<listitem>
<para>
<command>CREATE INDEX</command> can now use parallel processing
- while building B-tree indexes
+ while building a B-tree index
</para>
</listitem>
<listitem>
<listitem>
<para>
- Many other useful performance improvements, including a significant
- speedup to <command>ALTER TABLE ... ADD COLUMN</command> with a
- non-null column default, as it no longer rewrites the table data
+ Many other useful performance improvements, including the ability to
+ avoid a table rewrite for <command>ALTER TABLE ... ADD COLUMN</command>
+ with a non-null column default
</para>
</listitem>
<listitem>
<!--
+2018-01-19 [8b08f7d48] Local partitioned indexes
2018-02-19 [eb7ed3f30] Allow UNIQUE indexes on partitioned tables
2018-03-26 [555ee77a9] Handle INSERT .. ON CONFLICT with partitioned tables
-->
<para>
- Allow <literal>UNIQUE</literal> indexes on partitioned tables if
- the partition key is part of the index (Álvaro Herrera,
+ Support indexes on partitioned tables (Álvaro Herrera,
Amit Langote)
</para>
- </listitem>
- <listitem>
-<!--
-2018-01-19 [8b08f7d48] Local partitioned indexes
--->
+ <para>
+ An <quote>index</quote> on a partitioned table is not a physical
+ index across the whole partitioned table, but rather a template for
+ automatically creating similar indexes on each partition of the
+ table.
+ </para>
<para>
- Allow indexes on a partitioned table to be automatically created
- in new child partitions (Álvaro Herrera)
+ If the partition key is part of the index's column set, a
+ partitioned index may be declared <literal>UNIQUE</literal>.
+ It will represent a valid uniqueness constraint across the whole
+ partitioned table, even though each physical index only enforces
+ uniqueness within its own partition.
</para>
<para>
The new command <link linkend="sql-alterindex"><command>ALTER
- INDEX ATTACH PARTITION</command></link> allows indexes to be
- attached to partitions. This does not behave as a global index
- since the contents are private to each index.
+ INDEX ATTACH PARTITION</command></link> causes an existing index on
+ a partition to be associated with a matching index template for its
+ partitioned table. This provides flexibility in setting up a new
+ partitioned index for an existing partitioned table.
</para>
</listitem>
-->
<para>
- Perform aggregation on each partition, and then merge the results
+ Allow aggregate functions on partitioned tables to be evaluated
+ separately for each partition, subsequently merging the results
(Jeevan Chalke, Ashutosh Bapat, Robert Haas)
</para>
<para>
Allow server options related to memory and file sizes to be
- specified as a number of bytes (Beena Emerson)
+ specified in units of bytes (Beena Emerson)
</para>
<para>
- The new unit is <quote>B</quote>. This is in addition to the
+ The new unit suffix is <quote>B</quote>. This is in addition to the
existing units <quote>kB</quote>, <quote>MB</quote>, <quote>GB</quote>
and <quote>TB</quote>.
</para>
<para>
Add <application>psql</application> command <literal>\gdesc</literal>
- to display the column names and types of the query output (Pavel
- Stehule)
+ to display the names and types of the columns in a query result
+ (Pavel Stehule)
</para>
</listitem>