1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>Bulk Transfers</title> 7 <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.62.4" /> 9 <link rel="home" href="index.html" title="Getting Started with Replicated Berkeley DB Applications" /> 10 <link rel="up" href="addfeatures.html" title="Chapter��5.��Additional Features" /> 11 <link rel="previous" href="c2ctransfer.html" title="Client to Client Transfer" /> 12 </head> 13 <body> 14 <div class="navheader"> 15 <table width="100%" summary="Navigation header"> 16 <tr> 17 <th colspan="3" align="center">Bulk Transfers</th> 18 </tr> 19 <tr> 20 <td width="20%" align="left"><a accesskey="p" href="c2ctransfer.html">Prev</a>��</td> 21 <th width="60%" align="center">Chapter��5.��Additional Features</th> 22 <td width="20%" align="right">��</td> 23 </tr> 24 </table> 25 <hr /> 26 </div> 27 <div class="sect1" lang="en" xml:lang="en"> 28 <div class="titlepage"> 29 <div> 30 <div> 31 <h2 class="title" style="clear: both"><a id="bulk"></a>Bulk Transfers</h2> 32 </div> 33 </div> 34 <div></div> 35 </div> 36 <p> 37 By default, messages are sent from the master to replicas as they are generated. 38 This can degrade replication performance because the various participating 39 environments must handle a fair amount of network I/O activity. 40 </p> 41 <p> 42 You can alleviate this problem by configuring your master environment for bulk 43 transfers. Bulk transfers simply cause replication messages to accumulate in a 44 buffer until a triggering event occurs. When this event occurs, the entire 45 contents of the buffer is sent to the replica, thereby eliminating excessive 46 network I/O. 47 </p> 48 <p> 49 Note that if you are using replica to replica transfers, then you might want any 50 replica that can service replication requests to also be configured for bulk 51 transfers. 52 </p> 53 <p> 54 The events that result in a bulk transfer of replication messages to a replica 55 will differ depending on if the transmitting environment is a master or a 56 replica. 57 </p> 58 <p> 59 If the servicing environment is a master environment, then bulk a bulk transfer 60 occurs when: 61 </p> 62 <div class="orderedlist"> 63 <ol type="1"> 64 <li> 65 <p> 66 Bulk transfers are configured for the master environment, and 67 </p> 68 </li> 69 <li> 70 <p> 71 the message buffer is full or 72 </p> 73 </li> 74 <li> 75 <p> 76 a permanent record (for example, a transaction commit or a 77 checkpoint record) is placed in the buffer for the replica. 78 </p> 79 </li> 80 </ol> 81 </div> 82 <p> 83 If the servicing environment is a replica environment (that is, replica to replica 84 transfers are in use), then a bulk transfer occurs when: 85 </p> 86 <div class="orderedlist"> 87 <ol type="1"> 88 <li> 89 <p> 90 Bulk transfers are configured for the transmitting replica, and 91 </p> 92 </li> 93 <li> 94 <p> 95 the message buffer is full or 96 </p> 97 </li> 98 <li> 99 <p> 100 the replica servicing the request is able to completely satisfy 101 the request with the contents of the message buffer. 102 </p> 103 </li> 104 </ol> 105 </div> 106 <p> 107 To configure bulk transfers, specify 108 109 110 <span> 111 <tt class="literal">ReplicationConfig.BULK</tt> and 112 <tt class="literal">true</tt> to 113 <tt class="methodname">Environment.setReplicationConfig()</tt>. 114 To turn off this feature, specify 115 <tt class="literal">false</tt> for the 116 <tt class="literal">ReplicationConfig.BULK</tt> field. 117 </span> 118 </p> 119 </div> 120 <div class="navfooter"> 121 <hr /> 122 <table width="100%" summary="Navigation footer"> 123 <tr> 124 <td width="40%" align="left"><a accesskey="p" href="c2ctransfer.html">Prev</a>��</td> 125 <td width="20%" align="center"> 126 <a accesskey="u" href="addfeatures.html">Up</a> 127 </td> 128 <td width="40%" align="right">��</td> 129 </tr> 130 <tr> 131 <td width="40%" align="left" valign="top">Client to Client Transfer��</td> 132 <td width="20%" align="center"> 133 <a accesskey="h" href="index.html">Home</a> 134 </td> 135 <td width="40%" align="right" valign="top">��</td> 136 </tr> 137 </table> 138 </div> 139 </body> 140</html> 141