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>DB_ENV->rep_set_config()</title> 7 <link rel="stylesheet" href="apiReference.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Berkeley DB C API Reference" /> 10 <link rel="up" href="rep.html" title="Chapter��10.�� Replication Methods" /> 11 <link rel="prev" href="repclockskew.html" title="DB_ENV->rep_set_clockskew()" /> 12 <link rel="next" href="repset_limit.html" title="DB_ENV->rep_set_limit()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">DB_ENV->rep_set_config()</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="repclockskew.html">Prev</a>��</td> 22 <th width="60%" align="center">Chapter��10.�� 23 Replication Methods 24 </th> 25 <td width="20%" align="right">��<a accesskey="n" href="repset_limit.html">Next</a></td> 26 </tr> 27 </table> 28 <hr /> 29 </div> 30 <div class="sect1" lang="en" xml:lang="en"> 31 <div class="titlepage"> 32 <div> 33 <div> 34 <h2 class="title" style="clear: both"><a id="repconfig"></a>DB_ENV->rep_set_config()</h2> 35 </div> 36 </div> 37 </div> 38 <pre class="programlisting">#include <db.h> 39 40int 41DB_ENV->rep_set_config(DB_ENV *env, u_int32_t which, int onoff); </pre> 42 <p> 43 The <code class="methodname">DB_ENV->rep_set_config()</code> method configures the Berkeley DB 44 replication subsystem. 45 </p> 46 <p> 47 The database environment's replication subsystem may also be 48 configured using the environment's <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file. The 49 syntax of the entry in that file is a single line with the string 50 "rep_set_config", one or more whitespace characters, and the method 51 <span class="bold"><strong>which</strong></span> parameter as a string; for 52 example, "rep_set_config DB_REP_CONF_NOWAIT". Because the <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is 53 read when the database environment is opened, it will silently 54 overrule configuration done before that time. 55 </p> 56 <p> 57 The <code class="methodname">DB_ENV->rep_set_config()</code> method configures a database 58 environment, not only operations performed using the specified 59 <a class="link" href="env.html" title="Chapter��5.�� The DB_ENV Handle">DB_ENV</a> handle. 60 </p> 61 <p> 62 The <code class="methodname">DB_ENV->rep_set_config()</code> method may not be 63 called to set in-memory replication after the environment is 64 opened using the 65 <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> method. 66 This method may also not be called to set master leases after the 67 <a class="xref" href="repstart.html" title="DB_ENV->rep_start()">DB_ENV->rep_start()</a> or 68 <a class="xref" href="repmgrstart.html" title="DB_ENV->repmgr_start()">DB_ENV->repmgr_start()</a> methods 69 are called. For all other <span class="bold"><strong>which</strong></span> 70 parameters, this method may be called at any time during the life 71 of the application. 72 </p> 73 <p> 74 The <code class="methodname">DB_ENV->rep_set_config()</code> <span> 75 <span> 76 method returns a non-zero error value on failure and 0 on success. 77 </span> 78 79 </span> 80 </p> 81 <div class="sect2" lang="en" xml:lang="en"> 82 <div class="titlepage"> 83 <div> 84 <div> 85 <h3 class="title"><a id="id1698507"></a>Parameters</h3> 86 </div> 87 </div> 88 </div> 89 <div class="sect3" lang="en" xml:lang="en"> 90 <div class="titlepage"> 91 <div> 92 <div> 93 <h4 class="title"><a id="id1698294"></a>onoff</h4> 94 </div> 95 </div> 96 </div> 97 <p> 98 If the <span class="bold"><strong>onoff</strong></span> parameter is zero, the 99 configuration flag is turned off. 100Otherwise, it is turned on. All configuration flags are turned off by default. 101 </p> 102 </div> 103 <div class="sect3" lang="en" xml:lang="en"> 104 <div class="titlepage"> 105 <div> 106 <div> 107 <h4 class="title"><a id="id1698668"></a>which</h4> 108 </div> 109 </div> 110 </div> 111 <p> 112 The <span class="bold"><strong>which</strong></span> parameter must be set to 113 one of the following values: 114 </p> 115 <div class="itemizedlist"> 116 <ul type="disc"> 117 <li> 118 <p><a id="config_DB_REP_CONF_BULK"></a> 119 <code class="literal">DB_REP_CONF_BULK</code> 120 </p> 121 <p> 122 The replication master sends groups of records to the clients in a 123 single network transfer. 124 </p> 125 </li> 126 <li> 127 <p><a id="config_DB_REP_CONF_DELAYCLIENT"></a> 128 <code class="literal">DB_REP_CONF_DELAYCLIENT</code> 129 </p> 130 <p> 131 The client should delay synchronizing to a newly declared master. Clients configured in this way will remain 132 unsynchronized until the application calls the 133 <a class="xref" href="repsync.html" title="DB_ENV->rep_sync()">DB_ENV->rep_sync()</a> method. 134 </p> 135 </li> 136 <li> 137 <p><a id="config_DB_REP_CONF_INMEM"></a> 138 <code class="literal">DB_REP_CONF_INMEM</code> 139 </p> 140 <p> 141 Store internal replication information in memory only. 142 </p> 143 <p> 144 By default, replication creates files in the environment home directory 145 to preserve some internal information. If this configuration flag is turned 146 on, replication only stores this internal information in-memory and cannot 147 keep persistent state across a site crash or reboot. This results in the 148 following limitations: 149 </p> 150 <div class="itemizedlist"> 151 <ul type="circle"> 152 <li> 153 <p> 154 A master site should not reappoint itself master 155 immediately after crashing or rebooting because the application would incur a 156 slightly higher risk of client crashes. The former master site should rejoin 157 the replication group as a client. The application should either hold an 158 election or appoint a different site to be the next master. 159 </p> 160 </li> 161 <li> 162 <p> 163 An application has a slightly higher risk that elections will fail or be 164 unable to complete. Calling additional elections should eventually yield a 165 winner. 166 </p> 167 </li> 168 <li> 169 <p> 170 An application has a slight risk that the wrong site may win an election, 171 resulting in the loss of some data. This is consistent with the general loss 172 of data durability when running in-memory. 173 </p> 174 </li> 175 </ul> 176 </div> 177 <p> 178 This configuration flag can only be turned on before the environment 179 is opened with the <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> 180 method. Its value cannot be changed while the environment is open. 181 </p> 182 </li> 183 <li> 184 <p> 185 <code class="literal">DB_REP_CONF_LEASE</code> 186 </p> 187 <p> 188 Master leases will be used for this site. 189 </p> 190 <p> 191 Configuring this option may result in 192 <code class="literal">DB_REP_LEASE_EXPIRED</code> error returns 193 from the <a class="xref" href="dbget.html" title="DB->get()">DB->get()</a> and 194 <a class="xref" href="dbcget.html" title="DBcursor->get()">DBcursor->get()</a> methods 195 when attempting to read entries from a database after the site's 196 master lease has expired. 197 </p> 198 <p> 199 This configuration flag may not be set after the 200 <a class="xref" href="repmgrstart.html" title="DB_ENV->repmgr_start()">DB_ENV->repmgr_start()</a> method or the 201 <a class="xref" href="repstart.html" title="DB_ENV->rep_start()">DB_ENV->rep_start()</a> 202 method is called. 203 </p> 204 </li> 205 <li> 206 <p><a id="config_DB_REP_CONF_NOAUTOINIT"></a> 207 <code class="literal">DB_REP_CONF_NOAUTOINIT</code> 208 </p> 209 <p> 210 The replication master will not automatically re-initialize outdated 211 clients. 212 </p> 213 </li> 214 <li> 215 <p><a id="config_DB_REP_CONF_NOWAIT"></a> 216 <code class="literal">DB_REP_CONF_NOWAIT</code> 217 </p> 218 <p> 219 Berkeley DB method calls that would normally block while clients are 220 in recovery will return errors immediately. 221 </p> 222 </li> 223 <li> 224 <p><a id="config_DB_REPMGR_CONF_2SITE_STRICT"></a> 225 <code class="literal">DB_REPMGR_CONF_2SITE_STRICT</code> 226 </p> 227 <p> 228 Replication Manager observes the strict "majority" rule in managing 229 elections, even in a group with only 2 sites. This means the client 230 in a 2-site group will be unable to take over as master if the 231 original master fails or becomes disconnected. (See the <a href="../../programmer_reference/rep_elect.html" class="olink">Elections</a> section in the <em class="citetitle">Berkeley DB Programmer's Reference Guide</em> for more information.) Both sites in the 232 replication group should have the same value for this configuration flag. 233 </p> 234 </li> 235 </ul> 236 </div> 237 </div> 238 </div> 239 <div class="sect2" lang="en" xml:lang="en"> 240 <div class="titlepage"> 241 <div> 242 <div> 243 <h3 class="title"><a id="id1698684"></a>Errors</h3> 244 </div> 245 </div> 246 </div> 247 <p> 248 The <code class="methodname">DB_ENV->rep_set_config()</code> <span> 249 <span> 250 method may fail and return one of the following non-zero errors: 251 </span> 252 253 </span> 254 </p> 255 <div class="sect3" lang="en" xml:lang="en"> 256 <div class="titlepage"> 257 <div> 258 <div> 259 <h4 class="title"><a id="id1698868"></a>EINVAL</h4> 260 </div> 261 </div> 262 </div> 263 <p> 264 If setting in-memory replication after the database environment is already 265 opened; if setting master leases after replication is started; if setting 266 the 2-site strict majority rule for a Base API application; 267 or if an invalid flag value or parameter was specified. 268 </p> 269 </div> 270 </div> 271 <div class="sect2" lang="en" xml:lang="en"> 272 <div class="titlepage"> 273 <div> 274 <div> 275 <h3 class="title"><a id="id1699036"></a>Class</h3> 276 </div> 277 </div> 278 </div> 279 <p> 280 <a class="link" href="env.html" title="Chapter��5.�� The DB_ENV Handle">DB_ENV</a> 281 </p> 282 </div> 283 <div class="sect2" lang="en" xml:lang="en"> 284 <div class="titlepage"> 285 <div> 286 <div> 287 <h3 class="title"><a id="id1698657"></a>See Also</h3> 288 </div> 289 </div> 290 </div> 291 <p> 292 <a class="xref" href="rep.html#replist" title="Replication and Related Methods">Replication and Related Methods</a> 293 </p> 294 </div> 295 </div> 296 <div class="navfooter"> 297 <hr /> 298 <table width="100%" summary="Navigation footer"> 299 <tr> 300 <td width="40%" align="left"><a accesskey="p" href="repclockskew.html">Prev</a>��</td> 301 <td width="20%" align="center"> 302 <a accesskey="u" href="rep.html">Up</a> 303 </td> 304 <td width="40%" align="right">��<a accesskey="n" href="repset_limit.html">Next</a></td> 305 </tr> 306 <tr> 307 <td width="40%" align="left" valign="top">DB_ENV->rep_set_clockskew()��</td> 308 <td width="20%" align="center"> 309 <a accesskey="h" href="index.html">Home</a> 310 </td> 311 <td width="40%" align="right" valign="top">��DB_ENV->rep_set_limit()</td> 312 </tr> 313 </table> 314 </div> 315 </body> 316</html> 317