Re: Considering signal handling in plpython again

There are remaining two problems

1. Do we need to consider when to delete the extension hook or it's not
necessary?
As the destroy function _PG_fini doesn't work, I cannot find a good
place to reset to hook gracefully.
I tested the drop language plpythonu statement which will not remove
the python shared library in the current session,
So it seems to be safe to leave the cancel_handler_hook not be reset.
How about other extensions, for example plr. Does the "drop extension"
statement will not remove the loaded shared library in the process either?

-- Another idea is to register the hook at the beginning of
plpython_call_handler and unregister the hook at the end of
plpython_call_handler.

2. Do we need to use explicit hook list(List *cancel_hook_list) instead of
implicit cancel_hook(which relies on the extension to link the cancel_hook
inside their code
e.g. prev_hook = cancel_hook; cancel_hook=my_hook; void
my_hook(){mywork(); (*prev_hook)();} )?
I didn't find any explicit hook list in PG code base, is that a good
practice?

-- Hubert

On Mon, May 14, 2018 at 6:40 PM, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> wrote:

> On 14/05/18 10:56, Hubert Zhang wrote:
>
>> For nested SPI case, one option is to turn off the bool variable when
>> entering the SPI function(PLy_spi_prepare, PLy_spi_execute, PLy_cursor
>> etc.)
>> and turn on the bool variable again when exiting the SPI function.
>>
>
> Yeah, that seems reasonable.
>
> - Heikki
>

--
Thanks

Hubert Zhang