[WIP] In-place upgrade

This is really first patch which is not clean up, but it add in-place upgrade
functionality. The patch requires other clean up patches which I already send.
You can find aslo GIT repository with "workable" version.

Main point is that tuples are converted to latest version in SeqScan and
IndexScan node. All storage/access module is able process database 8.1-8.4.
(Page Layout 3 and 4).

What works:
- select - heap scan is ok, but index scan does not work on varlena datatypes. I
need to convert index key somewhere in index access.

What does not work:
- tuple conversion which contains arrays, composite datatypes and toast
- vacuum - it tries to cleanup old pages - probably better could be converted
them to the new format during processing...
- insert/delete/update

The Patch contains lot of extra comments and rubbish, but it is in process of
cleanup.

What I need to know/solve:

1) yes/no for this kind of online upgrade method
2) I'm not sure if the calling ExecStoreTuple correct.
3) I'm still looking best place to store old data structures and conversion
functions. My idea is to create new directories:
src/include/odf/v03/...
src/backend/storage/upgrade/
src/backend/access/upgrade
(odf = On Disk Format)

Links:
http://git.postgresql.org/?p=~davidfetter/upgrade_in_place/.git;a=summary
http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/postgres/postgresql-upgrade/

Thanks for your comments

Zdenek

--
Zdenek Kotala Sun Microsystems
Prague, Czech Republic http://sun.com/postgresql