Re: results via pgAdmin but not via psycopg2

From: Krystian Samp <samp(dot)krystian(at)gmail(dot)com>
To: Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net>
Cc: psycopg(at)postgresql(dot)org
Subject: Re: results via pgAdmin but not via psycopg2
Date: 2013-12-31 12:52:51
Message-ID: 5570D677-2875-4DE2-A6E1-7A615C173E86@gmail.com
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Hi Karsten,

Thank you so much, this was the problem indeed, and “connection.commit()” solved it.

Didn’t think about committing after a SELECT command.

Now I can peacefully end 2013!

Thanks and Happy New Year!

On 31 Dec 2013, at 12:07, Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net> wrote:

> now() always returns the transaction start timestamp.
>
> Might that be it ?
>
> Karsten
>
> On Tue, Dec 31, 2013 at 11:44:46AM +0000, Krystian Samp wrote:
>
>> Hello everyone,
>>
>> I’ve been struggling with an issue for 2 days now and couldn’t find the answer via google search.
>>
>> here’s a method of my db class:
>>
>> def get_old_feeds( self, not_refreshed_for_secs ):
>> cursor = self.connection.cursor( cursor_factory = psycopg2.extras.RealDictCursor )
>> cursor.execute( "SELECT id, url FROM feeds WHERE refreshed_on is not NULL AND refreshed_on < ( now() - interval '%s seconds' );", ( not_refreshed_for_secs, ) )
>> old_feeds = cursor.fetchall()
>> cursor.close()
>> return old_feeds
>>
>> there’s a loop that invokes this method every X minutes. All “old_feeds” get their value for “refreshed_on” updated to the current date when processed using this method:
>>
>> def set_feed_last_refresh( self, feed_id, refresh_datetime ):
>> cursor = self.connection.cursor()
>> cursor.execute( "UPDATE feeds SET refreshed_on = %s WHERE id = %s;", ( refresh_datetime, feed_id ) )
>> self.connection.commit()
>> cursor.close()
>>
>> The problem is that the select query in the first method returns some results only the first time it is run, all subsequent executions give 0 results. The odd thing is that when I issue exactly the same query via pgAdmin I get the results as one would expect.
>>
>> I’d highly appreciate your help with this issue,
>>
>> Thank you,
>> Krystian
>>
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