diff --git a/tools/dbslower.py b/tools/dbslower.py
index 9db225fde573..090d5218ac67 100755
--- a/tools/dbslower.py
+++ b/tools/dbslower.py
@@ -194,7 +194,7 @@
             args.pids = map(int, subprocess.check_output(
                                             "pidof postgres".split()).split())
 
-    usdts = map(lambda pid: USDT(pid=pid), args.pids)
+    usdts = list(map(lambda pid: USDT(pid=pid), args.pids))
     for usdt in usdts:
         usdt.enable_probe("query__start", "query_start")
         usdt.enable_probe("query__done", "query_end")
diff --git a/tools/dbstat.py b/tools/dbstat.py
index a89b09711607..a7d301b1f426 100755
--- a/tools/dbstat.py
+++ b/tools/dbstat.py
@@ -83,7 +83,7 @@
 program = program.replace("FILTER", "" if args.threshold == 0 else
         "if (delta / 1000000 < %d) { return 0; }" % args.threshold)
 
-usdts = map(lambda pid: USDT(pid=pid), args.pids)
+usdts = list(map(lambda pid: USDT(pid=pid), args.pids))
 for usdt in usdts:
     usdt.enable_probe("query__start", "probe_start")
     usdt.enable_probe("query__done", "probe_end")