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Re: How to find bad row with db api executemany()?

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From Dennis Lee Bieber <wlfraed@ix.netcom.com>
Subject Re: How to find bad row with db api executemany()?
Date Fri, 29 Mar 2013 23:38:18 -0400
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On Fri, 29 Mar 2013 21:19:22 -0400, Roy Smith <roy@panix.com> declaimed
the following in gmane.comp.python.general:

> In article <mailman.3977.1364605026.2939.python-list@python.org>,
>  Chris Angelico <rosuav@gmail.com> wrote:
> 
> > 
> > How much are you doing per transaction? The two extremes (everything
> > in one transaction, or each line in its own transaction) are probably
> > the worst for performance. See what happens if you pepper the code
> > with 'begin' and 'commit' statements (maybe every thousand or ten
> > thousand rows) to see if performance improves.
> > 
> > ChrisA
> 
> We're doing it all in one transaction, on purpose.  We start with an 
> initial dump, then get updates about once a day.  We want to make sure 
> that the updates either complete without errors, or back out cleanly.  
> If we ever had a partial daily update, the result would be a mess.
>
	As I recall, DB-API compliance should have started a transaction
when you submit a statement, so explicit "begin" should not be required.

	My suggestion would be to first try just breaking the .executemany()
into chunks rather than everything at once. Submit maybe 500-1000
records at a time via .executemany(), checking for errors -- if a block
errors you can still rollback() the entire transaction AND you have a
smaller set of data to examine. Then at the end, if no errors, do the
commit()
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
        wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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Re: How to find bad row with db api executemany()? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-03-29 18:25 -0400
  Re: How to find bad row with db api executemany()? Roy Smith <roy@panix.com> - 2013-03-29 20:41 -0400
    Re: How to find bad row with db api executemany()? Chris Angelico <rosuav@gmail.com> - 2013-03-30 11:57 +1100
      Re: How to find bad row with db api executemany()? Roy Smith <roy@panix.com> - 2013-03-29 21:19 -0400
        Re: How to find bad row with db api executemany()? Chris Angelico <rosuav@gmail.com> - 2013-03-30 13:05 +1100
        Re: How to find bad row with db api executemany()? Tim Chase <python.list@tim.thechases.com> - 2013-03-29 22:17 -0500
        Re: How to find bad row with db api executemany()? (PS) Tim Chase <python.list@tim.thechases.com> - 2013-03-29 22:38 -0500
        Re: How to find bad row with db api executemany()? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-03-29 23:38 -0400
    Re: How to find bad row with db api executemany()? Roy Smith <roy@panix.com> - 2013-03-29 22:44 -0400
      Re: How to find bad row with db api executemany()? Chris Angelico <rosuav@gmail.com> - 2013-03-30 13:49 +1100
        Re: How to find bad row with db api executemany()? Roy Smith <roy@panix.com> - 2013-03-29 23:09 -0400
          Re: How to find bad row with db api executemany()? Chris Angelico <rosuav@gmail.com> - 2013-03-30 14:14 +1100
            Re: How to find bad row with db api executemany()? Roy Smith <roy@panix.com> - 2013-03-29 23:36 -0400
              Re: How to find bad row with db api executemany()? Chris Angelico <rosuav@gmail.com> - 2013-03-30 14:57 +1100
                Re: How to find bad row with db api executemany()? Roy Smith <roy@panix.com> - 2013-03-30 00:10 -0400
                Re: How to find bad row with db api executemany()? Chris Angelico <rosuav@gmail.com> - 2013-03-30 15:21 +1100
                Re: How to find bad row with db api executemany()? Roy Smith <roy@panix.com> - 2013-03-30 10:19 -0400
        Re: How to find bad row with db api executemany()? rusi <rustompmody@gmail.com> - 2013-03-29 20:13 -0700
          Re: How to find bad row with db api executemany()? rusi <rustompmody@gmail.com> - 2013-03-29 20:15 -0700
          Re: How to find bad row with db api executemany()? Roy Smith <roy@panix.com> - 2013-03-29 23:40 -0400
      Re: How to find bad row with db api executemany()? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-03-29 23:53 -0400
      Re: How to find bad row with db api executemany()? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-03-30 00:19 -0400
      Re: How to find bad row with db api executemany()? Chris Angelico <rosuav@gmail.com> - 2013-03-30 15:24 +1100
      Re: How to find bad row with db api executemany()? Tim Chase <python.list@tim.thechases.com> - 2013-03-30 06:38 -0500

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