Currently when showing a BoM Overview, the stock_availability
is computed for each bom's component. This means that there will
be one read_group on report.stock.quantity by component. As this
is a postgresql View, querying it too often can degrade the overall
performances.
This commit tries to improve on that by computing the stock_availability
of all components without bom at the same level at the same time. Let's say
there is a BoM with 4 components, none of which has a bill of materials
of their own. Before this commit there would have been 4 read_groups, one
by component. Now there will only be 1 read_group.
Example speedup: customer database with 7M stock.moves,
7M stock.move.lines. BoM Overview with 33 nodes in the component
Tree: 3min30s -> 1min30s
X-original-commit: 8fa7a11bf41152a06537144c20d04921d3643272
Part-of: odoo/odoo#139067
Aurelien van Delft (avd)
b368860f28