Horton

Re: Add bump memory context type and use it for tuplesorts

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Matthias van de Meent <boekewurm+postgres@gmail.com>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2024-03-05T02:42:10Z
Lists: pgsql-hackers

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There've been a few changes to the memory allocators in the past week
and some of these changes also need to be applied to bump.c. So, I've
rebased the patches on top of today's master. See attached.

I also re-ran the performance tests to check the allocation
performance against the recently optimised aset, generation and slab
contexts.  The attached graph shows the time it took in seconds to
allocate 1GB of memory performing a context reset after 1MB. The
function I ran the test on is in the attached
pg_allocate_memory_test.patch.txt file.

The query I ran was:

select chksz,mtype,pg_allocate_memory_test_reset(chksz,
1024*1024,1024*1024*1024, mtype) from (values(8),(16),(32),(64))
sizes(chksz),(values('aset'),('generation'),('slab'),('bump'))
cxt(mtype) order by mtype,chksz;

David

Commits

  1. Update mmgr's README to mention BumpContext

  2. Push dedicated BumpBlocks to the tail of the blocks list

  3. Improve test coverage in bump.c

  4. Fix incorrect KeeperBlock macro in bump.c

  5. Use bump memory context for tuplesorts

  6. Introduce a bump memory allocator

  7. Enlarge bit-space for MemoryContextMethodID