Edit File - File Manager

Edit File: txn_stat.html

<html>
<head>
<title>Berkeley DB: DB_ENV-&gt;txn_stat</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>
DB_ENV-&gt;txn_stat
</td>
<td align=right>
<a href="../../db4-devel-4.7.25/api_c/api_core.html"><img src="../../db4-devel-4.7.25/images/api.gif" alt="API"></a>
<a href="../../db4-devel-4.7.25/ref/toc.html"><img src="../../db4-devel-4.7.25/images/ref.gif" alt="Ref"></a></td>
</tr></table>
<hr size=1 noshade>
<tt>
<pre>
#include &lt;db.h&gt;

int
DB_ENV-&gt;txn_stat(DB_ENV *env, DB_TXN_STAT **statp, u_int32_t flags);

int
DB_ENV-&gt;txn_stat_print(DB_ENV *env, u_int32_t flags);
</pre>
<hr size=1 noshade>
Description: DB_ENV-&gt;txn_stat
The DB_ENV-&gt;txn_stat method returns the transaction subsystem statistics.
The DB_ENV-&gt;txn_stat method creates a statistical structure of type
DB_TXN_STAT and copies a pointer to it into a user-specified memory
location.
Statistical structures are stored in allocated memory. If application-specific allocation
routines have been declared (see <a href="../../db4-devel-4.7.25/api_c/env_set_alloc.html">DB_ENV-&gt;set_alloc</a> for more
information), they are used to allocate the memory; otherwise, the
standard C library malloc(3) is used. The caller is
responsible for deallocating the memory. To deallocate the memory, free
the memory reference; references inside the returned memory need not be
individually freed.
The following DB_TXN_STAT fields will be filled in:
 
DbLsn st_last_ckp;<ul compact><li>The LSN of the last checkpoint.</ul>
time_t st_time_ckp;<ul compact><li>The time the last completed checkpoint finished (as the number of seconds
since the Epoch, returned by the IEEE/ANSI Std 1003.1 (POSIX) time function).</ul>
u_int32_t st_last_txnid;<ul compact><li>The last transaction ID allocated.</ul>
u_int32_t st_maxtxns;<ul compact><li>The maximum number of active transactions configured.</ul>
u_int32_t st_nactive;<ul compact><li>The number of transactions that are currently active.</ul>
u_int32_t st_nsnapshot;<ul compact><li>The number of transactions on the snapshot list. These are transactions
which modified a database opened with <a href="../../db4-devel-4.7.25/api_c/db_open.html#DB_MULTIVERSION">DB_MULTIVERSION</a>,
and which have committed or aborted, but the copies of pages they
created are still in the cache.</ul>
u_int32_t st_maxnactive;<ul compact><li>The maximum number of active transactions at any one time.</ul>
u_int32_t st_maxnsnapshot;<ul compact><li>The maximum number of transactions on the snapshot list at any one time.</ul>
u_int32_t st_nbegins;<ul compact><li>The number of transactions that have begun.</ul>
u_int32_t st_naborts;<ul compact><li>The number of transactions that have aborted.</ul>
u_int32_t st_ncommits;<ul compact><li>The number of transactions that have committed.</ul>
u_int32_t st_nrestores;<ul compact><li>The number of transactions that have been restored.</ul>
roff_t st_regsize;<ul compact><li>The size of the transaction region, in bytes.</ul>
u_int32_t st_region_wait;<ul compact><li>The number of times that a thread of control was forced to wait before
obtaining the transaction region mutex.</ul>
u_int32_t st_region_nowait;<ul compact><li>The number of times that a thread of control was able to obtain
the transaction region mutex without waiting.</ul>
DB_TXN_ACTIVE *st_txnarray;<ul compact><li>A pointer to an array of st_nactive DB_TXN_ACTIVE structures,
describing the currently active transactions. The following fields of
the DB_TXN_ACTIVE structure will be filled in:</ul>
 
u_int32_t txnid;<ul compact><li>The transaction ID of the transaction.</ul>
u_int32_t parentid;<ul compact><li>The transaction ID of the parent transaction (or 0, if no parent).</ul>
pid_t pid;<ul compact><li>The process ID of the originator of the transaction.</ul>
uintmax_t tid;<ul compact><li>The thread of control ID of the originator of the transaction.</ul>
DbLsn lsn;<ul compact><li>The current log sequence number when the transaction was begun.</ul>
DbLsn read_lsn;<ul compact><li>The log sequence number of reads for snapshot transactions.</ul>
u_int32_t mvcc_ref;<ul compact><li>The number of buffer copies created by this transaction that remain in cache.</ul>
u_int32_t status;<ul compact><li>One of the following list of constants: TXN_ABORTED, TXN_COMMITTED,
TXN_PREPARED, TXN_RUNNING.</ul>
u_int32_t xa_status;<ul compact><li>If the transaction is an XA transaction, the xa_status of the
transaction will be one of the following list of constants:
TXN_XA_ABORTED, TXN_XA_DEADLOCKED, TXN_XA_ENDED, TXN_XA_PREPARED,
TXN_XA_STARTED, or TXN_XA_SUSPENDED. Otherwise, the xa_status
will be 0.</ul>
u_int8_t xid[DB_XIDDATASIZE];<ul compact><li>If the transaction is an XA transaction, the transaction's XA ID. If
the transaction was prepared separately from the XA interfaces, the
transaction's Global ID. Otherwise, the xid contents are
undefined.</ul>
char name[];<ul compact><li>If a name was specified for the transaction, up to the first 50 bytes
of that name, followed by a nul termination byte.</ul>
 
 
The DB_ENV-&gt;txn_stat method may not be called before the <a href="../../db4-devel-4.7.25/api_c/env_open.html">DB_ENV-&gt;open</a> method is called.
The DB_ENV-&gt;txn_stat method
returns a non-zero error value on failure
and 0 on success.

Parameters 
 flags<ul compact><li>The flags parameter must be set to 0 or
the following value:
 
<a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a><ul compact><li>Reset statistics after returning their values.</ul>
 </ul>
 statp<ul compact><li>The statp parameter references memory into which
a pointer to the allocated statistics structure is copied.</ul> 
 
 Errors
The DB_ENV-&gt;txn_stat method
may fail and return one of the following non-zero errors:
 
EINVAL<ul compact><li>An
invalid flag value or parameter was specified.</ul>
 
<hr size=1 noshade>
Description: DB_ENV-&gt;txn_stat_print
The DB_ENV-&gt;txn_stat_print method displays the
transaction subsystem statistical information, as described for the DB_ENV-&gt;txn_stat method.
The information is printed to a specified output channel (see the
<a href="../../db4-devel-4.7.25/api_c/env_set_msgfile.html">DB_ENV-&gt;set_msgfile</a> method for more information), or passed to an
application callback function (see the <a href="../../db4-devel-4.7.25/api_c/env_set_msgcall.html">DB_ENV-&gt;set_msgcall</a> method for
more information).
The DB_ENV-&gt;txn_stat_print method may not be called before the <a href="../../db4-devel-4.7.25/api_c/env_open.html">DB_ENV-&gt;open</a> method is called.
The DB_ENV-&gt;txn_stat_print method
returns a non-zero error value on failure
and 0 on success.

Parameters 
 flags<ul compact><li>The flags parameter must be set to 0 or by bitwise inclusively OR'ing together one
or more of the following values:
 
<a name="DB_STAT_ALL">DB_STAT_ALL</a><ul compact><li>Display all available information.</ul>
<a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a><ul compact><li>Reset statistics after displaying their values.</ul>
 </ul>
 
<hr size=1 noshade>
 Class
<a href="../../db4-devel-4.7.25/api_c/env_class.html">DB_ENV</a>, <a href="../../db4-devel-4.7.25/api_c/txn_class.html">DB_TXN</a>
 See Also
<a href="../../db4-devel-4.7.25/api_c/txn_list.html">Transaction Subsystem and Related Methods</a>
</tt>
<table width="100%"><tr><td> </td><td align=right>
<a href="../../db4-devel-4.7.25/api_c/api_core.html"><img src="../../db4-devel-4.7.25/images/api.gif" alt="API"></a><a href="../../db4-devel-4.7.25/ref/toc.html"><img src="../../db4-devel-4.7.25/images/ref.gif" alt="Ref"></a>
</td></tr></table>
Copyright (c) 1996,2008 Oracle. All rights reserved.
</body>
</html>

Back to File Manager