<!--Copyright 1999,2008 Oracle. All rights reserved.--> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta name="GENERATOR" content="Mozilla/4.75 [en] (X11; U; Linux 2.2.16-22 i686) [Netscape]"> </head> <body> <h2> <a NAME="Transaction Commands"></a>Transaction Commands</h2> Transactions are used in a manner similar to the other subsystems. We create a handle to the transaction and then use it for a variety of operations. Some of the transaction commands use the environment instead. Those are presented first. The transaction command handle returned is the handle used by the various commands that can be transaction protected, such as <a href="../../docs/api_tcl/db_cursor.html">cursors</a>. <br> <hr WIDTH="100%"> <p><b>> <env> txn_checkpoint [-kbyte <i>kb</i>] [-min <i>min</i>]</b> <p>This command causes a checkpoint of the transaction region. It is a direct translation of the <a href="../../docs/api_c/txn_checkpoint.html">txn_checkpoint </a>function. It returns either a 0 (for success), a DB error message or it throws a Tcl error with a system message. The arguments are: <ul> <li> <b>-force</b>causes the checkpoint to occur regardless of inactivity <li> <b>-kbyte</b>causes the checkpoint to occur only if <b><i>kb</i></b> kilobytes of log data has been written since the last checkpoint <li> <b>-min</b> causes the checkpoint to occur only if <b><i>min</i></b> minutes have passed since the last checkpoint </ul> <hr WIDTH="100%"> <br><b>> <env> txn_stat</b> <p>This command returns transaction statistics. It is a direct translation of the <a href="../../docs/api_c/txn_stat.html">txn_stat</a> function. It will return a list of name/value pairs that correspond to the DB_TXN_STAT structure. <hr WIDTH="100%"> <br><b>> <env> txn_id_set </b><i> current max</i> <p>This is a diagnosic command that sets the next transaction id to be allocated and the maximum transaction <br>id, which is the point at which the relcaimation algorthm is triggered. <hr WIDTH="100%"> <br><b>> <txn> id</b> <p>This command returns the transaction id. It is a direct call to the <a href="../../docs/api_c/txn_id.html">txn_id</a> function. The typical use of this identifier is as the <b><i>locker</i></b> value for the <a href="lock.html">lock_get</a> and <a href="lock.html">lock_vec</a> calls. <hr WIDTH="100%"> <br><b>> <txn> prepare</b> <p>This command initiates a two-phase commit. It is a direct call to the <a href="../../docs/api_c/txn_prepare.html">txn_prepare</a> function. It returns either a 0 (for success), a DB error message or it throws a Tcl error with a system message. <hr WIDTH="100%"><a NAME="> <env> lock_vec"></a><b>> <env> txn_timeout <i>timeout</i></b> <p>This command sets thetransaction timeout for transactions started in the future in this environment. The timeout is in micorseconds. <br> <br> </body> </html>