<!--$Id: rep_clockskew.so,v 1.12 2008/02/01 18:53:41 bostic Exp $--> FOOO <!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DbEnv::rep_set_clockskew</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <table width="100%"><tr valign=top> <td> <b>DbEnv::rep_set_clockskew</b> </td> <td align=right> <a href="../../db47-devel-4.7.25/api_cxx/api_core.html"><img src="../../db47-devel-4.7.25/images/api.gif" alt="API"></a> <a href="../../db47-devel-4.7.25/ref/toc.html"><img src="../../db47-devel-4.7.25/images/ref.gif" alt="Ref"></a></td> </tr></table> <hr size=1 noshade> <tt> <b><pre> #include <db_cxx.h> <p> int DbEnv::rep_set_clockskew(u_int32_t fast_clock, u_int32_t slow_clock); <p> DbEnv::rep_get_clockskew(u_int32_t *fast_clockp, u_in32_t *slow_clockp); </pre></b> <hr size=1 noshade> <b>Description: DbEnv::rep_set_clockskew</b> <p>The DbEnv::rep_set_clockskew 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 href="../../db47-devel-4.7.25/api_cxx/rep_config.html">DbEnv::rep_set_config</a> method. Additionally, the user must also set the master lease timeout via the <a href="../../db47-devel-4.7.25/api_cxx/rep_timeout.html">DbEnv::rep_set_timeout</a> method and the number of sites in the replication group via the <a href="../../db47-devel-4.7.25/api_cxx/rep_nsites.html">DbEnv::rep_set_nsites</a> method. These methods may be called in any order. For a description of the clock skew values, see <a href="../../db47-devel-4.7.25/ref/rep/clock_skew.html">Clock skew</a>. For a description of master leases, see <a href="../../db47-devel-4.7.25/ref/rep/lease.html">Master leases</a>.</p> <p>These arguments can be used to express either raw measurements of a clock timing experiment or a percentage across machines. For instance a group of sites have a 2% variance, then <b>fast_clock</b> should be given as 102, and <b>slow_clock</b> should be set at 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="../../db47-devel-4.7.25/ref/env/db_config.html#DB_CONFIG">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="../../db47-devel-4.7.25/ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> file is read when the database environment is opened, it will silently overrule configuration done before that time.</p> <p>The DbEnv::rep_set_clockskew method configures a database environment, not only operations performed using the specified <a href="../../db47-devel-4.7.25/api_cxx/env_class.html">DbEnv</a> handle.</p> <p>The DbEnv::rep_set_clockskew method may not be called after the <a href="../../db47-devel-4.7.25/api_cxx/repmgr_start.html">DbEnv::repmgr_start</a> or <a href="../../db47-devel-4.7.25/api_cxx/rep_start.html">DbEnv::rep_start</a> methods are called.</p> <p>The DbEnv::rep_set_clockskew method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success. </p> <b>Parameters</b> <br> <b>fast_clock</b><ul compact><li>The value, relative to the <b>slow_clock</b>, of the fastest clock in the group of sites.</ul> <b>slow_clock</b><ul compact><li>The value of the slowest clock in the group of sites.</ul> <br> <br><b>Errors</b> <p>The DbEnv::rep_set_clockskew method may fail and throw <a href="../../db47-devel-4.7.25/api_cxx/except_class.html">DbException</a>, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:</p> <br> <b>EINVAL</b><ul compact><li>An invalid flag value or parameter was specified.</ul> <br> <hr size=1 noshade> <b>Description: DbEnv::rep_get_clockskew</b> <p>The DbEnv::rep_get_clockskew method returns the current clock skew values.</p> <p>The DbEnv::rep_get_clockskew method may be called at any time during the life of the application.</p> <p>The DbEnv::rep_get_clockskew method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success. </p> <b>Parameters</b> <br> <b>fast_clockp</b><ul compact><li>The <b>fast_clockp</b> parameter references memory into which the value for the fastest clock in the group of sites is copied.</ul> <b>slow_clockp</b><ul compact><li>The <b>slow_clockp</b> parameter references memory into which the value for the slowest clock in the group of sites is copied.</ul> <br> <hr size=1 noshade> <br><b>Class</b> <a href="../../db47-devel-4.7.25/api_cxx/env_class.html">DbEnv</a> <br><b>See Also</b> <a href="../../db47-devel-4.7.25/api_cxx/rep_list.html">Replication and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../../db47-devel-4.7.25/api_cxx/api_core.html"><img src="../../db47-devel-4.7.25/images/api.gif" alt="API"></a><a href="../../db47-devel-4.7.25/ref/toc.html"><img src="../../db47-devel-4.7.25/images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2008 Oracle. 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