diff --git a/tools/db_crashtest.py b/tools/db_crashtest.py
index 187f45995b..1e4eb66640 100644
--- a/tools/db_crashtest.py
+++ b/tools/db_crashtest.py
@@ -90,6 +90,9 @@ def main(argv):
                         --destroy_db_initially=0 \
                         --reopen=0 \
                         --readpercent=50 \
+                        --prefixpercent=5 \
+                        --writepercent=40 \
+                        --delpercent=5 \
                         --db=' + dirpath + '\
                         --max_key=100000000 ' + additional_opts],
                                  stderr=subprocess.PIPE, shell=True)
diff --git a/tools/db_crashtest2.py b/tools/db_crashtest2.py
index 2398efd918..a158574e65 100644
--- a/tools/db_crashtest2.py
+++ b/tools/db_crashtest2.py
@@ -107,6 +107,9 @@ def main(argv):
                 --destroy_db_initially=0 ' + killoption + ' \
                 --reopen=0 \
                 --readpercent=50 \
+                --prefixpercent=5 \
+                --writepercent=40 \
+                --delpercent=5 \
                 --db=' + dirpath + ' \
                 --max_key=100000000 ' + additional_opts]