1<!--$Id: db_sync.so,v 10.37 2007/10/24 16:06:06 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: DB->sync</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> 13<b>DB->sync</b> 14</td> 15<td align=right> 16<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a> 17<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db.h> 23<p> 24int 25DB->sync(DB *db, u_int32_t flags); 26</pre></b> 27<hr size=1 noshade> 28<b>Description: DB->sync</b> 29<p>The DB->sync method flushes any cached information to disk.</p> 30<p>If the database is in memory only, the DB->sync method has no effect and 31will always succeed.</p> 32<p><b>It is important to understand that flushing cached information to disk 33only minimizes the window of opportunity for corrupted data.</b> Although 34unlikely, it is possible for database corruption to happen if a system 35or application crash occurs while writing data to the database. To 36ensure that database corruption never occurs, applications must either: 37use transactions and logging with automatic recovery; use logging and 38application-specific recovery; or edit a copy of the database, and once 39all applications using the database have successfully called 40<a href="../api_c/db_close.html">DB->close</a>, atomically replace the original database with the 41updated copy.</p> 42<p>The DB->sync method 43returns a non-zero error value on failure 44and 0 on success. 45</p> 46<b>Parameters</b> <br> 47 <b>flags</b><ul compact><li>The <b>flags</b> parameter is currently unused, and must be set to 0.</ul> 48<br> 49<br><b>Errors</b> 50<p>The DB->sync method 51may fail and return one of the following non-zero errors:</p> 52<br> 53<b>DB_REP_HANDLE_DEAD</b><ul compact><li>The database handle has been invalidated because a replication election 54unrolled a committed transaction.</ul> 55<br> 56<br> 57<b>DB_REP_LOCKOUT</b><ul compact><li>The operation was blocked by client/master synchronization.</ul> 58<br> 59<br> 60<b>EINVAL</b><ul compact><li>An 61invalid flag value or parameter was specified.</ul> 62<br> 63<hr size=1 noshade> 64<br><b>Class</b> 65<a href="../api_c/db_class.html">DB</a> 66<br><b>See Also</b> 67<a href="../api_c/db_list.html">Databases and Related Methods</a> 68</tt> 69<table width="100%"><tr><td><br></td><td align=right> 70<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> 71</td></tr></table> 72<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 73</body> 74</html> 75
