Re: pgsql-server/src/backend catalog/index.c comma ...

"Hiroshi Inoue" <inoue(at)tpf(dot)co(dot)jp> writes:
> Why could you determine it ? Is PostgreSQL your system ?

Well, if you prefer, we can have a discussion and vote about it on pghackers.
But you have not answered my questions. Why was the code set up to
allow live reindexing of system tables via REINDEX TABLE, but not via
REINDEX INDEX or REINDEX DATABASE? It seems to me that those three
cases ought to work equally well or badly. Let's remove the restriction
from all three, if it's not needed.

>> Also, your assertion that it works doesn't convince me. That business
>> in reindex_table about doing two setRelhasindex() calls gave me the
>> willies. Why was that needed?

> The setRelhasIndex() has no meaning to other backends, i.e the false state
> is never visible to other backends.

Then why bother? I agree that it's probably not needed for other
backends --- since you have an exclusive lock on the table, nobody else
should be trying to examine it. But then why do it at all? The only
thing you need is to force IsIgnoringSystemIndexes true locally, which
would seem to me a much more secure way of proceeding.

The goal that I am trying to accomplish here is to make the reindexing
code more visibly safe and correct. I'm not convinced that we still
need live-reindexing capability in 7.4 (I think the btree space
recycling code solves the problem better). But I'm happy to leave it in
if these other questions can be addressed.

regards, tom lane