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From: Sami Imseih <samimseih@gmail.com>
Date: Mon, 14 Apr 2025 12:13:00 -0500
Message-ID: <CAA5RZ0s_Hta6PWDwY9Lf-c+14F+C13BK2ax=B6R7bmDNhN6xdQ@mail.gmail.com>
Subject: Re: Conflicting updates of command progress
To: Antonin Houska <ah@cybertec.at>
Cc: pgsql-hackers@postgresql.org
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> While working on [1] I realized that some field of pg_stat_progress_cluste has
> weird value.

Is there a repro that you can share that shows the weird values? It sounds like
the repro is on top of [1]. Is that right?

> AFAICS the current design does not consider that one progress-reporting
> command can be called by another one.

pgstat_progress_start_command should only be called once by the entry
point for the
command. In theory, we could end up in a situation where start_command
is called multiple times during the same top-level command;

> Not sure what the correct fix is. We can
> either ignore update requests from the "nested" commands, or display the

There is a pattern where we do

```
if (progress)
      pgstat_progress_update_param
```

cluster_rel can pass down a flag to index_build or others that update progress
to not report progress. Therefore, only the top level command is
updating progress.
what do you think?


[1] https://commitfest.postgresql.org/patch/5117/

--
Sami Imseih
Amazon Web Services (AWS)