r1798: Initial support for pooled connections

[clsql.git] / sql / pool.cl

diff --git a/sql/pool.cl b/sql/pool.cl
new file mode 100644 (file)
index 0000000..298f1e3
--- /dev/null
+++ b/sql/pool.cl
@@ -0,0 +1,59 @@
+;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*-
+;;;; *************************************************************************
+;;;; FILE IDENTIFICATION
+;;;;
+;;;; Name:          pool.cl
+;;;; Purpose:       Support function for connection pool
+;;;; Programmers:   Kevin M. Rosenberg
+;;;; Date Started:  Apr 2002
+;;;;
+;;;; $Id: pool.cl,v 1.1 2002/04/27 20:58:11 kevin Exp $
+;;;;
+;;;; This file, part of CLSQL, is Copyright (c) 2002 by Kevin M. Rosenberg
+;;;;
+;;;; CLSQL users are granted the rights to distribute and use this software
+;;;; as governed by the terms of the Lisp Lesser GNU Public License
+;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
+;;;; *************************************************************************
+
+(declaim (optimize (debug 3) (speed 3) (safety 1) (compilation-speed 0)))
+(in-package :clsql-sys)
+
+(defvar *db-pool* (make-hash-table :test #'equal))
+
+(defun make-conn-vector ()
+  "Creates an empty connection vector"
+  (make-array 5 :fill-pointer 0 :adjustable t))
+
+(defun find-or-create-conn-vector (connection-spec database-type)
+  "Find connection vector in hash table, creates a new conn-vector if not found"
+  (let* ((key (list connection-spec database-type))
+        (conn-vector (gethash *db-pool* key)))
+    (unless conn-vector
+      (setq conn-vector (make-conn-vector))
+      (setf (gethash *db-pool* key) conn-vector))
+    conn-vector))
+
+(defun acquire-from-pool (connection-spec database-type)
+  (let ((conn-vector (find-or-create-conn-vector connection-spec database-type)))
+    (when (zerop (length conn-vector))
+      (vector-push-extend 
+       (connect connection-spec :database-type database-type :if-exists :new) 
+       conn-vector))
+    (vector-pop conn-vector)))
+
+(defun release-to-pool (database)
+  (let ((conn-vector (find-or-create-conn-vector (connection-spec database)
+                                          (database-type database))))
+    (vector-push-extend database conn-vector)))
+
+(defun disconnect-pooled ()
+  "Disconnects all connections in the pool"
+  (maphash
+   #'(lambda (key conn-vector)
+       (declare (ignore key))
+       (dotimes (i (length conn-vector))
+        (disconnect (aref conn-vector i)))
+       (setf (fill-pointer conn-vector) 0))
+   *db-pool*)
+  t)