Re: Feature improvement: can we add queryId for pg_catalog.pg_stat_activity view?

On Wed, Mar 31, 2021 at 11:25:32AM +0800, Julien Rouhaud wrote:
> On Thu, Mar 25, 2021 at 10:36:38AM +0800, Julien Rouhaud wrote:
> > On Wed, Mar 24, 2021 at 01:02:00PM -0300, Alvaro Herrera wrote:
> > > On 2021-Mar-24, Julien Rouhaud wrote:
> > >
> > > > From e08c9d5fc86ba722844d97000798de868890aba3 Mon Sep 17 00:00:00 2001
> > > > From: Bruce Momjian <bruce(at)momjian(dot)us>
> > > > Date: Mon, 22 Mar 2021 17:43:23 -0400
> > > > Subject: [PATCH v20 2/3] Expose queryid in pg_stat_activity and
> > >
> > > > src/backend/executor/execMain.c | 9 ++
> > > > src/backend/executor/execParallel.c | 14 ++-
> > > > src/backend/executor/nodeGather.c | 3 +-
> > > > src/backend/executor/nodeGatherMerge.c | 4 +-
> > >
> > > Hmm...
> > >
> > > I find it odd that there's executor code that acquires the current query
> > > ID from pgstat, after having been put there by planner or ExecutorStart
> > > itself. Seems like a modularity violation. I wonder if it would make
> > > more sense to have the value maybe in struct EState (or perhaps there's
> > > a better place -- but I don't think they have a way to reach the
> > > QueryDesc anyhow), put there by ExecutorStart, so that places such as
> > > execParallel, nodeGather etc don't have to fetch it from pgstat but from
> > > EState.
> >
> > The current queryid is already available in the Estate, as the underlying
> > PlannedStmt contains it. The problem is that we want to display the top level
> > queryid, not the current query one, and the top level queryid is held in
> > pgstat.
>
> So is the current approach ok? If not I'm afraid that detecting and caching
> the top level queryid in the executor parts would lead to some code
> duplication.

I assume it is since Alvaro didn't reply. I am planning to apply this
soon.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

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