Import BSDDB 4.7.25 (as of svn r89086)
This commit is contained in:
Zachary Ware
164
docs/api_cxx/env_log_set_config.html
Normal file
164
docs/api_cxx/env_log_set_config.html
Normal file
@@ -0,0 +1,164 @@
|
||||
<!--$Id-->
|
||||
<!--Copyright (c) 1997,2008 Oracle. All rights reserved.-->
|
||||
<!--See the file LICENSE for redistribution information.-->
|
||||
<html>
|
||||
<head>
|
||||
<title>Berkeley DB: DbEnv::log_set_config</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::log_set_config</b>
|
||||
</td>
|
||||
<td align=right>
|
||||
<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a>
|
||||
<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td>
|
||||
</tr></table>
|
||||
<hr size=1 noshade>
|
||||
<tt>
|
||||
<b><pre>
|
||||
#include <db_cxx.h>
|
||||
<p>
|
||||
int
|
||||
DbEnv::log_set_config(u_int32_t flags, int onoff);
|
||||
<p>
|
||||
int
|
||||
DbEnv::log_get_config(u_int32_t which, int *onoffp)
|
||||
</pre></b>
|
||||
<hr size=1 noshade>
|
||||
<b>Description: DbEnv::log_set_config</b>
|
||||
<p>The DbEnv::log_set_config method configures the Berkeley DB logging
|
||||
subsystem.</p>
|
||||
<p>The DbEnv::log_set_config method configures a database environment, not only operations
|
||||
performed using the specified <a href="../api_cxx/env_class.html">DbEnv</a> handle.</p>
|
||||
<p>The DbEnv::log_set_config method may be called at any time during the life of the
|
||||
application.</p>
|
||||
<p>The DbEnv::log_set_config 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>flags</b><ul compact><li>The <b>flags</b> parameter must be set by bitwise inclusively <b>OR</b>'ing together one or more
|
||||
of the following values:
|
||||
<br>
|
||||
<a name="2"><!--meow--></a>
|
||||
<b><a name="DB_LOG_DIRECT">DB_LOG_DIRECT</a></b><ul compact><li>Turn off system buffering of Berkeley DB log files to avoid double caching.
|
||||
<p>Calling DbEnv::log_set_config with the DB_LOG_DIRECT flag only affects
|
||||
the specified <a href="../api_cxx/env_class.html">DbEnv</a> handle (and any other Berkeley DB handles opened
|
||||
within the scope of that handle).
|
||||
For consistent behavior across the environment, all <a href="../api_cxx/env_class.html">DbEnv</a>
|
||||
handles opened in the environment must either set the DB_LOG_DIRECT flag
|
||||
or the flag should be specified in the <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> configuration
|
||||
file.</p>
|
||||
<p>The DB_LOG_DIRECT flag may be used to configure Berkeley DB at any time during
|
||||
the life of the application.</p></ul>
|
||||
<a name="3"><!--meow--></a>
|
||||
<b><a name="DB_LOG_DSYNC">DB_LOG_DSYNC</a></b><ul compact><li>Configure Berkeley DB to flush log writes to the backing disk before returning
|
||||
from the write system call, rather than flushing log writes explicitly
|
||||
in a separate system call, as necessary. This is only available on some
|
||||
systems (for example, systems supporting the IEEE/ANSI Std 1003.1 (POSIX) standard
|
||||
O_DSYNC flag, or systems supporting the Windows FILE_FLAG_WRITE_THROUGH
|
||||
flag). This flag may result in inaccurate file modification times and
|
||||
other file-level information for Berkeley DB log files. This flag may offer
|
||||
a performance increase on some systems and a performance decrease on
|
||||
others.
|
||||
<p>Calling DbEnv::log_set_config with the DB_LOG_DSYNC flag only affects
|
||||
the specified <a href="../api_cxx/env_class.html">DbEnv</a> handle (and any other Berkeley DB handles opened
|
||||
within the scope of that handle).
|
||||
For consistent behavior across the environment, all <a href="../api_cxx/env_class.html">DbEnv</a>
|
||||
handles opened in the environment must either set the DB_LOG_DSYNC flag
|
||||
or the flag should be specified in the <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> configuration
|
||||
file.</p>
|
||||
<p>The DB_LOG_DSYNC flag may be used to configure Berkeley DB at any time during
|
||||
the life of the application.</p></ul>
|
||||
<a name="4"><!--meow--></a>
|
||||
<b><a name="DB_LOG_AUTO_REMOVE">DB_LOG_AUTO_REMOVE</a></b><ul compact><li>If set, Berkeley DB will automatically remove log files that are no longer
|
||||
needed.
|
||||
<p>Automatic log file removal is likely to make catastrophic recovery
|
||||
impossible.</p>
|
||||
<p>Replication applications will rarely want to configure automatic log
|
||||
file removal as it increases the likelihood a master will be unable to
|
||||
satisfy a client's request for a recent log record.</p>
|
||||
<p>Calling DbEnv::log_set_config with the DB_LOG_AUTO_REMOVE flag affects the
|
||||
database environment, including all threads of control accessing the
|
||||
database environment.</p>
|
||||
<p>The DB_LOG_AUTO_REMOVE flag may be used to configure Berkeley DB at any time during
|
||||
the life of the application.</p></ul>
|
||||
<a name="5"><!--meow--></a>
|
||||
<b><a name="DB_LOG_IN_MEMORY">DB_LOG_IN_MEMORY</a></b><ul compact><li>If set, maintain transaction logs in memory rather than on disk. This
|
||||
means that transactions exhibit the ACI (atomicity, consistency, and
|
||||
isolation) properties, but not D (durability); that is, database
|
||||
integrity will be maintained, but if the application or system fails,
|
||||
integrity will not persist. All database files must be verified and/or
|
||||
restored from a replication group master or archival backup after
|
||||
application or system failure.
|
||||
<p>When in-memory logs are configured and no more log buffer space is
|
||||
available, Berkeley DB methods may return an additional error value,
|
||||
<a name="DB_LOG_BUFFER_FULL">DB_LOG_BUFFER_FULL</a>. 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>Calling DbEnv::log_set_config with the DB_LOG_IN_MEMORY flag affects the
|
||||
database environment, including all threads of control accessing the
|
||||
database environment.</p>
|
||||
<p>The DB_LOG_IN_MEMORY flag may be used to configure Berkeley DB only before the
|
||||
<a href="../api_cxx/env_open.html">DbEnv::open</a> method is called.</p></ul>
|
||||
<a name="6"><!--meow--></a>
|
||||
<b><a name="DB_LOG_ZERO">DB_LOG_ZERO</a></b><ul compact><li>If set, zero all pages of a log file when that log file is created. This
|
||||
has shown to provide greater transaction throughput in some environments.
|
||||
The log file will be zeroed by the thread which needs to re-create the new log
|
||||
file. Other threads may not write to the log file while this is happening.
|
||||
<p>Calling DbEnv::log_set_config with the DB_LOG_ZERO flag affects the
|
||||
database environment, including all threads of control accessing the
|
||||
database environment.</p>
|
||||
<p>The DB_LOG_ZERO flag may be used to configure Berkeley DB only before the
|
||||
<a href="../api_cxx/env_open.html">DbEnv::open</a> method is called.</p></ul>
|
||||
<br></ul>
|
||||
<b>onoff</b><ul compact><li>If the <b>onoff</b> parameter is zero, the specified flags are cleared;
|
||||
otherwise they are set.</ul>
|
||||
<br>
|
||||
<br><b>Errors</b>
|
||||
<p>The DbEnv::log_set_config method
|
||||
may fail and throw
|
||||
<a href="../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::log_get_config</b>
|
||||
<p>The DbEnv::log_get_config method returns whether the specified <b>which</b>
|
||||
parameter is currently set or not.</p>
|
||||
<p>The DbEnv::log_get_config method may be called at any time during the life of the
|
||||
application.</p>
|
||||
<p>The DbEnv::log_get_config 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>which</b><ul compact><li>The <b>which</b> parameter is the message value for which configuration
|
||||
is being checked.</ul>
|
||||
<b>onoffp</b><ul compact><li>The <b>onoffp</b> parameter references memory into which
|
||||
the configuration of the specified <b>which</b> parameter is copied.</ul> If the returned <b>onoff</b> value is zero, the parameter is off;
|
||||
otherwise on.
|
||||
<br>
|
||||
<hr size=1 noshade>
|
||||
<br><b>Class</b>
|
||||
<a href="../api_cxx/env_class.html">DbEnv</a>
|
||||
<br><b>See Also</b>
|
||||
<a href="../api_cxx/env_list.html">Database Environments and Related Methods</a>
|
||||
</tt>
|
||||
<table width="100%"><tr><td><br></td><td align=right>
|
||||
<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a>
|
||||
</td></tr></table>
|
||||
<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font>
|
||||
</body>
|
||||
</html>
|
||||
Reference in New Issue
Block a user