HBASE-11717 Remove unused config 'hbase.offheapcache.percentage' from hbase-default.xml and book. (Anoop)

hbase-common/src/main/resources/hbase-default.xml

@@ -1063,15 +1063,6 @@ possible configurations would overwhelm and obscure the important.
     <value>false</value>
     <description>Use Thrift TCompactProtocol binary serialization protocol.</description>
   </property>
-  <property>
-    <name>hbase.offheapcache.percentage</name>
-    <value>0</value>
-    <description>The percentage of the off heap space (-XX:MaxDirectMemorySize) to be
-     allocated towards the experimental off heap "SlabCache" (This is different to
-     the BucketCache -- see the package javadoc for org.apache.hadoop.hbase.io.hfile
-     for more on your options). If you desire the cache to be disabled, simply set this
-      value to 0.</description>
-  </property>
   <property>
     <name>hbase.data.umask.enable</name>
     <value>false</value>

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CacheConfig.java

@@ -111,7 +111,6 @@ public class CacheConfig {
   public static final boolean DEFAULT_BUCKET_CACHE_COMBINED = true;
   public static final int DEFAULT_BUCKET_CACHE_WRITER_THREADS = 3;
   public static final int DEFAULT_BUCKET_CACHE_WRITER_QUEUE = 64;
-  public static final float DEFAULT_BUCKET_CACHE_COMBINED_PERCENTAGE = 0.9f;
 
  /**
    * Configuration key to prefetch all blocks of a given file into the block cache

hbase-server/src/test/java/org/apache/hadoop/hbase/mapred/TestTableSnapshotInputFormat.java

@@ -115,9 +115,6 @@ public class TestTableSnapshotInputFormat extends TableSnapshotInputFormatTestBa
         "Snapshot job should be configured for default LruBlockCache.",
         HConstants.HFILE_BLOCK_CACHE_SIZE_DEFAULT,
         job.getFloat(HConstants.HFILE_BLOCK_CACHE_SIZE_KEY, -1), 0.01);
-      Assert.assertEquals(
-        "Snapshot job should not use SlabCache.",
-        0, job.getFloat("hbase.offheapcache.percentage", -1), 0.01);
       Assert.assertEquals(
         "Snapshot job should not use BucketCache.",
         0, job.getFloat("hbase.bucketcache.size", -1), 0.01);

hbase-server/src/test/java/org/apache/hadoop/hbase/mapreduce/TestTableSnapshotInputFormat.java

@@ -162,9 +162,6 @@ public class TestTableSnapshotInputFormat extends TableSnapshotInputFormatTestBa
         "Snapshot job should be configured for default LruBlockCache.",
         HConstants.HFILE_BLOCK_CACHE_SIZE_DEFAULT,
         job.getConfiguration().getFloat(HConstants.HFILE_BLOCK_CACHE_SIZE_KEY, -1), 0.01);
-      Assert.assertEquals(
-        "Snapshot job should not use SlabCache.",
-        0, job.getConfiguration().getFloat("hbase.offheapcache.percentage", -1), 0.01);
       Assert.assertEquals(
         "Snapshot job should not use BucketCache.",
         0, job.getConfiguration().getFloat("hbase.bucketcache.size", -1), 0.01);

src/main/docbkx/book.xml

@@ -2082,8 +2082,8 @@ rs.close();
         xml:id="block.cache">
         <title>Block Cache</title>
 
-        <para>HBase provides three different BlockCache implementations: the default onheap
+        <para>HBase provides two different BlockCache implementations: the default onheap
-          LruBlockCache, BucketCache, and SlabCache, which are both (usually) offheap. This section
+          LruBlockCache and BucketCache, which is (usually) offheap. This section
           discusses benefits and drawbacks of each implementation, how to choose the appropriate
           option, and configuration options for each.</para>
 
@@ -2099,9 +2099,7 @@ rs.close();
           <para><classname>LruBlockCache</classname> is the original implementation, and is
               entirely within the Java heap. <classname>BucketCache</classname> is mainly
               intended for keeping blockcache data offheap, although BucketCache can also
-              keep data onheap and serve from a file-backed cache. There is also an older
+              keep data onheap and serve from a file-backed cache.
-              offheap BlockCache, called SlabCache that has since been deprecated and
-              removed in HBase 1.0.
           </para>
 
           <para>Fetching will always be slower when fetching from BucketCache,
@@ -2292,30 +2290,6 @@ rs.close();
         <section
           xml:id="offheap.blockcache">
           <title>Offheap Block Cache</title>
-          <section xml:id="offheap.blockcache.slabcache">
-            <title>How to Enable SlabCache</title>
-            <para><emphasis>SlabCache is deprecated and will be removed in 1.0!</emphasis></para>
-            <para> SlabCache is originally described in <link
-                xlink:href="http://blog.cloudera.com/blog/2012/01/caching-in-hbase-slabcache/">Caching
-                in Apache HBase: SlabCache</link>. Quoting from the API documentation for <link
-                xlink:href="http://hbase.apache.org/0.94/apidocs/org/apache/hadoop/hbase/io/hfile/DoubleBlockCache.html">DoubleBlockCache</link>,
-              the hosting class for SlabCache deploys,
-              DoubleBlockCache is an abstraction layer that combines two caches, the smaller onHeapCache and the
-              larger offHeapCache. CacheBlock attempts to cache the block in both caches, while
-              readblock reads first from the faster on heap cache before looking for the block in
-              the off heap cache. Metrics are the combined size and hits and misses of both
-              caches.</para>
-            <para>To enable SlabCache, set the float
-                <varname>hbase.offheapcache.percentage</varname> to some value between 0 and 1 in
-              the <filename>hbase-site.xml</filename> file on the RegionServer. The value will be multiplied by the
-              setting for <varname>-XX:MaxDirectMemorySize</varname> in the RegionServer's
-                <filename>hbase-env.sh</filename> configuration file and the result is used by
-              SlabCache as its offheap store. The onheap store will be the value of the float
-                <varname>HConstants.HFILE_BLOCK_CACHE_SIZE_KEY</varname> setting (some value between
-              0 and 1) multiplied by the size of the allocated Java heap.</para>
-            <para>Restart (or rolling restart) your cluster for the configurations to take effect.
-              Check logs for errors or unexpected behavior.</para>
-          </section>
           <section xml:id="enable.bucketcache">
             <title>How to Enable BucketCache</title>
                 <para>The usual deploy of BucketCache is via a managing class that sets up two caching tiers: an L1 onheap cache

src/main/docbkx/upgrading.xml

@@ -428,27 +428,6 @@ Successfully completed Log splitting
                 setup a secure HBase is on the way. </para>
         </section>
 
-        <section
-            xml:id="slabcache">
-            <title>Experimental off-heap cache: SlabCache</title>
-            <para> A new cache was contributed to 0.92.0 to act as a solution between using the
-                “on-heap” cache which is the current LRU cache the region servers have and the
-                operating system cache which is out of our control. To enable
-                    <emphasis>SlabCache</emphasis>, as this feature is being called, set
-                “-XX:MaxDirectMemorySize” in hbase-env.sh to the value for maximum direct memory
-                size and specify <property>hbase.offheapcache.percentage</property> in
-                    <filename>hbase-site.xml</filename> with the percentage that you want to
-                dedicate to off-heap cache. This should only be set for servers and not for clients.
-                Use at your own risk. See this blog post, <link
-                    xlink:href="http://www.cloudera.com/blog/2012/01/caching-in-hbase-slabcache/">Caching
-                    in Apache HBase: SlabCache</link>, for additional information on this new
-                experimental feature. </para>
-            <para>This feature has mostly been eclipsed in later HBases. See <link
-                    xlink:href="https://issues.apache.org/jira/browse/HBASE-7404 ">HBASE-7404 Bucket
-                    Cache:A solution about CMS,Heap Fragment and Big Cache on HBASE</link>,
-                etc.</para>
-        </section>
-
         <section>
             <title>Changes in HBase replication </title>
             <para>0.92.0 adds two new features: multi-slave and multi-master replication. The way to