Eliminate "parallel degree" terminology.

This terminology provoked widespread complaints.  So, instead, rename
the GUC max_parallel_degree to max_parallel_workers_per_gather
(leaving room for a possible future GUC max_parallel_workers that acts
as a system-wide limit), and rename the parallel_degree reloption to
parallel_workers.  Rename structure members to match.

These changes create a dump/restore hazard for users of PostgreSQL
9.6beta1 who have set the reloption (or applied the GUC using ALTER
USER or ALTER DATABASE).

3 files changed, 12 insertions, 12 deletions

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 50f6d4ea7fd..4f93e7062dd 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1998,16 +1998,16 @@ include_dir 'conf.d'
        </listitem>
       </varlistentry>
 
-      <varlistentry id="guc-max-parallel-degree" xreflabel="max_parallel_degree">
-       <term><varname>max_parallel_degree</varname> (<type>integer</type>)
+      <varlistentry id="guc-max-parallel-workers-per-gather" xreflabel="max_parallel_workers_per_gather">
+       <term><varname>max_parallel_workers_per_gather</varname> (<type>integer</type>)
        <indexterm>
-        <primary><varname>max_parallel_degree</> configuration parameter</primary>
+        <primary><varname>max_parallel_workers_per_gather</> configuration parameter</primary>
        </indexterm>
        </term>
        <listitem>
         <para>
-         Sets the maximum number of workers that can be started for an
-         individual parallel operation.  Parallel workers are taken from the
+         Sets the maximum number of workers that can be started by a single
+         <literal>Gather</literal> node.  Parallel workers are taken from the
          pool of processes established by
          <xref linkend="guc-max-worker-processes">.  Note that the requested
          number of workers may not actually be available at runtime.  If this
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index d1807ed0dbf..06e6392f737 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -909,14 +909,14 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXI
    </varlistentry>
 
    <varlistentry>
-    <term><literal>parallel_degree</> (<type>integer</>)</term>
+    <term><literal>parallel_workers</> (<type>integer</>)</term>
     <listitem>
      <para>
-      The parallel degree for a table is the number of workers that should
-      be used to assist a parallel scan of that table.  If not set, the
-      system will determine a value based on the relation size.  The actual
-      number of workers chosen by the planner may be less, for example due to
-      the setting of <xref linkend="guc-max-parallel-degree">.
+      This sets the number of workers that should be used to assist a parallel
+      scan of this table.  If not set, the system will determine a value based
+      on the relation size.  The actual number of workers chosen by the planner
+      may be less, for example due to
+      the setting of <xref linkend="guc-max-worker-processes">.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/release-9.6.sgml b/doc/src/sgml/release-9.6.sgml
index 38e19672495..a14545d5d80 100644
--- a/doc/src/sgml/release-9.6.sgml
+++ b/doc/src/sgml/release-9.6.sgml
@@ -153,7 +153,7 @@
        <para>
         Use of parallel query execution can be controlled through the new
         configuration parameters
-        <xref linkend="guc-max-parallel-degree">,
+        <xref linkend="guc-max-parallel-workers-per-gather">,
         <xref linkend="guc-force-parallel-mode">,
         <xref linkend="guc-parallel-setup-cost">, and
         <xref linkend="guc-parallel-tuple-cost">.