Re: [COMMITTERS] pgsql: Add new function dsa_allocate0.

From: Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [COMMITTERS] pgsql: Add new function dsa_allocate0.
Date: 2017-02-18 23:31:42
Message-ID: CAEepm=0ro7Wf8UOtCCGZsvSyL-18WpzKAoH-yUOuhEAY0z1ScA@mail.gmail.com
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On Sun, Feb 19, 2017 at 12:27 PM, Thomas Munro
<thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> On Sun, Feb 19, 2017 at 11:27 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> writes:
>>> On Sat, Feb 18, 2017 at 5:41 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>>> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>>>>> I'm thinking we should change this to look more like the
>>>>> MemoryContextAlloc interface.
>>
>>>> +1
>>
>>> Maybe something like the attached? I didn't add DSA_ALLOC_HUGE
>>> because there is currently no limit on allocation size (other than the
>>> limit on total size which you can set with dsa_set_size_limit, but
>>> that causes allocation failure, not a separate kind of error). Should
>>> there be a per-allocation size sanity check of 1GB like palloc?
>>
>> I think it's not a bad idea. It could help catch faulty allocation
>> requests (since I'd bet very few call sites actually intend to allocate
>> gigabytes in one go), and as Robert says, there is substantial value in
>> the semantics being as much like palloc() as possible. People are
>> likely to assume that even if it isn't true.
>
> Agreed. Here's a patch like that.

Oops, that had a typo in a comment. Here's a better one.

--
Thomas Munro
http://www.enterprisedb.com

Attachment Content-Type Size
dsa-extended-v3.patch application/octet-stream 5.5 KB

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