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>Chapter��5.��Additional Features</title> 7 <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Getting Started with Replicated Berkeley DB Applications" /> 10 <link rel="up" href="index.html" title="Getting Started with Replicated Berkeley DB Applications" /> 11 <link rel="prev" href="exampledoloop.html" title="Example Processing Loop" /> 12 <link rel="next" href="manageblock.html" title="Managing Blocking Operations" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">Chapter��5.��Additional Features</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="exampledoloop.html">Prev</a>��</td> 22 <th width="60%" align="center">��</th> 23 <td width="20%" align="right">��<a accesskey="n" href="manageblock.html">Next</a></td> 24 </tr> 25 </table> 26 <hr /> 27 </div> 28 <div class="chapter" lang="en" xml:lang="en"> 29 <div class="titlepage"> 30 <div> 31 <div> 32 <h2 class="title"><a id="addfeatures"></a>Chapter��5.��Additional Features</h2> 33 </div> 34 </div> 35 </div> 36 <div class="toc"> 37 <p> 38 <b>Table of Contents</b> 39 </p> 40 <dl> 41 <dt> 42 <span class="sect1"> 43 <a href="addfeatures.html#delayedsync">Delayed Synchronization</a> 44 </span> 45 </dt> 46 <dt> 47 <span class="sect1"> 48 <a href="manageblock.html">Managing Blocking Operations</a> 49 </span> 50 </dt> 51 <dt> 52 <span class="sect1"> 53 <a href="noautoinit.html">Stop Auto-Initialization</a> 54 </span> 55 </dt> 56 <dt> 57 <span class="sect1"> 58 <a href="c2ctransfer.html">Client to Client Transfer</a> 59 </span> 60 </dt> 61 <dd> 62 <dl> 63 <dt> 64 <span class="sect2"> 65 <a href="c2ctransfer.html#fmwrkpeerserver">Identifying Peers</a> 66 </span> 67 </dt> 68 </dl> 69 </dd> 70 <dt> 71 <span class="sect1"> 72 <a href="bulk.html">Bulk Transfers</a> 73 </span> 74 </dt> 75 </dl> 76 </div> 77 <p> 78 Beyond the basic functionality that we have discussed so far in 79 this book, there are several replication features that you 80 should understand. These are all optional to use, but provide 81 useful functionality under the right circumstances. 82 </p> 83 <p> 84 These additional features are: 85 </p> 86 <div class="orderedlist"> 87 <ol type="1"> 88 <li> 89 <p> 90 <a class="xref" href="addfeatures.html#delayedsync" title="Delayed Synchronization">Delayed Synchronization</a> 91 </p> 92 </li> 93 <li> 94 <p> 95 <a class="xref" href="manageblock.html" title="Managing Blocking Operations">Managing Blocking Operations</a> 96 </p> 97 </li> 98 <li> 99 <p> 100 <a class="xref" href="noautoinit.html" title="Stop Auto-Initialization">Stop Auto-Initialization</a> 101 </p> 102 </li> 103 <li> 104 <p> 105 <a class="xref" href="c2ctransfer.html" title="Client to Client Transfer">Client to Client Transfer</a> 106 </p> 107 </li> 108 <li> 109 <p> 110 <a class="xref" href="bulk.html" title="Bulk Transfers">Bulk Transfers</a> 111 </p> 112 </li> 113 </ol> 114 </div> 115 <div class="sect1" lang="en" xml:lang="en"> 116 <div class="titlepage"> 117 <div> 118 <div> 119 <h2 class="title" style="clear: both"><a id="delayedsync"></a>Delayed Synchronization</h2> 120 </div> 121 </div> 122 </div> 123 <p> 124 When a replication group has a new master, all replicas must 125 synchronize with that master. This means they must ensure 126 that the contents of their local database(s) are identical 127 to that contained by the new master. 128 </p> 129 <p> 130 This synchronization process can result in quite a lot of 131 network activity. It can also put a large strain on the 132 master server, especially if is part of a large 133 replication group or if there is somehow a large difference between 134 the master's database(s) and the contents of its replicas. 135 </p> 136 <p> 137 It is therefore possible to delay synchronization for any 138 replica that discovers it has a new master. You would do 139 this so as to give the master time to synchronize other 140 replicas before proceeding with the delayed replicas. 141 </p> 142 <p> 143 To delay synchronization of a replica environment, you 144 specify 145 <span> 146 <code class="literal">DB_REP_CONF_DELAYCLIENT</code> to 147 <code class="methodname">DB_ENV->rep_set_config()</code> 148 149 and then specify <code class="literal">1</code> to the <code class="literal">onoff</code> 150 parameter. (Specify <code class="literal">0</code> to turn the feature off.) 151 </span> 152 153 </p> 154 <p> 155 If you use delayed synchronization, then you must manually 156 synchronize the replica at some future time. Until you do this, the replica is out of 157 sync with the master, and it will ignore all database changes forwarded to it from 158 the master. 159 </p> 160 <p> 161 You synchronize a delayed replica by calling 162 <code class="methodname">DB_ENV->rep_sync()</code> 163 164 165 on the replica that has been delayed. 166 </p> 167 </div> 168 </div> 169 <div class="navfooter"> 170 <hr /> 171 <table width="100%" summary="Navigation footer"> 172 <tr> 173 <td width="40%" align="left"><a accesskey="p" href="exampledoloop.html">Prev</a>��</td> 174 <td width="20%" align="center">��</td> 175 <td width="40%" align="right">��<a accesskey="n" href="manageblock.html">Next</a></td> 176 </tr> 177 <tr> 178 <td width="40%" align="left" valign="top">Example Processing Loop��</td> 179 <td width="20%" align="center"> 180 <a accesskey="h" href="index.html">Home</a> 181 </td> 182 <td width="40%" align="right" valign="top">��Managing Blocking Operations</td> 183 </tr> 184 </table> 185 </div> 186 </body> 187</html> 188