Re: Querying an index's btree version

Thank you for the info, Peter.

Separate but related follow-up question: when you restore a DB from a
backup, does the restored index use the old format or the latest one?

Thank you,
Darren Lafreniere

On Wed, Mar 11, 2020 at 4:30 PM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:

> On Wed, Mar 11, 2020 at 1:26 PM Darren Lafreniere
> <dlafreniere(at)onezero(dot)com> wrote:
> > We've read that PG 12 has improved btree index support, and that the
> latest internal btree version was bumped from 3 to 4. Is it possible to
> query the btree version that a particular index is using? We'd like to
> automatically start a concurrent re-index if we detect any btree indexes
> are still on version 3.
>
> It's possible, but you have to install the superuser-only pageinspect
> extension. Here is how you'd determine that an index called
> 'pg_aggregate_fnoid_index' is on version 4:
>
> regression=# create extension pageinspect;
> CREATE EXTENSION
> regression=# select version from bt_metap('pg_aggregate_fnoid_index');
> version
> ---------
> 4
> (1 row)
>
> --
> Peter Geoghegan
>

--
*Darren Lafreniere*
Senior Software Engineer | oneZero Financial Systems

site: www.onezero.com
email: dlafreniere(at)onezero(dot)com

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