docs - clarify setting shared_preload_libraries (#9822)

7116f4f3 · Lisa Owen · GitHub · 3f1a7e23 · 7116f4f3 · 7116f4f3
3 changed file
--- a/gpdb-doc/dita/analytics/pl_container.xml
+++ b/gpdb-doc/dita/analytics/pl_container.xml
@@ -169,9 +169,15 @@
            <codeph>$GPHOME/greenplum_path.sh</codeph>:<codeblock>source $GPHOME/greenplum_path.sh</codeblock></li>
          <li>Make sure Greenplum Database is up and running:<codeblock>gpstate -s</codeblock>If
            it's not, start it:<codeblock>gpstart -a</codeblock></li>
-          <li>For PL/Container version 3 Beta only, enable the <codeph>plc_coordinator</codeph>
-            shared library using the
-            command:<codeblock>gpconfig -c shared_preload_libraries -v 'plc_coordinator'</codeblock></li>
+          <li>For PL/Container version 3 Beta only, add the <codeph>plc_coordinator</codeph>
+            shared library to the Greenplum Database <codeph>shared_preload_libraries</codeph>
+            server configuration parameter. Be sure to retain any previous setting of the
+            parameter. For example:<codeblock>gpconfig -s shared_preload_libraries
+Values on all segments are consistent
+GUC          : shared_preload_libraries
+Master  value: diskquota
+Segment value: diskquota
+gpconfig -c shared_preload_libraries -v 'diskquota,plc_coordinator'</codeblock></li>
          <li>Restart Greenplum Database:<codeblock>gpstop -ra</codeblock></li>
          <li>Login into one of the available databases, for example:
            <codeblock>psql postgres</codeblock></li>
@@ -426,11 +432,22 @@ postgres=# select dummyR();
      <body>
        <p>This step is required only if you have installed PL/Container 3 Beta. Before you remove
          the extension from your system with <codeph>gppkg</codeph>, remove the shared library
-          configuration for the <codeph>plc_coordinator</codeph> process. For example, the following
-          command comments-out the <codeph>shared_preload_libraries</codeph> setting in
-            <filepath>postgresql.conf
-          </filepath>:<codeblock>$ gpconfig -r shared_preload_libraries
-$ gpstop -ra</codeblock></p>
+          configuration for the <codeph>plc_coordinator</codeph> process:</p>
+        <ol>
+          <li>Examine the <codeph>shared_preload_libraries</codeph> server configuration
+            parameter setting.<codeblock>$ gpconfig -s shared_preload_libraries</codeblock><ul>
+              <li>If <codeph>plc_coordinator</codeph> is the only library listed, remove
+                the configuration parameter setting: <codeblock>$ gpconfig -r shared_preload_libraries</codeblock>
+                <p>Removing a server configuration parameter comments out the setting in the
+                <filepath>postgresql.conf</filepath> file.</p></li>
+              <li>If there are multiple libraries listed, remove
+                <codeph>plc_coordinator</codeph> from the list and re-set the configuration
+                parameter. For example, if <codeph>shared_preload_libraries</codeph> is set
+                to <codeph>'diskquota,plc_coordinator'</codeph>:
+                <codeblock>$ gpconfig -c shared_preload_libraries -v 'diskquota'</codeblock></li>
+            </ul></li>
+          <li>Restart the Greenplum Database cluster:<codeblock>$ gpstop -ra</codeblock></li>
+        </ol>
      </body>
    </topic>
    <topic xml:lang="en" id="topic_dty_fcj_kw" otherprops="pivotal">

--- a/gpdb-doc/dita/ref_guide/config_params/guc-list.xml
+++ b/gpdb-doc/dita/ref_guide/config_params/guc-list.xml
@@ -8159,6 +8159,8 @@
        is pgsql, perl, tcl, or python. By preloading a shared library, the library startup time is
        avoided when the library is first used. If a specified library is not found, the server will
        fail to start.</p>
+      <note>When you add a library to <codeph>shared_preload_libraries</codeph>, be sure to
+        retain any previous setting of the parameter.</note>
      <table id="shared_preload_libraries_table">
        <tgroup cols="3">
          <colspec colnum="1" colname="col1" colwidth="1*"/>

--- a/gpdb-doc/dita/ref_guide/modules/diskquota.xml
+++ b/gpdb-doc/dita/ref_guide/modules/diskquota.xml
@@ -18,7 +18,13 @@
        <li> Add the <codeph>diskquota</codeph> shared library to the Greenplum Database
            <codeph>shared_preload_libraries</codeph> server configuration parameter and restart
          Greenplum
-          Database.<codeblock>$ gpconfig -c shared_preload_libraries -v 'diskquota'
+          Database. Be sure to retain the previous setting of the configuration parameter.
+          For example:<codeblock>$ gpconfig -s shared_preload_libraries
+Values on all segments are consistent
+GUC          : shared_preload_libraries
+Master  value: auto_explain
+Segment value: auto_explain
+$ gpconfig -c shared_preload_libraries -v 'auto_explain,diskquota'
 $ gpstop -ar</codeblock></li>
        <li> Register the <codeph>diskquota</codeph> extension in databases where you want to
          enforce disk usage quotas. <codeph>diskquota</codeph> can be registered in up to ten