On Sun, Dec 27, 2009 at 2:45 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> it does make me wonder whether there's any point in retaining
>> CacheMemoryContext at all.
>
> Well, as per backend/utils/mmgr/README:
>
> CacheMemoryContext --- permanent storage for relcache, catcache, and
> related modules. This will never be reset or deleted, either, so it's
> not truly necessary to distinguish it from TopMemoryContext. But it
> seems worthwhile to maintain the distinction for debugging purposes.
>
> I'm not sure about the word "maintain" here; I can't recall whether
> there was any comparable concept before we invented the memory context
> mechanism. But I still think it's useful to distinguish cache activity
> from generic permanent memory allocations.
If we're really doing it, sure. But putting half of it in
TopMemoryContext and the other half in CacheMemoryContext is not
obviously of any value.
...Robert