When I am running this query REINDEX TABLE rgn_main; in postgresSQL 14, query got stuck when my project is live, and when i stops my project it executes.

In my Project i am excecuting only select query. My project is J2EE.
I did lot of R&D about this, this could be happly only when some other query is executing at that time which has acquired Exclusive lock, this may be one of the reason, but in my project i am using only select query, select query did not acquires Exclusive lock.

If any one know about this, and any possibe solution know please help.

Thanks you