I wrote:
> Actually, that whole para could do with a rewrite; whoever wrote
> it was obviously not familiar with Strunk & White's dictum
> "Omit needless words".
Looking closer, there were also some unnecessary inconsistencies with
the rest of the section, such as use of "records" rather than "rows",
and different markup choices. I propose the attached ... it's
actually a bit longer than the original, but that's because it
offers more details.
regards, tom lane
diff --git a/doc/src/sgml/perform.sgml b/doc/src/sgml/perform.sgml
index 715aff6..0f61b09 100644
--- a/doc/src/sgml/perform.sgml
+++ b/doc/src/sgml/perform.sgml
@@ -896,15 +896,16 @@ EXPLAIN ANALYZE SELECT * FROM tenk1 WHERE unique1 < 100 AND unique2 > 9000
</para>
<para>
- Generally, the <command>EXPLAIN</command> output will display details for
- every plan node which was generated by the query planner. However, there
- are cases where the executor is able to determine that certain nodes are
- not required; currently, the only node types to support this are the
- <literal>Append</literal> and <literal>MergeAppend</literal> nodes. These
- node types have the ability to discard subnodes which they are able to
- determine won't contain any records required by the query. It is possible
- to determine that nodes have been removed in this way by the presence of a
- "Subplans Removed" property in the <command>EXPLAIN</command> output.
+ Normally, <command>EXPLAIN</command> will display every plan node
+ created by the planner. However, there are cases where the executor
+ can determine that certain nodes need not be executed because they
+ cannot produce any rows, based on parameter values that were not
+ available at planning time. (Currently this can only happen for child
+ nodes of an Append or MergeAppend node that is scanning a partitioned
+ table.) When this happens, those plan nodes are omitted from
+ the <command>EXPLAIN</command> output and a <literal>Subplans
+ Removed: <replaceable>N</replaceable></literal> annotation appears
+ instead.
</para>
</sect2>
