Re: Re: [COMMITTERS] pgsql: Avoid extra locks in GetSnapshotData if old_snapshot_threshold <

On Wed, Jun 15, 2016 at 1:45 PM, Alvaro Herrera
<alvherre@2ndquadrant.com> wrote:

> Maybe it is possible to get into trouble if you're taking a sample for
> an expression index.

Maybe -- if you are using a function for an index expression which
does an explicit SELECT against some database table rather than
only using values from the row itself.  In such a case you would
have had to mark a function as IMMUTABLE which depends on table
contents.  I say you get to keep both pieces.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company