docs: add guc gp_max_slices (#4854)

c37385ab · Mel Kiyama · David Yozie · 277f31c8 · c37385ab · c37385ab
3 changed file
--- a/gpdb-doc/dita/ref_guide/config_params/guc-list.xml
+++ b/gpdb-doc/dita/ref_guide/config_params/guc-list.xml
@@ -367,6 +367,7 @@
            <li>
              <xref href="#gp_max_plan_size"/>
            </li>
+            <li><xref href="#gp_max_slices"/></li>
            <li>
              <xref href="#gp_motion_cost_per_row"/>
            </li>
@@ -2841,8 +2842,7 @@
                  2097152 </p><p><cmdname>CHECKSUM</cmdname>= <codeph>TRUE</codeph> |
                    <codeph>FALSE</codeph>
                </p><p><cmdname>COMPRESSTYPE</cmdname>= <codeph>ZLIB</codeph> |
-                    <codeph>ZSTD</codeph> |
+                    <codeph>ZSTD</codeph> | <codeph>QUICKLZ</codeph><sup>2</sup> |
-                    <codeph>QUICKLZ</codeph><sup>2</sup> |
                    <codeph>RLE</codeph>_<codeph>TYPE</codeph> | <codeph>NONE</codeph>
                </p><p><cmdname>COMPRESSLEVEL</cmdname>= integer between 0 and
                    19</p><p><cmdname>ORIENTATION</cmdname>= <codeph>ROW</codeph> |
@@ -3445,12 +3445,12 @@
  <topic id="gp_enable_query_metrics">
    <title>gp_enable_query_metrics</title>
    <body>
-      <p>Enables collection of query metrics. When query metrics collection is enabled, 
+      <p>Enables collection of query metrics. When query metrics collection is enabled, Greenplum
-        Greenplum Database collects metrics during query execution. The default is off.</p> 
+        Database collects metrics during query execution. The default is off.</p>
      <p>After changing this configuration parameter, Greenplum Database must be restarted for the
        change to take effect.</p>
-      <p>The Greenplum Database metrics collection extension, when enabled, sends the
+      <p>The Greenplum Database metrics collection extension, when enabled, sends the collected
-      collected metrics over UDP to a Pivotal Greenplum Command Center agent<sup>1</sup>. </p>
+        metrics over UDP to a Pivotal Greenplum Command Center agent<sup>1</sup>. </p>
      <note><sup>1</sup> The metrics collection extension is included in Pivotal's commercial
        version of Greenplum Database. Pivotal Greenplum Command Center is supported only with
        Pivotal Greenplum Database.</note>
@@ -4195,19 +4195,16 @@
  <topic id="gp_instrument_shmem_size">
    <title>gp_instrument_shmem_size</title>
    <body>
-      <p>The amount of shared memory, in kilobytes, allocated for query metrics.
+      <p>The amount of shared memory, in kilobytes, allocated for query metrics. The default is 5120
-      The default is 5120 and the maximum is 131072. At startup, if
+        and the maximum is 131072. At startup, if <codeph><xref href="#gp_enable_query_metrics"
-      <codeph><xref href="#gp_enable_query_metrics"
+            format="dita">gp_enable_query_metrics</xref></codeph> is set to on, Greenplum Database
-      format="dita">gp_enable_query_metrics</xref></codeph> is set to on,
+        allocates space in shared memory to save query metrics. This memory is organized as a header
-      Greenplum Database allocates space in shared memory to save query metrics.
+        and a list of slots. The number of slots needed depends on the number of concurrent queries
-      This memory is organized as a header and a list of slots. The number of
+        and the number of execution plan nodes per query. The default value, 5120, is based on a
-      slots needed depends on the number of concurrent queries and the number of
+        Greenplum Database system that executes a maximum of about 250 concurrent queries with 120
-      execution plan nodes per query. The default value, 5120, is based on a
+        nodes per query. If the <codeph>gp_enable_query_metrics</codeph> configuration parameter is
-      Greenplum Database system that executes a maximum of about 250 concurrent
+        off, or if the slots are exhausted, the metrics are maintained in local memory instead of in
-      queries with 120 nodes per query. If the
+        shared memory. </p>
-      <codeph>gp_enable_query_metrics</codeph> configuration parameter is off,
-      or if the slots are exhausted, the metrics are maintained in local memory
-      instead of in shared memory. </p>
      <table id="gp_instrument_shmem_size">
        <tgroup cols="3">
          <colspec colnum="1" colname="col1" colwidth="1*"/>
@@ -4224,7 +4221,8 @@
            <row>
              <entry colname="col1">integer <codeph>0 - 131072</codeph></entry>
              <entry colname="col2">5120</entry>
-              <entry colname="col3">master<p>system</p><p>restart</p></entry></row>
+              <entry colname="col3">master<p>system</p><p>restart</p></entry>
+            </row>
          </tbody>
        </tgroup>
      </table>
@@ -4606,6 +4604,42 @@
      </table>
    </body>
  </topic>
+  <topic id="gp_max_slices">
+    <title>gp_max_slices</title>
+    <body>
+      <p dir="ltr">Specifies the maximum number of slices (portions of a query plan that are
+        executed on segment instances) that can be generated by a query. If the query generates more
+        than the specified number of slices, Greenplum Database returns an error and does not
+        execute the query. The default value is <codeph>0</codeph>, no maximum value. </p>
+      <p>Executing a query that generates a large number of slices might affect Greenplum Database
+        performance. For example, a query that contains <codeph>UNION</codeph> or <codeph>UNION
+          ALL</codeph> operators over several complex views can generate a large number of slices.
+        You can run <codeph>EXPLAIN ANALYZE</codeph> on the query to view slice statistics for the
+        query.</p>
+      <table id="table_uwf_lzw_ldb">
+        <tgroup cols="3">
+          <colspec colnum="1" colname="col1" colwidth="1*"/>
+          <colspec colnum="2" colname="col2" colwidth="1*"/>
+          <colspec colnum="3" colname="col3" colwidth="1*"/>
+          <thead>
+            <row>
+              <entry colname="col1">Value Range</entry>
+              <entry colname="col2">Default</entry>
+              <entry colname="col3">Set Classifications</entry>
+            </row>
+          </thead>
+          <tbody>
+            <row>
+              <entry colname="col1">0 - INT_MAX</entry>
+              <entry colname="col2">0</entry>
+              <entry colname="col3">master<p>session</p><p>reload</p></entry>
+            </row>
+          </tbody>
+        </tgroup>
+      </table>
+    </body>
+  </topic>
  <topic id="gp_motion_cost_per_row">
    <title>gp_motion_cost_per_row</title>
    <body>

--- a/gpdb-doc/dita/ref_guide/config_params/guc_category-list.xml
+++ b/gpdb-doc/dita/ref_guide/config_params/guc_category-list.xml
@@ -679,6 +679,19 @@
        </simpletable>
      </body>
    </topic>
+    <topic id="topic_zd5_p32_mdb">
+      <title>Query Plan Execution</title>
+      <body>
+        <p>Control the query plan execution.</p>
+        <simpletable frame="none" id="simpletable_kbx_t32_mdb">
+          <strow>
+            <stentry>
+              <p><xref href="guc-list.xml#gp_max_slices">gp_max_slices</xref></p>
+            </stentry>
+          </strow>
+        </simpletable>
+      </body>
+    </topic>
  </topic>
  <topic id="topic29" xml:lang="en">
    <title id="kh155046">Error Reporting and Logging Parameters</title>
@@ -930,10 +943,10 @@
    <topic id="query-metrics">
      <title>Query Metrics Collection Parameters</title>
      <body>
-        <p>These parameters enable and configure query metrics collection. When enabled, 
+        <p>These parameters enable and configure query metrics collection. When enabled, Greenplum
-          Greenplum Database saves metrics to shared memory during query execution. These
+          Database saves metrics to shared memory during query execution. These metrics are used by
-          metrics are used by Pivotal Greenplum Command Center, which is included with 
+          Pivotal Greenplum Command Center, which is included with Pivotal's commercial version of
-          Pivotal's commercial version of Greenplum Database.</p> 
+          Greenplum Database.</p>
        <simpletable id="query-metrics" frame="none">
          <strow>
            <stentry>

--- a/gpdb-doc/dita/ref_guide/config_params/guc_config.ditamap
+++ b/gpdb-doc/dita/ref_guide/config_params/guc_config.ditamap
@@ -144,6 +144,7 @@
            <topicref href="guc-list.xml#gp_max_local_distributed_cache"/>
            <topicref href="guc-list.xml#gp_max_packet_size"/>
            <topicref href="guc-list.xml#gp_max_plan_size"/>
+            <topicref href="guc-list.xml#gp_max_slices"/>
            <topicref href="guc-list.xml#gp_motion_cost_per_row"/>
            <topicref href="guc-list.xml#gp_num_contents_in_cluster"/>
            <topicref href="guc-list.xml#gp_recursive_cte_prototype"/>