Re: Index split WAL reduction

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.

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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

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