Re: libpq async duplicate error results

2022-05-06 Thread Tom Lane
I wrote: > What is happening is that this bit in PQsendQueryStart is deciding > not to clear the message buffer because conn->cmd_queue_head isn't > NULL: > /* > * If this is the beginning of a query cycle, reset the error state. > * However, in pipeline mode with something already q

Re: libpq async duplicate error results

2022-05-06 Thread Tom Lane
Peter Eisentraut writes: > I took another look at this. The output from the test program at the > beginning of the thread is now (master branch): > ... > command = SELECT 'after'; > PQsendQuery() error: FATAL: terminating connection due to administrator > command > server closed the connection

Re: libpq async duplicate error results

2022-05-06 Thread Peter Eisentraut
I took another look at this. The output from the test program at the beginning of the thread is now (master branch): command = SELECT 'before'; result 1 status = PGRES_TUPLES_OK error message = "" command = SELECT pg_terminate_backend(pg_backend_pid()); result 1 status = PGRES_FATAL_ERROR erro

Re: libpq async duplicate error results

2022-02-24 Thread Tom Lane
Actually ... it now seems to me that there's live bugs in the interaction between pipeline mode and error-buffer clearing. Namely, that places like PQsendQueryStart will unconditionally clear the buffer even though we may be in the middle of a pipeline sequence, and the buffer might hold an error t

Re: libpq async duplicate error results

2022-02-23 Thread Tom Lane
I wrote: > However ... in the wake of 618c16707, I wonder if we should consider > an alternative definition, which is to NOT clear errorMessage when > starting a new pipelined query. (That would be this patch minus > the addition to pqPipelineProcessQueue.) Thanks to 618c16707, > the returned err

Re: libpq async duplicate error results

2022-02-20 Thread Tom Lane
Alvaro Herrera writes: > On 2022-Feb-07, Tom Lane wrote: >> I see that PQgetResult does a hacky "resetPQExpBuffer(&conn->errorMessage)" >> in between pipelined queries. It seems like if there are real usability >> issues in this area, they probably come from that not being well placed. >> In part

Re: libpq async duplicate error results

2022-02-16 Thread Tom Lane
Andres Freund writes: > On 2022-02-16 20:28:02 -0500, Tom Lane wrote: >> Uh ... then we'd have to cast away the const to do free(). > I was just thinking of > if ((const PGresult *) res == &OOM_result) Oh, I see. Sure, can do it like that. regards, tom lane

Re: libpq async duplicate error results

2022-02-16 Thread Andres Freund
Hi, On 2022-02-16 20:28:02 -0500, Tom Lane wrote: > Andres Freund writes: > > On 2022-02-16 18:51:37 -0500, Tom Lane wrote: > >> + /* Also, do nothing if the argument is OOM_result */ > >> + if (res == unconstify(PGresult *, &OOM_result)) > >> + return; > > > Wouldn't it make more sens

Re: libpq async duplicate error results

2022-02-16 Thread Tom Lane
Andres Freund writes: > On 2022-02-16 18:51:37 -0500, Tom Lane wrote: >> +/* Also, do nothing if the argument is OOM_result */ >> +if (res == unconstify(PGresult *, &OOM_result)) >> +return; > Wouldn't it make more sense to make res const, rather than unconstifying > &OOM_resu

Re: libpq async duplicate error results

2022-02-16 Thread Andres Freund
Hi, On 2022-02-16 18:51:37 -0500, Tom Lane wrote: > This seems workable, and you'll notice it fixes the duplicated text > in the test case Andres was worried about. Cool. I find it mildly scary that we didn't have any other tests verifying the libpq side of connection termination. Seems like we

Re: libpq async duplicate error results

2022-02-16 Thread Tom Lane
I wrote: >>> An idea that I don't have time to pursue right now is to track >>> how much of conn->errorMessage has been read out by PQgetResult, >>> and only report newly-added text in later PQgetResult calls of >>> a series, while PQerrorMessage would continue to report the >>> whole thing. Buffe

Re: libpq async duplicate error results

2022-02-08 Thread Alvaro Herrera
On 2022-Feb-07, Tom Lane wrote: > In any case, the particular example we're looking at here is connection > loss, which is not something that should greatly concern us as far as > pipeline semantics are concerned, because you're not getting any more > pipelined results anyway if that happens. In

Re: libpq async duplicate error results

2022-02-07 Thread Tom Lane
[ cc'ing Alvaro for pipeline questions ] Fabien COELHO writes: >> It is annoying that some of the text is duplicated in the second >> report, but in the end that's cosmetic, and I'm not sure we can >> improve it without breaking other things. In particular, we >> can't just think about what come

Re: libpq async duplicate error results

2022-02-05 Thread Fabien COELHO
Hello Tom, I concur with Fabien's analysis: we report the FATAL message from the server during the first PQgetResult, and then the second call discovers that the connection is gone and reports "server closed the connection unexpectedly". Those are two independent events (in libpq's view anywa

Re: libpq async duplicate error results

2022-02-03 Thread Tom Lane
Peter Eisentraut writes: > Tom, you worked on reorganzing the error message handling in libpq in > PostgreSQL 14 (commit ffa2e4670123124b92f037d335a1e844c3782d3f). Any > thoughts on this? Ah, sorry, I'd not noticed this thread. I concur with Fabien's analysis: we report the FATAL message from

Re: libpq async duplicate error results

2022-02-03 Thread Peter Eisentraut
Tom, you worked on reorganzing the error message handling in libpq in PostgreSQL 14 (commit ffa2e4670123124b92f037d335a1e844c3782d3f). Any thoughts on this? On 25.01.22 09:32, Peter Eisentraut wrote: This issue was discovered by Fabien in the SHOW_ALL_RESULTS thread.  I'm posting it here s

Re: libpq async duplicate error results

2022-01-27 Thread Peter Eisentraut
On 26.01.22 14:52, Fabien COELHO wrote: command = SELECT pg_terminate_backend(pg_backend_pid()); result 1 status = PGRES_FATAL_ERROR error message = "FATAL:  terminating connection due to administrator command " result 2 status = PGRES_FATAL_ERROR error message = "FATAL:  terminating connecti

Re: libpq async duplicate error results

2022-01-26 Thread Fabien COELHO
command = SELECT pg_terminate_backend(pg_backend_pid()); result 1 status = PGRES_FATAL_ERROR error message = "FATAL: terminating connection due to administrator command " result 2 status = PGRES_FATAL_ERROR error message = "FATAL: terminating connection due to administrator command server clo

libpq async duplicate error results

2022-01-25 Thread Peter Eisentraut
This issue was discovered by Fabien in the SHOW_ALL_RESULTS thread. I'm posting it here separately, because I think it ought to be addressed in libpq rather than with a workaround in psql, as proposed over there. When using PQsendQuery() + PQgetResult() and the server crashes during the exe