Re: Catalog_xmin is not advanced when a logical slot is lost

On 2022-Nov-21, sirisha chamarthi wrote:

> I have a old .partial file in the data directory to reproduce this.

I don't think the .partial file is in itself important.  But I think
this whole thing is a distraction. 

I managed to reproduce it
eventually, by messing with the slot and WAL at random, and my
conclusion is that we shouldn't mess with this at all for this bugfix.

Instead I'm going to do what Ashutosh mentioned at the start, which is
to verify both the restart_lsn and the invalidated_at, when deciding
whether to ignore the slot.

It seems to me that there is a bigger mess here, considering that we use
the effective_xmin in some places and the other xmin (the one that's
saved to disk) in others.  I have no patience for trying to disentangle
that at this point, though. 

--
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"Having your biases confirmed independently is how scientific progress is
made, and hence made our great society what it is today" (Mary Gardiner)