Re: FunctionCallN improvement.

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Neil Conway <neilc@samurai.com>
Cc: a_ogawa <a_ogawa@hi-ho.ne.jp>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2005-02-01T01:09:01Z
Lists: pgsql-hackers
Neil Conway <neilc@samurai.com> writes:
> On Mon, 2005-01-31 at 23:38 +0900, a_ogawa wrote:
>> (b)Define the macro that initialize FunctionCallInfoData, and use it 
>> instead of MemSet in all FunctionCallN, DirectFunctionCallN, 
>> OidFunctionCallN.
>> This macro is the following. 
>> 
>> #define InitFunctionCallInfoData(Fcinfo, Flinfo, Nargs)     \
>> do {                                                    \
>> (Fcinfo)->flinfo = Flinfo;                          \
>> (Fcinfo)->context = NULL;                           \
>> (Fcinfo)->resultinfo = NULL;                        \
>> (Fcinfo)->isnull = false;                           \
>> (Fcinfo)->nargs = Nargs;                            \
>> MemSet((Fcinfo)->argnull, 0, Nargs * sizeof(bool)); \
>> } while(0)
>> 
>> I think that plan(b) is better, because source code consistency 
>> and efficiency improve.

> I agree; I think the macro is a nice improvement to readability.

But a dead loss for performance, since it does a MemSet *and* some other
operations.  What's worse, it changes a word-aligned MemSet into a
non-aligned one, knocking out all the optimizations therein.

			regards, tom lane