Your layer has a label class with an SQL query that references fields that are not indexed, and you have selected the advanced option to prefer attribute queries over spatial queries. It's a good idea to index this field because it is used for querying features when drawing your map.
Solution
Check the drawing performance of your layer in ArcMap. If you are publishing, check the drawing performance of your service in the Preview window.
Learn more about previewing your map service
- If no changes are needed, you can accept the display performance as is.
- Alternatively, if you want to improve performance, you should index the fields reported to not have indexes. These fields are listed along with this warning.
More information
Attribute indexes can speed up attribute queries on feature classes and tables. For most types of queries, it is faster to look up a record on an indexed field than it is to search through the entire table.
Generally, you can improve overall performance using attribute indexes on key fields in your datasets.