Re: Prototype: In-place upgrade

The patch seems to be missing the new htup.c file.

Zdenek Kotala wrote:
> Attached patch is prototype of in-place upgrade as was presented on
> PGCon this year.
>
> Main idea is to learn postgres to handle different version of page and
> tuple structures.
>
> 1) page - Patch contains new page API and all code access page through
> this API. Functions check page version and return correct data to
> caller. It is mostly complete now. Only ItemId flags need finish.
>
> 2) tuple - HeapTuple structure has been extended with t_ver attribute
> which contains page layout version and direct access to HeapTupleHeader
> is forbidden. It is possible now only through HeapTuple* functions (see
> htup.c). (HeapTupleHeader access still stays in a several functions like
> heap_form_tuple).
>
> This patch version still does not allow to read old database, but it
> shows how it should work. Main disadvantage of this approach is
> performance penalty.
>
> Please, let me know your opinion about this approach.
>
> Future work:
> 1) learn WAL to process different tuple structure version
> 2) tuple conversion to new version and put it into executor
> (ExecStoreTuple)
> 3) multiversion MaxItemSize constant

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com