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HBASE-11268 HTablePool is now a deprecated class, should update docs to reflect this (Misty Stanley-Jones)

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Michael Stack 2014-05-30 10:45:50 -07:00
parent afbe165676
commit 380bfd11eb
1 changed files with 48 additions and 46 deletions
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@ -1518,27 +1518,25 @@ if (!b) {
any given time. When creating HTable instances, it is advisable to use the same <link any given time. When creating HTable instances, it is advisable to use the same <link
xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/HBaseConfiguration">HBaseConfiguration</link> xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/HBaseConfiguration">HBaseConfiguration</link>
instance. This will ensure sharing of ZooKeeper and socket instances to the RegionServers instance. This will ensure sharing of ZooKeeper and socket instances to the RegionServers
which is usually what you want. For example, this is preferred: which is usually what you want. For example, this is preferred:</para>
<programlisting>HBaseConfiguration conf = HBaseConfiguration.create(); <programlisting>HBaseConfiguration conf = HBaseConfiguration.create();
HTable table1 = new HTable(conf, "myTable"); HTable table1 = new HTable(conf, "myTable");
HTable table2 = new HTable(conf, "myTable");</programlisting> HTable table2 = new HTable(conf, "myTable");</programlisting>
as opposed to this: <para>as opposed to this:</para>
<programlisting>HBaseConfiguration conf1 = HBaseConfiguration.create(); <programlisting>HBaseConfiguration conf1 = HBaseConfiguration.create();
HTable table1 = new HTable(conf1, "myTable"); HTable table1 = new HTable(conf1, "myTable");
HBaseConfiguration conf2 = HBaseConfiguration.create(); HBaseConfiguration conf2 = HBaseConfiguration.create();
HTable table2 = new HTable(conf2, "myTable");</programlisting> HTable table2 = new HTable(conf2, "myTable");</programlisting>
For more information about how connections are handled in the HBase client, see <link
xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HConnectionManager.html">HConnectionManager</link>. </para> <para>For more information about how connections are handled in the HBase client,
<section see <link xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HConnectionManager.html">HConnectionManager</link>.
xml:id="client.connection.pooling"> </para>
<title>Connection Pooling</title> <section xml:id="client.connection.pooling"><title>Connection Pooling</title>
<para>For applications which require high-end multithreaded access (e.g., web-servers or <para>For applications which require high-end multithreaded access (e.g., web-servers or application servers that may serve many application threads
application servers that may serve many application threads in a single JVM), one in a single JVM), you can pre-create an <classname>HConnection</classname>, as shown in
solution is <link the following example:</para>
xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTablePool.html">HTablePool</link>. <example>
But as written currently, it is difficult to control client resource consumption when <title>Pre-Creating a <code>HConnection</code></title>
using HTablePool. </para>
<para> Another solution is to precreate an <classname>HConnection</classname> using
<programlisting>// Create a connection to the cluster. <programlisting>// Create a connection to the cluster.
HConnection connection = HConnectionManager.createConnection(Configuration); HConnection connection = HConnectionManager.createConnection(Configuration);
HTableInterface table = connection.getTable("myTable"); HTableInterface table = connection.getTable("myTable");
@ -1546,34 +1544,38 @@ HTableInterface table = connection.getTable("myTable");
table.close(); table.close();
// use the connection for other access to the cluster // use the connection for other access to the cluster
connection.close();</programlisting> connection.close();</programlisting>
Constructing HTableInterface implementation is very lightweight and resources are </example>
controlled/shared if you go this route. </para> <para>Constructing HTableInterface implementation is very lightweight and resources are
controlled.</para>
<warning>
<title><code>HTablePool</code> is Deprecated</title>
<para>Previous versions of this guide discussed <code>HTablePool</code>, which was
deprecated in HBase 0.94, 0.95, and 0.96, and removed in 0.98.1, by <link
xlink:href="https://issues.apache.org/jira/browse/HBASE-6580">HBASE-6500</link>.
Please use <link xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HConnection.html"><code>HConnection</code></link> instead.</para>
</warning>
</section> </section>
</section> </section>
<section <section xml:id="client.writebuffer"><title>WriteBuffer and Batch Methods</title>
xml:id="client.writebuffer"> <para>If <xref linkend="perf.hbase.client.autoflush" /> is turned off on
<title>WriteBuffer and Batch Methods</title> <link xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html">HTable</link>,
<para>If <xref <classname>Put</classname>s are sent to RegionServers when the writebuffer
linkend="perf.hbase.client.autoflush" /> is turned off on <link is filled. The writebuffer is 2MB by default. Before an HTable instance is
xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html">HTable</link>, discarded, either <methodname>close()</methodname> or
<classname>Put</classname>s are sent to RegionServers when the writebuffer is filled. <methodname>flushCommits()</methodname> should be invoked so Puts
The writebuffer is 2MB by default. Before an HTable instance is discarded, either will not be lost.
<methodname>close()</methodname> or <methodname>flushCommits()</methodname> should be </para>
invoked so Puts will not be lost. </para> <para>Note: <code>htable.delete(Delete);</code> does not go in the writebuffer! This only applies to Puts.
<para>Note: <code>htable.delete(Delete);</code> does not go in the writebuffer! This only </para>
applies to Puts. </para> <para>For additional information on write durability, review the <link xlink:href="../acid-semantics.html">ACID semantics</link> page.
<para>For additional information on write durability, review the <link </para>
xlink:href="../acid-semantics.html">ACID semantics</link> page. </para> <para>For fine-grained control of batching of
<para>For fine-grained control of batching of <classname>Put</classname>s or <classname>Put</classname>s or <classname>Delete</classname>s,
<classname>Delete</classname>s, see the <link see the <link xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html#batch%28java.util.List%29">batch</link> methods on HTable.
xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html#batch%28java.util.List%29">batch</link> </para>
methods on HTable. </para>
</section> </section>
<section <section xml:id="client.external"><title>External Clients</title>
xml:id="client.external"> <para>Information on non-Java clients and custom protocols is covered in <xref linkend="external_apis" />
<title>External Clients</title>
<para>Information on non-Java clients and custom protocols is covered in <xref
linkend="external_apis" />
</para> </para>
</section> </section>
</section> </section>