We plan to enable unique index on the task table and we have around 9 million records on the task table, I want to understand how long does it take to apply unique index on all the record and whats the impact
Indexing in ServiceNow does not usually take much time. Once the indexing process is completed, the system can automatically send a notification to the configured email address. In addition, you can manually verify whether the indexing has been completed by checking the respective table (for example, the index tables or logs) where the indexing status is stored.
if you want to much more info then you can refer the below thread
