Question: How to Know If Index is Forced on Query?
Answer: Let me tell you a brief story so you understand the context of the question.
How to Use Multiple Hints Together for a Query? – Interview Question of the Week #241
Question: How to Use Multiple Hints Together for a Query?
Answer: Of course, you can use multiple hints for a query. Here is an example of the same.
READPAST Query Hint: Skip Locked Rows in SQL Server
The READPAST query hint makes a read skip rows that another transaction has locked, instead of waiting for them. This post builds a five-seat demo, runs it in two windows and lists the cases where the hint does nothing. It also shows the work queue pattern that pairs READPAST with UPDLOCK.
ENABLE_PARALLEL_PLAN_PREFERENCE Limits: Rows Per Thread
The ENABLE_PARALLEL_PLAN_PREFERENCE limits are easy to miss: the hint can’t make every query parallel, and it can’t spread rows evenly over the threads. This post proves three limits from the last actual plan of demo queries, with the rows each thread processed and the reason a plan stays serial.
Force a Parallel Plan: ENABLE_PARALLEL_PLAN_PREFERENCE Hint
To force a parallel plan for one query, add the ENABLE_PARALLEL_PLAN_PREFERENCE hint to its OPTION clause. This post shows why a cheap query stays serial, runs a demo query with and without the hint, proves the difference from the last actual plan, and explains why the hint belongs in a test and not in every query.
Does NOLOCK Really Applies No Lock? – Interview Question of the Week #209
Does NOLOCK really applies no lock? No. NOLOCK takes a Sch-S, or schema stability, lock. Here is a simple script to see it for yourself.
SQL SERVER – Applying NOLOCK to Every Single Table in Select Statement – SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED
READ UNCOMMITTED changes session read isolation without adding NOLOCK to every table. A workshop procedure made the distinction useful.