diff --git a/geojson.c b/geojson.c
index 46132ff0..d65d61c9 100644
--- a/geojson.c
+++ b/geojson.c
@@ -1,3 +1,7 @@
+#ifdef MTRACE
+	#include <mcheck.h>
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>
@@ -1043,6 +1047,10 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
 }
 
 int main(int argc, char **argv) {
+#ifdef MTRACE
+	mtrace();
+#endif
+
 	extern int optind;
 	extern char *optarg;
 	int i;
@@ -1190,5 +1198,10 @@ int main(int argc, char **argv) {
 	ret = read_json(argc - optind, argv + optind, name ? name : outdir, layer, maxzoom, minzoom, outdb, &exclude, &include, exclude_all, droprate, buffer, tmpdir, gamma, prevent);
 
 	mbtiles_close(outdb, argv);
+
+#ifdef MTRACE
+	muntrace();
+#endif
+
 	return ret;
 }
diff --git a/tile.cc b/tile.cc
index 0fba44f2..ff20b9c4 100644
--- a/tile.cc
+++ b/tile.cc
@@ -780,6 +780,12 @@ long long write_tile(char **geoms, char *metabase, char *stringpool, unsigned *f
 				return count;
 			}
 		} else {
+			int i;
+			for (i = 0; i < nlayers; i++) {
+				pool_free(&keys1[i]);
+				pool_free(&values1[i]);
+			}
+
 			return count;
 		}
 	}