[GitHub] [kafka] rodesai commented on a change in pull request #10046: MINOR: Extends RocksDB docs

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rodesai commented on a change in pull request #10046:
URL: https://github.com/apache/kafka/pull/10046#discussion_r570627385



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File path: docs/streams/developer-guide/memory-mgmt.html
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@@ -168,7 +168,15 @@
       <h2><a class="toc-backref" href="#id3">RocksDB</a><a class="headerlink" href="#rocksdb" title="Permalink to this headline"></a></h2>
       <p> Each instance of RocksDB allocates off-heap memory for a block cache, index and filter blocks, and memtable (write buffer). Critical configs (for RocksDB version 4.1.0) include
         <code class="docutils literal"><span class="pre">block_cache_size</span></code>, <code class="docutils literal"><span class="pre">write_buffer_size</span></code> and <code class="docutils literal"><span class="pre">max_write_buffer_number</span></code>.  These can be specified through the
-        <code class="docutils literal"><span class="pre">rocksdb.config.setter</span></code> configuration.</li>
+        <code class="docutils literal"><span class="pre">rocksdb.config.setter</span></code> configuration.</p>
+      <p>Also, we recommend changing RocksDB's default memory allocator, because the default allocator may lead to increased memory consumption.
+        To change the memory allocator to <code>jemalloc</code>, you need to set the an environment variable before you start your Kafka Streams application:</p>
+      <pre>
+# example: install jemalloc (on Debian)
+$ apt install -y libjemalloc-dev
+# set LD_PRELOAD before you start your Kafka Streams application
+$ LD_PRELOAD="/usr/lib/x86_64-linux-gnu/libjemalloc.so”

Review comment:
       just doing `LD_PRELOAD=` will only set the variable for that one command, which isn't doing anything. This should either be:
   ```
   $ export LD_PRELOAD="/usr/lib/x86_64-linux-gnu/libjemalloc.so"
   $ <application>
   ```
   OR
   ```
   $ LD_PRELOAD="/usr/lib/x86_64-linux-gnu/libjemalloc.so" <application>
   ```
   
   




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