Re: ATTACH/DETACH PARTITION CONCURRENTLY

David Rowley <david.rowley@2ndquadrant.com>

From: David Rowley <david.rowley@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Michael Paquier <michael@paquier.xyz>, Sergei Kornilov <sk@zsrv.org>, Amit Langote <langote_amit_f8@lab.ntt.co.jp>, Andres Freund <andres@anarazel.de>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Simon Riggs <simon@2ndquadrant.com>
Date: 2019-02-21T21:03:56Z
Lists: pgsql-hackers
On Tue, 5 Feb 2019 at 01:54, Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Mon, Feb 4, 2019 at 12:02 AM David Rowley
> <david.rowley@2ndquadrant.com> wrote:
> > If the PartitionDesc from the parallel worker has an extra partition
> > than what was there when the plan was built then the partition index
> > to subplan index translation will be incorrect as the
> > find_matching_subplans_recurse() will call get_matching_partitions()
> > using the context with the PartitionDesc containing the additional
> > partition. The return value from get_matching_partitions() is fine,
> > it's just that the code inside the while ((i =
> > bms_next_member(partset, i)) >= 0) loop that will do the wrong thing.
> > It could even crash if partset has an index out of bounds of the
> > subplan_map or subpart_map arrays.
>
> Is there any chance you've missed the fact that in one of the later
> patches in the series I added code to adjust the subplan_map and
> subpart_map arrays to compensate for any extra partitions?

I admit that I hadn't looked at the patch, I was just going on what I
had read here.   I wasn't sure how the re-map would have been done as
some of the information is unavailable during execution, but I see now
that you're modified it so we send a list of Oids that we expect and
remap based on if an unexpected Oid is found.

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


Commits

  1. Allow ATTACH PARTITION with only ShareUpdateExclusiveLock.

  2. Change lock acquisition order in expand_inherited_rtentry.

  3. Move code for managing PartitionDescs into a new file, partdesc.c

  4. Remove more redundant relation locking during executor startup.

  5. Add assertions that we hold some relevant lock during relation open.

  6. Try to acquire relation locks in RangeVarGetRelid.