10003: Layer doesn't have an attribute index on fields used for a join

One of the join fields in your map layer does not have an attribute index. Using join fields with an index results in better drawing and query performance.


More information

The potential issue of using joins that have not been indexed revolves around two technical aspects in the software: attribute indexes and attribute joins.

Attribute indexes can speed up attribute queries on feature classes and tables and will directly affect drawing performance in your dynamic maps. 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. See Creating attribute indexes for more information.

Attribute joins append the fields of one table to those of another through a field that is common in both tables. In ArcMap, a join is usually used to attach more attributes to the attribute table of a map layer. Using indexed fields for your join will significantly improve performance in most situations.