Re: Speed dblink using alternate libpq tuple storage

On Thu, Feb 23, 2012 at 07:14:03PM +0900, Kyotaro HORIGUCHI wrote:
> Hello, this is new version of the patch.

Looks good.

> By the way, I would like to ask you one question. What is the
> reason why void* should be head or tail of the parameter list?

Aesthetical reasons:

1) PGresult and PGrowValue belong together.

2) void* is probably the context object for handler. When doing
object-oriented programming in C the main object is usually first.
Like libpq does - PGconn is always first argument.

But as libpq does not know the actual meaning of void* for handler,
is can be last param as well.

When I wrote the demo code, I noticed that it is unnatural to have
void* in the middle.

Last comment - if we drop the plan to make PQsetRowProcessorErrMsg()
usable outside of handler, we can simplify internal usage as well:
the PGresult->rowProcessorErrMsg can be dropped and let's use
->errMsg to transport the error message.

The PGresult is long-lived structure and adding fields for such
temporary usage feels wrong. There is no other libpq code between
row processor and getAnotherTuple, so the use is safe.

--
marko