Re: POC: Parallel processing of indexes in autovacuum

Hi,

On 09/05/25 15:33, Daniil Davydov wrote:
> Hi,
> As I promised - meet parallel index autovacuum with bgworkers
> (Parallel-index-autovacuum-with-bgworkers.patch). This is pretty
> simple implementation :
> 1) Added new table option `parallel_idx_autovac_enabled` that must be
> set to `true` if user wants autovacuum to process table in parallel.
> 2) Added new GUC variable `autovacuum_reserved_workers_num`. This is
> number of parallel workers from bgworkers pool that can be used only
> by autovacuum workers. The `autovacuum_reserved_workers_num` parameter
> actually reserves a requested part of the processes, the total number
> of which is equal to `max_worker_processes`.
> 3) When an autovacuum worker decides to process some table in
> parallel, it just sets `VacuumParams->nworkers` to appropriate value
> (> 0) and then the code is executed as if it were a regular VACUUM
> PARALLEL.
> 4) I kept test/modules/autovacuum as sandbox where you can play with
> parallel index autovacuum a bit.
>
> What do you think about this implementation?
>
I've reviewed the v1-0001 patch, the build on MacOS using meson+ninja is
failing:
❯❯❯ ninja -C build install
ninja: Entering directory `build'
[1/126] Compiling C object
src/backend/postgres_lib.a.p/utils_misc_guc_tables.c.o
FAILED: src/backend/postgres_lib.a.p/utils_misc_guc_tables.c.o
../src/backend/utils/misc/guc_tables.c:3613:4: error: incompatible
pointer to integer conversion initializing 'int' with an expression of
type 'void *' [-Wint-conversion]
 3613 |                         NULL,
      |                         ^~~~

It seems that the "autovacuum_reserved_workers_num" declaration on
guc_tables.c has an extra gettext_noop() call?

One other point is that as you've added TAP tests for the autovacuum I
think you also need to create a meson.build file as you already create
the Makefile.

You also need to update the src/test/modules/meson.build and
src/test/modules/Makefile to include the new test/modules/autovacuum
path.

--
Matheus Alcantara