Re: pg_rawdump

On Wed, Oct 20, 2010 at 5:30 PM, Stephen R. van den Berg <srb(at)cuci(dot)nl> wrote:
> Ideal would be: put the table-oid inside the header of each page
> (either in the official header, or in the special area).
> This way even lost blocks can be correlated to the same table.
> I'd still vote for the latest known table definition in the first
> page.  It's by no means perfect, but it will help 99% of all
> salvage attempts by an order of magnitude.

I don't think we should shrink the amount of usable space by 4 bytes
per block and break on-disk compatibility just to make it easier to
reconstruct corrupted tables.

I'm pretty dubious about the proposal to stuff an otherwise-useless
metapage in every heap, too. If you have many small tables, you just
doubled your disk utilization - worse than that, maybe, if some of
them are empty. If we needed a metapage anyway and had extra space to
play with, stuffing some useful forensic information in there might be
worthwhile, but I have a hard time thinking that forensics alone is a
sufficient justification for such a change.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company