- (if (zerop (length (free-connections pool)))
- (let ((conn (connect (connection-spec pool)
- :database-type (database-type pool) :if-exists :new)))
- (vector-push-extend conn (all-connections pool))
- (setf (conn-pool conn) pool)
- conn)
- (vector-pop (free-connections pool))))
+ (or (with-process-lock ((conn-pool-lock pool) "Acquire from pool")
+ (when (plusp (length (free-connections pool)))
+ (let ((pconn (vector-pop (free-connections pool))))
+ ;; test if connection still valid.
+ ;; Currently, on supported on MySQL
+ (cond
+ ((eq :mysql (database-type pconn))
+ (handler-case
+ (database-query "SHOW ERRORS LIMIT 1" pconn nil nil)
+ (error (e)
+ ;; we could check for error type 2006 for "SERVER GONE AWAY",
+ ;; but, it's safer just to disconnect the pooled conn for any error
+ (warn "Database connection ~S had an error when attempted to be acquired from the pool:
+ ~S
+Disconnecting.~%"
+ pconn e)
+ (ignore-errors (database-disconnect pconn))
+ nil)
+ (:no-error (res fields)
+ (declare (ignore res fields))
+ pconn)))
+ (t
+ pconn)))))
+ (let ((conn (connect (connection-spec pool)
+ :database-type (pool-database-type pool)
+ :if-exists :new
+ :make-default nil)))
+ (with-process-lock ((conn-pool-lock pool) "Acquire from pool")
+ (vector-push-extend conn (all-connections pool))
+ (setf (conn-pool conn) pool))
+ conn)))