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

On Sat, Feb 18, 2017 at 5:41 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> I'm thinking we should change this to look more like the
>> MemoryContextAlloc interface.  Let's have DSA_ALLOC_HUGE,
>> DSA_ALLOC_NO_OOM, and DSA_ALLOC_ZERO, just like the corresponding
>> MCXT_* flags, and a function dsa_allocate_extended() that takes a
>> flags argument.  Then, dsa_allocate(x,y) can be a macro for
>> dsa_allocate_extended(x,y,0) and dsa_allocate0(x,y) can be a macro for
>> dsa_allocate_extended(x,y,DSA_ALLOC_ZERO).  What this goof on my (and
>> Dilip's) part illustrates to me is that having this interface behave
>> significantly differently from the MemoryContextAlloc interface is
>> going to cause mistakes.
>
> +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?

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

-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers