Re: statement_timeout is not working as expected with postgres_fdw

On Thu, May 4, 2017 at 1:04 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Thu, May 4, 2017 at 10:18 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> On Thu, May 4, 2017 at 12:18 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>>> As soon as the first command fails due to timeout, we will set
>>> 'abort_cleanup_failure' which will make a toplevel transaction to
>>> abort and also won't allow other statements to execute. The patch is
>>> trying to enforce a 30-second timeout after statement execution, so it
>>> has to anyway wait till the command execution completes (irrespective
>>> of whether the command succeeds or fail).
>>
>> I don't understand what you mean by this. If the command doesn't
>> finish within 30 seconds, we *don't* wait for it to finish.
>>
>
> + /*
> + * Submit a query. Since we don't use non-blocking mode, this also can
> + * block. But its risk is relatively small, so we ignore that for now.
> + */
> + if (!PQsendQuery(conn, query))
> + {
> + pgfdw_report_error(WARNING, NULL, conn, false, query);
> + return false;
> + }
> +
> + /* Get the result of the query. */
> + if (pgfdw_get_cleanup_result(conn, endtime, &result))
> + return false;
>
> The 30 seconds logic is in function pgfdw_get_cleanup_result, can't
> the command hang in PQsendQuery?

Sure. I thought about trying to fix that too, by using
PQsetnonblocking(), but I thought the patch was doing enough already.

--
Robert Haas
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