It seems like Custom GUCs are still in need of some work, as shown in my
recent email. In particular, they are not transaction safe - if a
transaction attempts to do DefineCustomFooVariable() and that
transaction aborts, the placeholder setting that it used is already gone
by the time it tries to roll back GUC settings. I think this code at the
end of define_custom_variable()
/* * Free up as much as we conveniently can of the placeholder structure * (this neglects any
stackitems...) */ set_string_field(pHolder, pHolder->variable, NULL); set_string_field(pHolder,
&pHolder->reset_val,NULL);
free(pHolder);
needs to be removed and instead we need to save pHolder in a list along
with the GUC level, to be processed later by AtEOXact_GUC(), which would
do the right thing according to whether or not it had a commit or an abort.
I want to get this fixed before we consider custom settings for plperl
that have possible security implications.
Thoughts?
cheers
andrew