mirror of
https://github.com/berkeleydb/libdb.git
synced 2024-11-17 09:36:24 +00:00
202 lines
8.5 KiB
HTML
202 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>DbEnv::set_lg_bsize()</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="lsn.html" title="Chapter 8. The DbLsn Handle" />
|
|||
|
|
<link rel="prev" href="logstat_print.html" title="DbEnv::log_stat_print()" />
|
|||
|
|
<link rel="next" href="envset_lg_dir.html" title="DbEnv::set_lg_dir()" />
|
|||
|
|
</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">DbEnv::set_lg_bsize()</th>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="20%" align="left"><a accesskey="p" href="logstat_print.html">Prev</a> </td>
|
|||
|
|
<th width="60%" align="center">Chapter 8.
|
|||
|
|
The DbLsn Handle
|
|||
|
|
</th>
|
|||
|
|
<td width="20%" align="right"> <a accesskey="n" href="envset_lg_dir.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="envset_lg_bsize"></a>DbEnv::set_lg_bsize()</h2>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<pre class="programlisting">#include <db_cxx.h>
|
|||
|
|
|
|||
|
|
int
|
|||
|
|
DbEnv::set_lg_bsize(u_int32_t lg_bsize); </pre>
|
|||
|
|
<p>
|
|||
|
|
Sets the size of the in-memory log buffer, in bytes.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
When the logging subsystem is configured for on-disk logging, the
|
|||
|
|
default size of the in-memory log buffer is approximately 32KB. Log
|
|||
|
|
information is stored in-memory until the storage space fills up or
|
|||
|
|
transaction commit forces the information to be flushed to stable
|
|||
|
|
storage. In the presence of long-running transactions or transactions
|
|||
|
|
producing large amounts of data, larger buffer sizes can increase
|
|||
|
|
throughput.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
When the logging subsystem is configured for in-memory logging, the
|
|||
|
|
default size of the in-memory log buffer is 1MB. Log information is
|
|||
|
|
stored in-memory until the storage space fills up or transaction abort
|
|||
|
|
or commit frees up the memory for new transactions. In the presence
|
|||
|
|
of long-running transactions or transactions producing large amounts
|
|||
|
|
of data, the buffer size must be sufficient to hold all log
|
|||
|
|
information that can accumulate during the longest running
|
|||
|
|
transaction. When choosing log buffer and file sizes for in-memory
|
|||
|
|
logs, applications should ensure the in-memory log buffer size is
|
|||
|
|
large enough that no transaction will ever span the entire buffer, and
|
|||
|
|
avoid a state where the in-memory buffer is full and no space can be
|
|||
|
|
freed because a transaction that started in the first log "file" is
|
|||
|
|
still active.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The database environment's log buffer size 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 "set_lg_bsize", one
|
|||
|
|
or more whitespace characters, and the size in bytes. 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">DbEnv::set_lg_bsize()</code> method configures a database environment,
|
|||
|
|
not only operations performed using the specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> handle.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The <code class="methodname">DbEnv::set_lg_bsize()</code> method may not be called after the
|
|||
|
|
<a class="xref" href="envopen.html" title="DbEnv::open()">DbEnv::open()</a> method is called.
|
|||
|
|
If the database environment already exists when
|
|||
|
|
<a class="xref" href="envopen.html" title="DbEnv::open()">DbEnv::open()</a> is called, the
|
|||
|
|
information specified to <code class="methodname">DbEnv::set_lg_bsize()</code> will be ignored.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The <code class="methodname">DbEnv::set_lg_bsize()</code> <span>
|
|||
|
|
|
|||
|
|
<span>
|
|||
|
|
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.
|
|||
|
|
</span>
|
|||
|
|
</span>
|
|||
|
|
</p>
|
|||
|
|
<div class="sect2" lang="en" xml:lang="en">
|
|||
|
|
<div class="titlepage">
|
|||
|
|
<div>
|
|||
|
|
<div>
|
|||
|
|
<h3 class="title"><a id="id3640863"></a>Parameters</h3>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<div class="sect3" lang="en" xml:lang="en">
|
|||
|
|
<div class="titlepage">
|
|||
|
|
<div>
|
|||
|
|
<div>
|
|||
|
|
<h4 class="title"><a id="id3640859"></a>lg_bsize</h4>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
The <span class="bold"><strong>lg_bsize</strong></span> parameter is the size of
|
|||
|
|
the in-memory log buffer, in bytes.
|
|||
|
|
</p>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<div class="sect2" lang="en" xml:lang="en">
|
|||
|
|
<div class="titlepage">
|
|||
|
|
<div>
|
|||
|
|
<div>
|
|||
|
|
<h3 class="title"><a id="id3640743"></a>Errors</h3>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
The <code class="methodname">DbEnv::set_lg_bsize()</code> <span>
|
|||
|
|
|
|||
|
|
<span>
|
|||
|
|
method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
|
|||
|
|
exception, encapsulating one of the following non-zero errors, or 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="id3640996"></a>EINVAL</h4>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
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="id3640974"></a>Class</h3>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>,
|
|||
|
|
<a class="link" href="logc.html" title="The DbLogc Handle">DbLogc</a>,
|
|||
|
|
<a class="link" href="lsn.html" title="Chapter 8. The DbLsn Handle">DbLsn</a>
|
|||
|
|
</p>
|
|||
|
|
</div>
|
|||
|
|
<div class="sect2" lang="en" xml:lang="en">
|
|||
|
|
<div class="titlepage">
|
|||
|
|
<div>
|
|||
|
|
<div>
|
|||
|
|
<h3 class="title"><a id="id3641018"></a>See Also</h3>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
<a class="xref" href="lsn.html#loglist" title="Logging Subsystem and Related Methods">Logging Subsystem 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="logstat_print.html">Prev</a> </td>
|
|||
|
|
<td width="20%" align="center">
|
|||
|
|
<a accesskey="u" href="lsn.html">Up</a>
|
|||
|
|
</td>
|
|||
|
|
<td width="40%" align="right"> <a accesskey="n" href="envset_lg_dir.html">Next</a></td>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left" valign="top">DbEnv::log_stat_print() </td>
|
|||
|
|
<td width="20%" align="center">
|
|||
|
|
<a accesskey="h" href="index.html">Home</a>
|
|||
|
|
</td>
|
|||
|
|
<td width="40%" align="right" valign="top"> DbEnv::set_lg_dir()</td>
|
|||
|
|
</tr>
|
|||
|
|
</table>
|
|||
|
|
</div>
|
|||
|
|
</body>
|
|||
|
|
</html>
|