mirror of
https://github.com/berkeleydb/libdb.git
synced 2024-11-17 01:26:25 +00:00
215 lines
8.5 KiB
HTML
215 lines
8.5 KiB
HTML
|
<?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>Ex_rep_chan: a Replication Manager channel example</title>
|
|||
|
|
<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
|
|||
|
|
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
|
|||
|
|
<link rel="start" href="index.html" title="Berkeley DB Programmer's Reference Guide" />
|
|||
|
|
<link rel="up" href="rep.html" title="Chapter 12. Berkeley DB Replication" />
|
|||
|
|
<link rel="prev" href="rep_ex_rq.html" title="Ex_rep_base: putting it all together" />
|
|||
|
|
<link rel="next" href="xa.html" title="Chapter 13. Distributed Transactions" />
|
|||
|
|
</head>
|
|||
|
|
<body>
|
|||
|
|
<div xmlns="" class="navheader">
|
|||
|
|
<div class="libver">
|
|||
|
|
<p>Library Version 11.2.5.2</p>
|
|||
|
|
</div>
|
|||
|
|
<table width="100%" summary="Navigation header">
|
|||
|
|
<tr>
|
|||
|
|
<th colspan="3" align="center">Ex_rep_chan: a Replication Manager
|
|||
|
|
channel example</th>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="20%" align="left"><a accesskey="p" href="rep_ex_rq.html">Prev</a> </td>
|
|||
|
|
<th width="60%" align="center">Chapter 12.
|
|||
|
|
Berkeley DB Replication
|
|||
|
|
</th>
|
|||
|
|
<td width="20%" align="right"> <a accesskey="n" href="xa.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="rep_ex_chan"></a>Ex_rep_chan: a Replication Manager
|
|||
|
|
channel example</h2>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
Ex_rep_chan, found in the <code class="filename">examples/c/ex_rep_chan</code>
|
|||
|
|
subdirectory of the Berkeley DB distribution, is a simple but complete
|
|||
|
|
demonstration of a replicated application that uses the Replication
|
|||
|
|
Manager feature of channels to perform write forwarding. The
|
|||
|
|
application is a mock stock ticker. Although similar to the ex_rep_mgr
|
|||
|
|
example program, this example differs in that it provides an example of
|
|||
|
|
using Replication Manager message channels. Any site accepts a command
|
|||
|
|
to write data to the database. If the site is a client, then, using
|
|||
|
|
the channels feature, the application forwards the request to the
|
|||
|
|
master site. If the site is a master then the request is automatically
|
|||
|
|
handled locally. You can read and write stock values at any site
|
|||
|
|
without needing to know what site is currently the master.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The set of supported commands can be viewed with either the
|
|||
|
|
<span class="bold"><strong>help</strong></span> or the
|
|||
|
|
<span class="bold"><strong>?</strong></span> command. Several commands work with
|
|||
|
|
key/data pairs where the key is a stock symbol and the data is its
|
|||
|
|
value.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The command to retrieve and print the current site's database contents
|
|||
|
|
is <span class="bold"><strong>print</strong></span> or simply an empty input
|
|||
|
|
line. To read the contents of the master's database from any site use
|
|||
|
|
the <span class="bold"><strong>get key key ...</strong></span> command. That
|
|||
|
|
command will forward the read request to the master if necessary and
|
|||
|
|
return the key/data pairs for all given keys.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
There are two commands to put data into the database. Both commands
|
|||
|
|
take one or more key/data pairs, all of which are written into the
|
|||
|
|
database in a single transaction at the master site. The
|
|||
|
|
<span class="bold"><strong>put</strong></span> command sends the data to the
|
|||
|
|
master site, and simply waits for a status response. The
|
|||
|
|
<span class="bold"><strong>put_sync</strong></span> command sends the data to the
|
|||
|
|
master site, and uses a transaction token returned by the master to
|
|||
|
|
wait for the contents of that put to be available on the local
|
|||
|
|
site. This serves as a demonstration of the
|
|||
|
|
<a class="link" href="rep_ryw.html" title="Read your writes consistency">read your writes</a> consistency feature.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The Makefile created by the standard UNIX configuration will build the
|
|||
|
|
ex_rep_chan example on most platforms. Enter "make ex_rep_chan" to
|
|||
|
|
build it.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The synopsis for the program is as follows:
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
<code class="literal">ex_rep_chan <span class="bold"><strong>-h home</strong></span> <span class="bold"><strong>-l host:port</strong></span> [<span class="bold"><strong>-MC</strong></span>] [<span class="bold"><strong>-r host:port</strong></span>] [<span class="bold"><strong>-R host:port</strong></span>] [<span class="bold"><strong>-p priority</strong></span>] [<span class="bold"><strong>-v</strong></span>]</code>
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The options are as follows:
|
|||
|
|
</p>
|
|||
|
|
<div class="variablelist">
|
|||
|
|
<dl>
|
|||
|
|
<dt>
|
|||
|
|
<span class="term">
|
|||
|
|
<span class="bold">
|
|||
|
|
<strong>-h</strong>
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</dt>
|
|||
|
|
<dd>Specify a home directory for the database environment.</dd>
|
|||
|
|
<dt>
|
|||
|
|
<span class="term">
|
|||
|
|
<span class="bold">
|
|||
|
|
<strong>-l</strong>
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</dt>
|
|||
|
|
<dd>Listen on local host "host" at port "port" for incoming connections.</dd>
|
|||
|
|
<dt>
|
|||
|
|
<span class="term">
|
|||
|
|
<span class="bold">
|
|||
|
|
<strong>-M</strong>
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</dt>
|
|||
|
|
<dd>Configure this process as a master.</dd>
|
|||
|
|
<dt>
|
|||
|
|
<span class="term">
|
|||
|
|
<span class="bold">
|
|||
|
|
<strong>-C</strong>
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</dt>
|
|||
|
|
<dd>Configure this process as a client.</dd>
|
|||
|
|
<dt>
|
|||
|
|
<span class="term">
|
|||
|
|
<span class="bold">
|
|||
|
|
<strong>-r</strong>
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</dt>
|
|||
|
|
<dd>
|
|||
|
|
Identifies the helper site used for joining the group.
|
|||
|
|
</dd>
|
|||
|
|
<dt>
|
|||
|
|
<span class="term">
|
|||
|
|
<span class="bold">
|
|||
|
|
<strong>-R</strong>
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</dt>
|
|||
|
|
<dd>
|
|||
|
|
Identifies a remote peer to be used for joining the group. This
|
|||
|
|
peer is used for syncing purposes. See
|
|||
|
|
<a class="xref" href="rep_mastersync.html#rep_c2c_sync" title="Client-to-client synchronization">Client-to-client synchronization</a>
|
|||
|
|
for more information.
|
|||
|
|
</dd>
|
|||
|
|
<dt>
|
|||
|
|
<span class="term">
|
|||
|
|
<span class="bold">
|
|||
|
|
<strong>-p</strong>
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</dt>
|
|||
|
|
<dd>
|
|||
|
|
Set the election priority. See
|
|||
|
|
<a class="xref" href="rep_elect.html" title="Elections">Elections</a> for more
|
|||
|
|
information.
|
|||
|
|
</dd>
|
|||
|
|
<dt>
|
|||
|
|
<span class="term">
|
|||
|
|
<span class="bold">
|
|||
|
|
<strong>-v</strong>
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</dt>
|
|||
|
|
<dd>
|
|||
|
|
Indicates that additional informational and debugging output
|
|||
|
|
should be enabled.
|
|||
|
|
</dd>
|
|||
|
|
</dl>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
A typical ex_rep_chan session begins with a command such as the
|
|||
|
|
following, to start a master:
|
|||
|
|
</p>
|
|||
|
|
<pre class="programlisting">ex_rep_chan -M -h DIR1 -l localhost:30100</pre>
|
|||
|
|
<p>
|
|||
|
|
and several clients:
|
|||
|
|
</p>
|
|||
|
|
<pre class="programlisting">ex_rep_chan -C -h DIR2 -l localhost:30101 -r localhost:30100
|
|||
|
|
ex_rep_chan -C -h DIR3 -l localhost:30102 -r localhost:30100
|
|||
|
|
ex_rep_chan -C -h DIR4 -l localhost:30103 -r localhost:30100</pre>
|
|||
|
|
</div>
|
|||
|
|
<div class="navfooter">
|
|||
|
|
<hr />
|
|||
|
|
<table width="100%" summary="Navigation footer">
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left"><a accesskey="p" href="rep_ex_rq.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="xa.html">Next</a></td>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left" valign="top">Ex_rep_base: putting it all together </td>
|
|||
|
|
<td width="20%" align="center">
|
|||
|
|
<a accesskey="h" href="index.html">Home</a>
|
|||
|
|
</td>
|
|||
|
|
<td width="40%" align="right" valign="top"> Chapter 13.
|
|||
|
|
Distributed Transactions
|
|||
|
|
</td>
|
|||
|
|
</tr>
|
|||
|
|
</table>
|
|||
|
|
</div>
|
|||
|
|
</body>
|
|||
|
|
</html>
|