartz"
<kb****@loyaltymatrix.com> wrote:
>is there any way I can run this query?

What query? You didn't show us your SQL.

Servus
Manfred

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Nov 23 '05 #1
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