Re: Label switcher function

Thanks for your reviewing.

The attached patch is a revised version.
I don't have any objections to your comments.

(2010/12/07 4:38), Robert Haas wrote:
> 2010/11/25 KaiGai Kohei<kaigai@ak.jp.nec.com>:
>> The attached patch is a revised one.
>>
>> It provides two hooks; the one informs core PG whether the supplied
>> function needs to be hooked, or not. the other is an actual hook on
>> prepare, start, end and abort of function invocations.
>>
>>   typedef bool (*needs_function_call_type)(Oid fn_oid);
>>
>>   typedef void (*function_call_type)(FunctionCallEventType event,
>>                                      FmgrInfo *flinfo, Datum *private);
>>
>> The hook prototype was a bit modified since the suggestion from
>> Robert. Because FmgrInfo structure contain OID of the function,
>> it might be redundant to deliver OID of the function individually.
>>
>> Rest of parts are revised according to the comment.
>>
>> I also fixed up source code comments which might become incorrect.
>
> FCET_PREPARE looks completely unnecessary to me.  Any necessary
> one-time work can easily be done at FCET_START time, assuming that the
> private-data field is initialized to (Datum) 0.
>
It seems to me a reasonable assumption.
I revised the code, and modified source code comments to ensure
the private shall be initialized to (Datum) 0.

> I'm fairly certain that the following is not portable:
>
> +       ObjectAddress   object = { .classId = ProcedureRelationId,
> +                                                          .objectId = fn_oid,
> +                                                          .objectSubId = 0 };
>
Fixed.

> I'd suggest renaming needs_function_call_type and function_call_type
> to needs_fmgr_hook_type and fmgr_hook_type.
>
I also think the suggested names are better than before.

According to the renaming, FunctionCallEventType was also renamed to
FmgrHookEventType. Perhaps, it is a reasonable change.

Thanks,
--
KaiGai Kohei <kaigai@ak.jp.nec.com>