SQL Server: Trace Flag 4135

What is the Trace Flag 4135 in SQL Server and what i开发者_开发问答s the purpose of this flage? Should it be enabled? How to enable it?

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From this answer on serverfault:

The traceflag disables an optimization in the query optimizer. The optimization caused the issue described in the KB article when you try to insert into a table by selecting from the table itself. As turning on the traceflag could result in a perf degradation, you only should use it if you run into the issue described in the KB article.

KB Article
Thread on the topic