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<h1>DB_ENV->txn_stat</h1>
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<h3><pre>
#include <db.h>
<p>
int
DB_ENV->txn_stat(DB_ENV *env, DB_TXN_STAT **statp, u_int32_t flags);
</pre></h3>
<h1>Description</h1>
<p>The DB_ENV->txn_stat method returns the transaction subsystem statistics.
<p>The <b>flags</b> value must be set to 0 or
the following value:
<p><dl compact>
<p><dt><a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a><dd>Reset statistics after returning their values.
</dl>
<p>The DB_ENV->txn_stat method creates a statistical structure of type
DB_TXN_STAT and copies a pointer to it into a user-specified memory
location.
<p>Statistical structures are created in allocated memory. If application-specific allocation
routines have been declared (see <a href="../api_c/env_set_alloc.html">DB_ENV->set_alloc</a> for more
information), they are used to allocate the memory; otherwise, the
library <b>malloc</b>(3) interface 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.
<p>The following DB_TXN_STAT fields will be filled in:
<p><dl compact>
<dt><a href="../api_c/lsn_class.html">DB_LSN</a> st_last_ckp;<dd>The LSN of the last checkpoint.
<dt>time_t st_time_ckp;<dd>The time the last completed checkpoint finished (as the number of seconds
since the Epoch, returned by the IEEE/ANSI Std 1003.1 (POSIX) <b>time</b> interface).
<dt>u_int32_t st_last_txnid;<dd>The last transaction ID allocated.
<dt>u_int32_t st_maxtxns;<dd>The maximum number of active transactions possible.
<dt>u_int32_t st_nactive;<dd>The number of transactions that are currently active.
<dt>u_int32_t st_maxnactive;<dd>The maximum number of active transactions at any one time.
<dt>u_int32_t st_nbegins;<dd>The number of transactions that have begun.
<dt>u_int32_t st_naborts;<dd>The number of transactions that have aborted.
<dt>u_int32_t st_ncommits;<dd>The number of transactions that have committed.
<dt>u_int32_t st_nrestores;<dd>The number of transactions that have been restored.
<dt>u_int32_t st_regsize;<dd>The size of the region.
<dt>u_int32_t st_region_wait;<dd>The number of times that a thread of control was forced to wait before
obtaining the region lock.
<dt>u_int32_t st_region_nowait;<dd>The number of times that a thread of control was able to obtain
the region lock without waiting.
<dt>DB_TXN_ACTIVE *st_txnarray;<dd>A pointer to an array of <b>st_nactive</b> DB_TXN_ACTIVE structures,
describing the currently active transactions. The following fields of
the DB_TXN_ACTIVE structure will be filled in:
<p><dl compact>
<p><dt>u_int32_t txnid;<dd>The transaction ID of the transaction.
<dt>u_int32_t parentid;<dd>The transaction ID of the parent transaction (or 0, if no parent).
<dt><a href="../api_c/lsn_class.html">DB_LSN</a> lsn;<dd>The current log sequence number when the transaction was begun.
</dl>
</dl>
<p>The DB_ENV->txn_stat method returns a non-zero error value on failure and 0 on success.
<h1>Errors</h1>
<p>The DB_ENV->txn_stat method may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions.
If a catastrophic error has occurred, the DB_ENV->txn_stat method may fail and
return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>,
in which case all subsequent Berkeley DB calls will fail in the same way.
<h1>Class</h1>
<a href="../api_c/env_class.html">DB_ENV</a>, <a href="../api_c/txn_class.html">DB_TXN</a>
<h1>See Also</h1>
<a href="../api_c/txn_list.html">Transaction Subsystem and Related Methods</a>
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