Re: WIP csv logs

Tom Lane wrote:
> Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
>
>> I wonder, if we were to use an LWLock to protect writing to the stderr
>> pipe, would it be too contentious?
>>
>
> Sorry, that's a nonstarter.
>
> 1. Not all our processes are connected to shared memory. Even the ones
> that are don't necessarily have PGPROCs.
>
> 2. If somebody crashes while holding the lock, the entire system
> including the postmaster soon freezes up.
>
> 3. Having the postmaster take LWLocks is verboten anyway, mainly because
> of problem #2.
>
>
>

Ugh. Well, until this problem is solved I'm not prepared to commit a
patch that purports to provide machine readable logs. The only
non-locking solution I can think of is to have one set of pipes per
backend rather than one set per cluster. That could get pretty ugly,
though, and have all sorts of problems with portability.

I'm starting to wonder if the CSVlog patch needs to be put on hold at
least for 8.4. If we do, I think I should at least commit the piece that
prevents rotation in the middle of a line, and possible even backpatch it.

cheers

andrew