Re: [HACKERS] [COMMITTERS] pgsql: Release note updates. - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: [HACKERS] [COMMITTERS] pgsql: Release note updates.
Date
Msg-id 20170207155931.vgzv5umuyfvp4bqz@alvherre.pgsql
Whole thread Raw
In response to Re: [HACKERS] [COMMITTERS] pgsql: Release note updates.  (Alvaro Herrera <alvherre@2ndquadrant.com>)
Responses Re: [HACKERS] [COMMITTERS] pgsql: Release note updates.  (Pavan Deolasee <pavan.deolasee@gmail.com>)
List pgsql-hackers
Alvaro Herrera wrote:
> Tom Lane wrote:
> > Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> 
> > > May I suggest
> > 
> > > +      If <command>CREATE INDEX CONCURRENTLY</> was used to build an index
> > > +      that depends on a column not previously indexed, then rows
> > > +      updated by transactions that ran concurrently with
> > > +      the <command>CREATE INDEX</> command could have missed receiving
> > > +      index entries.
> > 
> > Can we say "pre-existing rows that were updated by...", or is that
> > too optimistic?
> 
> Hmm.  Now that I think about it, it is probably possible to have a
> transaction started before CIC that inserted a bunch of rows, and then
> runs the UPDATE during the CIC race window.  Maybe there's a reason the
> bug wouldn't hit in that case but I don't see it, and I'm not able to
> test it right now to verify.

Pavan adds that it's possible to have a transaction do INSERT while CIC
is running, then some other transaction executes the UPDATE.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services



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