Re: vacuumdb: add --dry-run - Mailing list pgsql-hackers

From Nathan Bossart
Subject Re: vacuumdb: add --dry-run
Date
Msg-id aRJW2_Yy9ALMkZUa@nathan
Whole thread Raw
In response to vacuumdb: add --dry-run  (Corey Huinker <corey.huinker@gmail.com>)
Responses Re: vacuumdb: add --dry-run
List pgsql-hackers
On Mon, Nov 10, 2025 at 02:44:41PM -0500, Corey Huinker wrote:
> This is a small patch to add a new option to vacuumdb to answer the
> question "what commands will actually be run by this combination of
> command-line switches against this database?" without actually running the
> commands.

My attempts to test this all got stuck in wait_on_slots().  I haven't
looked too closely, but I suspect the issue is that the socket never
becomes readable because we don't send a query.  If I set free_slot->inUse
to false before printing the command, it no longer hangs.  We probably want
to create a function in parallel_slot.c to mark slots that we don't intend
to give a query as idle.

-- 
nathan



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