1<!--$Id: log_stat.so,v 10.59 2007/09/21 20:06:02 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB: DbEnv::log_stat</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td> 13<b>DbEnv::log_stat</b> 14</td> 15<td align=right> 16<a href="/api_cxx/api_core.html"><img src="/images/api.gif" alt="API"></a> 17<a href="/ref/toc.html"><img src="/images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db_cxx.h> 23<p> 24int 25DbEnv::log_stat(DB_LOG_STAT **statp, u_int32_t flags); 26<p> 27int 28DbEnv::log_stat_print(u_int32_t flags); 29</pre></b> 30<hr size=1 noshade> 31<b>Description: DbEnv::log_stat</b> 32<p>The DbEnv::log_stat method returns the logging subsystem statistics.</p> 33<p>The DbEnv::log_stat method creates a statistical structure of type 34DB_LOG_STAT and copies a pointer to it into a user-specified memory 35location.</p> 36<p>Statistical structures are stored in allocated memory. If application-specific allocation 37routines have been declared (see <a href="/api_cxx/env_set_alloc.html">DbEnv::set_alloc</a> for more 38information), they are used to allocate the memory; otherwise, the 39standard C library <b>malloc</b>(3) is used. The caller is 40responsible for deallocating the memory. To deallocate the memory, free 41the memory reference; references inside the returned memory need not be 42individually freed.</p> 43<p>The following DB_LOG_STAT fields will be filled in:</p> 44<br> 45<b>u_int32_t st_magic;</b><ul compact><li>The magic number that identifies a file as a log file.</ul> 46<b>u_int32_t st_version;</b><ul compact><li>The version of the log file type.</ul> 47<b>int st_mode;</b><ul compact><li>The mode of any created log files.</ul> 48<b>u_int32_t st_lg_bsize;</b><ul compact><li>The in-memory log record cache size.</ul> 49<b>u_int32_t st_lg_size;</b><ul compact><li>The log file size.</ul> 50<b>u_int32_t st_record;</b><ul compact><li>The number of records written to this log.</ul> 51<b>u_int32_t st_w_mbytes;</b><ul compact><li>The number of megabytes written to this log.</ul> 52<b>u_int32_t st_w_bytes;</b><ul compact><li>The number of bytes over and above <b>st_w_mbytes</b> written to this log.</ul> 53<b>u_int32_t st_wc_mbytes;</b><ul compact><li>The number of megabytes written to this log since the last checkpoint.</ul> 54<b>u_int32_t st_wc_bytes;</b><ul compact><li>The number of bytes over and above <b>st_wc_mbytes</b> written to this log 55since the last checkpoint.</ul> 56<b>u_int32_t st_wcount;</b><ul compact><li>The number of times the log has been written to disk.</ul> 57<b>u_int32_t st_wcount_fill;</b><ul compact><li>The number of times the log has been written to disk because the 58in-memory log record cache filled up.</ul> 59<b>u_int32_t st_rcount;</b><ul compact><li>The number of times the log has been read from disk.</ul> 60<b>u_int32_t st_scount;</b><ul compact><li>The number of times the log has been flushed to disk.</ul> 61<b>u_int32_t st_cur_file;</b><ul compact><li>The current log file number.</ul> 62<b>u_int32_t st_cur_offset;</b><ul compact><li>The byte offset in the current log file.</ul> 63<b>u_int32_t st_disk_file;</b><ul compact><li>The log file number of the last record known to be on disk.</ul> 64<b>u_int32_t st_disk_offset;</b><ul compact><li>The byte offset of the last record known to be on disk.</ul> 65<b>u_int32_t st_maxcommitperflush;</b><ul compact><li>The maximum number of commits contained in a single log flush.</ul> 66<b>u_int32_t st_mincommitperflush;</b><ul compact><li>The minimum number of commits contained in a single log flush that 67contained a commit.</ul> 68<b>roff_t st_regsize;</b><ul compact><li>The size of the log region, in bytes.</ul> 69<b>u_int32_t st_region_wait;</b><ul compact><li>The number of times that a thread of control was forced to wait before 70obtaining the log region mutex.</ul> 71<b>u_int32_t st_region_nowait;</b><ul compact><li>The number of times that a thread of control was able to obtain 72the log region mutex without waiting.</ul> 73<br> 74<p>The DbEnv::log_stat method may not be called before the <a href="/api_cxx/env_open.html">DbEnv::open</a> method is called.</p> 75<p>The DbEnv::log_stat method 76either returns a non-zero error value 77or throws an exception that encapsulates a non-zero error value on 78failure, and returns 0 on success. 79</p> 80<b>Parameters</b> <br> 81 <b>flags</b><ul compact><li>The <b>flags</b> parameter must be set to 0 or 82the following value: 83<br> 84<b><a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a></b><ul compact><li>Reset statistics after returning their values.</ul> 85<br></ul> 86 <b>statp</b><ul compact><li>The <b>statp</b> parameter references memory into which 87a pointer to the allocated statistics structure is copied.</ul> 88<br> 89<br><b>Errors</b> 90<p>The DbEnv::log_stat method 91may fail and throw 92<a href="/api_cxx/except_class.html">DbException</a>, 93encapsulating one of the following non-zero errors, or return one of 94the following non-zero errors:</p> 95<br> 96<b>EINVAL</b><ul compact><li>An 97invalid flag value or parameter was specified.</ul> 98<br> 99<hr size=1 noshade> 100<b>Description: DbEnv::log_stat_print</b> 101<p>The DbEnv::log_stat_print method displays the 102logging subsystem statistical information, as described for the DbEnv::log_stat method. 103The information is printed to a specified output channel (see the 104<a href="/api_cxx/env_set_msgfile.html">DbEnv::set_msgfile</a> method for more information), or passed to an 105application callback function (see the <a href="/api_cxx/env_set_msgcall.html">DbEnv::set_msgcall</a> method for 106more information).</p> 107<p>The DbEnv::log_stat_print method may not be called before the <a href="/api_cxx/env_open.html">DbEnv::open</a> method is called.</p> 108<p>The DbEnv::log_stat_print method 109either returns a non-zero error value 110or throws an exception that encapsulates a non-zero error value on 111failure, and returns 0 on success. 112</p> 113<b>Parameters</b> <br> 114 <b>flags</b><ul compact><li>The <b>flags</b> parameter must be set to 0 or by bitwise inclusively <b>OR</b>'ing together one 115or more of the following values: 116<br> 117<b><a name="DB_STAT_ALL">DB_STAT_ALL</a></b><ul compact><li>Display all available information.</ul> 118<b><a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a></b><ul compact><li>Reset statistics after displaying their values.</ul> 119<br></ul> 120<br> 121<hr size=1 noshade> 122<br><b>Class</b> 123<a href="/api_cxx/env_class.html">DbEnv</a>, <a href="/api_cxx/logc_class.html">DbLogc</a>, <a href="/api_cxx/lsn_class.html">DbLsn</a> 124<br><b>See Also</b> 125<a href="/api_cxx/log_list.html">Logging Subsystem and Related Methods</a> 126</tt> 127<table width="100%"><tr><td><br></td><td align=right> 128<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> 129</td></tr></table> 130<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 131</body> 132</html> 133
