Re: Index recreation details with REINDEX TABLE CONCURRENTLY

On Wed, 2023-05-10 at 10:04 -0500, Matthew Planchard wrote:
> We're working on setting up some regular jobs to reindex tables where we
> wind up generating a lot of index bloat. We're planning on using REINDEX
> ... CONCURRENTLY. We'd like to reindex all of the indexes on the tables.
>
> In some of our environments, these tables are very large and under high
> load, and we want to minimize the resource consumption of index
> recreation if possible.
>
> With that in mind, my question is: does REINDEX TABLE CONCURRENTLY
> operate on the indexes of the table in parallel, or sequentially? If
> in parallel, I imagine we would see less DB resource utilization by
> updating one index at a time.

If you use REINDEX TABLE CONCURRENTLY, the indexes will be built one
after the other.  Set "max_parallel_maintenance_workers" to 0 to keep
the resource utilization low (at the price of a longer duration).

Yours,
Laurenz Albe