diff --git a/common/thorhelper/thorsort.hpp b/common/thorhelper/thorsort.hpp
index f158fd0e2f3..4fa00a0cfb3 100644
--- a/common/thorhelper/thorsort.hpp
+++ b/common/thorhelper/thorsort.hpp
@@ -23,20 +23,9 @@
 #include "thorhelper.hpp"
 #include "jsort.hpp"
 
-//#define DEFAULT_MERGE_SORT
-
 extern THORHELPER_API void msortvecstableinplace(void ** rows, size_t n, const ICompare & compare, void ** temp);
 extern THORHELPER_API void parmsortvecstableinplace(void ** rows, size_t n, const ICompare & compare, void ** temp);
 
-inline void parsortvecstableinplace(void ** rows, size_t n, const ICompare & compare, void ** stableTablePtr, unsigned maxCores=0)
-{
-#ifdef DEFAULT_MERGE_SORT
-    parmsortvecstableinplace(rows, n, compare, stableTablePtr);
-#else
-    parqsortvecstableinplace(rows, n, compare, stableTablePtr, maxCores);
-#endif
-}
-
 extern THORHELPER_API void tbbqsortvec(void **a, size_t n, const ICompare & compare);
 extern THORHELPER_API void tbbqsortstable(void ** rows, size_t n, const ICompare & compare, void ** temp);
 
diff --git a/thorlcr/thorutil/thmem.cpp b/thorlcr/thorutil/thmem.cpp
index 5647704fdc6..1c856f501ae 100644
--- a/thorlcr/thorutil/thmem.cpp
+++ b/thorlcr/thorutil/thmem.cpp
@@ -596,7 +596,10 @@ void CThorExpandingRowArray::doSort(rowidx_t n, void **const rows, ICompare &com
             dbgassertex(NULL != stableTable);
             stableTablePtr = stableTable;
         }
-        parsortvecstableinplace(rows, n, compare, stableTablePtr, maxCores);
+        if (useMergeSort)
+            parmsortvecstableinplace(rows, n, compare, stableTablePtr);
+        else
+            parqsortvecstableinplace(rows, n, compare, stableTablePtr, maxCores);
     }
     else
         parqsortvec((void **)rows, n, compare, maxCores);
@@ -720,6 +723,12 @@ void CThorExpandingRowArray::setup(IThorRowInterfaces *_rowIf, EmptyRowSemantics
         ReleaseThorRow(stableTable);
         stableTable = NULL;
     }
+    if (stableSort_none != stableSort)
+    {
+        StringBuffer algorithm;
+        activity.getOpt(THOROPT_SORT_ALGORITHM, algorithm);
+        useMergeSort = !strieq(algorithm, "quicksort");
+    }
 }
 
 void CThorExpandingRowArray::clearRows()
diff --git a/thorlcr/thorutil/thmem.hpp b/thorlcr/thorutil/thmem.hpp
index eeb371a31e1..ac7a1dd60ee 100644
--- a/thorlcr/thorutil/thmem.hpp
+++ b/thorlcr/thorutil/thmem.hpp
@@ -281,6 +281,7 @@ class graph_decl CThorExpandingRowArray : public CSimpleInterface
     const void **rows = nullptr;
     void **stableTable = nullptr;
     bool throwOnOom = true; // tested during array expansion (resize())
+    bool useMergeSort = true;
     EmptyRowSemantics emptyRowSemantics = ers_forbidden;
     StableSortFlag stableSort = stableSort_none;
     rowidx_t maxRows = 0;  // Number of rows that can fit in the allocated memory.
diff --git a/thorlcr/thorutil/thormisc.hpp b/thorlcr/thorutil/thormisc.hpp
index 2bfbc0d5998..6ab3bd784d1 100644
--- a/thorlcr/thorutil/thormisc.hpp
+++ b/thorlcr/thorutil/thormisc.hpp
@@ -113,6 +113,7 @@
 #define THOROPT_MEMORY_SPILL_AT "memorySpillAt"                 // The threshold (%) that roxiemem will request memory to be reduced (default=80)
 #define THOROPT_FAIL_ON_LEAKS "failOnLeaks"                     // If any leaks are detected at the end of graph, fail the query (default=false)
 #define THOROPT_SOAP_TRACE_LEVEL "soapTraceLevel"               // The trace SOAP level (default=1)
+#define THOROPT_SORT_ALGORITHM "sortAlgorithm"                  // The algorithm used to sort records (quicksort/mergesort)
 
 
 #define INITIAL_SELFJOIN_MATCH_WARNING_LEVEL 20000  // max of row matches before selfjoin emits warning