Caching in filter selectable values

[PaulPoulain]

When you create a filter in a report, the list of possible values is automatically calculated from the related field.
This is sometimes highly time consuming, because of the SQL query that is built.

We could speed up by:

• letting the layer creator enter the list of possible values. For example, in Koha, statistics.type can have localuse, issue, return, renew, writeoff, payment, onsite_checkout only. Urungi seems to do something like "SELECT DISTINCT type FROM statistics" that is very long to run. Same thing with values calculated from a coded field (leader, field 100): they have a limited and known list of possible values. The SELECT FROM extractValue(marcxml//... is very long (more than 30 seconds sometimes !!!)

To do: in the field definition, have a tab with 3 options:

• auto-calculated (as currently, default value)
• list of values entered manually by the layer creator. Values separated by ,
• SQL query manually entered by the layer creator