Re: what about _PG_fini

2009/12/23 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> =?ISO-8859-1?Q?C=E9dric_Villemain?= <cedric(dot)villemain(dot)debian(at)gmail(dot)com> writes:
>> I wonder what is the future of "_PG_fini", documentation say at [1]:
>> "Note that _PG_fini will only be called during an unload of the file,
>> not during process termination. (Presently, unloads are disabled and
>> will never occur, but this may change in the future.)"
>
> What we'd need to work out before (re)enabling _PG_fini is some
> consistent rules for allowing multiple modules to get into *and out of*
> the same hook pointers.  The current coding methods are very
> load-order-dependent, and that would have to be fixed somehow.

Ok, thank you for clarification.

>
>> 1. do we want a _PG_fini which is call on server stop ?
>> 2. what's actually the best way to execute some code when server stop,
>> if one have ideas ... ?
>
> In any case, _PG_fini would have approximately nothing to do with "code
> to be executed on server stop".  It would happen at session end,
> typically.
>
> Personally I'd suggest putting whatever you have in mind into your
> service start/stop scripts.

Yes, I thought it was probably the simplest way to do it.

for information I have some functions to make a snapshot of the blocks
which are in buffer cache (it is a max of 32KB per segment) and to
reload them when server start. Option to execute them without
'external' code could have been fine.

>
>                        regards, tom lane
>