Looker typically generates these suggestions by executing a
SELECT DISTINCT query on the field. For some large tables this query can be too slow or create too large of a database load.
suggestions you can hard-code a list of possible values instead, greatly improving performance. This parameter can also be useful if you do not want certain values from a field to appear as suggestions, by specifying a more limited list.
Replace the default suggestions for the Colors dimension with a hard-coded list: