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<h2 class="title" style="clear: both"><a id="upgrade_4_8_mpool"></a>Minor Change in Behavior of DB_MPOOLFILE->get</h2>
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<p>
DB 4.8 introduces some performance enhancements, based on the use
of shared/exclusive latches instead of locks in some areas of the
internal buffer management code. This change will affect how the
<code class="classname">DB_MPOOL</code> interface handles dirty buffers.
</p>
<p> Because of these
changes, <code class="methodname">DB_MPOOLFILE->get</code> will now
acquire an exclusive latch on the buffer if
the <code class="literal">DB_MPOOL_DIRTY</code>
or <code class="literal">DB_MPOOL_EDIT</code> flags are specified. This
could lead to an application deadlock if the application tries to
fetch the buffer again, without an
intervening <code class="methodname">DB_MPOOLFILE->put</code> call.
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<p>
If your application uses the <code class="literal">DB_MPOOL</code>
interface, and especially the <code class="literal">DB_MPOOL_DIRTY</code>
and <code class="literal">DB_MPOOL_EDIT</code> flags, you should review your
code to ensure that this behavior change does not cause your
application to deadlock.
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