Horton

Re: Large writable variables

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: Robert Haas <robertmhaas@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Thomas Munro <thomas.munro@enterprisedb.com>
Date: 2018-10-16T17:17:02Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2018-10-16 12:41:44 -0400, Robert Haas wrote:
>> In terms of a function that returns both const and non-const
>> variables, it seems a bit sketchy that the caller would know what the
>> function is doing in particular cases and make decisions based on it,
>> but maybe that's just how life is.

> I don't think it's necessary the callers doing so in most cases. E.g. in
> the DestReceiver case, it'll be the choice of the testreceiver (say
> intorel_receive modifying things for DestIntoRel), not the caller
> choosing when to modify things.  The caller / users of dest receivers
> won't necessarily know.

Yeah, I think the use-case is more like "this API specifies non-const
pointers, but some instances can return pointers to const objects,
while others return non-const objects".  Changing the API to const
isn't better, it just moves where you have to cast away const.

			regards, tom lane

Commits

  1. Apply unconstify() in more places

  2. Improve unconstify() documentation

  3. Drop const cast from dlsym() calls

  4. Const-ify a few more large static tables.

  5. Improve tzparse's handling of TZDEFRULES ("posixrules") zone data.

  6. Avoid statically allocating statement cache in ecpglib/prepare.c.

  7. Reorder FmgrBuiltin members, saving 25% in size.

  8. Add macro to cast away const without allowing changes to underlying type.

  9. Mark constantly allocated dest receiver as const.

  10. Avoid statically allocating formatting.c's format string caches.

  11. Correct constness of system attributes in heap.c & prerequisites.

  12. Avoid statically allocating gmtsub()'s timezone workspace.

  13. Correct constness of a few variables.

  14. Move the replication lag tracker into heap memory.