New commands are <command><link linkend="SQL-CREATESTATISTICS">CREATE</></>,

<command><link linkend="SQL-ALTERSTATISTICS">ALTER</></>, and

<command><link linkend="SQL-DROPSTATISTICS">DROP STATISTICS</></>. This is helpful in

estimating query memory usage and ... HOW IS RATIO USED?

estimating query memory usage and when combining the statistics from

individual columns.

</para>

</listitem>

</para>

</listitem>

<listitem>

<!--

Author: Robert Haas <rhaas@postgresql.org>

2017-03-16 [b30fb56b0] postgres_fdw: Push down <literal>FULL JOIN</>s with restriction clau

-->

<para>

Improve optimization of <literal>FULL JOIN</> queries containing subqueries in the

<literal>FROM</> clause (Etsuro Fujita)

</para>

</listitem>

<listitem>

<!--

Author: Tom Lane <tgl@sss.pgh.pa.us>

-->

<para>

Allow explicit control over <command><link linkend="SQL-EXPLAIN">EXPLAIN</></>'s display of planning and execution

time (Stephen Frost)

time (Ashutosh Bapat)

</para>

<para>

</para>

</listitem>

<listitem>

<!--

Author: Robert Haas <rhaas@postgresql.org>

2017-03-16 [b30fb56b0] postgres_fdw: Push down <literal>FULL JOIN</>s with restriction clau

-->

<para>

Allow push down of <literal>FULL JOIN</> queries containing subqueries in the

<literal>FROM</> clause to foreign servers (Etsuro Fujita)

</para>

</listitem>

<listitem>

<!--

Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>