We added trigram index for char fields since https://github.com/odoo/odoo/pull/83015.
But if `unaccent` is installed in the database (and isn't force to
`False` on field), these new trigram indexes are pointless and cost a
lot for nothing (almost nothing, it still can be used for equality
operator but in this case a btree will be far more efficient).
The simple way to fix it is to add `unaccent(<column>)` in the index
trigram definition, but unfortunately `unaccent` is not immutable and
may therefore not be indexed. In order to make `unaccent` indexable, we
must declare it as immutable (see
https://stackoverflow.com/questions/11005036/does-postgresql-support-accent-insensitive-collations/11007216#11007216
for more information and how to do that).
With this patch, trigram indexes are created with `unaccent(<column>)`
if the function `unaccent` is available in the database, and for the
fields that are not declared with `unaccent=False`. Moreover, we issue
a warning when `unaccent` is available but is not immutable, in which
case most trigram indexes will be useless.
odoo/upgrade#3736
task-2551518
closesodoo/odoo#95943
Signed-off-by: Rémy Voet <ryv@odoo.com>
Rémy Voet (ryv)
4087bcdc5e