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Update pg_upgrade docs to mention its use in a less risk-warning way,

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and update the pg_upgrade docs to mention its reliance on no changes to
the storage format (the later based on Robert Haas's patch).
This commit is contained in:
Bruce Momjian 2011-01-31 15:21:51 -05:00
parent ff20fbd6c2
commit 49450f01ec
2 changed files with 18 additions and 12 deletions
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16
doc/src/sgml/pgupgrade.sgml
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@ -17,9 +17,19 @@
</para>
<para>
<application>pg_upgrade</> works because, though new features are
regularly added to PostgreSQL major releases, the internal data storage
format rarely changes. <application>pg_upgrade</> does its best to
Major PostgreSQL releases regularly add new features that often
change the layout of the system tables, but the internal data storage
format rarely changes. <application>pg_upgrade</> uses this fact
to perform rapid upgrades by creating new system tables and simply
reusing the old user data files. If a future major release ever
changes the data storage format in a way that makes the old data
format unreadable, <application>pg_upgrade</> will not be usable
for such upgrades. (The community will attempt to avoid such
situations.)
</para>
<para>
<application>pg_upgrade</> does its best to
make sure the old and new clusters are binary-compatible, e.g. by
checking for compatible compile-time settings, including 32/64-bit
binaries. It is important that

14
doc/src/sgml/runtime.sgml
View file

@ -1692,17 +1692,13 @@ pg_dumpall -p 5432 | psql -d postgres -p 5433
</sect2>
<sect2 id="upgrading-methods-other">
<title>Other data migration methods</title>
<title>Non-Dump Upgrade Methods</title>
<para>
The <filename>contrib</> program
<link linkend="pgupgrade"><application>pg_upgrade</application></link>
allows an installation to be migrated in-place from one major
<productname>PostgreSQL</> version to the next. Keep in mind that this
method does not provide any scope for running old and new versions
concurrently. Also, <application>pg_upgrade</application> is much less
battle-tested than <application>pg_dump</application>, so having an
up-to-date backup is strongly recommended in case something goes wrong.
The <link linkend="pgupgrade">pg_upgrade</link> module allows an
installation to be migrated in-place from one major
<productname>PostgreSQL</> version to the next. Upgrades can be
performed in minutes.
</para>
<para>