Re: pgbnech: allow to cancel queries during benchmark

>> +/* send cancel requests to all connections */
>> +static void
>> +cancel_all()
>> +{
>> +    for (int i = 0; i < nclients; i++)
>> +    {
>> +        char errbuf[1];
>> +        if (client_states[i].cancel != NULL)
>> +            (void) PQcancel(client_states[i].cancel, errbuf, sizeof(errbuf));
>> +    }
>> +}
>> +
>> 
>> Why in case of errors from PQCancel the error message is neglected? I
>> think it's better to print out the error message in case of error.
> 
> Is the message useful for pgbench users? I saw the error is ignored
> in pg_dump, for example in bin/pg_dump/parallel.c

I think the situation is different from pg_dump.  Unlike pg_dump, if
PQcancel does not work, users can fix the problem by using
pg_terminate_backend or kill command. In order to make this work, an
appropriate error message is essential.

Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
English: http://www.sraoss.co.jp/index_en/
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