Horton

Re: Allow cancelling VACUUM of nbtrees with corrupted right links

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Andres Freund <andres@anarazel.de>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2018-06-27T20:02:25Z
Lists: pgsql-hackers 
On Wed, Jun 27, 2018 at 12:52 PM, Andres Freund <andres@anarazel.de> wrote:
> A related question is if it matters - without complicating the code I
> don't see how we could release all the locks in that loop. Therefore no
> interrupts can be accepted.  I hope I'm missing something?

I agree.

In general, page deletion is the most complicated part of nbtree
concurrency, by far (if we just had the basic L&Y, the concurrency
aspects would be far easier to grasp). Doing better in
_bt_unlink_halfdead_page() seems extremely difficult, and very
unlikely to be worthwhile.

-- 
Peter Geoghegan

Commits

  1. Check for interrupts inside the nbtree page deletion code.