1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>Release 4.4: DB_JOINENV</title> 7 <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Berkeley DB Programmer's Reference Guide" /> 10 <link rel="up" href="upgrade_4_4_toc.html" title="Chapter��41.��Upgrading Berkeley DB 4.3 applications to Berkeley DB 4.4" /> 11 <link rel="prev" href="upgrade_4_4_isolation.html" title="Release 4.4: DB_DEGREE_2, DB_DIRTY_READ" /> 12 <link rel="next" href="upgrade_4_4_mutex.html" title="Release 4.4: mutexes" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">Release 4.4: DB_JOINENV</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="upgrade_4_4_isolation.html">Prev</a>��</td> 22 <th width="60%" align="center">Chapter��41.��Upgrading Berkeley DB 4.3 applications to Berkeley DB 4.4</th> 23 <td width="20%" align="right">��<a accesskey="n" href="upgrade_4_4_mutex.html">Next</a></td> 24 </tr> 25 </table> 26 <hr /> 27 </div> 28 <div class="sect1" lang="en" xml:lang="en"> 29 <div class="titlepage"> 30 <div> 31 <div> 32 <h2 class="title" style="clear: both"><a id="upgrade_4_4_joinenv"></a>Release 4.4: DB_JOINENV</h2> 33 </div> 34 </div> 35 </div> 36 <p>The semantics of joining existing Berkeley DB database environments has changed 37in the 4.4 release. Previously:</p> 38 <div class="orderedlist"> 39 <ol type="1"> 40 <li>Applications joining existing environments, but not configuring some of 41the subsystems configured in the environment when it was created, would 42not be configured for those subsystems.</li> 43 <li>Applications joining existing environments, but configuring additional 44subsystems in addition to the subsystems configured in the environment 45when it was created, would cause additional subsystems to be configured 46in the database environment.</li> 47 </ol> 48 </div> 49 <p>In the 4.4 release, the semantics have been simplified to make it easier 50to write robust applications. In the 4.4 release:</p> 51 <div class="orderedlist"> 52 <ol type="1"> 53 <li>Applications joining existing environments, but not configuring some of 54the subsystems configured in the environment when it was created, will 55now automatically be configured for all of the subsystems configured in 56the environment.</li> 57 <li>Applications joining existing environments, but configuring additional 58subsystems in addition to the subsystems configured in the environment 59when it was created, will fail, as no additional subsystems can be 60configured for a database environment after it is created.</li> 61 </ol> 62 </div> 63 <p>In other words, the choice of subsystems initialized for a Berkeley DB 64database environment is specified by the thread of control initially 65creating the environment. Any subsequent thread of control joining the 66environment will automatically be configured to use the same subsystems 67as were created in the environment (unless the thread of control 68requests a subsystem not available in the environment, which will fail). 69Applications joining an environment, able to adapt to whatever 70subsystems have been configured in the environment, should open the 71environment without specifying any subsystem flags. Applications 72joining an environment, requiring specific subsystems from their 73environments, should open the environment specifying those specific 74subsystem flags.</p> 75 <p>The DB_JOINENV flag has been changed to have no effect in the Berkeley DB 4.4 76release. Applications should require no changes, although uses of the 77DB_JOINENV flag may be removed.</p> 78 </div> 79 <div class="navfooter"> 80 <hr /> 81 <table width="100%" summary="Navigation footer"> 82 <tr> 83 <td width="40%" align="left"><a accesskey="p" href="upgrade_4_4_isolation.html">Prev</a>��</td> 84 <td width="20%" align="center"> 85 <a accesskey="u" href="upgrade_4_4_toc.html">Up</a> 86 </td> 87 <td width="40%" align="right">��<a accesskey="n" href="upgrade_4_4_mutex.html">Next</a></td> 88 </tr> 89 <tr> 90 <td width="40%" align="left" valign="top">Release 4.4: DB_DEGREE_2, DB_DIRTY_READ��</td> 91 <td width="20%" align="center"> 92 <a accesskey="h" href="index.html">Home</a> 93 </td> 94 <td width="40%" align="right" valign="top">��Release 4.4: mutexes</td> 95 </tr> 96 </table> 97 </div> 98 </body> 99</html> 100