1<!--$Id: nosync.so,v 1.7 2004/09/28 14:13:09 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB Reference Guide: Release 4.2: Client replication environments</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td><b><dl><dt>Berkeley DB Reference Guide:<dd>Upgrading Berkeley DB Applications</dl></b></td> 13<td align=right><a href="/upgrade.4.2/repinit.html"><img src="/images/prev.gif" alt="Prev"></a><a href="/toc.html"><img src="/images/ref.gif" alt="Ref"></a><a href="/upgrade.4.2/tcl.html"><img src="/images/next.gif" alt="Next"></a> 14</td></tr></table> 15<p align=center><b>Release 4.2: Client replication environments</b></p> 16<p>In previous Berkeley DB releases, replication clients always behaved as if 17<a href="/api_c/env_set_flags.html#DB_TXN_NOSYNC">DB_TXN_NOSYNC</a> behavior was configured, that is, clients would 18not write or synchronously flush their log when receiving a transaction 19commit or prepare message. However, applications needing a high level 20of transactional guarantee may need a write and synchronous flush on 21the client. By default in the Berkeley DB 4.2 release, client database 22environments write and synchronously flush their logs when receiving a 23transaction commit or prepare message. Applications not needing such 24a high level of transactional guarantee should use the environment's 25<a href="/api_c/env_set_flags.html#DB_TXN_NOSYNC">DB_TXN_NOSYNC</a> flag to configure their client database 26environments to not do the write or flush on transaction commit, as this 27will increase their performance. Regardless of the setting of the 28<a href="/api_c/env_set_flags.html#DB_TXN_NOSYNC">DB_TXN_NOSYNC</a> flag, clients will always write and flush on 29transaction prepare.</p> 30<table width="100%"><tr><td><br></td><td align=right><a href="/upgrade.4.2/repinit.html"><img src="/images/prev.gif" alt="Prev"></a><a href="/toc.html"><img src="/images/ref.gif" alt="Ref"></a><a href="/upgrade.4.2/tcl.html"><img src="/images/next.gif" alt="Next"></a> 31</td></tr></table> 32<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 33</body> 34</html> 35