Re: [PATCH] fastpacth-locks compile time options

Hope this patch will be usefull/

On Mon, Sep 18, 2023 at 5:47 PM Sergey Sergey <ioxgrey(at)gmail(dot)com> wrote:

> While replaying our production workload we have found Postgres spending a
> lot of time inside TimescaleDB planner. The planner itself need an
> information about whether a table involved is a TimescaleDB hypertable. So
> planner need an access to TimescaleDB internal metainformation tables. This
> planner access become extremely slow when you have a lot of tables involved
> and you are beyond fast-path lock limit
>
> This humble example makes only 2330 tps on REL_15_STABLE but 27041tps on
> patched version with 64 slots for fast-path locks.
>
> \set bid random(1,1000)
>
> BEGIN;
> select bbalance from pgbench_branches where bid = :bid
> UNION
> select bbalance from pgbench_branches2 where bid = :bid
> UNION
> select bbalance from pgbench_branches3 where bid = :bid
> UNION
> select bbalance from pgbench_branches4 where bid = :bid
> UNION
> select bbalance from pgbench_branches5 where bid = :bid
> UNION
> select bbalance from pgbench_branches6 where bid = :bid
> UNION
> select bbalance from pgbench_branches7 where bid = :bid
> UNION
> select bbalance from pgbench_branches8 where bid = :bid
> UNION
> select bbalance from pgbench_branches9 where bid = :bid
> UNION
> select bbalance from pgbench_branches10 where bid = :bid
> UNION
> select bbalance from pgbench_branches11 where bid = :bid
> UNION
> select bbalance from pgbench_branches12 where bid = :bid
> UNION
> select bbalance from pgbench_branches13 where bid = :bid
> UNION
> select bbalance from pgbench_branches14 where bid = :bid
> UNION
> select bbalance from pgbench_branches15 where bid = :bid
> UNION
> select bbalance from pgbench_branches16 where bid = :bid
> UNION
> select bbalance from pgbench_branches17 where bid = :bid
> UNION
> select bbalance from pgbench_branches18 where bid = :bid
> UNION
> select bbalance from pgbench_branches19 where bid = :bid
> UNION
> select bbalance from pgbench_branches20 where bid = :bid;
> END;
>
> First i try to make the number of fast-path locks as a GUC parameter. But
> it implies a lot of changes with PGPROC structure. Next I implement it as a
> compile-time parameter.
>