Your layer has a label class with an SQL query that cannot be optimized by the drawing engine. The map service can reduce the number of queries sent to the database in most circumstances, but the SQL query used by this label class cannot take advantage of this optimization.
Solution
Check the drawing performance of your map 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 remove any vendor-specific SQL syntax from your query. This allows the drawing engine to optimize the number of queries to the database.
More information
Map services can reduce the number of queries sent to the database if the SQL queries used by labeling are simple. Vendor-specific SQL logic cannot be optimized by the drawing engine.