<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>DB_ENV->rep_set_clockskew()</title> <link rel="stylesheet" href="apiReference.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> <link rel="start" href="index.html" title="Berkeley DB C API Reference" /> <link rel="up" href="rep.html" title="Chapter 10. Replication Methods" /> <link rel="prev" href="repmessage.html" title="DB_ENV->rep_process_message()" /> <link rel="next" href="repconfig.html" title="DB_ENV->rep_set_config()" /> </head> <body> <div xmlns="" class="navheader"> <div class="libver"> <p>Library Version 11.2.5.3</p> </div> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">DB_ENV->rep_set_clockskew()</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="repmessage.html">Prev</a> </td> <th width="60%" align="center">Chapter 10. Replication Methods </th> <td width="20%" align="right"> <a accesskey="n" href="repconfig.html">Next</a></td> </tr> </table> <hr /> </div> <div class="sect1" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h2 class="title" style="clear: both"><a id="repclockskew"></a>DB_ENV->rep_set_clockskew()</h2> </div> </div> </div> <pre class="programlisting">#include <db.h> int DB_ENV->rep_set_clockskew(DB_ENV *env, u_int32_t fast_clock, u_int32_t slow_clock); </pre> <p> The <code class="methodname">DB_ENV->rep_set_clockskew()</code> method sets the clock skew ratio among replication group members based on the fastest and slowest measurements among the group for use with master leases. Calling this method is optional; the default values for clock skew assume no skew. The user must also configure leases via the <a class="xref" href="repconfig.html" title="DB_ENV->rep_set_config()">DB_ENV->rep_set_config()</a> method. Additionally, the user must also set the master lease timeout via the <a class="xref" href="repset_timeout.html" title="DB_ENV->rep_set_timeout()">DB_ENV->rep_set_timeout()</a> method. For Base API applications, the user must also set the number of sites in the replication group via the <a class="xref" href="repnsites.html" title="DB_ENV->rep_set_nsites()">DB_ENV->rep_set_nsites()</a> method. These methods may be called in any order. For a description of the clock skew values, see <a href="../../programmer_reference/rep_clock_skew.html" class="olink">Clock skew</a> in the <em class="citetitle">Berkeley DB Programmer's Reference Guide</em>. For a description of master leases, see <a href="../../programmer_reference/rep_lease.html" class="olink">Master leases</a> in the <em class="citetitle">Berkeley DB Programmer's Reference Guide</em>. </p> <p> These arguments can be used to express either raw measurements of a clock timing experiment or a percentage across machines. For example, if a group of sites has a 2% variance, then <span class="bold"><strong>fast_clock</strong></span> should be set to 102, and <span class="bold"><strong>slow_clock</strong></span> should be set to 100. Or, for a 0.03% difference, you can use 10003 and 10000 respectively. </p> <p> The database environment's replication subsystem may also be 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 syntax of the entry in that file is a single line with the string "rep_set_clockskew", one or more whitespace characters, and the clockskew specified in two parts: the fast_clock and the slow_clock. For example, "rep_set_clockskew 102 100". Because the <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is read when the database environment is opened, it will silently overrule configuration done before that time. </p> <p> The <code class="methodname">DB_ENV->rep_set_clockskew()</code> method configures a database environment, not only operations performed using the specified <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a> handle. </p> <p> The <code class="methodname">DB_ENV->rep_set_clockskew()</code> method may not be called after the <a class="xref" href="repmgrstart.html" title="DB_ENV->repmgr_start()">DB_ENV->repmgr_start()</a> or <a class="xref" href="repstart.html" title="DB_ENV->rep_start()">DB_ENV->rep_start()</a> methods are called. </p> <p> The <code class="methodname">DB_ENV->rep_set_clockskew()</code> <span> <span> method returns a non-zero error value on failure and 0 on success. </span> </span> </p> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp54086744"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp54061616"></a>fast_clock</h4> </div> </div> </div> <p> The value, relative to the <span class="bold"><strong>slow_clock</strong></span>, of the fastest clock in the group of sites. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp54076984"></a>slow_clock</h4> </div> </div> </div> <p> The value of the slowest clock in the group of sites. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp54052304"></a>Errors</h3> </div> </div> </div> <p> The <code class="methodname">DB_ENV->rep_set_clockskew()</code> <span> <span> method may fail and return one of the following non-zero errors: </span> </span> </p> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp54097928"></a>EINVAL</h4> </div> </div> </div> <p> If the method was called after replication is started with a call to the <a class="xref" href="repmgrstart.html" title="DB_ENV->repmgr_start()">DB_ENV->repmgr_start()</a> or the <a class="xref" href="repstart.html" title="DB_ENV->rep_start()">DB_ENV->rep_start()</a> method; or if an invalid flag value or parameter was specified. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp54061680"></a>Class</h3> </div> </div> </div> <p> <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp54100152"></a>See Also</h3> </div> </div> </div> <p> <a class="xref" href="rep.html#replist" title="Replication and Related Methods">Replication and Related Methods</a> </p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="repmessage.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="rep.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="repconfig.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">DB_ENV->rep_process_message() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> DB_ENV->rep_set_config()</td> </tr> </table> </div> </body> </html>