diff options
| author | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2013-06-27 15:31:04 -0400 |
|---|---|---|
| committer | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2013-06-27 15:32:58 -0400 |
| commit | 9db4ad44eb02326bbe8eeaf7d1dd452844764a20 (patch) | |
| tree | c31441281eebb1ad48a6d4e5a90e01e790322d2c /doc/src | |
| parent | 863fad1bcc9de52381e117bfecc89dfb4a52f84a (diff) | |
| download | postgresql-9db4ad44eb02326bbe8eeaf7d1dd452844764a20.tar.gz postgresql-9db4ad44eb02326bbe8eeaf7d1dd452844764a20.zip | |
Update pg_resetxlog's documentation on multixacts
I added some more functionality to it in 0ac5ad5134f27 but neglected to
add it to the docs.
Per Peter Eisentraut in message
1367112171.32604.4.camel@vanquo.pezone.net
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/pg_resetxlog.sgml | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/doc/src/sgml/ref/pg_resetxlog.sgml b/doc/src/sgml/ref/pg_resetxlog.sgml index 90c772195cd..c680680fe78 100644 --- a/doc/src/sgml/ref/pg_resetxlog.sgml +++ b/doc/src/sgml/ref/pg_resetxlog.sgml @@ -27,7 +27,7 @@ PostgreSQL documentation <arg choice="opt"><option>-o</option> <replaceable class="parameter">oid</replaceable></arg> <arg choice="opt"><option>-x</option> <replaceable class="parameter">xid</replaceable></arg> <arg choice="opt"><option>-e</option> <replaceable class="parameter">xid_epoch</replaceable></arg> - <arg choice="opt"><option>-m</option> <replaceable class="parameter">mxid</replaceable></arg> + <arg choice="opt"><option>-m</option> <replaceable class="parameter">mxid</replaceable>,<replaceable class="parameter">mxid</replaceable></arg> <arg choice="opt"><option>-O</option> <replaceable class="parameter">mxoff</replaceable></arg> <arg choice="opt"><option>-l</option> <replaceable class="parameter">xlogfile</replaceable></arg> <arg choice="plain"><replaceable>datadir</replaceable></arg> @@ -81,7 +81,7 @@ PostgreSQL documentation <option>-m</>, <option>-O</>, and <option>-l</> options allow the next OID, next transaction ID, next transaction ID's - epoch, next multitransaction ID, next multitransaction offset, and WAL + epoch, next and oldest multitransaction ID, next multitransaction offset, and WAL starting address values to be set manually. These are only needed when <command>pg_resetxlog</command> is unable to determine appropriate values by reading <filename>pg_control</>. Safe values can be determined as @@ -104,12 +104,16 @@ PostgreSQL documentation <listitem> <para> - A safe value for the next multitransaction ID (<option>-m</>) + A safe value for the next multitransaction ID (first part of <option>-m</>) can be determined by looking for the numerically largest file name in the directory <filename>pg_multixact/offsets</> under the - data directory, adding one, and then multiplying by 65536. As above, - the file names are in hexadecimal, so the easiest way to do this is to - specify the option value in hexadecimal and add four zeroes. + data directory, adding one, and then multiplying by 65536. + Conversely, a safe value for the oldest multitransaction ID (second part of + <option>-m</>) + can be determined by looking for the numerically smallest + file name in the same directory and multiplying by 65536. + As above, the file names are in hexadecimal, so the easiest way to do + this is to specify the option value in hexadecimal and append four zeroes. </para> </listitem> @@ -118,9 +122,9 @@ PostgreSQL documentation A safe value for the next multitransaction offset (<option>-O</>) can be determined by looking for the numerically largest file name in the directory <filename>pg_multixact/members</> under the - data directory, adding one, and then multiplying by 65536. As above, - the file names are in hexadecimal, so the easiest way to do this is to - specify the option value in hexadecimal and add four zeroes. + data directory, adding one, and then multiplying by 52352. As above, + the file names are in hexadecimal. There is no simple recipe such as + the ones above of appending zeroes. </para> </listitem> |