Check out the discussion in the video . A colleague once shared a story of a company that dismissed a developer because the developer had run a query counting records without using NOLOCK. The OLTP environment experienced a brief disruption from this and thus the developer was dismissed. In general, avoid running queries in production and if you are required to run queries, either use queries that have either been pre-created or use queries that have been approved. Exceptions do exist.
As a note about NOLOCK based on this video:
- Be careful about overanalysis in situations where it doesn't matter
- Know what NOLOCK means when thinking about querying data
- Pay attention to OLTP and OLAP contexts
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We look at some of the drawbacks to using this hint along with some of the advantages. Context and situation matters the most when we consider using this. Also, there are other ways to set this at the beginning of the transaction, so that we don't have to specify on each table.
One regular point I like to remind my audience, especially as of recent: we can often solve the same problem with a variety of techniques. While we look at one or two ways to solve the problem, these aren't the only ways we can approach this problem. The most appropriate solution to a problem is one in which you can troubleshoot quickly in the future and one in which you understand. Be careful about applying solutions that solve a problem, but introduce new problems in the future.
A great re-occuring example of this is my discussion on alerting best practices. There are a variety of alerts everywhere for everything in today's development environments, but many of these alerts cause more issues than they solve (one of which is creating a distraction). Be careful about "easy" solutions which introduce bigger problems. Know your environment and where to apply the best solution. Of course, all these being written, it is helpful to learn new techniques to solve problems because they may be useful in the future.