diff --git a/modules/database/src/std/rec/compressRecord.c b/modules/database/src/std/rec/compressRecord.c
index b6fafb4ab3..74933bb3d8 100644
--- a/modules/database/src/std/rec/compressRecord.c
+++ b/modules/database/src/std/rec/compressRecord.c
@@ -149,12 +149,15 @@ static int compare(const void *arg1, const void *arg2)
     else               return  1;
 }
 
+#define min(a, b) ((a) < (b) ? (a) : (b))
+
 static int compress_array(compressRecord *prec,
     double *psource, int no_elements)
 {
-    epicsInt32 i,j;
+    epicsInt32 j;
     epicsInt32 n, nnew;
     epicsInt32 nsam = prec->nsam;
+    epicsUInt32 samples_written = 0;
     double value;
 
     /* skip out of limit data */
@@ -167,61 +170,54 @@ static int compress_array(compressRecord *prec,
     }
     if (prec->n <= 0)
         prec->n = 1;
-    if (no_elements < prec->n && prec->pbuf != menuYesNoYES)
-        return 1; /*dont do anything*/
-    n = no_elements;
+    n = prec->n;
 
-    /* determine number of samples to take */
-    if (no_elements < nsam * n)
-        nnew = (no_elements / n);
-    else nnew = nsam;
+    nnew = min(no_elements, nsam * n);
 
-    /* compress according to specified algorithm */
-    switch (prec->alg){
-    case compressALG_N_to_1_Low_Value:
-        /* compress N to 1 keeping the lowest value */
-        for (i = 0; i < nnew; i++) {
+    while (nnew > 0)
+    {
+        if (nnew < n && prec->pbuf != menuYesNoYES)
+            break;
+
+        n = min(n, nnew);
+        switch (prec->alg)
+        {
+        case compressALG_N_to_1_Low_Value:
             value = *psource++;
-            for (j = 1; j < n; j++, psource++) {
+            for (j = 1; j < n; j++, psource++)
+            {
                 if (value > *psource)
                     value = *psource;
             }
-            put_value(prec, &value, 1);
-        }
-        break;
-    case compressALG_N_to_1_High_Value:
-        /* compress N to 1 keeping the highest value */
-        for (i = 0; i < nnew; i++){
+            break;
+        case compressALG_N_to_1_High_Value:
             value = *psource++;
-            for (j = 1; j < n; j++, psource++) {
+            for (j = 1; j < n; j++, psource++)
+            {
                 if (value < *psource)
                     value = *psource;
             }
-            put_value(prec, &value, 1);
-        }
-        break;
-    case compressALG_N_to_1_Average:
-        /* compress N to 1 keeping the average value */
-        for (i = 0; i < nnew; i++) {
-            value = 0;
-            for (j = 0; j < n; j++, psource++)
+            break;
+        case compressALG_N_to_1_Average:
+            value = *psource++;
+            for (j = 1; j < n; j++, psource++)
+            {
                 value += *psource;
-            value /= n;
-            put_value(prec, &value, 1);
-        }
-        break;
-
-    case compressALG_N_to_1_Median:
-        /* compress N to 1 keeping the median value */
-        /* note: sorts source array (OK; it's a work pointer) */
-        for (i = 0; i < nnew; i++, psource += nnew) {
+            }
+            value = value / n;
+            break;
+        case compressALG_N_to_1_Median:
+            /* note: sorts source array (OK; it's a work pointer) */
             qsort(psource, n, sizeof(double), compare);
             value = psource[n / 2];
-            put_value(prec, &value, 1);
+            psource += n;
+            break;
         }
-        break;
+        nnew -= n;
+        put_value(prec, &value, 1);
+        samples_written++;
     }
-    return 0;
+    return (samples_written > 0);
 }
 
 static int array_average(compressRecord *prec,
diff --git a/modules/database/test/std/rec/compressTest.c b/modules/database/test/std/rec/compressTest.c
index ed5f31e638..cedb28f485 100644
--- a/modules/database/test/std/rec/compressTest.c
+++ b/modules/database/test/std/rec/compressTest.c
@@ -469,6 +469,38 @@ testNto1Average(void) {
     testdbCleanup();
 }
 
+void testNto2Average(void) {
+    DBADDR wfaddr, caddr;
+
+    testDiag("Test N to 1 Average, NSAM=2, N=2");
+
+    testdbPrepare();
+
+    testdbReadDatabase("recTestIoc.dbd", NULL, NULL);
+
+    recTestIoc_registerRecordDeviceDriver(pdbbase);
+
+    testdbReadDatabase("compressTest.db", NULL, "INP=wf,ALG=N to 1 Average,BALG=FIFO Buffer,NSAM=2,N=2");
+
+    eltc(0);
+    testIocInitOk();
+    eltc(1);
+
+    fetchRecordOrDie("wf", wfaddr);
+    fetchRecordOrDie("comp", caddr);
+
+    writeToWaveform(&wfaddr, 4, 1., 2., 3., 4.);
+
+    dbScanLock(caddr.precord);
+    dbProcess(caddr.precord);
+
+    checkArrD("comp", 2, 1.5, 3.5, 0, 0);
+    dbScanUnlock(caddr.precord);
+
+    testIocShutdownOk();
+    testdbCleanup();
+}
+
 void
 testNto1AveragePartial(void) {
     double buf = 0.0;
@@ -517,6 +549,36 @@ testNto1AveragePartial(void) {
     testdbCleanup();
 }
 
+void
+testNtoMPartial(void) {
+    DBADDR wfaddr, caddr;
+
+    testDiag("Test Average, N to M, Partial");
+
+    testdbPrepare();
+    testdbReadDatabase("recTestIoc.dbd", NULL, NULL);
+    recTestIoc_registerRecordDeviceDriver(pdbbase);
+    testdbReadDatabase("compressTest.db", NULL, "INP=wf,ALG=N to 1 Average,BALG=FIFO Buffer,NSAM=2,N=3,PBUF=YES");
+
+    eltc(0);
+    testIocInitOk();
+    eltc(1);
+
+    fetchRecordOrDie("wf", wfaddr);
+    fetchRecordOrDie("comp", caddr);
+
+    writeToWaveform(&wfaddr, 4, 1., 2., 3., 4.);
+
+    dbScanLock(caddr.precord);
+    dbProcess(caddr.precord);
+
+    checkArrD("comp", 2, 2.0, 4.0, 0, 0);
+    dbScanUnlock(caddr.precord);
+
+    testIocShutdownOk();
+    testdbCleanup();
+}
+
 void
 testNto1LowValue(void) {
     double buf = 0.0;
@@ -634,12 +696,14 @@ testAIAveragePartial(void) {
 
 MAIN(compressTest)
 {
-    testPlan(132);
+    testPlan(134);
     testFIFOCirc();
     testLIFOCirc();
     testArrayAverage();
     testNto1Average();
+    testNto2Average();
     testNto1AveragePartial();
+    testNtoMPartial();
     testAIAveragePartial();
     testNto1LowValue();
     return testDone();