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Improve wording of upgrade section.

This commit is contained in:
Bruce Momjian
2002-08-22 15:31:07 +00:00
parent 0f1112923c
commit 5530b0c666
2 changed files with 30 additions and 35 deletions

View File

@ -14,7 +14,7 @@
alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
<P>Last updated: Tue Jul 30 11:05:09 EDT 2002</P>
<P>Last updated: Thu Aug 22 11:30:58 EDT 2002</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@ -82,7 +82,7 @@
<A href="#3.9">3.9</A>) What are the <I>pg_sorttempNNN.NN</I>
files in my database directory?<BR>
<A href="#3.10">3.10</A>) Why do I need to do a dump and restore
to upgrade PostgreSQL?<BR>
to upgrade PostgreSQL releases?<BR>
<H2 align="center">Operational Questions</H2>
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running at the time, it is safe to delete the pg_tempNNN.NN
files.</P>
<H4><A name="3.10">3.10</A>) Why do I need to do a dump and restore
to upgrade PostgreSQL?</H4>
<H4><A name="3.10">3.10</A>) Why do I need to do a dump and restore
to upgrade between major PostgreSQL releases?</H4>
<P>The PostgreSQL team tries very heard to maintain compatability across
minor releases. So upgrading from 7.2 to 7.2.1 does not require a dump a
restore. However, new features are continuously being adding and
sometimes this requires new fields to be added to system tables.
<P>The PostgreSQL team makes only small changes between minor releases,
so upgrading from 7.2 to 7.2.1 does not require a dump and restore.
However, major releases often change the internal format of system
tables and data files. These changes are often complex, so we don't
maintain backward compatability for data files. A dump outputs data
in a generic format that can then be loaded in using the new internal
format.
<P>These changes may be across many tables and so maintaining backward
compatability would be quite difficult. Thus, restoring from a dump is
required to make everything work.
<P>Note that the actual on-disk file format does not change very often,
a feature the pg_upgrade script uses quite successfully. There the dump
is used create the necessary information in the system tables. The data
files are then just copied across. This method is not as guarenteed as
the dump/restore method but when it works it can make upgrades very
efficient.
<P>In releases where the on-disk format does not change, the
<i>pg_upgrade</i> script can be used to upgrade without a dump/restore.
The release notes mention whether <i>pg_upgrade</i> is available for the
release.
<HR>