What Are the Risks of Deleting an Index from an Ultra-large Table?

Deleting an index is risky. You are advised not to delete an index unless necessary. The reasons are as follows:

• Deleting an index will deteriorate the performance of queries that use the index. Slow SQL statements consume all system resources, which affects workloads.
• When an index is deleted, the table is locked and other users cannot access the table, which affects system availability.
• When an index is deleted, index data may be lost or damaged, which affects data consistency.
• If workloads are affected after an index is deleted, the index needs to be rebuilt, which is time-consuming for ultra-large tables.