Re: Plan caching and serialization for reuse across executions

Andrei Lepikhov <lepihov@gmail.com> writes:
> I wouldn't recommend this obsolete version of the extension. Since the 
> QueryId was introduced, we have redesigned it extensively, with the 
> basic idea that QueryId serves as a 'query plan class' and that matching 
> parse trees provide a proof of matching incoming queries with their 
> corresponding [parameterised] plans.

That's fairly scary, considering all the work that's been done to
intentionally fuzz different queries together to make them look
like "the same query" to pg_stat_statements.  While that's fine
for pg_stat_statements, it makes it really questionable to assume
that QueryId is a sufficient proof of semantic equivalence.

(I recall having objected to the whole concept of moving queryjumble.c
into core on the grounds that it could not serve multiple masters.
I think this proves my point...)

            regards, tom lane