diff --git a/src/decoderbufs.c b/src/decoderbufs.c
index 1c5e5e4..ba34503 100644
--- a/src/decoderbufs.c
+++ b/src/decoderbufs.c
@@ -370,34 +370,41 @@ static bool geography_point_as_decoderbufs_point(Datum datum,
 static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
                             Oid typoutput, Datum datum) {
   Numeric num;
-  bytea *valptr;
-  const char *output;
-  Point *p;
+  bytea *valptr = NULL;
+  const char *output = NULL;
+  Point *p = NULL;
   int size = 0;
   switch (typid) {
     case BOOLOID:
       datum_msg->datum_bool = DatumGetBool(datum);
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_BOOL;
       break;
     case INT2OID:
       datum_msg->datum_int32 = DatumGetInt16(datum);
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_INT32;
       break;
     case INT4OID:
       datum_msg->datum_int32 = DatumGetInt32(datum);
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_INT32;
       break;
     case INT8OID:
     case OIDOID:
       datum_msg->datum_int64 = DatumGetInt64(datum);
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_INT64;
       break;
     case FLOAT4OID:
       datum_msg->datum_float = DatumGetFloat4(datum);
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_FLOAT;
       break;
     case FLOAT8OID:
       datum_msg->datum_double = DatumGetFloat8(datum);
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_DOUBLE;
       break;
     case NUMERICOID:
       num = DatumGetNumeric(datum);
       if (!numeric_is_nan(num)) {
         datum_msg->datum_double = numeric_to_double_no_overflow(num);
+        datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_DOUBLE;
       }
       break;
     case CHAROID:
@@ -409,6 +416,7 @@ static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
     case UUIDOID:
       output = OidOutputFunctionCall(typoutput, datum);
       datum_msg->datum_string = pnstrdup(output, strlen(output));
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_STRING;
       break;
     case TIMESTAMPOID:
     /*
@@ -417,6 +425,7 @@ static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
     case TIMESTAMPTZOID:
       output = timestamptz_to_str(DatumGetTimestampTz(datum));
       datum_msg->datum_string = pnstrdup(output, strlen(output));
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_STRING;
       break;
     case BYTEAOID:
       valptr = DatumGetByteaPCopy(datum);
@@ -424,6 +433,7 @@ static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
       datum_msg->datum_bytes.data = palloc(size);
       memcpy(datum_msg->datum_bytes.data, (uint8_t *)VARDATA(valptr), size);
       datum_msg->datum_bytes.len = size;
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_BYTES;
       break;
     case POINTOID:
       p = DatumGetPointP(datum);
@@ -432,6 +442,7 @@ static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
       dp.y = p->y;
       datum_msg->datum_point = palloc(sizeof(Decoderbufs__Point));
       memcpy(datum_msg->datum_point, &dp, sizeof(dp));
+      datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_POINT;
       break;
     default:
       // PostGIS uses dynamic OIDs so we need to check the type again here
@@ -439,6 +450,7 @@ static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
         elog(DEBUG1, "Converting geography point to datum_point");
         datum_msg->datum_point = palloc(sizeof(Decoderbufs__Point));
         geography_point_as_decoderbufs_point(datum, datum_msg->datum_point);
+        datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_POINT;
       } else {
         elog(WARNING, "Encountered unknown typid: %d, using bytes", typid);
         output = OidOutputFunctionCall(typoutput, datum);
@@ -447,6 +459,7 @@ static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
         datum_msg->datum_bytes.data = palloc(size);
         memcpy(datum_msg->datum_bytes.data, (uint8_t *)output, size);
         datum_msg->datum_bytes.len = len;
+        datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_BYTES;
       }
       break;
   }