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<title>Berkeley DB: DbEnv::txn_stat</title>
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<h1>DbEnv::txn_stat</h1>
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#include <db_cxx.h>
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DbEnv::txn_stat(DB_TXN_STAT **statp);
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<p>The DbEnv::txn_stat method
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creates a statistical structure and copies a pointer to it into a
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user-specified memory location.
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<p>Statistical structures are created in allocated memory. If application-specific allocation
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routines have been declared (see <a href="../api_cxx/env_set_alloc.html">DbEnv::set_alloc</a> for more
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information), they are used to allocate the memory; otherwise, the
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library function <b>malloc</b>(3) is used. The caller is
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responsible for deallocating the memory. To deallocate the memory, free
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the memory reference; references inside the returned memory need not be
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<p>The transaction region statistics are stored in a structure of type
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DB_TXN_STAT. The following DB_TXN_STAT fields will be filled in:
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<dt><a href="../api_cxx/lsn_class.html">DbLsn</a> st_last_ckp;<dd>The LSN of the last checkpoint.
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<dt><a href="../api_cxx/lsn_class.html">DbLsn</a> st_pending_ckp;<dd>The LSN of any checkpoint that is currently in progress. If
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<b>st_pending_ckp</b> is the same as <b>st_last_ckp</b> there
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is no checkpoint in progress.
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<dt>time_t st_time_ckp;<dd>The time the last completed checkpoint finished (as the number of seconds
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since the Epoch, returned by the IEEE/ANSI Std 1003.1 (POSIX) <b>time</b> interface).
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<dt>u_int32_t st_last_txnid;<dd>The last transaction ID allocated.
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<dt>u_int32_t st_maxtxns;<dd>The maximum number of active transactions possible.
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<dt>u_int32_t st_nactive;<dd>The number of transactions that are currently active.
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<dt>u_int32_t st_maxnactive;<dd>The maximum number of active transactions at any one time.
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<dt>u_int32_t st_nbegins;<dd>The number of transactions that have begun.
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<dt>u_int32_t st_naborts;<dd>The number of transactions that have aborted.
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<dt>u_int32_t st_ncommits;<dd>The number of transactions that have committed.
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<dt>u_int32_t st_regsize;<dd>The size of the region.
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<dt>u_int32_t st_region_wait;<dd>The number of times that a thread of control was forced to wait before
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obtaining the region lock.
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<dt>u_int32_t st_region_nowait;<dd>The number of times that a thread of control was able to obtain
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the region lock without waiting.
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<dt>DB_TXN_ACTIVE * st_txnarray;<dd>A pointer to an array of <b>st_nactive</b> DB_TXN_ACTIVE structures,
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describing the currently active transactions. The following fields of
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the DB_TXN_ACTIVE structure will be filled in:
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<p><dt>u_int32_t txnid;<dd>The transaction ID of the transaction.
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<dt>u_int32_t parentid;<dd>The transaction ID of the parent transaction (or 0, if no parent).
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<dt><a href="../api_cxx/lsn_class.html">DbLsn</a> lsn;<dd>The log sequence number of the transaction-begin record.
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<p>The DbEnv::txn_stat method either returns a non-zero error value or throws an exception that
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encapsulates a non-zero error value on failure, and returns 0 on success.
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<p>The DbEnv::txn_stat method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods.
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If a catastrophic error has occurred, the DbEnv::txn_stat method may fail and either
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return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a> or throw an exception encapsulating
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<a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>, in which case all subsequent Berkeley DB calls will fail
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<a href="../api_cxx/dbenv_class.html">DbEnv</a>, <a href="../api_cxx/txn_class.html">DbTxn</a>
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<a href="../api_cxx/env_set_tx_max.html">DbEnv::set_tx_max</a>,
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<a href="../api_cxx/env_set_tx_recover.html">DbEnv::set_tx_recover</a>,
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<a href="../api_cxx/env_set_tx_timestamp.html">DbEnv::set_tx_timestamp</a>,
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<a href="../api_cxx/txn_abort.html">DbTxn::abort</a>,
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<a href="../api_cxx/txn_begin.html">DbEnv::txn_begin</a>,
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<a href="../api_cxx/txn_checkpoint.html">DbEnv::txn_checkpoint</a>,
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<a href="../api_cxx/txn_commit.html">DbTxn::commit</a>,
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<a href="../api_cxx/txn_discard.html">DbTxn::discard</a>,
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<a href="../api_cxx/txn_id.html">DbTxn::id</a>,
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<a href="../api_cxx/txn_prepare.html">DbTxn::prepare</a>,
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<a href="../api_cxx/txn_recover.html">DbEnv::txn_recover</a>,
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<a href="../api_cxx/txn_stat.html">DbEnv::txn_stat</a>.
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