When defining your entities, you can specify indexes, in addition to the ones automatically created by OutSystems.
For each foreign key you create with its delete rule set to Protect or Delete, OutSystems automatically creates an index. On the database, this index is prefixed with OSIDX.
CREATE INDEX OSIDX_<internal name> ON <Entity> (<reference attribute>)
Automatic indexes are deleted if the attribute Delete Rule is changed to Ignore.
You can define your own indexes, improve the performance of your applications. When you create an index, OutSystems creates it on the database with the OSIDX prefix.
CREATE UNIQUE INDEX OSIDX_<internal name> ON <Entity> (<attributes>)
Not Unique index
CREATE INDEX OSIDX_<internal name> ON <Entity> (<attributes>)
If you are using an Oracle database, you can define the Indexes tablespace, in the Configuration Tool.