10.6. JPA locking query hints

<div class="paragraph">

JPA 2.0 introduced two query hints:

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<div class="dlist">
<dl>
<dt class="hdlist1">javax.persistence.lock.timeout</dt>
<dd>

it gives the number of milliseconds a lock acquisition request will wait before throwing an exception

</dd>
<dt class="hdlist1">javax.persistence.lock.scope</dt>
<dd>

defines the [_scope_](http://docs.oracle.com/javaee/7/api/javax/persistence/PessimisticLockScope.html) of the lock acquisition request.
The scope can either be `NORMAL` (default value) or `EXTENDED`. The `EXTENDED` scope will cause a lock acquisition request to be passed to other owned table structured (e.g. `@Inheritance(strategy=InheritanceType.JOINED)`, `@ElementCollection`)

</dd>
</dl>
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<div id="locking-jpa-query-hints-timeout-example" class="exampleblock">
<div class="title">Example 278. `javax.persistence.lock.timeout` example</div>
<div class="content">
<div class="listingblock">
<div class="content">
<pre class="prettyprint highlight">`entityManager.find(
    Person.class, id, LockModeType.PESSIMISTIC_WRITE,
    Collections.singletonMap( "javax.persistence.lock.timeout", 200 )
);`</pre>
</div>
</div>
<div class="listingblock">
<div class="content">
<pre class="prettyprint highlight">`SELECT explicitlo0_.id     AS id1_0_0_,
       explicitlo0_."name" AS name2_0_0_
FROM   person explicitlo0_
WHERE  explicitlo0_.id = 1
FOR UPDATE wait 2`</pre>
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<div class="admonitionblock note">
<table>
<tr>
<td class="icon">

</td>
<td class="content">
<div class="paragraph">

Not all JDBC database drivers support setting a timeout value for a locking request.
If not supported, the Hibernate dialect ignores this query hint.

</div>
</td>
</tr>
</table>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">

</td>
<td class="content">
<div class="paragraph">

The `javax.persistence.lock.scope` is [not yet supported](https://hibernate.atlassian.net/browse/HHH-9636) as specified by the JPA standard.

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</td>
</tr>
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<div class="sect2">