Horton

Re: Expand palloc/pg_malloc API

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-09-14T04:53:06Z
Lists: pgsql-hackers 
I wrote:
> It kind of feels that the argument order should be pointer, oldsize, size.
> It feels even more strongly that people will get the ordering wrong,
> whichever we choose.  Is there a way to make that more bulletproof?

Actually ... an even-more-terrifyingly-plausible misuse is that the
supplied oldsize is different from the actual previous allocation.
We should try to check that.  In MEMORY_CONTEXT_CHECKING builds
it should be possible to assert that oldsize == requested_size.
We don't have that data if !MEMORY_CONTEXT_CHECKING, but we could
at least assert that oldsize <= allocated chunk size.

			regards, tom lane

Commits

  1. Add repalloc0 and repalloc0_array

  2. Expand palloc/pg_malloc API for more type safety

  3. Assorted examples of expanded type-safer palloc/pg_malloc API