diff --git a/geojson.cpp b/geojson.cpp
index 1ae9805..ec42043 100644
--- a/geojson.cpp
+++ b/geojson.cpp
@@ -20,6 +20,8 @@
 #include <sys/resource.h>
 #include <pthread.h>
 #include <vector>
+#include <set>
+#include <string>
 
 extern "C" {
 #include "jsonpull/jsonpull.h"
@@ -151,7 +153,7 @@ void parse_geometry(int t, json_object *j, long long *bbox, long long *fpos, FIL
 	}
 }
 
-int serialize_geometry(json_object *geometry, json_object *properties, const char *reading, int line, volatile long long *layer_seq, volatile long long *progress_seq, long long *metapos, long long *geompos, long long *indexpos, struct pool *exclude, struct pool *include, int exclude_all, FILE *metafile, FILE *geomfile, FILE *indexfile, struct memfile *poolfile, struct memfile *treefile, const char *fname, int basezoom, int layer, double droprate, long long *file_bbox, json_object *tippecanoe, int segment, int *initialized, unsigned *initial_x, unsigned *initial_y, struct reader *readers) {
+int serialize_geometry(json_object *geometry, json_object *properties, const char *reading, int line, volatile long long *layer_seq, volatile long long *progress_seq, long long *metapos, long long *geompos, long long *indexpos, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, FILE *metafile, FILE *geomfile, FILE *indexfile, struct memfile *poolfile, struct memfile *treefile, const char *fname, int basezoom, int layer, double droprate, long long *file_bbox, json_object *tippecanoe, int segment, int *initialized, unsigned *initial_x, unsigned *initial_y, struct reader *readers) {
 	json_object *geometry_type = json_hash_get(geometry, "type");
 	if (geometry_type == NULL) {
 		static int warned = 0;
@@ -224,10 +226,10 @@ int serialize_geometry(json_object *geometry, json_object *properties, const cha
 	for (i = 0; i < nprop; i++) {
 		if (properties->keys[i]->type == JSON_STRING) {
 			if (exclude_all) {
-				if (!is_pooled(include, properties->keys[i]->string, VT_STRING)) {
+				if (include->count(std::string(properties->keys[i]->string)) == 0) {
 					continue;
 				}
-			} else if (is_pooled(exclude, properties->keys[i]->string, VT_STRING)) {
+			} else if (exclude->count(std::string(properties->keys[i]->string)) != 0) {
 				continue;
 			}
 
@@ -354,7 +356,7 @@ int serialize_geometry(json_object *geometry, json_object *properties, const cha
 	return 1;
 }
 
-void parse_json(json_pull *jp, const char *reading, volatile long long *layer_seq, volatile long long *progress_seq, long long *metapos, long long *geompos, long long *indexpos, struct pool *exclude, struct pool *include, int exclude_all, FILE *metafile, FILE *geomfile, FILE *indexfile, struct memfile *poolfile, struct memfile *treefile, char *fname, int basezoom, int layer, double droprate, long long *file_bbox, int segment, int *initialized, unsigned *initial_x, unsigned *initial_y, struct reader *readers) {
+void parse_json(json_pull *jp, const char *reading, volatile long long *layer_seq, volatile long long *progress_seq, long long *metapos, long long *geompos, long long *indexpos, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, FILE *metafile, FILE *geomfile, FILE *indexfile, struct memfile *poolfile, struct memfile *treefile, char *fname, int basezoom, int layer, double droprate, long long *file_bbox, int segment, int *initialized, unsigned *initial_x, unsigned *initial_y, struct reader *readers) {
 	long long found_hashes = 0;
 	long long found_features = 0;
 	long long found_geometries = 0;
diff --git a/geojson.hpp b/geojson.hpp
index f96d6e3..d493e41 100644
--- a/geojson.hpp
+++ b/geojson.hpp
@@ -6,8 +6,8 @@ struct parse_json_args {
 	long long *metapos;
 	long long *geompos;
 	long long *indexpos;
-	struct pool *exclude;
-	struct pool *include;
+	std::set<std::string> *exclude;
+	std::set<std::string> *include;
 	int exclude_all;
 	FILE *metafile;
 	FILE *geomfile;
@@ -27,5 +27,5 @@ struct parse_json_args {
 };
 
 struct json_pull *json_begin_map(char *map, long long len);
-void parse_json(json_pull *jp, const char *reading, volatile long long *layer_seq, volatile long long *progress_seq, long long *metapos, long long *geompos, long long *indexpos, struct pool *exclude, struct pool *include, int exclude_all, FILE *metafile, FILE *geomfile, FILE *indexfile, struct memfile *poolfile, struct memfile *treefile, char *fname, int basezoom, int layer, double droprate, long long *file_bbox, int segment, int *initialized, unsigned *initial_x, unsigned *initial_y, struct reader *readers);
+void parse_json(json_pull *jp, const char *reading, volatile long long *layer_seq, volatile long long *progress_seq, long long *metapos, long long *geompos, long long *indexpos, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, FILE *metafile, FILE *geomfile, FILE *indexfile, struct memfile *poolfile, struct memfile *treefile, char *fname, int basezoom, int layer, double droprate, long long *file_bbox, int segment, int *initialized, unsigned *initial_x, unsigned *initial_y, struct reader *readers);
 void *run_parse_json(void *v);
diff --git a/main.cpp b/main.cpp
index 11162cd..ca82ec6 100644
--- a/main.cpp
+++ b/main.cpp
@@ -22,6 +22,7 @@
 #include <getopt.h>
 #include <vector>
 #include <string>
+#include <set>
 
 #ifdef __APPLE__
 #include <sys/types.h>
@@ -297,7 +298,7 @@ void *run_sort(void *v) {
 	return NULL;
 }
 
-void do_read_parallel(char *map, long long len, long long initial_offset, const char *reading, struct reader *reader, volatile long long *progress_seq, struct pool *exclude, struct pool *include, int exclude_all, char *fname, int basezoom, int source, int nlayers, double droprate, int *initialized, unsigned *initial_x, unsigned *initial_y) {
+void do_read_parallel(char *map, long long len, long long initial_offset, const char *reading, struct reader *reader, volatile long long *progress_seq, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, char *fname, int basezoom, int source, int nlayers, double droprate, int *initialized, unsigned *initial_x, unsigned *initial_y) {
 	long long segs[CPUS + 1];
 	segs[0] = 0;
 	segs[CPUS] = len;
@@ -376,8 +377,8 @@ struct read_parallel_arg {
 	const char *reading;
 	struct reader *reader;
 	volatile long long *progress_seq;
-	struct pool *exclude;
-	struct pool *include;
+	std::set<std::string> *exclude;
+	std::set<std::string> *include;
 	int exclude_all;
 	char *fname;
 	int maxzoom;
@@ -426,7 +427,7 @@ void *run_read_parallel(void *v) {
 	return NULL;
 }
 
-void start_parsing(int fd, FILE *fp, long long offset, long long len, volatile int *is_parsing, pthread_t *parallel_parser, const char *reading, struct reader *reader, volatile long long *progress_seq, struct pool *exclude, struct pool *include, int exclude_all, char *fname, int basezoom, int source, int nlayers, double droprate, int *initialized, unsigned *initial_x, unsigned *initial_y) {
+void start_parsing(int fd, FILE *fp, long long offset, long long len, volatile int *is_parsing, pthread_t *parallel_parser, const char *reading, struct reader *reader, volatile long long *progress_seq, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, char *fname, int basezoom, int source, int nlayers, double droprate, int *initialized, unsigned *initial_x, unsigned *initial_y) {
 	// This has to kick off an intermediate thread to start the parser threads,
 	// so the main thread can get back to reading the next input stage while
 	// the intermediate thread waits for the completion of the parser threads.
@@ -842,7 +843,7 @@ void radix(struct reader *reader, int nreaders, FILE *geomfile, int geomfd, FILE
 	}
 }
 
-int read_input(std::vector<source> &sources, char *fname, const char *layername, int maxzoom, int minzoom, int basezoom, double basezoom_marker_width, sqlite3 *outdb, struct pool *exclude, struct pool *include, int exclude_all, double droprate, int buffer, const char *tmpdir, double gamma, int *prevent, int *additional, int read_parallel, int forcetable, const char *attribution) {
+int read_input(std::vector<source> &sources, char *fname, const char *layername, int maxzoom, int minzoom, int basezoom, double basezoom_marker_width, sqlite3 *outdb, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, double droprate, int buffer, const char *tmpdir, double gamma, int *prevent, int *additional, int read_parallel, int forcetable, const char *attribution) {
 	int ret = EXIT_SUCCESS;
 
 	struct reader reader[CPUS];
@@ -1730,9 +1731,7 @@ int main(int argc, char **argv) {
 	const char *attribution = NULL;
 	std::vector<source> sources;
 
-	struct pool exclude, include;
-	pool_init(&exclude, 0);
-	pool_init(&include, 0);
+	std::set<std::string> exclude, include;
 	int exclude_all = 0;
 	int read_parallel = 0;
 	int files_open_at_start;
@@ -1891,12 +1890,12 @@ int main(int argc, char **argv) {
 			break;
 
 		case 'x':
-			pool(&exclude, optarg, VT_STRING);
+			exclude.insert(std::string(optarg));
 			break;
 
 		case 'y':
 			exclude_all = 1;
-			pool(&include, optarg, VT_STRING);
+			include.insert(std::string(optarg));
 			break;
 
 		case 'X':
@@ -2089,8 +2088,5 @@ int main(int argc, char **argv) {
 		exit(EXIT_FAILURE);
 	}
 
-	pool_free(&exclude);
-	pool_free(&include);
-
 	return ret;
 }