blocking

Should I change the 'locks' configuration in SQL Server?

Should I change the 'locks' configuration in SQL Server?

I recently got a fantastic question from a reader regarding lock usage in SQL Server:

One of my production databases has a total lock count around 25,000 (select count(*) from sys.dm_tran_locks). The configuration setting for locks is set to the default of zero. This lock count is due to multiple procedures which frequently run and use the same 2-3 tables, repeatedly taking out and releasing locks. Do I need to change the configuration for locks or look into the SP’s so they can finish more quickly, rather than creating locks?

How to Choose Between RCSI and Snapshot Isolation Levels

How to Choose Between RCSI and Snapshot Isolation Levels

SQL Server offers two flavors of optimistic locking for traditional disk-based tables: Read Committed Snapshot Isolation (RCSI), and Snapshot Isolation. They are each great tools to reduce blocking and make applications faster, particularly in databases that have lots of tiny reads and writes that need to be quick, or mixed-use patterns (lots of little reads and writes + larger reporting queries).

Both isolation levels are available in SQL Server Standard Edition and Web Edition as well as Enterprise. That’s right, they’re cheap and easy. Each of them are controlled by database level settings, and default to disabled for new user databases when you install SQL Server and leave the default settings on the model database.

When should you pick one or the other? And when might you enable both?

Why ROWLOCK Hints Can Make Queries Slower and Blocking Worse in SQL Server

Why ROWLOCK Hints Can Make Queries Slower and Blocking Worse in SQL Server

Sometimes when SQL Server gets slow, developers and DBAs find that the problem is blocking. After lots of work to identify the query or queries which are the blockers, frequently one idea is to add ROWLOCK hints to the queries to solve the problem or to disable PAGE locks on the table. This often backfires - here’s why.

The DBA Sees Your Blocking Spids... A Bird's Eye Summary of Blocking

The DBA Sees Your Blocking Spids... A Bird's Eye Summary of Blocking

Update from Kendra (Nov 2018): I’m keeping this post for posterity, but I REALLY don’t recommend the script. You’d be much better off using a production monitoring tool that did this job, or @AdamMachanic ‘s sp_WhoIsActive.

Maybe you’re a user in a reporting database running a long query in the read committed isolation level, merrily blocking a process which needs to load data.