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| <div class="sub-title"><span class="package-label-in-type">Package</span> <a href="package-summary.html">org.apache.hadoop.hbase.regionserver</a></div> |
| <h1 title="Class ReadPointCalculationLock" class="title">Class ReadPointCalculationLock</h1> |
| </div> |
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| <div class="inheritance">org.apache.hadoop.hbase.regionserver.ReadPointCalculationLock</div> |
| </div> |
| <section class="class-description" id="class-description"> |
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| <div class="type-signature"><span class="annotations">@Private |
| </span><span class="modifiers">public class </span><span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/regionserver/ReadPointCalculationLock.html#line-41">ReadPointCalculationLock</a></span> |
| <span class="extends-implements">extends <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html" title="class or interface in java.lang" class="external-link">Object</a></span></div> |
| <div class="block">Lock to manage concurrency between <a href="RegionScanner.html" title="interface in org.apache.hadoop.hbase.regionserver"><code>RegionScanner</code></a> and |
| <a href="HRegion.html#getSmallestReadPoint()"><code>HRegion.getSmallestReadPoint()</code></a>. We need to ensure that while we are calculating the |
| smallest read point, no new scanners can modify the scannerReadPoints Map. We used to achieve |
| this by synchronizing on the scannerReadPoints object. But this may block the read thread and |
| reduce the read performance. Since the scannerReadPoints object is a |
| <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/ConcurrentHashMap.html" title="class or interface in java.util.concurrent" class="external-link"><code>ConcurrentHashMap</code></a>, which is thread-safe, so the |
| <a href="RegionScanner.html" title="interface in org.apache.hadoop.hbase.regionserver"><code>RegionScanner</code></a> can record their read points concurrently, what it needs to do is just |
| acquiring a shared lock. When we calculate the smallest read point, we need to acquire an |
| exclusive lock. This can improve read performance in most scenarios, only not when we have a lot |
| of delta operations, like <a href="../client/Append.html" title="class in org.apache.hadoop.hbase.client"><code>Append</code></a> or |
| <a href="../client/Increment.html" title="class in org.apache.hadoop.hbase.client"><code>Increment</code></a>. So we introduce a flag to enable/disable this |
| feature.</div> |
| </section> |
| <section class="summary"> |
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| <div class="table-header col-first">Modifier and Type</div> |
| <div class="table-header col-second">Class</div> |
| <div class="table-header col-last">Description</div> |
| <div class="col-first even-row-color"><code>static enum </code></div> |
| <div class="col-second even-row-color"><code><a href="ReadPointCalculationLock.LockType.html" class="type-name-link" title="enum class in org.apache.hadoop.hbase.regionserver">ReadPointCalculationLock.LockType</a></code></div> |
| <div class="col-last even-row-color"> </div> |
| </div> |
| </section> |
| </li> |
| <!-- =========== FIELD SUMMARY =========== --> |
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| <section class="field-summary" id="field-summary"> |
| <h2>Field Summary</h2> |
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| <div class="table-header col-first">Modifier and Type</div> |
| <div class="table-header col-second">Field</div> |
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| <div class="col-first even-row-color"><code>private <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/locks/Lock.html" title="class or interface in java.util.concurrent.locks" class="external-link">Lock</a></code></div> |
| <div class="col-second even-row-color"><code><a href="#lock" class="member-name-link">lock</a></code></div> |
| <div class="col-last even-row-color"> </div> |
| <div class="col-first odd-row-color"><code>private <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/locks/ReadWriteLock.html" title="class or interface in java.util.concurrent.locks" class="external-link">ReadWriteLock</a></code></div> |
| <div class="col-second odd-row-color"><code><a href="#readWriteLock" class="member-name-link">readWriteLock</a></code></div> |
| <div class="col-last odd-row-color"> </div> |
| <div class="col-first even-row-color"><code>private final boolean</code></div> |
| <div class="col-second even-row-color"><code><a href="#useReadWriteLockForReadPoints" class="member-name-link">useReadWriteLockForReadPoints</a></code></div> |
| <div class="col-last even-row-color"> </div> |
| </div> |
| </section> |
| </li> |
| <!-- ======== CONSTRUCTOR SUMMARY ======== --> |
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| <section class="constructor-summary" id="constructor-summary"> |
| <h2>Constructor Summary</h2> |
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| <div class="table-header col-first">Constructor</div> |
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| <div class="col-constructor-name even-row-color"><code><a href="#%3Cinit%3E(org.apache.hadoop.conf.Configuration)" class="member-name-link">ReadPointCalculationLock</a><wbr>(org.apache.hadoop.conf.Configuration conf)</code></div> |
| <div class="col-last even-row-color"> </div> |
| </div> |
| </section> |
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| <div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code>(package private) void</code></div> |
| <div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#lock(org.apache.hadoop.hbase.regionserver.ReadPointCalculationLock.LockType)" class="member-name-link">lock</a><wbr>(<a href="ReadPointCalculationLock.LockType.html" title="enum class in org.apache.hadoop.hbase.regionserver">ReadPointCalculationLock.LockType</a> lockType)</code></div> |
| <div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> </div> |
| <div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code>(package private) void</code></div> |
| <div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#unlock(org.apache.hadoop.hbase.regionserver.ReadPointCalculationLock.LockType)" class="member-name-link">unlock</a><wbr>(<a href="ReadPointCalculationLock.LockType.html" title="enum class in org.apache.hadoop.hbase.regionserver">ReadPointCalculationLock.LockType</a> lockType)</code></div> |
| <div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"> </div> |
| </div> |
| </div> |
| </div> |
| <div class="inherited-list"> |
| <h3 id="methods-inherited-from-class-java.lang.Object">Methods inherited from class java.lang.<a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html" title="class or interface in java.lang" class="external-link">Object</a></h3> |
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| </section> |
| </li> |
| </ul> |
| </section> |
| <section class="details"> |
| <ul class="details-list"> |
| <!-- ============ FIELD DETAIL =========== --> |
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| <section class="field-details" id="field-detail"> |
| <h2>Field Details</h2> |
| <ul class="member-list"> |
| <li> |
| <section class="detail" id="useReadWriteLockForReadPoints"> |
| <h3>useReadWriteLockForReadPoints</h3> |
| <div class="member-signature"><span class="modifiers">private final</span> <span class="return-type">boolean</span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/regionserver/ReadPointCalculationLock.html#line-49">useReadWriteLockForReadPoints</a></span></div> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="lock"> |
| <h3>lock</h3> |
| <div class="member-signature"><span class="modifiers">private</span> <span class="return-type"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/locks/Lock.html" title="class or interface in java.util.concurrent.locks" class="external-link">Lock</a></span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/regionserver/ReadPointCalculationLock.html#line-50">lock</a></span></div> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="readWriteLock"> |
| <h3>readWriteLock</h3> |
| <div class="member-signature"><span class="modifiers">private</span> <span class="return-type"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/locks/ReadWriteLock.html" title="class or interface in java.util.concurrent.locks" class="external-link">ReadWriteLock</a></span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/regionserver/ReadPointCalculationLock.html#line-51">readWriteLock</a></span></div> |
| </section> |
| </li> |
| </ul> |
| </section> |
| </li> |
| <!-- ========= CONSTRUCTOR DETAIL ======== --> |
| <li> |
| <section class="constructor-details" id="constructor-detail"> |
| <h2>Constructor Details</h2> |
| <ul class="member-list"> |
| <li> |
| <section class="detail" id="<init>(org.apache.hadoop.conf.Configuration)"> |
| <h3>ReadPointCalculationLock</h3> |
| <div class="member-signature"><span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/regionserver/ReadPointCalculationLock.html#line-53">ReadPointCalculationLock</a></span><wbr><span class="parameters">(org.apache.hadoop.conf.Configuration conf)</span></div> |
| </section> |
| </li> |
| </ul> |
| </section> |
| </li> |
| <!-- ============ METHOD DETAIL ========== --> |
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| <section class="method-details" id="method-detail"> |
| <h2>Method Details</h2> |
| <ul class="member-list"> |
| <li> |
| <section class="detail" id="lock(org.apache.hadoop.hbase.regionserver.ReadPointCalculationLock.LockType)"> |
| <h3>lock</h3> |
| <div class="member-signature"><span class="return-type">void</span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/regionserver/ReadPointCalculationLock.html#line-63">lock</a></span><wbr><span class="parameters">(<a href="ReadPointCalculationLock.LockType.html" title="enum class in org.apache.hadoop.hbase.regionserver">ReadPointCalculationLock.LockType</a> lockType)</span></div> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="unlock(org.apache.hadoop.hbase.regionserver.ReadPointCalculationLock.LockType)"> |
| <h3>unlock</h3> |
| <div class="member-signature"><span class="return-type">void</span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/regionserver/ReadPointCalculationLock.html#line-77">unlock</a></span><wbr><span class="parameters">(<a href="ReadPointCalculationLock.LockType.html" title="enum class in org.apache.hadoop.hbase.regionserver">ReadPointCalculationLock.LockType</a> lockType)</span></div> |
| </section> |
| </li> |
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