core/state/snapshot: increase batch size during diffToDisk (#816)

core/state/snapshot/snapshot.go

@@ -635,7 +635,7 @@ func diffToDisk(bottom *diffLayer) (*diskLayer, bool, error) {
 			// Ensure we don't delete too much data blindly (contract can be
 			// huge). It's ok to flush, the root will go missing in case of a
 			// crash and we'll detect and regenerate the snapshot.
-			if batch.ValueSize() > ethdb.IdealBatchSize {
+			if batch.ValueSize() > 64*1024*1024 {
 				if err := batch.Write(); err != nil {
 					log.Crit("Failed to write storage deletions", "err", err)
 				}
@@ -661,7 +661,7 @@ func diffToDisk(bottom *diffLayer) (*diskLayer, bool, error) {
 		// Ensure we don't write too much data blindly. It's ok to flush, the
 		// root will go missing in case of a crash and we'll detect and regen
 		// the snapshot.
-		if batch.ValueSize() > ethdb.IdealBatchSize {
+		if batch.ValueSize() > 64*1024*1024 {
 			if err := batch.Write(); err != nil {
 				log.Crit("Failed to write storage deletions", "err", err)
 			}