[PyGreSQL] PyGreSQL Digest, Vol 46, Issue 4

Mon Apr 23 05:37:51 EDT 2007

Joseph and Chris,
Thanks for your suggestions. I will try the various tips you gave, but will also post the code later today in case anyone can point out something that's been glaring at me. The more I think about it, the more it seems to me that it's neither the connection nor the database, that it's probably the business of validating/formatting the code, but it doesn't make a whole lot of sense given that the number of function calls (which is proportional to the number of rows in the table from which data is fetched) doesn't seem to make a large difference.
Anyway, perhaps you'll be able to tell me more when I post some code.
Hagop

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Today's Topics:

   1. Re: PyGreSQL Digest, Vol 46, Issue 3 (Joseph Armbruster)

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Message: 1
Date: Sat, 21 Apr 2007 19:15:12 -0400
From: "Joseph Armbruster" 
Subject: Re: [PyGreSQL] PyGreSQL Digest, Vol 46, Issue 3
To: pygresql at vex.net
Message-ID:
 <938f42d70704211615j4631cc23q23e3ec26b5ecda80 at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

Hagop,

Do you have a pastebin of your code or a reasonably equivalent snippet?
Include the corresponding SQL create table and inserts.

Joseph Armbruster

On 4/21/07, pygresql-request at vex.net 
 wrote:
>
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> or, via email, send a message with subject or body 'help' to
>         pygresql-request at Vex.Net
>
> You can reach the person managing the list at
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>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of PyGreSQL digest..."
>
>
> Today's Topics:
>
>    1. pygresql connection speeds issue (Hagop Narsesian)
>    2. Re: pygresql connection speeds issue (Christoph Zwerschke)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 21 Apr 2007 03:29:33 -0700 (PDT)
> From: Hagop Narsesian 
> Subject: [PyGreSQL] pygresql connection speeds issue
> To: pygresql at Vex.Net
> Message-ID: <60744.10079.qm at web63610.mail.re1.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> Hello all,
> I'm quite new to pygresql and very new to the list.
>
> I am using pygresql for python 2.4 to connect to my
> postgresql 8.2 db. I normally open the connection only
> for the duration of the action I require, and then
> close it again. When I perform inserts or deletes, the
> process is quick. But when I have to carry out a
> select query, it can take up to 6 or 7 seconds, even
> for queries from tables that are no larger than 60 or
> 70 rows and that are indexed.
>
> Initially I thought this was because of the overheads
> of the connection, but in this event, inserts should
> also take very long, shouldn't they?
>
> I carry out some basic validations and formatting
> after fetching the query, but I'm pretty sure this
> can't be taking up the time, as it remains slow even
> when I fetch a single row, and it doesn't seem to
> matter too much whether it's 1 row 150, and I rarely
> fetch any more than about 150.
>
> Anyone have any suggestions? Should I be keeping
> connections open all the time?
> Hagop
>
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> ------------------------------
>
> Message: 2
> Date: Sat, 21 Apr 2007 13:14:11 +0200
> From: Christoph Zwerschke 
> Subject: Re: [PyGreSQL] pygresql connection speeds issue
> To: PyGreSQL Development 

> Message-ID: <4629F203.3030503 at online.de>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi Hagop,
>
> > But when I have to carry out a select query,
> > it can take up to 6 or 7 seconds, even for queries
> > from tables that are no larger than 60 or 70 rows
> > and that are indexed.
> > ...
> > Initially I thought this was because of the overheads
> > of the connection, but in this event, inserts should
> > also take very long, shouldn't they?
>
> You're right, creating a connection is a certain overhead, but it should
> not be THAT much ;-) Something that is also important is to VACUUM your
> database tables, but for a table with 60 rows that cannot be the reason
> as well (plus PostgreSQL 8.2 has auto vaccuum). So something in your
> database setup seems to be foul. Have a look at the database server
> logs. What happens if you do the same things with PgAdmin? Does it
> happen with both the pg and pgdb adapters?
>
> If you're worried about the connection overhead you can use a connection
> pool (e.g. http://www.webwareforpython.org/DBUtils), but this is
> certainly not causing the delays you are seeing here.
>
> -- Chris
>
>
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> End of PyGreSQL Digest, Vol 46, Issue 3
> ***************************************
>
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