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

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In article <mailman.3977.1364605026.2939.python-list@python.org>,
 Chris Angelico <rosuav@gmail.com> wrote:

> On Sat, Mar 30, 2013 at 11:41 AM, Roy Smith <roy@panix.com> wrote:
> > In article <mailman.3971.1364595940.2939.python-list@python.org>,
> >  Dennis Lee Bieber <wlfraed@ix.netcom.com> wrote:
> >
> >> If using MySQLdb, there isn't all that much difference... MySQLdb is
> >> still compatible with MySQL v4 (and maybe even v3), and since those
> >> versions don't have "prepared statements", .executemany() essentially
> >> turns into something that creates a newline delimited "list" of
> >> "identical" (but for argument substitution) statements and submits that
> >> to MySQL.
> >
> > Shockingly, that does appear to be the case.  I had thought during my
> > initial testing that I was seeing far greater throughput, but as I got
> > more into the project and started doing some side-by-side comparisons,
> > it the differences went away.
> 
> 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.

Hmmm, on the other hand, I could probably try doing the initial dump the 
way you describe.  If it fails, we can just delete the whole thing and 
start again.

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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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