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<p>
In previous releases, configuring lock or transaction timeout values or calling the <a href="../api_reference/C/txnbegin.html" class="olink">DB_ENV->txn_begin()</a>
method with the <a href="../api_reference/C/txnbegin.html#txnbegin_DB_TXN_NOWAIT" class="olink">DB_TXN_NOWAIT</a> flag caused database operation methods to return
<a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a>, or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
exception. This required applications to unnecessarily handle multiple errors or
exception types.
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In the Berkeley DB 4.2 release, with one exception, database operations will no longer return
<a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a> or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
exception. Instead, database operations will return
<a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_DEADLOCK" class="olink">DB_LOCK_DEADLOCK</a> or throw a <a href="../api_reference/CXX/dbdeadlock.html" class="olink">DbDeadlockException</a>
exception. This change should require no application changes, as applications must
already be dealing with the possible <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_DEADLOCK" class="olink">DB_LOCK_DEADLOCK</a> error return or <a href="../api_reference/CXX/dbdeadlock.html" class="olink">DbDeadlockException</a>
exception from database operations.
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The one exception to this rule is the <a href="../api_reference/C/dbget.html" class="olink">DB->get()</a> method using the <a href="../api_reference/C/dbget.html#dbget_DB_CONSUME_WAIT" class="olink">DB_CONSUME_WAIT</a> flag to consume records
from a Queue. If lock or transaction timeouts are set, this method and flag combination may
return <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a> or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
exception.
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Applications wanting to distinguish between true deadlocks and timeouts can configure database
operation methods to return <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a> or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
exception using the <a href="../api_reference/C/envset_flags.html#envset_flags_DB_TIME_NOTGRANTED" class="olink">DB_TIME_NOTGRANTED</a> flag.
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The <a href="../api_reference/C/lockget.html" class="olink">DB_ENV->lock_get()</a> and <a href="../api_reference/C/lockvec.html" class="olink">DB_ENV->lock_vec()</a> methods will continue to return
<a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a>, or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
exception as they have previously done.
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