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Create a "relation mapping" infrastructure to support changing the relfilenodes

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of shared or nailed system catalogs.  This has two key benefits:

* The new CLUSTER-based VACUUM FULL can be applied safely to all catalogs.

* We no longer have to use an unsafe reindex-in-place approach for reindexing
  shared catalogs.

CLUSTER on nailed catalogs now works too, although I left it disabled on
shared catalogs because the resulting pg_index.indisclustered update would
only be visible in one database.

Since reindexing shared system catalogs is now fully transactional and
crash-safe, the former special cases in REINDEX behavior have been removed;
shared catalogs are treated the same as non-shared.

This commit does not do anything about the recently-discussed problem of
deadlocks between VACUUM FULL/CLUSTER on a system catalog and other
concurrent queries; will address that in a separate patch.  As a stopgap,
parallel_schedule has been tweaked to run vacuum.sql by itself, to avoid
such failures during the regression tests.
This commit is contained in:
Tom Lane
2010-02-07 20:48:13 +00:00
parent 7fc30c488f
commit b9b8831ad6
54 changed files with 2316 additions and 585 deletions
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12
doc/src/sgml/ref/cluster.sgml
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@@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/cluster.sgml,v 1.47 2009/09/19 10:23:26 petere Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/cluster.sgml,v 1.48 2010/02/07 20:48:09 tgl Exp $
PostgreSQL documentation
-->
@@ -30,12 +30,12 @@ CLUSTER [VERBOSE]
<title>Description</title>
<para>
<command>CLUSTER</command> instructs <productname>PostgreSQL</productname>
<command>CLUSTER</command> instructs <productname>PostgreSQL</productname>
to cluster the table specified
by <replaceable class="parameter">table_name</replaceable>
based on the index specified by
<replaceable class="parameter">index_name</replaceable>. The index must
already have been defined on
already have been defined on
<replaceable class="parameter">table_name</replaceable>.
</para>
@@ -46,9 +46,9 @@ CLUSTER [VERBOSE]
not clustered. That is, no attempt is made to store new or
updated rows according to their index order. (If one wishes, one can
periodically recluster by issuing the command again. Also, setting
the table's <literal>FILLFACTOR</literal> storage parameter to less than 100% can aid
in preserving cluster ordering during updates, since updated rows
are preferentially kept on the same page.)
the table's <literal>FILLFACTOR</literal> storage parameter to less than
100% can aid in preserving cluster ordering during updates, since updated
rows are kept on the same page if enough space is available there.)
</para>
<para>