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Adjust pg_resetxlog to handle 8.0 WAL file names properly.

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This commit is contained in:
Tom Lane
2004-12-20 01:42:11 +00:00
parent 8562b032d8
commit 59bffa3707
2 changed files with 35 additions and 15 deletions
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22
doc/src/sgml/ref/pg_resetxlog.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/pg_resetxlog.sgml,v 1.8 2003/11/29 19:51:39 pgsql Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/pg_resetxlog.sgml,v 1.9 2004/12/20 01:42:09 tgl Exp $
PostgreSQL documentation
-->
@ -22,7 +22,7 @@ PostgreSQL documentation
<arg> -n </arg>
<arg> -o <replaceable class="parameter">oid</replaceable> </arg>
<arg> -x <replaceable class="parameter">xid</replaceable> </arg>
<arg> -l <replaceable class="parameter">fileid</replaceable>,<replaceable class="parameter">seg</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>
</refsynopsisdiv>
@ -79,17 +79,25 @@ PostgreSQL documentation
<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,
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 number currently existing in
the directory <filename>pg_xlog</> under the data directory. The addresses are also in hexadecimal and
have two parts. For example, if <filename>000000FF0000003A</> is the
largest entry in <filename>pg_xlog</>, <literal>-l 0xFF,0x3B</> will work.
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.