*hi* this function *ConnectionPool_getConnection* is designed badly。 between code *LOCK(P->mutex)* and *END_LOCK*, *Connection_ping* and *Connection_new* may block long time (reconnect/connect to sql server),so other threads will wait long time.

* should't block when locked!!!!*

see below code for detail: *Connection_T ConnectionPool_getConnection(T P) {* * Connection_T con = NULL;* * assert(P);* * LOCK(P->mutex) * * {* * int size = Vector_size(P->pool);* * for (int i = 0; i < size; i++) {* * con = Vector_get(P->pool, i);* * if (Connection_isAvailable(con) && Connection_ping(con)) {* * Connection_setAvailable(con, false);* * goto done;* * } * * }* * con = NULL;* * if (size < P->maxConnections) {* * con = Connection_new(P, &P->error);* * if (con) {* * Connection_setAvailable(con, false);* * Vector_push(P->pool, con);* * } else {* * DEBUG("Failed to create connection -- %s\n", P->error);* * FREE(P->error);* * }* * }* * }* *done: * * END_LOCK;* * return con;* *}*