Cherry pick Rows out in EXPLAIN ANALYZE

src/backend/cdb/cdbvars.c

@@ -277,6 +277,7 @@ int			gp_hashagg_groups_per_bucket = 5;
 int			gp_motion_slice_noop = 0;
 
 /* Cloudberry Database Experimental Feature GUCs */
+bool		gp_enable_explain_rows_out = false;
 bool		gp_enable_explain_allstat = false;
 bool		gp_enable_motion_deadlock_sanity = false;	/* planning time sanity
 														 * check */

src/backend/commands/explain_gp.c

@@ -1703,6 +1703,66 @@ cdbexplain_showExecStats(struct PlanState *planstate, ExplainState *es)
 	}
 	pfree(extraData.data);
 
+	/*
+	 * Print "Rows out"
+	 */
+
+	if (gp_enable_explain_rows_out && es->analyze && ns->ninst > 0) {
+		double alltuples = 0;
+		double maxtuples = ns->insts[0].ntuples;
+		int maxseg = 0;
+		double mintuples = ns->insts[0].ntuples;
+		int minseg = 0;
+
+		for (i = 0; i < ns->ninst; i++)
+		{
+			CdbExplain_StatInst *nsi = &ns->insts[i];
+
+			alltuples += nsi->ntuples;
+
+			if (nsi->ntuples > maxtuples) {
+				maxtuples = nsi->ntuples;
+				maxseg = ns->segindex0 + i;
+			}
+
+			if (nsi->ntuples < mintuples) {
+				mintuples = nsi->ntuples;
+				minseg = ns->segindex0 + i;
+			}
+		}
+
+		double avgtuples = alltuples / ns->ninst;
+
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			/*
+			 * create a header for all stats: separate each individual stat by an
+			 * underscore, separate the grouped stats for each node by a slash
+			 */
+			appendStringInfoSpaces(es->str, es->indent * 2);
+			appendStringInfoString(es->str, "Rows out: ");
+
+			appendStringInfo(es->str,
+								 "%0.2f rows avg x %d workers, %0.f rows max (seg%d), %0.f rows min (seg%d).\n",
+								 avgtuples,
+								 ns->ninst,
+								 maxtuples,
+								 maxseg,
+								 mintuples,
+								 minseg);
+		}
+		else {
+			// ExplainOpenGroup("Rows Out", NULL, false, es);
+			ExplainPropertyInteger("Workers", ns->ninst, es);
+			ExplainPropertyFloat("Average Rows", avgtuples, 1, es);
+			ExplainPropertyFloat("Max Rows", maxtuples, 0, es);
+			ExplainPropertyInteger("Max Rows Segment", maxseg, es);
+			ExplainPropertyFloat("Min Rows", mintuples, 0, es);
+			ExplainPropertyInteger("Min Rows Segment", minseg, es);
+			// ExplainCloseGroup("Rows out", NULL, false, es);
+		}
+	}
+
 	/*
 	 * Dump stats for all workers.
 	 */

src/backend/utils/misc/guc_gp.c

@@ -772,6 +772,17 @@ struct config_bool ConfigureNamesBool_gp[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"gp_enable_explain_rows_out", PGC_USERSET, CLIENT_CONN_OTHER,
+			gettext_noop("Experimental feature: print avg, min and max rows out in segments in EXPLAIN ANALYZE."),
+			NULL,
+			GUC_NO_SHOW_ALL | GUC_NOT_IN_SAMPLE
+		},
+		&gp_enable_explain_rows_out,
+		false,
+		NULL, NULL, NULL
+	},
+
 	{
 		{"gp_enable_explain_allstat", PGC_USERSET, CLIENT_CONN_OTHER,
 			gettext_noop("Experimental feature: dump stats for all segments in EXPLAIN ANALYZE."),

src/include/cdb/cdbvars.h

@@ -626,6 +626,13 @@ extern bool gp_enable_agg_pushdown;
  */
 extern bool gp_enable_preunique;
 
+/* May Cloudberry print statistics as average, minimum and maximum rows out
+ * during EXPLAIN ANALYZE?
+ *
+ */
+
+extern bool gp_enable_explain_rows_out;
+
 /* May Cloudberry dump statistics for all segments as a huge ugly string
  * during EXPLAIN ANALYZE?
  *

src/include/utils/unsync_guc_name.h

@@ -178,6 +178,7 @@
 		"gp_enable_agg_pushdown",
 		"gp_enable_ao_indexscan",
 		"gp_enable_direct_dispatch",
+		"gp_enable_explain_rows_out",
 		"gp_enable_explain_allstat",
 		"gp_enable_fast_sri",
 		"gp_enable_global_deadlock_detector",

src/test/regress/expected/gp_explain.out

@@ -436,6 +436,22 @@ explain analyze SELECT * FROM explaintest;
 (8 rows)
 
 set gp_enable_explain_allstat=DEFAULT;
+-- Test explain rows out.
+set gp_enable_explain_rows_out=on;
+explain analyze SELECT * FROM explaintest;
+                                                          QUERY PLAN                                                           
+-------------------------------------------------------------------------------------------------------------------------------
+ Gather Motion 3:1  (slice1; segments: 3)  (cost=0.00..3.10 rows=10 width=4) (actual time=0.266..0.384 rows=5 loops=2)
+   ->  Seq Scan on explaintest  (cost=0.00..3.10 rows=4 width=4) (actual time=0.011..0.013 rows=2 loops=2)
+         Rows out: 3.33 rows avg x 3 workers, 5 rows max (seg1), 2 rows min (seg2).
+   (slice0)    Executor memory: 322K bytes.
+   (slice1)    Executor memory: 50K bytes avg x 3 workers, 50K bytes max (seg0).
+ Memory used:  128000kB
+ Optimizer: Postgres query optimizer
+ Total runtime: 2.600 ms
+(8 rows)
+
+set gp_enable_explain_rows_out=DEFAULT;
 --
 -- Test GPDB-specific EXPLAIN (SLICETABLE) option.
 --

src/test/regress/expected/gp_explain_optimizer.out

@@ -458,6 +458,22 @@ explain analyze SELECT * FROM explaintest;
 (8 rows)
 
 set gp_enable_explain_allstat=DEFAULT;
+-- Test explain rows out.
+set gp_enable_explain_rows_out=on;
+explain analyze SELECT * FROM explaintest;
+                                                          QUERY PLAN                                                           
+-------------------------------------------------------------------------------------------------------------------------------
+ Gather Motion 3:1  (slice1; segments: 3)  (cost=0.00..431.00 rows=10 width=4) (actual time=0.298..0.302 rows=5 loops=2)
+   ->  Seq Scan on explaintest  (cost=0.00..431.00 rows=4 width=4) (actual time=0.013..0.015 rows=2 loops=2)
+         Rows out: 3.33 rows avg x 3 workers, 5 rows max (seg1), 2 rows min (seg2).
+   (slice0)    Executor memory: 290K bytes.
+   (slice1)    Executor memory: 50K bytes avg x 3 workers, 50K bytes max (seg0).
+ Memory used:  128000kB
+ Optimizer: Pivotal Optimizer (GPORCA) version 3.2.0
+ Total runtime: 1.577 ms
+(8 rows)
+
+set gp_enable_explain_rows_out=DEFAULT;
 --
 -- Test GPDB-specific EXPLAIN (SLICETABLE) option.
 --

src/test/regress/sql/gp_explain.sql

@@ -228,6 +228,11 @@ set gp_enable_explain_allstat=on;
 explain analyze SELECT * FROM explaintest;
 set gp_enable_explain_allstat=DEFAULT;
 
+-- Test explain rows out.
+set gp_enable_explain_rows_out=on;
+explain analyze SELECT * FROM explaintest;
+set gp_enable_explain_rows_out=DEFAULT;
+
 
 --
 -- Test GPDB-specific EXPLAIN (SLICETABLE) option.