Increase RocksDB max-background-compactions and background-thread-count to 4 by default. Improves fast sync times even on a t3.large instance (2 cores). (#1364)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

services/kvstore/src/main/java/tech/pegasys/pantheon/services/kvstore/RocksDbConfiguration.java

@@ -94,7 +94,7 @@ public class RocksDbConfiguration {
     @CommandLine.Option(
         names = {"--Xrocksdb-max-background-compactions"},
         hidden = true,
-        defaultValue = "1",
+        defaultValue = "4",
         paramLabel = "<INTEGER>",
         description =
             "Maximum number of RocksDB background compactions (default: ${DEFAULT-VALUE})")
@@ -103,7 +103,7 @@ public class RocksDbConfiguration {
     @CommandLine.Option(
         names = {"--Xrocksdb-background-thread-count"},
         hidden = true,
-        defaultValue = "1",
+        defaultValue = "4",
         paramLabel = "<INTEGER>",
         description = "Number of RocksDB background threads (default: ${DEFAULT-VALUE})")
     int backgroundThreadCount;