diff --git a/config.m4 b/config.m4
index 48efd17..e6a2dfd 100644
--- a/config.m4
+++ b/config.m4
@@ -296,6 +296,28 @@ if test "$PHP_MEMCACHED" != "no"; then
       AC_MSG_RESULT([no])
     fi
 
+    ORIG_CFLAGS="$CFLAGS"
+    ORIG_LIBS="$LIBS"
+  
+    CFLAGS="$CFLAGS $PHP_LIBMEMCACHED_INCLUDES"
+    LIBS="$LIBS $PHP_LIBMEMCACHED_LIBS"
+
+    AC_CACHE_CHECK([whether memcached_exist is defined], ac_cv_have_memcached_exist, [
+      AC_TRY_LINK(
+        [ #include <libmemcached/memcached.h> ],
+        [ memcached_exist (NULL, NULL, 0); ],
+        [ ac_cv_have_memcached_exist="yes" ],
+        [ ac_cv_have_memcached_exist="no" ]
+      )
+    ])
+
+    CFLAGS="$ORIG_CFLAGS"
+    LIBS="$ORIG_LIBS"
+
+    if test "$ac_cv_have_memcached_exist" = "yes"; then
+      AC_DEFINE(HAVE_MEMCACHED_EXIST, [1], [Whether memcached_exist is defined])
+    fi
+
     PHP_MEMCACHED_FILES="php_memcached.c php_libmemcached_compat.c  g_fmt.c"
 
     if test "$PHP_SYSTEM_FASTLZ" != "no"; then
diff --git a/php_memcached.c b/php_memcached.c
index f5a9ea2..6f4ae3b 100644
--- a/php_memcached.c
+++ b/php_memcached.c
@@ -332,6 +332,25 @@ static void php_memc_destroy(struct memc_obj *m_obj, zend_bool persistent);
 ****************************************/
 
 
+memcached_return php_memcached_exist (memcached_st *memc, zend_string *key)
+{
+#ifdef HAVE_MEMCACHED_EXIST
+	return memcached_exist (memc, key->val, key->len);
+#else
+	memcached_return rc = MEMCACHED_SUCCESS;
+	uint32_t flags = 0;
+	size_t value_length = 0;
+	char *value = NULL;
+
+	value = memcached_get (memc, key->val, key->len, &value_length, &flags, &rc);
+	if (value) {
+		free (value);
+	}
+	return rc;
+#endif
+}
+
+
 char *php_memc_printable_func (zend_fcall_info *fci, zend_fcall_info_cache *fci_cache)
 {
 	char *buffer = NULL;
diff --git a/php_memcached_private.h b/php_memcached_private.h
index 2929818..ffca963 100644
--- a/php_memcached_private.h
+++ b/php_memcached_private.h
@@ -192,6 +192,8 @@ int php_memc_sess_list_entry(void);
 
 char *php_memc_printable_func (zend_fcall_info *fci, zend_fcall_info_cache *fci_cache TSRMLS_DC);
 
+memcached_return php_memcached_exist (memcached_st *memc, zend_string *key);
+
 #endif /* PHP_MEMCACHED_PRIVATE_H */
 
 /*
diff --git a/php_memcached_session.c b/php_memcached_session.c
index 5f66e41..85baad0 100644
--- a/php_memcached_session.c
+++ b/php_memcached_session.c
@@ -277,7 +277,7 @@ success:
 PS_CLOSE_FUNC(memcached)
 {
 	memcached_sess *memc_sess = PS_GET_MOD_DATA();
-	
+
 	if (!memc_sess) {
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Session is not allocated, check session.save_path value");
 		return FAILURE;
@@ -336,8 +336,9 @@ PS_READ_FUNC(memcached)
 		*val = zend_string_init(payload, payload_len, 1);
 		free(payload);
 		return SUCCESS;
-	} else if (status = MEMCACHED_NOTFOUND) {
+	} else if (status == MEMCACHED_NOTFOUND) {
 		*val = ZSTR_EMPTY_ALLOC();
+		return SUCCESS;
 	} else {
 		return FAILURE;
 	}
@@ -351,7 +352,7 @@ PS_WRITE_FUNC(memcached)
 	memcached_return status;
 	memcached_sess *memc_sess = PS_GET_MOD_DATA();
 	size_t key_length;
-	
+
 	if (!memc_sess) {
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Session is not allocated, check session.save_path value");
 		return FAILURE;
@@ -409,39 +410,34 @@ PS_GC_FUNC(memcached)
 PS_CREATE_SID_FUNC(memcached)
 {
 	zend_string *sid;
-	int maxfail = 3;
+	int retries = 3;
 	memcached_sess *memc_sess = PS_GET_MOD_DATA();
+	time_t expiration = PS(gc_maxlifetime);
 
-	do {
+	if (!memc_sess) {
+		return NULL;
+	}
+
+	while (retries-- > 0) {
 		sid = php_session_create_id((void**)&memc_sess);
-		if (!sid) {
-			if (--maxfail < 0) {
-				return NULL;
-			} else {
-				continue;
-			}
-		}
-		/* Check collision */
-		/* FIXME: mod_data(memc_sess) should not be NULL (User handler could be NULL) */
-		if (memc_sess && memcached_exist(memc_sess->memc_sess, sid->val, sid->len) == MEMCACHED_SUCCESS) {
-			if (sid) {
-				zend_string_release(sid);
-				sid = NULL;
-			}
-			if (--maxfail < 0) {
-				return NULL;
-			}
-		}
-	} while(!sid);
 
-	return sid;
+		if (sid) {
+			if (memcached_add(memc_sess->memc_sess, sid->val, sid->len, "0", 0, expiration, 0) == MEMCACHED_SUCCESS) {
+				return sid;
+			}
+			else {
+				zend_string_release(sid);
+			}
+		}
+	}
+	return NULL;
 }
 
 PS_VALIDATE_SID_FUNC(memcached)
 {
 	memcached_sess *memc_sess = PS_GET_MOD_DATA();
 
-	if (memcached_exist(memc_sess->memc_sess, key->val, key->len) == MEMCACHED_SUCCESS) {
+	if (php_memcached_exist(memc_sess->memc_sess, key) == MEMCACHED_SUCCESS) {
 		return SUCCESS;
 	} else {
 		return FAILURE;