Re: pgsql: Use the regular main processing loop also in walsenders.

On 07.10.2012 12:24, Thom Brown wrote:
> On 6 October 2012 22:52, Thom Brown<thom(at)linux(dot)com> wrote:
>> On 5 October 2012 15:26, Heikki Linnakangas<heikki(dot)linnakangas(at)iki(dot)fi> wrote:
>>> Use the regular main processing loop also in walsenders.
>>>
>>> The regular backend's main loop handles signal handling and error recovery
>>> better than the current WAL sender command loop does. For example, if the
>>> client hangs and a SIGTERM is received before starting streaming, the
>>> walsender will now terminate immediately, rather than hang until the
>>> connection times out.
>>
>> This commit seems to have broken the WAL sender in at least one
>> scenario. I have a primary and 2 standbys, standby 1 receiving WAL
>> stream from the primary, and standby 2 receiving WAL stream from
>> standby 1 (chain configuration). If I attempt to restart standby 1,
>> it hangs and the WAL sender process on standby 1 uses 100% CPU.
>>
>> The following error is logged too:
>> FATAL: terminating walreceiver process due to administrator command
>>
>> I can shut down standby 1 without issue only if I shut down standby 2 before it.
>
> This was just a description of the scenario I was using. The same
> occurs with just 1 standby and attempting to shut down the primary.

Fixed, thanks for the report. I set ProcDiePending = true to kill the
process, but that didn't do anything without also setting
InterruptPending = true. On second thoughts, it wasn't a very good way
to make walsender exit, anyway, so I changed it to use proc_exit(0),
like it used to.

- Heikki