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authorTom Lane <tgl@sss.pgh.pa.us>2021-11-29 12:13:13 -0500
committerTom Lane <tgl@sss.pgh.pa.us>2021-11-29 12:13:13 -0500
commitce43b3dc52c90082981f2f1de5351a95fc21c405 (patch)
treef9582fe9bc6c85fef9db1d3ce3e360964ae4d729
parent1b1e4bfe7da770ad159c0f4291925a3597a65dbc (diff)
Doc: improve documentation about ORDER BY in matviews.
Remove the confusing use of ORDER BY in an example materialized view. It adds nothing to the example, but might encourage people to follow bad practice. Clarify REFRESH MATERIALIZED VIEW's note about whether view ordering is retained (it isn't). Maciek Sakrejda Discussion: https://postgr.es/m/CAOtHd0D-OvrUU0C=4hX28p4BaSE1XL78BAQ0VcDaLLt8tdUzsg@mail.gmail.com
-rw-r--r--doc/src/sgml/ref/refresh_materialized_view.sgml10
-rw-r--r--doc/src/sgml/rules.sgml3
2 files changed, 4 insertions, 9 deletions
diff --git a/doc/src/sgml/ref/refresh_materialized_view.sgml b/doc/src/sgml/ref/refresh_materialized_view.sgml
index 3bf88844478..675d6090f3c 100644
--- a/doc/src/sgml/ref/refresh_materialized_view.sgml
+++ b/doc/src/sgml/ref/refresh_materialized_view.sgml
@@ -93,12 +93,10 @@ REFRESH MATERIALIZED VIEW [ CONCURRENTLY ] <replaceable class="parameter">name</
<title>Notes</title>
<para>
- While the default index for future
- <link linkend="sql-cluster"><command>CLUSTER</command></link>
- operations is retained, <command>REFRESH MATERIALIZED VIEW</command> does not
- order the generated rows based on this property. If you want the data
- to be ordered upon generation, you must use an <literal>ORDER BY</literal>
- clause in the backing query.
+ If there is an <literal>ORDER BY</literal> clause in the materialized
+ view's defining query, the original contents of the materialized view
+ will be ordered that way; but <command>REFRESH MATERIALIZED
+ VIEW</command> does not guarantee to preserve that ordering.
</para>
</refsect1>
diff --git a/doc/src/sgml/rules.sgml b/doc/src/sgml/rules.sgml
index 6065b1c2a31..4aa4e00e017 100644
--- a/doc/src/sgml/rules.sgml
+++ b/doc/src/sgml/rules.sgml
@@ -962,9 +962,6 @@ CREATE MATERIALIZED VIEW sales_summary AS
WHERE invoice_date &lt; CURRENT_DATE
GROUP BY
seller_no,
- invoice_date
- ORDER BY
- seller_no,
invoice_date;
CREATE UNIQUE INDEX sales_summary_seller