If we already have an extension_state array but see a new extension_id
much larger than the highest the extension_id we've previously seen,
the old code might have failed to expand the array to a large enough
size, leading to disaster. Also, if we don't have an extension array
at all and need to create one, we should make sure that it's big enough
that we don't have to resize it instantly.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: http://postgr.es/m/2949591.1758570711@sss.pgh.pa.us
Backpatch-through: 18
Modules can use RegisterExtensionExplainOption to register new
EXPLAIN options, and GetExplainExtensionId, GetExplainExtensionState,
and SetExplainExtensionState to store related state inside the
ExplainState object.
Since this substantially increases the amount of code that needs
to handle ExplainState-related tasks, move a few bits of existing
code to a new file explain_state.c and add the rest of this
infrastructure there.
See the comments at the top of explain_state.c for further
explanation of how this mechanism works.
This does not yet provide a way for such such options to do anything
useful. The intention is that we'll add hooks for that purpose in a
separate commit.
Discussion: http://postgr.es/m/CA+TgmoYSzg58hPuBmei46o8D3SKX+SZoO4K_aGQGwiRzvRApLg@mail.gmail.com
Reviewed-by: Srinath Reddy <srinath2133@gmail.com>
Reviewed-by: Andrei Lepikhov <lepihov@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
