little fix

source/common/src/tmsg.c

@@ -2219,7 +2219,10 @@ int32_t tSerializeSAlterDbReq(void *buf, int32_t bufLen, SAlterDbReq *pReq) {
   if (tEncodeI8(&encoder, pReq->cacheLast) < 0) return -1;
   if (tEncodeI8(&encoder, pReq->replications) < 0) return -1;
   if (tEncodeI32(&encoder, pReq->sstTrigger) < 0) return -1;
+
+  // 1st modification
   if (tEncodeI32(&encoder, pReq->minRows) < 0) return -1;
+
   tEndEncode(&encoder);
 
   int32_t tlen = encoder.pos;
@@ -2247,8 +2250,12 @@ int32_t tDeserializeSAlterDbReq(void *buf, int32_t bufLen, SAlterDbReq *pReq) {
   if (tDecodeI8(&decoder, &pReq->cacheLast) < 0) return -1;
   if (tDecodeI8(&decoder, &pReq->replications) < 0) return -1;
   if (tDecodeI32(&decoder, &pReq->sstTrigger) < 0) return -1;
+
+  // 1st modification
   if (!tDecodeIsEnd(&decoder)) {
     if (tDecodeI32(&decoder, &pReq->minRows) < 0) return -1;
+  } else {
+    pReq->minRows = -1;
   }
   tEndDecode(&decoder);