Horton

Re: Speed dblink using alternate libpq tuple storage

Marko Kreen <markokr@gmail.com>

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From: Marko Kreen <markokr@gmail.com>
To: Kyotaro HORIGUCHI <horiguchi.kyotaro@oss.ntt.co.jp>
Cc: greg@2ndquadrant.com, pgsql-hackers@postgresql.org, mmoncure@gmail.com, shigeru.hanada@gmail.com
Date: 2012-02-23T12:34:16Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix COPY FROM for null marker strings that correspond to invalid encoding.

  2. Improve labeling of pg_test_fsync open_sync test output.

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