Re: add queryEnv to ExplainOneQuery_hook

On Fri, Jan 12, 2018 at 12:16 AM, Tatsuro Yamada
<yamada.tatsuro@lab.ntt.co.jp> wrote:
> I found a variable (queryEnv) which should be added in
> ExplainOneQuery_hook because if it is missing, hook function
> can't call ExplainOnePlan.
> Sorry if this wasn't correct.
>
> Please find attached a patch.

Yeah, I think you're right.  That's an oversight in 18ce3a4a.  I'm
surprised we haven't heard any complaints sooner if there are advisors
using that hook[1] and expecting to be able to forward to
ExplainOnePlan(), but I suppose it would nearly always works to call
ExplainOnePlan() with NULL as queryEnv.  It'd currently only be
non-NULL for trigger functions running SQL to access transition
tables, which is a bit obscure: you'd need to run EXPLAIN inside a
suitable trigger function (though in future there might be more ways
to create named tuplestore relations).

[1] https://www.postgresql.org/message-id/20161113222804.o2uw7c2fish67iej%40alap3.anarazel.de

-- 
Thomas Munro
http://www.enterprisedb.com