update mt-store-cp-experimental to comply with new gocql version

cmd/mt-store-cp-experimental/main.go

@@ -280,8 +280,10 @@ func worker(id int, jobs <-chan string, wg *sync.WaitGroup, sourceSession, destS
 			if *verbose {
 				log.Printf("id=%d processing rownum=%d table=%q key=%q ts=%d query=%q data='%x'\n", id, atomic.LoadUint64(&doneRows)+1, tableIn, key, ts, query, data)
 			}
-
-			batch.Query(insertQuery, data, key, ts, ttl)
+			// As 'data' is re-used for each scan, we need to make a copy of the []byte slice before assigning it to a new batch.
+			safeData := make([]byte, len(data))
+			copy(safeData, data)
+			batch.Query(insertQuery, safeData, key, ts, ttl)
 
 			if batch.Size() >= *maxBatchSize {
 				if *verbose {

store/cassandra/cassandra.go

@@ -533,12 +533,10 @@ func (c *CassandraStore) SearchTable(ctx context.Context, key schema.AMKey, tabl
 		if len(b) < 2 {
 			return itgens, errChunkTooSmall
 		}
-		// due to changes in gocql we need to manually copy the []byte before
-		// creating an itergen
-		// reference: https://github.com/gocql/gocql/pull/1167
-		copiedBytes := make([]byte, len(b))
-		copy(copiedBytes, b)
-		itgen, err := chunk.NewIterGen(uint32(t0), intervalHint, copiedBytes)
+		// As 'b' is re-used for each scan, we need to make a copy of the []byte slice before assigning it to a new IterGen.
+		safeBytes := make([]byte, len(b))
+		copy(safeBytes, b)
+		itgen, err := chunk.NewIterGen(uint32(t0), intervalHint, safeBytes)
 		if err != nil {
 			return itgens, err
 		}