1<!--Copyright 1999,2008 Oracle. All rights reserved.--> 2<html> 3<head> 4 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> 5 <meta name="GENERATOR" content="Mozilla/4.75 [en] (X11; U; Linux 2.2.16-22 i686) [Netscape]"> 6</head> 7<body> 8 9<h2> 10<a NAME="Transaction Commands"></a>Transaction Commands</h2> 11Transactions are used in a manner similar to the other subsystems. 12We create a handle to the transaction and then use it for a variety 13of operations. Some of the transaction commands use the environment 14instead. Those are presented first. The transaction command 15handle returned is the handle used by the various commands that can be 16transaction protected, such as <a href="/docs/api_tcl/db_cursor.html">cursors</a>. 17<br> 18<hr WIDTH="100%"> 19<p><b>> <env> txn_checkpoint [-kbyte <i>kb</i>] [-min <i>min</i>]</b> 20<p>This command causes a checkpoint of the transaction region. It 21is a direct translation of the <a href="/docs/api_c/txn_checkpoint.html">txn_checkpoint 22</a>function. 23It returns either a 0 (for success), a DB error message or it throws a 24Tcl error with a system message. The arguments are: 25<ul> 26<li> 27<b>-force</b>causes the checkpoint to occur regardless of inactivity 28 29<li> 30<b>-kbyte</b>causes the checkpoint to occur only if <b><i>kb</i></b> kilobytes 31of log data has been written since the last checkpoint 32 33<li> 34<b>-min</b> causes the checkpoint to occur only if <b><i>min</i></b> minutes 35have passed since the last checkpoint 36</ul> 37 38<hr WIDTH="100%"> 39<br><b>> <env> txn_stat</b> 40<p>This command returns transaction statistics. It is a direct translation 41of the <a href="/docs/api_c/txn_stat.html">txn_stat</a> function. 42It will return a list of name/value pairs that correspond to the DB_TXN_STAT 43structure. 44<hr WIDTH="100%"> 45<br><b>> <env> txn_id_set </b><i> current max</i> 46<p>This is a diagnosic command that sets the next transaction id to be 47allocated and the maximum transaction 48<br>id, which is the point at which the relcaimation algorthm is triggered. 49<hr WIDTH="100%"> 50<br><b>> <txn> id</b> 51<p>This command returns the transaction id. It is a direct call to 52the <a href="/docs/api_c/txn_id.html">txn_id</a> function. The 53typical use of this identifier is as the <b><i>locker</i></b> value for 54the <a href="lock.html">lock_get</a> and <a href="lock.html">lock_vec</a> 55calls. 56<hr WIDTH="100%"> 57<br><b>> <txn> prepare</b> 58<p>This command initiates a two-phase commit. It is a direct call 59to the <a href="/docs/api_c/txn_prepare.html">txn_prepare</a> function. 60It returns either a 0 (for success), a DB error message or it throws a 61Tcl error with a system message. 62<hr WIDTH="100%"><a NAME="> <env> lock_vec"></a><b>> <env> txn_timeout 63<i>timeout</i></b> 64<p>This command sets thetransaction timeout for transactions started in 65the future in this environment. The timeout is in micorseconds. 66<br> 67<br> 68</body> 69</html> 70