Aurélien (avd)
875244b08e
PG12 introduced an optimization for CTEs that automatically inlines
CTEs if they are only refered once in the parent query. Prior to that
CTEs were always materialzed, meaning that PG created a sort of temp
table on the fly to store the result of the CTE's evaluation.
Whereas this leads to performance improvements in general, in the
particular case of _select_companies_rates this inlining becomes a
performance bottleneck. This is because while the currency_rate CTE
is only refered once in both purchase_report and product_margin,
the join condition (cr.date_end is null or cr.date_end > ...)
requires evaluating the CTE's date_end subquery twice. This, combined
with the fact that in PG12 the planner goes for a Nested Loop JOIN instead
of a HASH Join in PG10 makes the performances of the whole query
much worse in PG12 than in PG10.
Adding MATERIALIZED before the CTE definition forces PG to evaluate the
subquery first using its own plan. This removes the need to rescan the
subquery each time the Merge JOIN filter has to be applied, which
is a good strategy in this specific situation.
Examples of query timings change before and after PR:
Number of POs | Before PR | After PR
2000 | 7s | 345ms
7000 | 23s | 1.1s
opw-2930578
closes odoo/odoo#106100
X-original-commit: c4d841e81904745a24669e1a05f0d21ca7f2c85d
Signed-off-by: Raphael Collet <rco@odoo.com>
Signed-off-by: Van Delft Aurélien (avd) <avd@odoo.com>
Odoo
Odoo is a suite of web based open source business apps.
The main Odoo Apps include an Open Source CRM, Website Builder, eCommerce, Warehouse Management, Project Management, Billing & Accounting, Point of Sale, Human Resources, Marketing, Manufacturing, ...
Odoo Apps can be used as stand-alone applications, but they also integrate seamlessly so you get a full-featured Open Source ERP when you install several Apps.
Getting started with Odoo
For a standard installation please follow the Setup instructions from the documentation.
To learn the software, we recommend the Odoo eLearning, or Scale-up, the business game. Developers can start with the developer tutorials