| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, David Rowley <dgrowleyml(at)gmail(dot)com>, Yura Sokolov <y(dot)sokolov(at)postgrespro(dot)ru>, PostgreSQL Developers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Reducing the chunk header sizes on all memory context types |
| Date: | 2022-08-09 19:21:57 |
| Message-ID: | 36081.1660072917@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Andres Freund <andres(at)anarazel(dot)de> writes:
> I think it's fine, given that we can change this at any time, but it's
> probably worth to explicitly agree that this will for now restrict us to 8
> context methods?
Do we really need it to be that tight? I know we only have 3 methods today,
but 8 doesn't seem that far away. If there were six bits reserved for
this I'd be happier.
>> # We also add a restriction that block sizes for all 3 of the memory
>> # allocators cannot be 1GB or larger. We would be unable to store the
>> # number of bytes that the block is offset from the chunk stored beyond this
>> #1GB boundary on any block that was larger than 1GB.
Losing MemoryContextAllocHuge would be very bad, so I assume this comment
is not telling the full truth.
regards, tom lane
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