gpperfmon: consolidate cpu skew and row skew behave test

Doing any kind of intensive work should show up in gpperfmon for both
cpu skew and row skew, so putting them together as they can be tested at
the same time.
Signed-off-by: NMarbin Tan <mtan@pivotal.io>

gpMgmt/test/behave/mgmt_utils/gpperfmon.feature

@@ -86,6 +86,34 @@ Feature: gpperfmon
         When the user truncates "diskspace_history" tables in "gpperfmon"
         Then wait until the results from boolean sql "SELECT count(*) > 0 FROM diskspace_history" is "true"
 
+    """
+    The gpperfmon_skew_cpu_and_cpu_elapsed does not work on MacOS because of Sigar lib limitations.
+    To run all the other scenarios and omit this test on MacOS, use:
+    $ behave test/behave/mgmt_utils/gpperfmon.feature --tags @gpperfmon --tags ~@gpperfmon_skew_cpu_and_cpu_elapsed
+    """
+    @gpperfmon_skew_cpu_and_cpu_elapsed
+    Scenario: gpperfmon records skew_cpu and cpu_elapsed
+        Given gpperfmon is configured and running in qamode
+        Given the user truncates "queries_history" tables in "gpperfmon"
+        Given database "gptest" is dropped and recreated
+        When below sql is executed in "gptest" db
+        """
+        CREATE TABLE sales (id int, date date, amt decimal(10,2))
+        DISTRIBUTED BY (id);
+        """
+        When below sql is executed in "gptest" db
+        """
+        insert into sales values(generate_series(2,10), '2016-12-01', generate_series(1,20));
+        insert into sales values(1, '2016-12-01', generate_series(1,10000000));
+        """
+        When below sql is executed in "gptest" db
+        """
+        select count(*) from sales;
+        """
+        Then wait until the results from boolean sql "SELECT count(*) > 0 FROM queries_history where cpu_elapsed > 1 and query_text like 'select count(*)%'" is "true"
+        Then wait until the results from boolean sql "SELECT count(*) > 0 FROM queries_history where skew_cpu > 0.05 and db = 'gptest'" is "true"
+        Then wait until the results from boolean sql "SELECT count(*) > 0 FROM queries_history where skew_rows > 0 and db = 'gptest'" is "true"
+
     @gpperfmon_partition
     Scenario: gpperfmon keeps all partitions upon restart if partition_age not set, drops excess partitions otherwise
         Given gpperfmon is configured and running in qamode
@@ -123,52 +151,3 @@ Feature: gpperfmon
         And wait until the process "gpsmon" is up
         # Note that the code considers partition_age + 1 as the number of partitions to keep
         Then wait until the results from boolean sql "SELECT count(*) = 5 FROM pg_partitions WHERE tablename = 'diskspace_history'" is "true"
-
-    @gpperfmon_skew_rows
-    Scenario: gpperfmon detects row skew
-        Given gpperfmon is configured and running in qamode
-        Given database "gptest" is dropped and recreated
-        Given the user runs "psql gptest -c 'create table test_row_skew( id int, val int ) DISTRIBUTED BY ( id );'"
-        Then psql should return a return code of 0
-        When the user truncates "queries_history" tables in "gpperfmon"
-        # 1 million skewed rows too few to detect skew, but 10M seems to let gpperfmon detect row skew. Why?
-        And the user runs "psql gptest -c 'INSERT INTO test_row_skew SELECT 1, i FROM generate_series(1,10000000) AS i;'"
-        Then psql should return a return code of 0
-        Then wait until the results from boolean sql "SELECT count(*) > 0 FROM queries_history where skew_rows > 0" is "true"
-
-    """
-    The gpperfmon_skew_cpu_and_cpu_elapsed does not work on MacOS because of Sigar lib limitations.
-    To run all the other scenarios and omit this test on MacOS, use:
-    $ behave test/behave/mgmt_utils/gpperfmon.feature --tags @gpperfmon --tags ~@gpperfmon_skew_cpu_and_cpu_elapsed
-    """
-    @gpperfmon_skew_cpu_and_cpu_elapsed
-    Scenario: gpperfmon records skew_cpu and cpu_elapsed
-        Given gpperfmon is configured and running in qamode
-        Given the user truncates "queries_history" tables in "gpperfmon"
-        Given database "gptest" is dropped and recreated
-        When below sql is executed in "gptest" db
-        """
-        CREATE TABLE sales (id int, date date, amt decimal(10,2))
-        DISTRIBUTED BY (id)
-        PARTITION BY RANGE (date)
-        ( START (date '2016-11-01') INCLUSIVE
-          END (date '2016-12-02') EXCLUSIVE
-          EVERY (INTERVAL '1 day') );
-        """
-        When below sql is executed in "gptest" db
-        """
-        insert into sales values(generate_series(1,1000000),'2016-12-01',21);
-        insert into sales values(generate_series(1,1000000),'2016-11-30',21);
-        insert into sales values(generate_series(1,1000000),'2016-11-29',21);
-        insert into sales values(generate_series(1,1000000),'2016-11-28',21);
-        insert into sales values(generate_series(1,1000000),'2016-11-25',21);
-        insert into sales values(generate_series(1,1000000),'2016-11-24',21);
-        insert into sales values(generate_series(1,10000000),'2016-11-30',2333);
-        """
-        When below sql is executed in "gptest" db
-        """
-        select count(*) from sales where date between '2016-11-30' and '2016-11-30';
-        """
-        Then wait until the results from boolean sql "SELECT count(*) > 0 FROM queries_history where cpu_elapsed > 1 and query_text like 'select count(*)%'" is "true"
-        Then wait until the results from boolean sql "SELECT count(*) > 0 FROM queries_history where skew_cpu > 0.05 and db = 'gptest'" is "true"
-