diff options
Diffstat (limited to 'doc/src/sgml/ref/pg_resetxlog.sgml')
| -rw-r--r-- | doc/src/sgml/ref/pg_resetxlog.sgml | 86 |
1 files changed, 59 insertions, 27 deletions
diff --git a/doc/src/sgml/ref/pg_resetxlog.sgml b/doc/src/sgml/ref/pg_resetxlog.sgml index 6651a0b588c..f5915adacd4 100644 --- a/doc/src/sgml/ref/pg_resetxlog.sgml +++ b/doc/src/sgml/ref/pg_resetxlog.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/pg_resetxlog.sgml,v 1.9 2004/12/20 01:42:09 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/pg_resetxlog.sgml,v 1.10 2005/04/28 21:47:10 tgl Exp $ PostgreSQL documentation --> @@ -22,6 +22,7 @@ PostgreSQL documentation <arg> -n </arg> <arg> -o <replaceable class="parameter">oid</replaceable> </arg> <arg> -x <replaceable class="parameter">xid</replaceable> </arg> + <arg> -m <replaceable class="parameter">mxid</replaceable> </arg> <arg> -l <replaceable class="parameter">timelineid</replaceable>,<replaceable class="parameter">fileid</replaceable>,<replaceable class="parameter">seg</replaceable> </arg> <arg choice="plain"><replaceable>datadir</replaceable></arg> </cmdsynopsis> @@ -73,34 +74,65 @@ PostgreSQL documentation </para> <para> - The <literal>-o</>, <literal>-x</>, and <literal>-l</> switches allow - the next OID, next transaction ID, and WAL starting address values to + The <literal>-o</>, <literal>-x</>, <literal>-m</>, and <literal>-l</> + switches allow the next OID, next transaction ID, next multi-transaction + ID, 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</>. A safe value for the - next transaction ID may be determined by looking for the numerically largest - file name in the directory <filename>pg_clog</> under the data directory, - adding one, - and then multiplying by 1048576. Note that the file names are in - hexadecimal. It is usually easiest to specify the switch value in - hexadecimal too. For example, if <filename>0011</> is the largest entry - in <filename>pg_clog</>, <literal>-x 0x1200000</> will work (five trailing - zeroes provide the proper multiplier). - The WAL starting address should be - larger than any file name currently existing in - the directory <filename>pg_xlog</> under the data directory. - These names are also in hexadecimal and have three parts. The first - part is the <quote>timeline ID</> and should usually be kept the same. - Do not choose a value larger than 255 (<literal>0xFF</>) for the third - part; instead increment the second part and reset the third part to 0. - For example, if <filename>00000001000000320000004A</> is the - largest entry in <filename>pg_xlog</>, <literal>-l 0x1,0x32,0x4B</> will - work; but if the largest entry is - <filename>000000010000003A000000FF</>, choose <literal>-l 0x1,0x3B,0x0</> - or more. - There is no comparably easy way to determine a next OID that's beyond - the largest one in the database, but fortunately it is not critical to - get the next-OID setting right. + by reading <filename>pg_control</>. Safe values may be determined as + follows: + + <itemizedlist> + <listitem> + <para> + A safe value for the next transaction ID (<literal>-x</>) + may be determined by looking for the numerically largest + file name in the directory <filename>pg_clog</> under the data directory, + adding one, + and then multiplying by 1048576. Note that the file names are in + hexadecimal. It is usually easiest to specify the switch value in + hexadecimal too. For example, if <filename>0011</> is the largest entry + in <filename>pg_clog</>, <literal>-x 0x1200000</> will work (five + trailing zeroes provide the proper multiplier). + </para> + </listitem> + + <listitem> + <para> + A safe value for the next multi-transaction ID (<literal>-m</>) + may 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 switch value in hexadecimal and add four zeroes. + </para> + </listitem> + + <listitem> + <para> + The WAL starting address (<literal>-l</>) should be + larger than any file name currently existing in + the directory <filename>pg_xlog</> under the data directory. + These names are also in hexadecimal and have three parts. The first + part is the <quote>timeline ID</> and should usually be kept the same. + Do not choose a value larger than 255 (<literal>0xFF</>) for the third + part; instead increment the second part and reset the third part to 0. + For example, if <filename>00000001000000320000004A</> is the + largest entry in <filename>pg_xlog</>, <literal>-l 0x1,0x32,0x4B</> will + work; but if the largest entry is + <filename>000000010000003A000000FF</>, choose <literal>-l 0x1,0x3B,0x0</> + or more. + </para> + </listitem> + + <listitem> + <para> + There is no comparably easy way to determine a next OID that's beyond + the largest one in the database, but fortunately it is not critical to + get the next-OID setting right. + </para> + </listitem> + </itemizedlist> </para> <para> |