Horton

Re: Reducing the chunk header sizes on all memory context types

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: David Rowley <dgrowleyml@gmail.com>, Julien Rouhaud <rjuju123@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2022-10-06T19:23:16Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2022-10-06 15:10:44 -0400, Tom Lane wrote:
>> Andres Freund <andres@anarazel.de> writes:
>>> Maybe worth printing the method ID as well?

>> I doubt it'd be useful.

> I was thinking it could be useful to see whether the bits are likely to be the
> result of wipe_mem(). But I guess for that we should print the whole byte,
> rather than just the method. Perhaps not worth it.

I think printing the whole int64 header word would be appropriate if
we were hoping for something like that.  Still not sure if it's useful.
On the other hand, if control gets there then you are probably in need
of debugging help ...

			regards, tom lane

Commits

  1. Harden memory context allocators against bogus chunk pointers.

  2. Improve our ability to detect bogus pointers passed to pfree et al.

  3. Remove MemoryContextContains().

  4. Remove uses of MemoryContextContains in nodeAgg.c and nodeWindowAgg.c.

  5. Temporarily make MemoryContextContains return false

  6. Make MemoryContextContains work correctly again

  7. Make more effort to put a sentinel at the end of allocated memory

  8. Fix some possibly latent bugs in slab.c

  9. Various cleanups of the new memory context header code

  10. Revert "Add missing padding from MemoryChunk struct"

  11. Use MAXALIGN() in calculations using sizeof(SlabBlock)

  12. Add missing padding from MemoryChunk struct

  13. Improve performance of and reduce overheads of memory management