diff --git a/tools/rw-heatmaps/.gitignore b/tools/rw-heatmaps/.gitignore
new file mode 100644
index 00000000000..e92d21d11be
--- /dev/null
+++ b/tools/rw-heatmaps/.gitignore
@@ -0,0 +1,6 @@
+results-*.csv
+rw-heatmaps
+*.jpg
+*.jpeg
+*.png
+*.tiff
diff --git a/tools/rw-heatmaps/rw-benchmark.sh b/tools/rw-heatmaps/rw-benchmark.sh
index 66d89cdd8a5..209414aa436 100755
--- a/tools/rw-heatmaps/rw-benchmark.sh
+++ b/tools/rw-heatmaps/rw-benchmark.sh
@@ -2,17 +2,17 @@
 
 #set -x
 
-RATIO_LIST="1/128 1/8 1/4 1/2 2/1 4/1 8/1 128/1"
-VALUE_SIZE_POWER_RANGE="8 14"
-CONN_CLI_COUNT_POWER_RANGE="5 11"
-REPEAT_COUNT=5
-RUN_COUNT=200000
-
-KEY_SIZE=256
-KEY_SPACE_SIZE=$((1024 * 64))
-BACKEND_SIZE="$((20 * 1024 * 1024 * 1024))"
-RANGE_RESULT_LIMIT=100
-CLIENT_PORT="23790"
+RATIO_LIST="${RATIO_LIST:-1/128 1/8 1/4 1/2 2/1 4/1 8/1 128/1}"
+VALUE_SIZE_POWER_RANGE="${VALUE_SIZE_POWER_RANGE:-8 14}"
+CONN_CLI_COUNT_POWER_RANGE="${CONN_CLI_COUNT_POWER_RANGE:-5 11}"
+REPEAT_COUNT="${REPEAT_COUNT:-5}"
+RUN_COUNT="${RUN_COUNT:-200000}"
+
+KEY_SIZE="${KEY_SIZE:-256}"
+KEY_SPACE_SIZE="${KEY_SPACE_SIZE:-$((1024 * 64))}"
+BACKEND_SIZE="${BACKEND_SIZE:-$((20 * 1024 * 1024 * 1024))}"
+RANGE_RESULT_LIMIT="${RANGE_RESULT_LIMIT:-100}"
+CLIENT_PORT="${CLIENT_PORT:-23790}"
 
 COMMIT=