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18          <th colspan="3" align="center">db_recover</th>
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20        <tr>
21          <td width="20%" align="left"><a accesskey="p" href="db_printlog.html">Prev</a> </td>
22          <th width="60%" align="center">Appendix 1. 
23                Berkeley DB Command Line Utilities
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30    <div class="sect1" lang="en" xml:lang="en">
31      <div class="titlepage">
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33          <div>
34            <h2 class="title" style="clear: both"><a id="db_recover"></a>db_recover</h2>
35          </div>
36        </div>
37      </div>
38      <pre class="programlisting">db_recover [-cefVv] [-h home] [-P password] [-t [[CC]YY]MMDDhhmm[.SS]]]  </pre>
39      <p>
40         The <span class="command"><strong>db_recover</strong></span> utility must be run after an unexpected application,
41         Berkeley DB, or system failure to restore the database to a consistent
42         state.  All committed transactions are guaranteed to appear after
43         <span class="command"><strong>db_recover</strong></span> has run, and all uncommitted transactions will be
44         completely undone.
45    </p>
46      <p>
47         Note that this utility performs the same action as if the
48         environment is opened with the 
49         <a class="link" href="envopen.html#envopen_DB_RECOVER">DB_RECOVER</a>
50         flag.  If <code class="literal">DB_RECOVER</code> is specified on environment open,
51         then use of this utility is not necessary.
52    </p>
53      <p>
54        The options are as follows:
55    </p>
56      <div class="itemizedlist">
57        <ul type="disc">
58          <li>
59            <p>
60                  <span class="bold"><strong>-c</strong></span>
61            </p>
62            <p>
63                Perform catastrophic recovery instead of normal recovery.
64            </p>
65          </li>
66          <li>
67            <p>
68                 <span class="bold"><strong>-e</strong></span>
69            </p>
70            <p>
71                 Retain the environment after running recovery.  This option will
72                 rarely be used unless a <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is
73                 present in the home directory.  If a <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is
74                 not present, then the regions will be created with default parameter
75                 values.
76            </p>
77          </li>
78          <li>
79            <p>
80                 <span class="bold"><strong>-f</strong></span>
81            </p>
82            <p>
83                 Display a message on the standard output showing the percent of
84                 recovery completed.
85            </p>
86          </li>
87          <li>
88            <p>
89                 <span class="bold"><strong>-h</strong></span>
90            </p>
91            <p>
92                 Specify a home directory for the database environment; by default, the
93                 current working directory is used.
94            </p>
95          </li>
96          <li>
97            <p>
98                 <span class="bold"><strong>-P</strong></span>
99            </p>
100            <p>
101                 Specify an environment password.  Although Berkeley DB utilities
102                 overwrite password strings as soon as possible, be aware there may be
103                 a window of vulnerability on systems where unprivileged users can see
104                 command-line arguments or where utilities are not able to overwrite
105                 the memory containing the command-line arguments.
106            </p>
107          </li>
108          <li>
109            <p>
110                 <span class="bold"><strong>-t</strong></span>
111            </p>
112            <p>
113                 Recover to the time specified rather than to the most current possible
114                 date.  The timestamp argument should be in the form
115                 <code class="literal">[[CC]YY]MMDDhhmm[.SS]</code> where each pair of letters represents the
116                 following:
117            </p>
118            <div class="itemizedlist">
119              <ul type="circle">
120                <li>
121                  <p>
122                        <span class="bold"><strong>CC</strong></span>
123                    </p>
124                  <p>
125                        The first two digits of the year (the century).
126                    </p>
127                </li>
128                <li>
129                  <p>
130                        <span class="bold"><strong>YY</strong></span>
131                    </p>
132                  <p>
133                        The second two digits of the year. If "YY" is specified, but "CC" is not, a
134                        value for "YY" between 69 and 99 results in a "CC" value of 19. Otherwise, a
135                        "CC" value of 20 is used.
136                    </p>
137                </li>
138                <li>
139                  <p>
140                        <span class="bold"><strong>MM</strong></span>
141                    </p>
142                  <p>
143                        The month of the year, from 1 to 12.
144                    </p>
145                </li>
146                <li>
147                  <p>
148                        <span class="bold"><strong>DD</strong></span>
149                    </p>
150                  <p>
151                        The day of the month, from 1 to 31.
152                    </p>
153                </li>
154                <li>
155                  <p>
156                        <span class="bold"><strong>hh</strong></span>
157                    </p>
158                  <p>
159                        The hour of the day, from 0 to 23.
160                    </p>
161                </li>
162                <li>
163                  <p>
164                        <span class="bold"><strong>mm</strong></span>
165                    </p>
166                  <p>
167                        The minute of the hour, from 0 to 59.
168                    </p>
169                </li>
170                <li>
171                  <p>
172                        <span class="bold"><strong>SS</strong></span>
173                    </p>
174                  <p>
175                        The second of the minute, from 0 to 61.
176                    </p>
177                </li>
178              </ul>
179            </div>
180            <p>
181                 If the "CC" and "YY" letter pairs are not specified, the values
182                 default to the current year.  If the "SS" letter pair is not
183                 specified, the value defaults to 0.
184            </p>
185          </li>
186          <li>
187            <p>
188                 <span class="bold"><strong>-V</strong></span>
189            </p>
190            <p>
191                 Write the library version number to the standard output, and exit.
192            </p>
193          </li>
194          <li>
195            <p>
196                 <span class="bold"><strong>-v</strong></span>
197            </p>
198            <p>
199                Run in verbose mode.
200            </p>
201          </li>
202        </ul>
203      </div>
204      <p>
205         In the case of catastrophic recovery, an archival copy — or
206         <span class="emphasis"><em>snapshot</em></span> — of all database files must be
207         restored along with all of the log files written since the database
208         file snapshot was made. (If disk space is a problem, log files may be
209         referenced by symbolic links).  For further information on creating a
210         database snapshot, see <a href="../../programmer_reference/transapp_archival.html" class="olink">Archival Procedures</a>.  For
211         further information on performing recovery, see <a href="../../programmer_reference/transapp_recovery.html" class="olink">Recovery Procedures</a>.
212    </p>
213      <p>
214         If the failure was not catastrophic, the files present on the system
215         at the time of failure are sufficient to perform recovery.
216    </p>
217      <p>
218         If log files are missing, <span class="command"><strong>db_recover</strong></span> will identify the missing log
219         file(s) and fail, in which case the missing log files need to be
220         restored and recovery performed again.
221    </p>
222      <p>
223         The <span class="command"><strong>db_recover</strong></span> utility uses a Berkeley DB environment (as described
224         for the <span class="bold"><strong>-h</strong></span> option, the environment
225         variable <span class="bold"><strong>DB_HOME</strong></span>, or because the
226         utility was run in a directory containing a Berkeley DB environment). 
227         In order to avoid environment corruption when using a Berkeley DB
228         environment, <span class="command"><strong>db_recover</strong></span> should always be given the chance to detach
229         from the environment and exit gracefully.  To cause <span class="command"><strong>db_recover</strong></span> to
230         release all environment resources and exit cleanly, send it an
231         interrupt signal (SIGINT).
232    </p>
233      <p>
234         The <span class="command"><strong>db_recover</strong></span> utility exits 0 on success, and &gt;0 if an error
235         occurs.
236    </p>
237      <div class="sect2" lang="en" xml:lang="en">
238        <div class="titlepage">
239          <div>
240            <div>
241              <h3 class="title"><a id="id1719853"></a>Environment Variables</h3>
242            </div>
243          </div>
244        </div>
245        <div class="sect3" lang="en" xml:lang="en">
246          <div class="titlepage">
247            <div>
248              <div>
249                <h4 class="title"><a id="id1720416"></a>DB_HOME</h4>
250              </div>
251            </div>
252          </div>
253          <p>
254                          If the <span class="bold"><strong>-h</strong></span> option is not specified and
255                          the environment variable DB_HOME is set, it is used as the path of the
256                          database home, as described in the
257                          <a class="xref" href="envopen.html" title="DbEnv::open()">DbEnv::open()</a>
258                          method.
259                     </p>
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