8000 Update pg_resetxlog's documentation on multixacts · postgrespro/postgres_cluster@9db4ad4 · GitHub
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Update pg_resetxlog's documentation on multixacts
I added some more functionality to it in 0ac5ad5 but neglected to add it to the docs. Per Peter Eisentraut in message 1367112171.32604.4.camel@vanquo.pezone.net
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‎doc/src/sgml/ref/pg_resetxlog.sgml‎

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@@ -27,7 +27,7 @@ PostgreSQL documentation
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<arg choice="opt"><option>-o</option> <replaceable class="parameter">oid</replaceable></arg>
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<arg choice="opt"><option>-x</option> <replaceable class="parameter">xid</replaceable></arg>
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<arg choice="opt"><option>-e</option> <replaceable class="parameter">xid_epoch</replaceable></arg>
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<arg choice="opt"><option>-m</option> <replaceable class="parameter">mxid</replaceable></arg>
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<arg choice="opt"><option>-m</option> <replaceable class="parameter">mxid</replaceable>,<replaceable class="parameter">mxid</replaceable></arg>
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<arg choice="opt"><option>-O</option> <replaceable class="parameter">mxoff</replaceable></arg>
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<arg choice="opt"><option>-l</option> <replaceable class="parameter">xlogfile</replaceable></arg>
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<arg choice="plain"><replaceable>datadir</replaceable></arg>
@@ -81,7 +81,7 @@ PostgreSQL documentation
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<option>-m</>, <option>-O</>,
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and <option>-l</>
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options allow the next OID, next transaction ID, next transaction ID's
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epoch, next multitransaction ID, next multitransaction offset, and WAL
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epoch, next and oldest multitransaction ID, next multitransaction offset, and WAL
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starting address values to be set manually. These are only needed when
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<command>pg_resetxlog</command> is unable to determine appropriate values
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by reading <filename>pg_control</>. Safe values can be determined as
@@ -104,12 +104,16 @@ PostgreSQL documentation
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<listitem>
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<para>
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A safe value for the next multitransaction ID (<option>-m</>)
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A safe value for the next multitransaction ID (first part of <option>-m</>)
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can be determined by looking for the numerically largest
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file name in the directory <filename>pg_multixact/offsets</> under the
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data directory, adding one, and then multiplying by 65536. As above,
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the file names are in hexadecimal, so the easiest way to do this is to
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specify the option value in hexadecimal and add four zeroes.
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data directory, adding one, and then multiplying by 65536.
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Conversely, a safe value for the oldest multitransaction ID (second part of
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<option>-m</>)
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can be determined by looking for the numerically smallest
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file name in the same directory and multiplying by 65536.
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As above, the file names are in hexadecimal, so the easiest way to do
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this is to specify the option value in hexadecimal and append four zeroes.
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</para>
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</listitem>
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@@ -118,9 +122,9 @@ PostgreSQL documentation
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A safe value for the next multitransaction offset (<option>-O</>)
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can be determined by looking for the numerically largest
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file name in the directory <filename>pg_multixact/members</> under the
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data directory, adding one, and then multiplying by 65536. As above,
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the file names are in hexadecimal, so the easiest way to do this is to
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specify the option value in hexadecimal and add four zeroes.
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data directory, adding one, and then multiplying by 52352. As above,
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the file names are in hexadecimal. There is no simple recipe such as
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the ones above of appending zeroes.
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</para>
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</listitem>
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‎src/bin/pg_resetxlog/pg_resetxlog.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1036,7 +1036,7 @@ usage(void)
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printf(_(" -e XIDEPOCH set next transaction ID epoch\n"));
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printf(_(" -f force update to be done\n"));
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printf(_(" -l XLOGFILE force minimum WAL starting location for new transaction log\n"));
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printf(_(" -m XID,OLDEST set next multitransaction ID and oldest value\n"));
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printf(_(" -m XID,XID set next and oldest multitransaction ID\n"));
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printf(_(" -n no update, just show extracted control values (for testing)\n"));
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printf(_(" -o OID set next OID\n"));
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printf(_(" -O OFFSET set next multitransaction offset\n"));

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