Re: Support for REINDEX CONCURRENTLY

On 10/8/12 6:12 PM, Tom Lane wrote:
> Jim Nasby <jim@nasby.net> writes:
>> Yeah, what's the risk to renaming an index during concurrent access?
>
> SnapshotNow searches for the pg_class row could get broken by *any*
> transactional update of that row, whether it's for a change of relname
> or some other field.
>
> A lot of these problems would go away if we rejiggered the definition of
> SnapshotNow to be more like MVCC.  We have discussed that in the past,
> but IIRC it's not exactly a simple or risk-free change in itself.
> Still, maybe we should start thinking about doing that instead of trying
> to make REINDEX CONCURRENTLY safe given the existing infrastructure.

Yeah, I was just trying to remember what other situations this has come up in. My recollection is that there's been a couple other cases where that would be useful.

My recollection is also that such a change would be rather large... but it might be smaller than all the other work-arounds that are needed because we don't have that...
-- 
Jim C. Nasby, Database Architect                   jim@nasby.net
512.569.9461 (cell)                         http://jim.nasby.net