diff --git a/pgworker/pgworker/pg_worker.c b/pgworker/pgworker/pg_worker.c
index 021753f..09cd6b0 100644
--- a/pgworker/pgworker/pg_worker.c
+++ b/pgworker/pgworker/pg_worker.c
@@ -69,7 +69,7 @@ int debug = 0;
 
 #define MAX_PARAM_DIGIT_NUM 2
 #define MAX_PARAM_COUNT 99
-int count_params(const char *stmt) {
+static int count_params(const char *stmt) {
   const char *paramPtr = stmt;
   const char *spacePtr;
   char numBuf[MAX_PARAM_DIGIT_NUM + 1];
@@ -205,7 +205,7 @@ int pg_worker_work(void *handle, void *work_handle, char *input, char *output) {
 }
 
 
-int break_input(pg_worker_handle_t *pwh, char *input) {
+static int break_input(pg_worker_handle_t *pwh, char *input) {
   char *param, *nextptr;
   int cnt=0;
 
@@ -250,7 +250,7 @@ int break_input(pg_worker_handle_t *pwh, char *input) {
 
 
 #define MAX_RESULT_DIGIT_NUM 2
-int populate_output_format(pg_worker_handle_t *pwh, PGresult *pgr, 
+static int populate_output_format(pg_worker_handle_t *pwh, PGresult *pgr, 
 			   char *output, int tuple_num) {
   const char *formatPtr = pwh->pch->output_format_string;
   const char *tmpPtr = formatPtr;
@@ -304,7 +304,7 @@ int populate_output_format(pg_worker_handle_t *pwh, PGresult *pgr,
 }
 
 
-int process(pg_worker_handle_t *pwh, char *input, char *output) {
+static int process(pg_worker_handle_t *pwh, char *input, char *output) {
   int i, j, t, f, res;
   char *s;
   PGresult *pgr;