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<chapter id="mvcc">

<title>Concurrency Control</title>

transaction. And this large expense is mostly wasted, since in

practice most applications do not do the sorts of things that could

result in problems. (Certainly the example above is rather contrived

and unlikely to represent real software.)Accordingly,

and unlikely to represent real software.)For these reasons,

<productname>PostgreSQL</productname> does not implement predicate

locking, and so far as we are aware no other production DBMS does either.

locking.

</para>

<para>