Re: [WIP]Vertical Clustered Index (columnar store extension) - take2

On Tue, Jul 22, 2025 at 8:12 PM Japin Li <japinli(at)hotmail(dot)com> wrote:
...
> 1.
> I encountered another crash while checking VCI's internal relations.
>
> rm -rf demo
> initdb -D demo
> cat <<EOF >demo/postgresql.auto.conf
> shared_preload_libraries = 'vci'
> max_worker_processes = '20'
> EOF
>
> pg_ctl -D demo start
>
> cat <<EOF | psql postgres
> CREATE EXTENSION vci;
> CREATE TABLE t (id int, info text);
> CREATE INDEX ON t USING vci (id);
> SELECT relname FROM pg_class WHERE relname ~ '^vci_*' LIMIT 1 \gset
> SELECT * FROM :relname;
> \d+ :relname
> REFRESH MATERIALIZED VIEW :relname;
> EOF
>
> VCI's definition of internal relations as materialized views lacks the
> corresponding view bodies.
>
> + /*
> + * @see
> + * https://www.postgresql.jp/document/9.4/html/catalog-pg-rewrite.html
> + */
> + new_rel_reltup->relhasrules = true;
> +
> + new_rel->rd_att->tdtypeid = new_type_oid;
> +
> + InsertPgClassTuple(pg_class, new_rel, new_oid, (Datum) 0, (Datum) 0);
>
> Given that VCI's internal relations are materialized views, are VCI workers
> responsible for their periodic refreshment?
>
> Or is it by design that users are unable to read the internal relations?
>

IIUC, those VCI internal relations (implemented as materialized views)
are entirely managed by VCI logic. Users are not required to be aware
of them, and they definitely are not meant to tamper with them.

The REFRESH that you attempted should have caused a more graceful error, like:
ERROR: extension "vci" prohibits this operation on view
"vci_0000016482_00000_d"
So, thanks for reporting that the ERROR failed. Investigating...

======
Kind Regards,
Peter Smith.
Fujitsu Australia