On 7/11/24 16:18, Richard Guo wrote:
On Fri, Jun 28, 2024 at 10:14 PM Andrei Lepikhov <lepi...@gmail.com> wrote:
I got the point about Memoize over join, but as a join still calls
replace_nestloop_params to replace parameters in its clauses, why not to
invent something similar to find Memoize keys inside specific JoinPath
node? It is not the issue of this patch, though - but is it doable?
I don't think it's impossible to do, but I'm skeptical that there's an
easy way to identify all the cache keys for joinrels, without having
available ppi_clauses and lateral_vars.
Ok
IMO, the code:
if (bms_nonempty_difference(outerPlan->chgParam, node->keyparamids))
cache_purge_all(node);
is a good place to check an assertion: is it really the parent query
parameters that make a difference between memoize keys and node list of
parameters?
I don't think we have enough info available here to identify which
params within outerPlan->chgParam are from outer levels. Maybe we can
store root->outer_params in the MemoizeState node to help with this
assertion, but I'm not sure if it's worth the trouble.
Got it
Attached is an updated version of this patch.
I'm not sure about stability of output format of AVG aggregate across
different platforms. Maybe better to return the result of comparison
between the AVG() and expected value?
--
regards, Andrei Lepikhov
