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Diffstat (limited to 'docs/api_reference/CXX/envlog_set_config.html')
| -rw-r--r-- | docs/api_reference/CXX/envlog_set_config.html | 370 |
1 files changed, 233 insertions, 137 deletions
diff --git a/docs/api_reference/CXX/envlog_set_config.html b/docs/api_reference/CXX/envlog_set_config.html index 275364f4..0e3f0969 100644 --- a/docs/api_reference/CXX/envlog_set_config.html +++ b/docs/api_reference/CXX/envlog_set_config.html @@ -14,7 +14,7 @@ <body> <div xmlns="" class="navheader"> <div class="libver"> - <p>Library Version 11.2.5.3</p> + <p>Library Version 12.1.6.1</p> </div> <table width="100%" summary="Navigation header"> <tr> @@ -43,20 +43,20 @@ int DbEnv::log_set_config(u_int32_t flags, int onoff); </pre> <p> - The <code class="methodname">DbEnv::log_set_config()</code> method configures the Berkeley DB - logging subsystem. + The <code class="methodname">DbEnv::log_set_config()</code> method + configures the Berkeley DB logging subsystem. </p> <p> - The <code class="methodname">DbEnv::log_set_config()</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. + The <code class="methodname">DbEnv::log_set_config()</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::log_set_config()</code> method may be called at any time during - the life of the application. + The <code class="methodname">DbEnv::log_set_config()</code> method may be + called at any time during the life of the application. </p> <p> - The <code class="methodname">DbEnv::log_set_config()</code> <span> + The <code class="methodname">DbEnv::log_set_config()</code> <span> <span> method either returns a non-zero error value or throws an @@ -69,7 +69,7 @@ DbEnv::log_set_config(u_int32_t flags, int onoff); </pre> <div class="titlepage"> <div> <div> - <h3 class="title"><a id="idp3003376"></a>Parameters</h3> + <h3 class="title"><a id="idp3009400"></a>Parameters</h3> </div> </div> </div> @@ -77,155 +77,250 @@ DbEnv::log_set_config(u_int32_t flags, int onoff); </pre> <div class="titlepage"> <div> <div> - <h4 class="title"><a id="idp3010232"></a>flags</h4> + <h4 class="title"><a id="idp3003320"></a>flags</h4> </div> </div> </div> <p> - The <span class="bold"><strong>flags</strong></span> parameter must be set by - bitwise inclusively <span class="bold"><strong>OR</strong></span>'ing together - one or more of the following values: - </p> + The <span class="bold"><strong>flags</strong></span> parameter must + be set by bitwise inclusively + <span class="bold"><strong>OR</strong></span>'ing together one or + more of the following values: + </p> <div class="itemizedlist"> <ul type="disc"> <li> - <p><a id="log_set_config_DB_LOG_DIRECT"></a> - <code class="literal">DB_LOG_DIRECT</code> - </p> + <p><a id="log_set_config_DB_LOG_AUTO_REMOVE"></a> + <code class="literal">DB_LOG_AUTO_REMOVE</code> + </p> <p> - Turn off system buffering of Berkeley DB log files to avoid double - caching. - </p> + If set, Berkeley DB will automatically remove log + files that are no longer needed. + </p> <p> - Calling <code class="methodname">DbEnv::log_set_config()</code> with the DB_LOG_DIRECT flag only - affects the specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> handle (and any other - Berkeley DB handles opened within the scope of that handle). For - consistent behavior across the environment, all - <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">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="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> configuration file. - </p> + Automatic log file removal is likely to make + catastrophic recovery impossible. + </p> <p> - The <code class="literal">DB_LOG_DIRECT</code> flag may be used to configure Berkeley DB at any - time during the life of the application. - </p> + Replication Manager applications operate in a + group-aware manner for log file removal, and + automatic log file removal simplifies the + application. + </p> + <p> + Replication Base API 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 + <code class="methodname">DbEnv::log_set_config()</code> + with the <code class="literal">DB_LOG_AUTO_REMOVE</code> flag + affects the database environment, including all + threads of control accessing the database + environment. + </p> + <p> + The <code class="literal">DB_LOG_AUTO_REMOVE</code> flag may + be used to configure Berkeley DB at any time during + the life of the application. + </p> </li> <li> - <p><a id="log_set_config_DB_LOG_DSYNC"></a> - <code class="literal">DB_LOG_DSYNC</code> - </p> + <p><a id="log_set_config_DB_LOG_BLOB"></a> + <code class="literal">DB_LOG_BLOB</code> + </p> <p> - 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> + Enables full logging of + <a class="link" href="blob.html" title="Chapter 14. Binary Large Objects">BLOB</a> data. Only use + this flag if using replication or running a hot + backup; otherwise, it will impose a performance + penalty on BLOB operations. + </p> <p> - Calling <code class="methodname">DbEnv::log_set_config()</code> with the DB_LOG_DSYNC flag only - affects the specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> handle (and any other - Berkeley DB handles opened within the scope of that handle). For - consistent behavior across the environment, all - <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">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="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> configuration file. - </p> + This flag is off by default, unless Replication is + enabled for the environment. In that case, it is + on by default. + </p> <p> - The <code class="literal">DB_LOG_DSYNC</code> flag may be used to configure Berkeley DB at any time - during the life of the application. - </p> + The <code class="literal">DB_LOG_BLOB</code> flag may be + used to configure Berkeley DB at any time during + the life of the application. + </p> </li> <li> - <p><a id="log_set_config_DB_LOG_AUTO_REMOVE"></a> - <code class="literal">DB_LOG_AUTO_REMOVE</code> - </p> + <p><a id="log_set_config_DB_LOG_DIRECT"></a> + <code class="literal">DB_LOG_DIRECT</code> + </p> <p> - If set, Berkeley DB will automatically remove log files that are no - longer needed. - </p> + Turn off system buffering of Berkeley DB log files + to avoid double caching. + </p> <p> - Automatic log file removal is likely to make catastrophic recovery - impossible. - </p> + Calling + <code class="methodname">DbEnv::log_set_config()</code> + with the DB_LOG_DIRECT flag only affects the + specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> + handle (and any other Berkeley DB handles opened + within the scope of that handle). For consistent + behavior across the environment, all + <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">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="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> configuration file. + </p> <p> - Replication Manager applications operate in a - group-aware manner for log file removal, and automatic log - file removal simplifies the application. - </p> + The <code class="literal">DB_LOG_DIRECT</code> flag may be + used to configure Berkeley DB at any time during + the life of the application. + </p> + </li> + <li> + <p><a id="log_set_config_DB_LOG_DSYNC"></a> + <code class="literal">DB_LOG_DSYNC</code> + </p> <p> - Replication Base API 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> + 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> <p> - Calling <code class="methodname">DbEnv::log_set_config()</code> with the - <code class="literal">DB_LOG_AUTO_REMOVE</code> flag - affects the database environment, including all threads of control - accessing the database environment. - </p> + Calling + <code class="methodname">DbEnv::log_set_config()</code> + with the DB_LOG_DSYNC flag only affects the + specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> + handle (and any other Berkeley DB handles opened + within the scope of that handle). For consistent + behavior across the environment, all + <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">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="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> configuration file. + </p> <p> - The <code class="literal">DB_LOG_AUTO_REMOVE</code> flag may be used to configure Berkeley DB at - any time during the life of the application. - </p> + The <code class="literal">DB_LOG_DSYNC</code> flag may be + used to configure Berkeley DB at any time during + the life of the application. + </p> </li> <li> <p><a id="log_set_config_DB_LOG_IN_MEMORY"></a> - <code class="literal">DB_LOG_IN_MEMORY</code> - </p> + <code class="literal">DB_LOG_IN_MEMORY</code> + </p> <p> - 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> + 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> <p> - When in-memory logs are configured and no more log buffer space is - available, Berkeley DB methods may return an additional error value, - <code class="literal">DB_LOG_BUFFER_FULL</code>. 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> + When in-memory logs are configured and no more log + buffer space is available, Berkeley DB methods may + return an additional error value, + <code class="literal">DB_LOG_BUFFER_FULL</code>. 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 <code class="methodname">DbEnv::log_set_config()</code> with the - <code class="literal">DB_LOG_IN_MEMORY</code> flag - affects the database environment, including all threads of control - accessing the database environment. - </p> + Calling + <code class="methodname">DbEnv::log_set_config()</code> + with the <code class="literal">DB_LOG_IN_MEMORY</code> flag + affects the database environment, including all + threads of control accessing the database + environment. + </p> <p> - The <code class="literal">DB_LOG_IN_MEMORY</code> flag may be used to configure Berkeley DB only - before the <a class="xref" href="envopen.html" title="DbEnv::open()">DbEnv::open()</a> - method is called. - </p> + The <code class="literal">DB_LOG_IN_MEMORY</code> flag may be + used to configure Berkeley DB only before the + <a class="xref" href="envopen.html" title="DbEnv::open()">DbEnv::open()</a> + method is called. + </p> </li> <li> + <p><a id="log_set_config_DB_LOG_NOSYNC"></a> + <code class="literal">DB_LOG_NOSYNC</code> + </p> <p> - <code class="literal">DB_LOG_ZERO</code> - </p> + If set, the transaction log is not flushed from the + operating system cache to stable storage when a + transaction commits or the logging system switches + log files. This can further increase performance + when all of the applications in an environment use + less-than-durable transactions (DB_TXN_NOSYNC and + DB_TXN_WRITE_NOSYNC). + </p> <p> - 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> + Turning on <code class="literal">DB_LOG_NOSYNC</code> removes + the durability guarantee of current or future + DB_TXN_SYNC transactions, as well as any + transactions which have been active since the last + checkpoint. All database files must be verified + and/or restored from a replication group master or + archival backup after system failure. + </p> <p> - Calling <code class="methodname">DbEnv::log_set_config()</code> with the - <code class="literal">DB_LOG_ZERO</code> flag affects only the current environment handle. - </p> + Turning off <code class="literal">DB_LOG_NOSYNC</code> may be + done at any time. Current and future DB + DB_TXN_SYNC transactions will return to full ACID + characteristics once a checkpoint or log file + switch occurs. + </p> <p> - The <code class="literal">DB_LOG_ZERO</code> flag may be used to configure Berkeley DB at any time. - </p> + Calling + <code class="methodname">DbEnv::log_set_config()</code> + with the <code class="literal">DB_LOG_NOSYNC</code> flag + affects the database environment, including all + threads of control accessing the database + environment. + </p> + <p> + The <code class="literal">DB_LOG_NOSYNC</code> flag may be + used to configure Berkeley DB at any time. + <a class="xref" href="envopen.html" title="DbEnv::open()">DbEnv::open()</a> + method is called. + </p> + </li> + <li> + <p> + <code class="literal">DB_LOG_ZERO</code> + </p> + <p> + 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> + <p> + Calling + <code class="methodname">DbEnv::log_set_config()</code> + with the <code class="literal">DB_LOG_ZERO</code> flag + affects only the current environment handle. + </p> + <p> + The <code class="literal">DB_LOG_ZERO</code> flag may be used + to configure Berkeley DB at any time. + </p> </li> </ul> </div> @@ -234,26 +329,27 @@ DbEnv::log_set_config(u_int32_t flags, int onoff); </pre> <div class="titlepage"> <div> <div> - <h4 class="title"><a id="idp3000264"></a>onoff</h4> + <h4 class="title"><a id="idp3027824"></a>onoff</h4> </div> </div> </div> <p> - If the <span class="bold"><strong>onoff</strong></span> parameter is zero, the - specified flags are cleared; otherwise they are set. - </p> + If the <span class="bold"><strong>onoff</strong></span> parameter is + zero, the specified flags are cleared; otherwise they are + set. + </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h3 class="title"><a id="idp3017968"></a>Errors</h3> + <h3 class="title"><a id="idp2999456"></a>Errors</h3> </div> </div> </div> <p> - The <code class="methodname">DbEnv::log_set_config()</code> <span> + The <code class="methodname">DbEnv::log_set_config()</code> <span> <span> method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a> @@ -261,12 +357,12 @@ DbEnv::log_set_config(u_int32_t flags, int onoff); </pre> of the following non-zero errors: </span> </span> - </p> + </p> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h4 class="title"><a id="idp3030248"></a>EINVAL</h4> + <h4 class="title"><a id="idp3025848"></a>EINVAL</h4> </div> </div> </div> @@ -279,25 +375,25 @@ DbEnv::log_set_config(u_int32_t flags, int onoff); </pre> <div class="titlepage"> <div> <div> - <h3 class="title"><a id="idp3036528"></a>Class</h3> + <h3 class="title"><a id="idp3020320"></a>Class</h3> </div> </div> </div> <p> - <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> - </p> + <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> + </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h3 class="title"><a id="idp3006832"></a>See Also</h3> + <h3 class="title"><a id="idp2995432"></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> + <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"> |