IMPALA-9467: [DOCS] live_progress enabled by default in interactive mode

The following documents were impacted by the change:
- impala_live_progress.xml, revised to explain new behavior
- impala_shell_options.xml, added --disable_live_progress option

Change-Id: I94e624b7bb916ecb5aeb4f007c0610807f7b18cf
Reviewed-on: http://gerrit.cloudera.org:8080/15442
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Reviewed-by: Alice Fan <fan309@gmail.com>
Reviewed-by: Joe McDonnell <joemcdonnell@cloudera.com>

docs/shared/impala_common.xml

@@ -1514,22 +1514,23 @@ alter table partitioned_data set tblproperties ('numRows'='1030000', 'STATS_GENE
       </p>
 
       <p id="live_reporting_details">
-        The output from this query option is printed to standard error. The output is only
-        displayed in interactive mode, that is, not when the <codeph>-q</codeph> or
-        <codeph>-f</codeph> options are used.
+        The output from this query option is printed to standard
+        error. The output is  displayed only in interactive mode, not when the <codeph>-q</codeph>
+        or <codeph>-f</codeph> options are used. 
       </p>
 
       <p id="live_progress_live_summary_asciinema">
         To see how the <codeph>LIVE_PROGRESS</codeph> and <codeph>LIVE_SUMMARY</codeph> query
         options work in real time, see
         <xref href="https://asciinema.org/a/1rv7qippo0fe7h5k1b6k4nexk" scope="external" format="html">this
-        animated demo</xref>.
+          animated demo</xref>.
       </p>
-
+      
       <p rev="2.5.0" id="runtime_filter_mode_blurb">
-        Because the runtime filtering feature is enabled by default only for local processing,
-        the other filtering-related query options have the greatest effect when used in
-        combination with the setting <codeph>RUNTIME_FILTER_MODE=GLOBAL</codeph>.
+        Because the runtime filtering feature is
+        enabled by default only for local processing, the other filtering-related query options have
+        the greatest effect when used in combination with the setting
+          <codeph>RUNTIME_FILTER_MODE=GLOBAL</codeph>. 
       </p>
 
       <note id="square_bracket_hint_caveat" rev="IMPALA-2522">

docs/topics/impala_live_progress.xml

@@ -37,33 +37,29 @@ under the License.
 
   <conbody>
 
-    <p rev="2.3.0"> When the <codeph>LIVE_PROGRESS</codeph> query option is set
-      to <codeph>TRUE</codeph>, Impala displays an interactive progress bar
-      showing roughly what percentage of processing has been completed for
-      queries submitted through the <cmdname>impala-shell</cmdname> command.
-      When the query finishes, the progress bar is erased from the
-        <cmdname>impala-shell</cmdname> console output. </p>
+    <p> In Impala 3.4.0 and higher when you start the Impala shell in interactive mode, the
+        <codeph>LIVE_PROGRESS</codeph> query option is set to <codeph>TRUE</codeph> by default. When
+      you run a query, the live progress bar appears in the output of a query. The bar shows roughly
+      the percentage of completed processing. When the query finishes, the live progress bar
+      disappears from the console output. </p>
     <p>Starting in <keyword keyref="impala31"/>, the summary output also
       includes the queuing status consisting of whether the query was queued and
       what was the latest queuing reason.</p>
     <p><b>Type:</b>
       <codeph>Boolean</codeph></p>
     <p><b>Default:</b>
-      <codeph>FALSE (0)</codeph></p>
+      <codeph>TRUE (0)</codeph></p>
 
     <p conref="../shared/impala_common.xml#common/command_line_blurb"/>
-    <p>
-      You can enable this query option within <cmdname>impala-shell</cmdname>
-      by starting the shell with the <codeph>--live_progress</codeph>
-      command-line option.
-      You can still turn this setting off and on again within the shell through the
-      <codeph>SET</codeph> command.
-    </p>
+    <p> You can turn off <codeph>LIVE_PROGRESS</codeph> within the shell 
+      using the <codeph>SET</codeph> command. You can also turn off
+      LIVE_PROGRESS by starting the shell with the <codeph>--disable_live_progress</codeph>
+      command-line option.</p>
 
     <p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
     <p conref="../shared/impala_common.xml#common/live_reporting_details"/>
     <p>
-      For a more detailed way of tracking the progress of an interactive query through
+      For tracking the progress of an interactive query through
       all phases of processing, see <xref href="impala_live_summary.xml#live_summary"/>.
     </p>
 
@@ -74,18 +70,17 @@ under the License.
       data, the progress bar might reach 100% before the query is entirely finished.
       For example, the query might do work to perform aggregations after all the
       table data has been read. If many of your queries fall into this category,
-      consider using the <codeph>LIVE_SUMMARY</codeph> option instead for
-      more granular progress reporting.
+      consider using the <codeph>LIVE_SUMMARY</codeph> option for more granular progress
+      reporting.
     </p>
-    <p conref="../shared/impala_common.xml#common/impala_shell_progress_reports_compute_stats_caveat"/>
+    <p
+      conref="../shared/impala_common.xml#common/impala_shell_progress_reports_compute_stats_caveat"/>
     <p conref="../shared/impala_common.xml#common/impala_shell_progress_reports_shell_only_caveat"/>
 
     <p conref="../shared/impala_common.xml#common/added_in_230"/>
 
     <p conref="../shared/impala_common.xml#common/example_blurb"/>
-<codeblock><![CDATA[[localhost:21000] > set live_progress=true;
-LIVE_PROGRESS set to true
-[localhost:21000] > select count(*) from customer;
+<codeblock><![CDATA[[localhost:21000] > select count(*) from customer;
 +----------+
 | count(*) |
 +----------+

docs/topics/impala_shell_options.xml

@@ -530,10 +530,15 @@ under the License.
             </row>
             <row rev="2.3.0">
               <entry>--live_progress</entry>
-              <entry>N/A</entry>
+              <entry>live_progress=true</entry>
               <entry>Prints a progress bar showing roughly the percentage complete for each query.
-              The information is updated interactively as the query progresses.
-              See <xref href="impala_live_progress.xml#live_progress"/>.</entry>
+                The information is updated interactively as the query progresses.
+                See <xref href="impala_live_progress.xml#live_progress"/>.</entry>
+            </row>
+            <row>
+              <entry>--disable_live_progress</entry>
+              <entry>live_progress=false</entry>
+              <entry>A command line flag allows users to disable live_progress in the interactive mode.</entry>
             </row>
             <row rev="2.3.0">
               <entry>--live_summary</entry>