Re: Index split WAL reduction

Sorry, please disregard.  Newer patch being added.

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Bruce Momjian wrote:
>
> Your patch has been added to the PostgreSQL unapplied patches list at:
>
>     http://momjian.postgresql.org/cgi-bin/pgpatches
>
> It will be applied as soon as one of the PostgreSQL committers reviews
> and approves it.
>
> ---------------------------------------------------------------------------
>
>
> Heikki Linnakangas wrote:
> > Here's an updated patch that fixes a bug with full_page_writes, and an
> > alignment issue in replay code. Also added a new test case to
> > crashtest.sh that exercises the fixed bug.
> >
> > Has anyone looked at this? I now consider it ready for committing, if
> > no-one sees a problem with it.
> >
> > Here's the original description of the patch:
> >
> > > Currently, an index split writes all the data on the split page to
> > > WAL. That's a lot of WAL traffic. The tuples that are copied to the
> > > right page need to be WAL logged, but the tuples that stay on the
> > > original page don't.
> > >
> > > Here's a patch to do that. It needs further testing, I have used the
> > > attached crude crashtest.sh to test the basics, but we need to test
> > > the more obscure cases like splitting non-leaf or root page.
> > >
> > > On a test case that inserts 10000 rows in increasing key order with a
> > > 100 characters wide text-field as key, the patch reduced the total
> > > generated WAL traffic from 45MB to 33MB, or ~ 25%. Your mileage may
> > > vary, depending on the tuple and key sizes, and the order of inserts.
> >
> > --
> >    Heikki Linnakangas
> >    EnterpriseDB   http://www.enterprisedb.com
>
> [ application/x-shellscript is not supported, skipping... ]
>
>
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> --
>   Bruce Momjian   bruce@momjian.us
>   EnterpriseDB    http://www.enterprisedb.com
>
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--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +