diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index e7f2d6c0ca..445a0db7c5 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -29,6 +29,8 @@
 #include "utils/fmgroids.h"
 #include "utils/fmgrprotos.h"
 #include "utils/lsyscache.h"
+#include "utils/memutils.h"
+#include "utils/selfuncs.h"
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
@@ -321,11 +323,6 @@ dependency_degree(int numrows, HeapTuple *rows, int k, AttrNumber *dependency,
 		group_size++;
 	}
 
-	pfree(items);
-	pfree(values);
-	pfree(isnull);
-	pfree(mss);
-
 	/* Compute the 'degree of validity' as (supporting/total). */
 	return (n_supporting_rows * 1.0 / numrows);
 }
@@ -358,6 +355,7 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
 
 	/* result */
 	MVDependencies *dependencies = NULL;
+	MemoryContext	cxt;
 
 	numattrs = bms_num_members(attrs);
 
@@ -372,6 +370,11 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
 
 	Assert(numattrs >= 2);
 
+	/* tracks memory allocated by dependency_degree calls */
+	cxt = AllocSetContextCreate(CurrentMemoryContext,
+								"dependency_degree cxt",
+								ALLOCSET_DEFAULT_SIZES);
+
 	/*
 	 * We'll try build functional dependencies starting from the smallest ones
 	 * covering just 2 columns, to the largest ones, covering all columns
@@ -390,10 +393,17 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
 		{
 			double		degree;
 			MVDependency *d;
+			MemoryContext oldcxt;
+
+			/* release memory used by dependency degree calculation */
+			oldcxt = MemoryContextSwitchTo(cxt);
 
 			/* compute how valid the dependency seems */
 			degree = dependency_degree(numrows, rows, k, dependency, stats, attrs);
 
+			MemoryContextSwitchTo(oldcxt);
+			MemoryContextReset(cxt);
+
 			/*
 			 * if the dependency seems entirely invalid, don't store it
 			 */
@@ -435,6 +445,8 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
 		DependencyGenerator_free(DependencyGenerator);
 	}
 
+	MemoryContextDelete(cxt);
+
 	return dependencies;
 }