Re: Improving REINDEX for system indexes (long)

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Tom, would you summarize what REINDEX currently _doesn't_ do?
> 
> As of CVS tip I think the only deficiency is that indexes on the shared
> catalogs (pg_database, pg_shadow, pg_group) have to be reindexed in
> place, rather than being rebuilt with a new relfilenode as is done for
> CLUSTER or TRUNCATE.  In-place reindexing isn't crash-safe, since if
> you fail you're left with a half-built (effectively corrupt) index.
> 
> I don't see any way to avoid that, though, since we cannot change the
> relfilenode value for a shared index.
> 
> I was toying with the notion of changing btree index build to not write
> the metapage until the index is fully built; in this way, at least the
> corrupted state of the index would be obvious.  (You'd get "not a btree"
> failures.)

Oh, that's great. I can't imagine a lot of traffic in those shared
tables anyway.  So you implemented all the ideas in the email --- great.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073