Horton

Re: hyrax vs. RelationBuildPartitionDesc

Alvaro Herrera <alvherre@2ndquadrant.com>

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From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-03-13T18:21:45Z
Lists: pgsql-hackers 
On 2019-Mar-13, Robert Haas wrote:

> On Wed, Mar 13, 2019 at 1:38 PM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> > A bit, yes, but not overly so, and it's less fragile that not having
> > such a protection.  Anything that allocates in CacheMemoryContext needs
> > to be very careful anyway.
> 
> True, but I think it's more fragile than either of the options I proposed.

You do?  Unless I misunderstood, your options are:

1. (the patch you attached) create a temporary memory context that is
used for everything, then at the end copy the good stuff to CacheMemCxt
(or a sub-context thereof).  This still needs to copy.

2. create a temp memory context, do everything there, do retail freeing
of everything we don't want, reparenting the context to CacheMemCxt.
Hope we didn't forget to pfree anything.

How is any of those superior to what I propose?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Load relcache entries' partitioning data on-demand, not immediately.

  2. Prevent memory leaks associated with relcache rd_partcheck structures.

  3. Don't copy PartitionBoundInfo in set_relation_partition_info.

  4. Further reduce memory footprint of CLOBBER_CACHE_ALWAYS testing.

  5. Fix some oversights in commit 2455ab488.

  6. Defend against leaks into RelationBuildPartitionDesc.

  7. Allow ATTACH PARTITION with only ShareUpdateExclusiveLock.