Commit 5530b0c6 authored by Bruce Momjian's avatar Bruce Momjian

Improve wording of upgrade section.

parent 0f111292
Frequently Asked Questions (FAQ) for PostgreSQL Frequently Asked Questions (FAQ) for PostgreSQL
Last updated: Tue Jul 30 11:05:09 EDT 2002 Last updated: Thu Aug 22 11:30:58 EDT 2002
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
...@@ -53,7 +53,8 @@ ...@@ -53,7 +53,8 @@
3.7) What debugging features are available? 3.7) What debugging features are available?
3.8) Why do I get "Sorry, too many clients" when trying to connect? 3.8) Why do I get "Sorry, too many clients" when trying to connect?
3.9) What are the pg_sorttempNNN.NN files in my database directory? 3.9) What are the pg_sorttempNNN.NN files in my database directory?
3.10) Why do I need to do a dump and restore to upgrade PostgreSQL? 3.10) Why do I need to do a dump and restore to upgrade PostgreSQL
releases?
Operational Questions Operational Questions
...@@ -602,23 +603,20 @@ ...@@ -602,23 +603,20 @@
a backend crashes during a sort. If you have no backends running at a backend crashes during a sort. If you have no backends running at
the time, it is safe to delete the pg_tempNNN.NN files. the time, it is safe to delete the pg_tempNNN.NN files.
3.10) Why do I need to do a dump and restore to upgrade PostgreSQL? 3.10) Why do I need to do a dump and restore to upgrade between major
PostgreSQL releases?
The PostgreSQL team tries very heard to maintain compatability across The PostgreSQL team makes only small changes between minor releases,
minor releases. So upgrading from 7.2 to 7.2.1 does not require a dump so upgrading from 7.2 to 7.2.1 does not require a dump and restore.
a restore. However, new features are continuously being adding and However, major releases often change the internal format of system
sometimes this requires new fields to be added to system tables. tables and data files. These changes are often complex, so we don't
maintain backward compatability for data files. A dump outputs data in
These changes may be across many tables and so maintaining backward a generic format that can then be loaded in using the new internal
compatability would be quite difficult. Thus, restoring from a dump is format.
required to make everything work.
In releases where the on-disk format does not change, the pg_upgrade
Note that the actual on-disk file format does not change very often, a script can be used to upgrade without a dump/restore. The release
feature the pg_upgrade script uses quite successfully. There the dump notes mention whether pg_upgrade is available for the release.
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.
_________________________________________________________________ _________________________________________________________________
Operational Questions Operational Questions
......
...@@ -14,7 +14,7 @@ ...@@ -14,7 +14,7 @@
alink="#0000ff"> alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1> <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= <P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
...@@ -82,7 +82,7 @@ ...@@ -82,7 +82,7 @@
<A href="#3.9">3.9</A>) What are the <I>pg_sorttempNNN.NN</I> <A href="#3.9">3.9</A>) What are the <I>pg_sorttempNNN.NN</I>
files in my database directory?<BR> files in my database directory?<BR>
<A href="#3.10">3.10</A>) Why do I need to do a dump and restore <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> <H2 align="center">Operational Questions</H2>
...@@ -786,24 +786,21 @@ ...@@ -786,24 +786,21 @@
running at the time, it is safe to delete the pg_tempNNN.NN running at the time, it is safe to delete the pg_tempNNN.NN
files.</P> files.</P>
<H4><A name="3.10">3.10</A>) Why do I need to do a dump and restore <H4><A name="3.10">3.10</A>) Why do I need to do a dump and restore
to upgrade PostgreSQL?</H4> to upgrade between major PostgreSQL releases?</H4>
<P>The PostgreSQL team tries very heard to maintain compatability across <P>The PostgreSQL team makes only small changes between minor releases,
minor releases. So upgrading from 7.2 to 7.2.1 does not require a dump a so upgrading from 7.2 to 7.2.1 does not require a dump and restore.
restore. However, new features are continuously being adding and However, major releases often change the internal format of system
sometimes this requires new fields to be added to system tables. tables and data files. These changes are often complex, so we don't
maintain backward compatability for data files. A dump outputs data
<P>These changes may be across many tables and so maintaining backward in a generic format that can then be loaded in using the new internal
compatability would be quite difficult. Thus, restoring from a dump is format.
required to make everything work.
<P>In releases where the on-disk format does not change, the
<P>Note that the actual on-disk file format does not change very often, <i>pg_upgrade</i> script can be used to upgrade without a dump/restore.
a feature the pg_upgrade script uses quite successfully. There the dump The release notes mention whether <i>pg_upgrade</i> is available for the
is used create the necessary information in the system tables. The data release.
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.
<HR> <HR>
......
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