Re: Using PQexecQuery in pipeline mode produces unexpected Close messages

At Tue, 21 Jun 2022 11:42:59 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in 
> At Fri, 17 Jun 2022 20:31:50 +0200, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote in 
> > Others to think about:
> > 
> > PQisBusy (I think no changes are needed),
> 
> Agreed.
> 
> > PQfn (I think it should accept a call in PGASYNC_PIPELINE_IDLE mode;
> > fully untested in pipeline mode),
> 
> Does a PQ_PIPELINE_OFF path need that? Rather I thought that we need
> Assert(!conn->asyncStatus != PGASYNC_PIPELINE_IDLE) there.  But anyway
> we might need a test for this path.

In the attached, PQfn() is used while in pipeline mode and
PGASYNC_PIPELINE_IDLE. Both error out and effectivelly no-op.

> > PQexitPipelineMode (I think it needs to return error; needs test case),
> 
> Agreed about test case. Currently the function doesn't handle
> PGASYNC_IDLE so I thought that PGASYNC_PIPELINE_IDLE also don't need a
> care.  If the function treats PGASYNC_PIPELINE_IDLE state as error,
> the regression test fails (but I haven't examine it furtuer.)

PQexitPipelineMode() is called while PGASYNC_PIPELINE_IDLE.

> > PQsendFlushRequest (I think it should let through; ditto).
> 
> Does that mean exit without pushing 'H' message?

I didn't do anything on this in the sttached.

By the way, I noticed that "libpq_pipeline uniqviol" intermittently
fails for uncertain reasons.

> result 574/575: pipeline aborted
> ...........................................................
> done writing
> 
> libpq_pipeline:1531: got unexpected NULL

The "...........done writing" is printed too late in the error cases.

This causes the TAP test fail, but I haven't find what's happnening at
the time.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center