Tablockx Table Hint in SQL Server

The Tablockx Hint is sql server is used to specify that an exclusive table level lock should be acquired for the duration of operation. This hint prevents other transaction, reading or modifying the table until the lock is released.

It is stronger version of Tablock. This acquires an exclusive table – level lock for entire table. It is very useful for bulk insert , update or delete where we want to ensure exclusive access to the table.

It can improve performance for large operation by reducing lock connection but in other hand transaction that attempt to read or modify the table will be blocked. In the high concurrency environment, it can cause of performance bottlenecks.

See the example

Imagine a financial system where, at the end of each month, the accounting team performs a final adjustment to all entries in the Transactions table. To ensure no other transactions (read/write) happen during the adjustment, we can use TABLOCKX. The whole Transactions table is exclusively locked. No other session can read, update, or insert into the table during the transaction. This ensures data integrity during sensitive batch operations.