res_pjsip_outbound_registration: Fix leak on vector add failure.
[asterisk/asterisk.git] / res / res_odbc.c
index 85de1fa..24f63a9 100644 (file)
@@ -1,7 +1,7 @@
 /*
  * Asterisk -- An open source telephony toolkit.
  *
- * Copyright (C) 1999 - 2008, Digium, Inc.
+ * Copyright (C) 1999 - 2012, Digium, Inc.
  *
  * Mark Spencer <markster@digium.com>
  *
  * \arg See also: \ref cdr_odbc
  */
 
+/*! \li \ref res_odbc.c uses the configuration file \ref res_odbc.conf
+ * \addtogroup configuration_file Configuration Files
+ */
+
+/*! 
+ * \page res_odbc.conf res_odbc.conf
+ * \verbinclude res_odbc.conf.sample
+ */
+
 /*** MODULEINFO
        <depend>generic_odbc</depend>
+       <depend>res_odbc_transaction</depend>
        <depend>ltdl</depend>
+       <support_level>core</support_level>
  ***/
 
 #include "asterisk.h"
 
-ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
-
 #include "asterisk/file.h"
 #include "asterisk/channel.h"
 #include "asterisk/config.h"
@@ -53,66 +62,6 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/strings.h"
 #include "asterisk/threadstorage.h"
 
-/*** DOCUMENTATION
-       <function name="ODBC" language="en_US">
-               <synopsis>
-                       Controls ODBC transaction properties.
-               </synopsis>
-               <syntax>
-                       <parameter name="property" required="true">
-                               <enumlist>
-                                       <enum name="transaction">
-                                               <para>Gets or sets the active transaction ID.  If set, and the transaction ID does not
-                                               exist and a <replaceable>database name</replaceable> is specified as an argument, it will be created.</para>
-                                       </enum>
-                                       <enum name="forcecommit">
-                                               <para>Controls whether a transaction will be automatically committed when the channel
-                                               hangs up.  Defaults to false.  If a <replaceable>transaction ID</replaceable> is specified in the optional argument,
-                                               the property will be applied to that ID, otherwise to the current active ID.</para>
-                                       </enum>
-                                       <enum name="isolation">
-                                               <para>Controls the data isolation on uncommitted transactions.  May be one of the
-                                               following: <literal>read_committed</literal>, <literal>read_uncommitted</literal>,
-                                               <literal>repeatable_read</literal>, or <literal>serializable</literal>.  Defaults to the
-                                               database setting in <filename>res_odbc.conf</filename> or <literal>read_committed</literal>
-                                               if not specified.  If a <replaceable>transaction ID</replaceable> is specified as an optional argument, it will be
-                                               applied to that ID, otherwise the current active ID.</para>
-                                       </enum>
-                               </enumlist>
-                       </parameter>
-                       <parameter name="argument" required="false" />
-               </syntax>
-               <description>
-                       <para>The ODBC() function allows setting several properties to influence how a connected
-                       database processes transactions.</para>
-               </description>
-       </function>
-       <application name="ODBC_Commit" language="en_US">
-               <synopsis>
-                       Commits a currently open database transaction.
-               </synopsis>
-               <syntax>
-                       <parameter name="transaction ID" required="no" />
-               </syntax>
-               <description>
-                       <para>Commits the database transaction specified by <replaceable>transaction ID</replaceable>
-                       or the current active transaction, if not specified.</para>
-               </description>
-       </application>
-       <application name="ODBC_Rollback" language="en_US">
-               <synopsis>
-                       Rollback a currently open database transaction.
-               </synopsis>
-               <syntax>
-                       <parameter name="transaction ID" required="no" />
-               </syntax>
-               <description>
-                       <para>Rolls back the database transaction specified by <replaceable>transaction ID</replaceable>
-                       or the current active transaction, if not specified.</para>
-               </description>
-       </application>
- ***/
-
 struct odbc_class
 {
        AST_LIST_ENTRY(odbc_class) list;
@@ -122,15 +71,24 @@ struct odbc_class
        char *password;
        char *sanitysql;
        SQLHENV env;
-       unsigned int haspool:1;              /*!< Boolean - TDS databases need this */
        unsigned int delme:1;                /*!< Purge the class */
        unsigned int backslash_is_escape:1;  /*!< On this database, the backslash is a native escape sequence */
        unsigned int forcecommit:1;          /*!< Should uncommitted transactions be auto-committed on handle release? */
        unsigned int isolation;              /*!< Flags for how the DB should deal with data in other, uncommitted transactions */
-       unsigned int limit;                  /*!< Maximum number of database handles we will allow */
-       int count;                           /*!< Running count of pooled connections */
-       unsigned int idlecheck;              /*!< Recheck the connection if it is idle for this long (in seconds) */
-       struct ao2_container *obj_container;
+       unsigned int conntimeout;            /*!< Maximum time the connection process should take */
+       unsigned int maxconnections;         /*!< Maximum number of allowed connections */
+       /*! When a connection fails, cache that failure for how long? */
+       struct timeval negative_connection_cache;
+       /*! When a connection fails, when did that last occur? */
+       struct timeval last_negative_connect;
+       /*! A pool of available connections */
+       AST_LIST_HEAD_NOLOCK(, odbc_obj) connections;
+       /*! Lock to protect the connections */
+       ast_mutex_t lock;
+       /*! Condition to notify any pending connection requesters */
+       ast_cond_t cond;
+       /*! The total number of current connections */
+       size_t connection_cnt;
 };
 
 static struct ao2_container *class_container;
@@ -139,17 +97,10 @@ static AST_RWLIST_HEAD_STATIC(odbc_tables, odbc_cache_tables);
 
 static odbc_status odbc_obj_connect(struct odbc_obj *obj);
 static odbc_status odbc_obj_disconnect(struct odbc_obj *obj);
-static int odbc_register_class(struct odbc_class *class, int connect);
-static void odbc_txn_free(void *data);
-static void odbc_release_obj2(struct odbc_obj *obj, struct odbc_txn_frame *tx);
+static void odbc_register_class(struct odbc_class *class, int connect);
 
 AST_THREADSTORAGE(errors_buf);
 
-static struct ast_datastore_info txn_info = {
-       .type = "ODBC_Transaction",
-       .destroy = odbc_txn_free,
-};
-
 struct odbc_txn_frame {
        AST_LIST_ENTRY(odbc_txn_frame) list;
        struct ast_channel *owner;
@@ -167,7 +118,7 @@ struct odbc_txn_frame {
        char name[0];                   /*!< Name of this transaction ID */
 };
 
-static const char *isolation2text(int iso)
+const char *ast_odbc_isolation2text(int iso)
 {
        if (iso == SQL_TXN_READ_COMMITTED) {
                return "read_committed";
@@ -182,7 +133,7 @@ static const char *isolation2text(int iso)
        }
 }
 
-static int text2isolation(const char *txt)
+int ast_odbc_text2isolation(const char *txt)
 {
        if (strncasecmp(txt, "read_", 5) == 0) {
                if (strncasecmp(txt + 5, "c", 1) == 0) {
@@ -201,175 +152,11 @@ static int text2isolation(const char *txt)
        }
 }
 
-static struct odbc_txn_frame *find_transaction(struct ast_channel *chan, struct odbc_obj *obj, const char *name, int active)
-{
-       struct ast_datastore *txn_store;
-       AST_LIST_HEAD(, odbc_txn_frame) *oldlist;
-       struct odbc_txn_frame *txn = NULL;
-
-       if (!chan && obj && obj->txf && obj->txf->owner) {
-               chan = obj->txf->owner;
-       } else if (!chan) {
-               /* No channel == no transaction */
-               return NULL;
-       }
-
-       ast_channel_lock(chan);
-       if ((txn_store = ast_channel_datastore_find(chan, &txn_info, NULL))) {
-               oldlist = txn_store->data;
-       } else {
-               /* Need to create a new datastore */
-               if (!(txn_store = ast_datastore_alloc(&txn_info, NULL))) {
-                       ast_log(LOG_ERROR, "Unable to allocate a new datastore.  Cannot create a new transaction.\n");
-                       ast_channel_unlock(chan);
-                       return NULL;
-               }
-
-               if (!(oldlist = ast_calloc(1, sizeof(*oldlist)))) {
-                       ast_log(LOG_ERROR, "Unable to allocate datastore list head.  Cannot create a new transaction.\n");
-                       ast_datastore_free(txn_store);
-                       ast_channel_unlock(chan);
-                       return NULL;
-               }
-
-               txn_store->data = oldlist;
-               AST_LIST_HEAD_INIT(oldlist);
-               ast_channel_datastore_add(chan, txn_store);
-       }
-
-       AST_LIST_LOCK(oldlist);
-       ast_channel_unlock(chan);
-
-       /* Scanning for an object is *fast*.  Scanning for a name is much slower. */
-       if (obj != NULL || active == 1) {
-               AST_LIST_TRAVERSE(oldlist, txn, list) {
-                       if (txn->obj == obj || txn->active) {
-                               AST_LIST_UNLOCK(oldlist);
-                               return txn;
-                       }
-               }
-       }
-
-       if (name != NULL) {
-               AST_LIST_TRAVERSE(oldlist, txn, list) {
-                       if (!strcasecmp(txn->name, name)) {
-                               AST_LIST_UNLOCK(oldlist);
-                               return txn;
-                       }
-               }
-       }
-
-       /* Nothing found, create one */
-       if (name && obj && (txn = ast_calloc(1, sizeof(*txn) + strlen(name) + 1))) {
-               struct odbc_txn_frame *otxn;
-
-               strcpy(txn->name, name); /* SAFE */
-               txn->obj = obj;
-               txn->isolation = obj->parent->isolation;
-               txn->forcecommit = obj->parent->forcecommit;
-               txn->owner = chan;
-               txn->active = 1;
-
-               /* On creation, the txn becomes active, and all others inactive */
-               AST_LIST_TRAVERSE(oldlist, otxn, list) {
-                       otxn->active = 0;
-               }
-               AST_LIST_INSERT_TAIL(oldlist, txn, list);
-
-               obj->txf = txn;
-               obj->tx = 1;
-       }
-       AST_LIST_UNLOCK(oldlist);
-
-       return txn;
-}
-
-static struct odbc_txn_frame *release_transaction(struct odbc_txn_frame *tx)
-{
-       if (!tx) {
-               return NULL;
-       }
-
-       ast_debug(2, "release_transaction(%p) called (tx->obj = %p, tx->obj->txf = %p)\n", tx, tx->obj, tx->obj ? tx->obj->txf : NULL);
-
-       /* If we have an owner, disassociate */
-       if (tx->owner) {
-               struct ast_datastore *txn_store;
-               AST_LIST_HEAD(, odbc_txn_frame) *oldlist;
-
-               ast_channel_lock(tx->owner);
-               if ((txn_store = ast_channel_datastore_find(tx->owner, &txn_info, NULL))) {
-                       oldlist = txn_store->data;
-                       AST_LIST_LOCK(oldlist);
-                       AST_LIST_REMOVE(oldlist, tx, list);
-                       AST_LIST_UNLOCK(oldlist);
-               }
-               ast_channel_unlock(tx->owner);
-               tx->owner = NULL;
-       }
-
-       if (tx->obj) {
-               /* If we have any uncommitted transactions, they are handled when we release the object */
-               struct odbc_obj *obj = tx->obj;
-               /* Prevent recursion during destruction */
-               tx->obj->txf = NULL;
-               tx->obj = NULL;
-               odbc_release_obj2(obj, tx);
-       }
-       ast_free(tx);
-       return NULL;
-}
-
-static void odbc_txn_free(void *vdata)
-{
-       struct odbc_txn_frame *tx;
-       AST_LIST_HEAD(, odbc_txn_frame) *oldlist = vdata;
-
-       ast_debug(2, "odbc_txn_free(%p) called\n", vdata);
-
-       AST_LIST_LOCK(oldlist);
-       while ((tx = AST_LIST_REMOVE_HEAD(oldlist, list))) {
-               release_transaction(tx);
-       }
-       AST_LIST_UNLOCK(oldlist);
-       AST_LIST_HEAD_DESTROY(oldlist);
-       ast_free(oldlist);
-}
-
-static int mark_transaction_active(struct ast_channel *chan, struct odbc_txn_frame *tx)
-{
-       struct ast_datastore *txn_store;
-       AST_LIST_HEAD(, odbc_txn_frame) *oldlist;
-       struct odbc_txn_frame *active = NULL, *txn;
-
-       if (!chan && tx && tx->owner) {
-               chan = tx->owner;
-       }
-
-       ast_channel_lock(chan);
-       if (!(txn_store = ast_channel_datastore_find(chan, &txn_info, NULL))) {
-               ast_channel_unlock(chan);
-               return -1;
-       }
-
-       oldlist = txn_store->data;
-       AST_LIST_LOCK(oldlist);
-       AST_LIST_TRAVERSE(oldlist, txn, list) {
-               if (txn == tx) {
-                       txn->active = 1;
-                       active = txn;
-               } else {
-                       txn->active = 0;
-               }
-       }
-       AST_LIST_UNLOCK(oldlist);
-       ast_channel_unlock(chan);
-       return active ? 0 : -1;
-}
-
 static void odbc_class_destructor(void *data)
 {
        struct odbc_class *class = data;
+       struct odbc_obj *obj;
+
        /* Due to refcounts, we can safely assume that any objects with a reference
         * to us will prevent our destruction, so we don't need to worry about them.
         */
@@ -382,8 +169,14 @@ static void odbc_class_destructor(void *data)
        if (class->sanitysql) {
                ast_free(class->sanitysql);
        }
-       ao2_ref(class->obj_container, -1);
+
+       while ((obj = AST_LIST_REMOVE_HEAD(&class->connections, list))) {
+               ao2_ref(obj, -1);
+       }
+
        SQLFreeHandle(SQL_HANDLE_ENV, class->env);
+       ast_mutex_destroy(&class->lock);
+       ast_cond_destroy(&class->cond);
 }
 
 static int null_hash_fn(const void *obj, const int flags)
@@ -394,32 +187,49 @@ static int null_hash_fn(const void *obj, const int flags)
 static void odbc_obj_destructor(void *data)
 {
        struct odbc_obj *obj = data;
-       struct odbc_class *class = obj->parent;
-       obj->parent = NULL;
+
        odbc_obj_disconnect(obj);
-       ast_mutex_destroy(&obj->lock);
-       ao2_ref(class, -1);
 }
 
-static void destroy_table_cache(struct odbc_cache_tables *table) {
+static void destroy_table_cache(struct odbc_cache_tables *table)
+{
        struct odbc_cache_columns *col;
+
        ast_debug(1, "Destroying table cache for %s\n", table->table);
+
        AST_RWLIST_WRLOCK(&table->columns);
        while ((col = AST_RWLIST_REMOVE_HEAD(&table->columns, list))) {
                ast_free(col);
        }
        AST_RWLIST_UNLOCK(&table->columns);
        AST_RWLIST_HEAD_DESTROY(&table->columns);
+
        ast_free(table);
 }
 
 /*!
  * \brief Find or create an entry describing the table specified.
- * \param obj An active ODBC handle on which to query the table
- * \param table Tablename to describe
+ * \param database Name of an ODBC class on which to query the table
+ * \param tablename Tablename to describe
  * \retval A structure describing the table layout, or NULL, if the table is not found or another error occurs.
  * When a structure is returned, the contained columns list will be
  * rdlock'ed, to ensure that it will be retained in memory.
+ *
+ * XXX This creates a connection and disconnects it. In some situations, the caller of
+ * this function has its own connection and could donate it to this function instead of
+ * needing to create another one.
+ *
+ * XXX The automatic readlock of the columns is awkward. It's done because it's possible for
+ * multiple threads to have references to the table, and the table is not refcounted. Possible
+ * changes here would be
+ * * Eliminate the table cache entirely. The use of ast_odbc_find_table() is generally
+ *   questionable. The only real good use right now is from ast_realtime_require_field() in
+ *   order to make sure the DB has the expected columns in it. Since that is only used sparingly,
+ *   the need to cache tables is questionable. Instead, the table structure can be fetched from
+ *   the DB directly each time, resulting in a single owner of the data.
+ * * Make odbc_cache_tables a refcounted object.
+ *
+ * \since 1.6.1
  */
 struct odbc_cache_tables *ast_odbc_find_table(const char *database, const char *tablename)
 {
@@ -428,8 +238,8 @@ struct odbc_cache_tables *ast_odbc_find_table(const char *database, const char *
        char columnname[80];
        SQLLEN sqlptr;
        SQLHSTMT stmt = NULL;
-       int res = 0, error = 0, try = 0;
-       struct odbc_obj *obj = ast_odbc_request_obj(database, 0);
+       int res = 0, error = 0;
+       struct odbc_obj *obj;
 
        AST_RWLIST_RDLOCK(&odbc_tables);
        AST_RWLIST_TRAVERSE(&odbc_tables, tableptr, list) {
@@ -440,13 +250,10 @@ struct odbc_cache_tables *ast_odbc_find_table(const char *database, const char *
        if (tableptr) {
                AST_RWLIST_RDLOCK(&tableptr->columns);
                AST_RWLIST_UNLOCK(&odbc_tables);
-               if (obj) {
-                       ast_odbc_release_obj(obj);
-               }
                return tableptr;
        }
 
-       if (!obj) {
+       if (!(obj = ast_odbc_request_obj(database, 0))) {
                ast_log(LOG_WARNING, "Unable to retrieve database handle for table description '%s@%s'\n", tablename, database);
                AST_RWLIST_UNLOCK(&odbc_tables);
                return NULL;
@@ -456,23 +263,13 @@ struct odbc_cache_tables *ast_odbc_find_table(const char *database, const char *
        do {
                res = SQLAllocHandle(SQL_HANDLE_STMT, obj->con, &stmt);
                if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
-                       if (try == 0) {
-                               try = 1;
-                               ast_odbc_sanity_check(obj);
-                               continue;
-                       }
                        ast_log(LOG_WARNING, "SQL Alloc Handle failed on connection '%s'!\n", database);
                        break;
                }
 
                res = SQLColumns(stmt, NULL, 0, NULL, 0, (unsigned char *)tablename, SQL_NTS, (unsigned char *)"%", SQL_NTS);
                if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
-                       if (try == 0) {
-                               try = 1;
-                               SQLFreeHandle(SQL_HANDLE_STMT, stmt);
-                               ast_odbc_sanity_check(obj);
-                               continue;
-                       }
+                       SQLFreeHandle(SQL_HANDLE_STMT, stmt);
                        ast_log(LOG_ERROR, "Unable to query database columns on connection '%s'.\n", database);
                        break;
                }
@@ -513,7 +310,7 @@ struct odbc_cache_tables *ast_odbc_find_table(const char *database, const char *
                                entry->octetlen = entry->size;
                        }
 
-                       ast_verb(10, "Found %s column with type %hd with len %ld, octetlen %ld, and numlen (%hd,%hd)\n", entry->name, entry->type, (long) entry->size, (long) entry->octetlen, entry->decimals, entry->radix);
+                       ast_debug(3, "Found %s column with type %hd with len %ld, octetlen %ld, and numlen (%hd,%hd)\n", entry->name, entry->type, (long) entry->size, (long) entry->octetlen, entry->decimals, entry->radix);
                        /* Insert column info into column list */
                        AST_LIST_INSERT_TAIL(&(tableptr->columns), entry, list);
                }
@@ -530,9 +327,7 @@ struct odbc_cache_tables *ast_odbc_find_table(const char *database, const char *
                destroy_table_cache(tableptr);
                tableptr = NULL;
        }
-       if (obj) {
-               ast_odbc_release_obj(obj);
-       }
+       ast_odbc_release_obj(obj);
        return tableptr;
 }
 
@@ -566,111 +361,53 @@ int ast_odbc_clear_cache(const char *database, const char *tablename)
 
 SQLHSTMT ast_odbc_direct_execute(struct odbc_obj *obj, SQLHSTMT (*exec_cb)(struct odbc_obj *obj, void *data), void *data)
 {
-       int attempt;
        SQLHSTMT stmt;
 
-       for (attempt = 0; attempt < 2; attempt++) {
-               stmt = exec_cb(obj, data);
-
-               if (stmt) {
-                       break;
-               } else if (obj->tx) {
-                       ast_log(LOG_WARNING, "Failed to execute, but unable to reconnect, as we're transactional.\n");
-                       break;
-               } else {
-                       obj->up = 0;
-                       ast_log(LOG_WARNING, "SQL Exec Direct failed.  Attempting a reconnect...\n");
-
-                       odbc_obj_disconnect(obj);
-                       odbc_obj_connect(obj);
-               }
-       }
+       stmt = exec_cb(obj, data);
 
        return stmt;
 }
 
 SQLHSTMT ast_odbc_prepare_and_execute(struct odbc_obj *obj, SQLHSTMT (*prepare_cb)(struct odbc_obj *obj, void *data), void *data)
 {
-       int res = 0, i, attempt;
-       SQLINTEGER nativeerror=0, numfields=0;
-       SQLSMALLINT diagbytes=0;
-       unsigned char state[10], diagnostic[256];
+       int res = 0;
        SQLHSTMT stmt;
 
-       for (attempt = 0; attempt < 2; attempt++) {
-               /* This prepare callback may do more than just prepare -- it may also
-                * bind parameters, bind results, etc.  The real key, here, is that
-                * when we disconnect, all handles become invalid for most databases.
-                * We must therefore redo everything when we establish a new
-                * connection. */
-               stmt = prepare_cb(obj, data);
-
-               if (stmt) {
-                       res = SQLExecute(stmt);
-                       if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
-                               if (res == SQL_ERROR) {
-                                       SQLGetDiagField(SQL_HANDLE_STMT, stmt, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                                       for (i = 0; i < numfields; i++) {
-                                               SQLGetDiagRec(SQL_HANDLE_STMT, stmt, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                                               ast_log(LOG_WARNING, "SQL Execute returned an error %d: %s: %s (%d)\n", res, state, diagnostic, diagbytes);
-                                               if (i > 10) {
-                                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                                                       break;
-                                               }
-                                       }
-                               }
+       /* This prepare callback may do more than just prepare -- it may also
+        * bind parameters, bind results, etc.  The real key, here, is that
+        * when we disconnect, all handles become invalid for most databases.
+        * We must therefore redo everything when we establish a new
+        * connection. */
+       stmt = prepare_cb(obj, data);
+       if (!stmt) {
+               return NULL;
+       }
 
-                               if (obj->tx) {
-                                       ast_log(LOG_WARNING, "SQL Execute error, but unable to reconnect, as we're transactional.\n");
-                                       break;
-                               } else {
-                                       ast_log(LOG_WARNING, "SQL Execute error %d! Attempting a reconnect...\n", res);
-                                       SQLFreeHandle(SQL_HANDLE_STMT, stmt);
-                                       stmt = NULL;
-
-                                       obj->up = 0;
-                                       /*
-                                        * While this isn't the best way to try to correct an error, this won't automatically
-                                        * fail when the statement handle invalidates.
-                                        */
-                                       ast_odbc_sanity_check(obj);
-                                       continue;
-                               }
-                       } else {
-                               obj->last_used = ast_tvnow();
-                       }
-                       break;
-               } else if (attempt == 0) {
-                       ast_odbc_sanity_check(obj);
+       res = SQLExecute(stmt);
+       if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
+               if (res == SQL_ERROR) {
+                       ast_odbc_print_errors(SQL_HANDLE_STMT, stmt, "SQL Execute");
                }
+
+               ast_log(LOG_WARNING, "SQL Execute error %d!\n", res);
+               SQLFreeHandle(SQL_HANDLE_STMT, stmt);
+               stmt = NULL;
        }
 
        return stmt;
 }
 
-int ast_odbc_smart_execute(struct odbc_obj *obj, SQLHSTMT stmt) 
+int ast_odbc_smart_execute(struct odbc_obj *obj, SQLHSTMT stmt)
 {
-       int res = 0, i;
-       SQLINTEGER nativeerror=0, numfields=0;
-       SQLSMALLINT diagbytes=0;
-       unsigned char state[10], diagnostic[256];
+       int res = 0;
 
        res = SQLExecute(stmt);
        if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
                if (res == SQL_ERROR) {
-                       SQLGetDiagField(SQL_HANDLE_STMT, stmt, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                       for (i = 0; i < numfields; i++) {
-                               SQLGetDiagRec(SQL_HANDLE_STMT, stmt, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                               ast_log(LOG_WARNING, "SQL Execute returned an error %d: %s: %s (%d)\n", res, state, diagnostic, diagbytes);
-                               if (i > 10) {
-                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                                       break;
-                               }
-                       }
+                       ast_odbc_print_errors(SQL_HANDLE_STMT, stmt, "SQL Execute");
                }
-       } else
-               obj->last_used = ast_tvnow();
-       
+       }
+
        return res;
 }
 
@@ -691,39 +428,47 @@ SQLRETURN ast_odbc_ast_str_SQLGetData(struct ast_str **buf, int pmaxlen, SQLHSTM
        return res;
 }
 
-int ast_odbc_sanity_check(struct odbc_obj *obj) 
+struct ast_str *ast_odbc_print_errors(SQLSMALLINT handle_type, SQLHANDLE handle, const char *operation)
 {
-       char *test_sql = "select 1";
-       SQLHSTMT stmt;
-       int res = 0;
-
-       if (!ast_strlen_zero(obj->parent->sanitysql))
-               test_sql = obj->parent->sanitysql;
-
-       if (obj->up) {
-               res = SQLAllocHandle(SQL_HANDLE_STMT, obj->con, &stmt);
-               if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
-                       obj->up = 0;
-               } else {
-                       res = SQLPrepare(stmt, (unsigned char *)test_sql, SQL_NTS);
-                       if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
-                               obj->up = 0;
-                       } else {
-                               res = SQLExecute(stmt);
-                               if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
-                                       obj->up = 0;
-                               }
-                       }
+       struct ast_str *errors = ast_str_thread_get(&errors_buf, 16);
+       SQLINTEGER nativeerror = 0;
+       SQLINTEGER numfields = 0;
+       SQLSMALLINT diagbytes = 0;
+       SQLSMALLINT i;
+       unsigned char state[10];
+       unsigned char diagnostic[256];
+
+       ast_str_reset(errors);
+       SQLGetDiagField(handle_type, handle, 1, SQL_DIAG_NUMBER, &numfields,
+                       SQL_IS_INTEGER, &diagbytes);
+       for (i = 0; i < numfields; i++) {
+               SQLGetDiagRec(handle_type, handle, i + 1, state, &nativeerror,
+                               diagnostic, sizeof(diagnostic), &diagbytes);
+               ast_str_append(&errors, 0, "%s%s", ast_str_strlen(errors) ? "," : "", state);
+               ast_log(LOG_WARNING, "%s returned an error: %s: %s\n", operation, state, diagnostic);
+               /* XXX Why is this here? */
+               if (i > 10) {
+                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
+                       break;
                }
-               SQLFreeHandle (SQL_HANDLE_STMT, stmt);
        }
 
-       if (!obj->up && !obj->tx) { /* Try to reconnect! */
-               ast_log(LOG_WARNING, "Connection is down attempting to reconnect...\n");
-               odbc_obj_disconnect(obj);
-               odbc_obj_connect(obj);
-       }
-       return obj->up;
+       return errors;
+}
+
+unsigned int ast_odbc_class_get_isolation(struct odbc_class *class)
+{
+       return class->isolation;
+}
+
+unsigned int ast_odbc_class_get_forcecommit(struct odbc_class *class)
+{
+       return class->forcecommit;
+}
+
+const char *ast_odbc_class_get_name(struct odbc_class *class)
+{
+       return class->name;
 }
 
 static int load_odbc_config(void)
@@ -733,8 +478,8 @@ static int load_odbc_config(void)
        struct ast_variable *v;
        char *cat;
        const char *dsn, *username, *password, *sanitysql;
-       int enabled, pooling, limit, bse, forcecommit, isolation;
-       unsigned int idlecheck;
+       int enabled, bse, conntimeout, forcecommit, isolation, maxconnections;
+       struct timeval ncache = { 0, 0 };
        int preconnect = 0, res = 0;
        struct ast_flags config_flags = { 0 };
 
@@ -755,32 +500,18 @@ static int load_odbc_config(void)
                        /* Reset all to defaults for each class of odbc connections */
                        dsn = username = password = sanitysql = NULL;
                        enabled = 1;
-                       preconnect = idlecheck = 0;
-                       pooling = 0;
-                       limit = 0;
+                       preconnect = 0;
                        bse = 1;
+                       conntimeout = 10;
                        forcecommit = 0;
                        isolation = SQL_TXN_READ_COMMITTED;
+                       maxconnections = 1;
                        for (v = ast_variable_browse(config, cat); v; v = v->next) {
-                               if (!strcasecmp(v->name, "pooling")) {
-                                       if (ast_true(v->value))
-                                               pooling = 1;
-                               } else if (!strncasecmp(v->name, "share", 5)) {
-                                       /* "shareconnections" is a little clearer in meaning than "pooling" */
-                                       if (ast_false(v->value))
-                                               pooling = 1;
-                               } else if (!strcasecmp(v->name, "limit")) {
-                                       sscanf(v->value, "%d", &limit);
-                                       if (ast_true(v->value) && !limit) {
-                                               ast_log(LOG_WARNING, "Limit should be a number, not a boolean: '%s'.  Setting limit to 1023 for ODBC class '%s'.\n", v->value, cat);
-                                               limit = 1023;
-                                       } else if (ast_false(v->value)) {
-                                               ast_log(LOG_WARNING, "Limit should be a number, not a boolean: '%s'.  Disabling ODBC class '%s'.\n", v->value, cat);
-                                               enabled = 0;
-                                               break;
-                                       }
-                               } else if (!strcasecmp(v->name, "idlecheck")) {
-                                       sscanf(v->value, "%d", &idlecheck);
+                               if (!strcasecmp(v->name, "pooling") ||
+                                               !strncasecmp(v->name, "share", 5) ||
+                                               !strcasecmp(v->name, "limit") ||
+                                               !strcasecmp(v->name, "idlecheck")) {
+                                       ast_log(LOG_WARNING, "The 'pooling', 'shared_connections', 'limit', and 'idlecheck' options were replaced by 'max_connections'.  See res_odbc.conf.sample.\n");
                                } else if (!strcasecmp(v->name, "enabled")) {
                                        enabled = ast_true(v->value);
                                } else if (!strcasecmp(v->name, "pre-connect")) {
@@ -795,13 +526,34 @@ static int load_odbc_config(void)
                                        sanitysql = v->value;
                                } else if (!strcasecmp(v->name, "backslash_is_escape")) {
                                        bse = ast_true(v->value);
+                               } else if (!strcasecmp(v->name, "connect_timeout")) {
+                                       if (sscanf(v->value, "%d", &conntimeout) != 1 || conntimeout < 1) {
+                                               ast_log(LOG_WARNING, "connect_timeout must be a positive integer\n");
+                                               conntimeout = 10;
+                                       }
+                               } else if (!strcasecmp(v->name, "negative_connection_cache")) {
+                                       double dncache;
+                                       if (sscanf(v->value, "%lf", &dncache) != 1 || dncache < 0) {
+                                               ast_log(LOG_WARNING, "negative_connection_cache must be a non-negative integer\n");
+                                               /* 5 minutes sounds like a reasonable default */
+                                               ncache.tv_sec = 300;
+                                               ncache.tv_usec = 0;
+                                       } else {
+                                               ncache.tv_sec = (int)dncache;
+                                               ncache.tv_usec = (dncache - ncache.tv_sec) * 1000000;
+                                       }
                                } else if (!strcasecmp(v->name, "forcecommit")) {
                                        forcecommit = ast_true(v->value);
                                } else if (!strcasecmp(v->name, "isolation")) {
-                                       if ((isolation = text2isolation(v->value)) == 0) {
+                                       if ((isolation = ast_odbc_text2isolation(v->value)) == 0) {
                                                ast_log(LOG_ERROR, "Unrecognized value for 'isolation': '%s' in section '%s'\n", v->value, cat);
                                                isolation = SQL_TXN_READ_COMMITTED;
                                        }
+                               } else if (!strcasecmp(v->name, "max_connections")) {
+                                       if (sscanf(v->value, "%30d", &maxconnections) != 1 || maxconnections < 1) {
+                                               ast_log(LOG_WARNING, "max_connections must be a positive integer\n");
+                                               maxconnections = 1;
+                                        }
                                }
                        }
 
@@ -822,22 +574,12 @@ static int load_odbc_config(void)
                                        return res;
                                }
 
-                               new->obj_container = ao2_container_alloc(1, null_hash_fn, ao2_match_by_addr);
-
-                               if (pooling) {
-                                       new->haspool = pooling;
-                                       if (limit) {
-                                               new->limit = limit;
-                                       } else {
-                                               ast_log(LOG_WARNING, "Pooling without also setting a limit is pointless.  Changing limit from 0 to 5.\n");
-                                               new->limit = 5;
-                                       }
-                               }
-
                                new->backslash_is_escape = bse ? 1 : 0;
                                new->forcecommit = forcecommit ? 1 : 0;
                                new->isolation = isolation;
-                               new->idlecheck = idlecheck;
+                               new->conntimeout = conntimeout;
+                               new->negative_connection_cache = ncache;
+                               new->maxconnections = maxconnections;
 
                                if (cat)
                                        ast_copy_string(new->name, cat, sizeof(new->name));
@@ -856,6 +598,9 @@ static int load_odbc_config(void)
                                        break;
                                }
 
+                               ast_mutex_init(&new->lock);
+                               ast_cond_init(&new->cond, NULL);
+
                                odbc_register_class(new, preconnect);
                                ast_log(LOG_NOTICE, "Registered ODBC class '%s' dsn->[%s]\n", cat, dsn);
                                ao2_ref(new, -1);
@@ -869,9 +614,8 @@ static int load_odbc_config(void)
 
 static char *handle_cli_odbc_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
 {
-       struct ao2_iterator aoi = ao2_iterator_init(class_container, 0);
+       struct ao2_iterator aoi;
        struct odbc_class *class;
-       struct odbc_obj *current;
        int length = 0;
        int which = 0;
        char *ret = NULL;
@@ -888,6 +632,7 @@ static char *handle_cli_odbc_show(struct ast_cli_entry *e, int cmd, struct ast_c
                if (a->pos != 2)
                        return NULL;
                length = strlen(a->word);
+               aoi = ao2_iterator_init(class_container, 0);
                while ((class = ao2_iterator_next(&aoi))) {
                        if (!strncasecmp(a->word, class->name, length) && ++which > a->n) {
                                ret = ast_strdup(class->name);
@@ -897,6 +642,7 @@ static char *handle_cli_odbc_show(struct ast_cli_entry *e, int cmd, struct ast_c
                                break;
                        }
                }
+               ao2_iterator_destroy(&aoi);
                if (!ret && !strncasecmp(a->word, "all", length) && ++which > a->n) {
                        ret = ast_strdup("all");
                }
@@ -908,42 +654,23 @@ static char *handle_cli_odbc_show(struct ast_cli_entry *e, int cmd, struct ast_c
        aoi = ao2_iterator_init(class_container, 0);
        while ((class = ao2_iterator_next(&aoi))) {
                if ((a->argc == 2) || (a->argc == 3 && !strcmp(a->argv[2], "all")) || (!strcmp(a->argv[2], class->name))) {
-                       int count = 0;
+                       char timestr[80];
+                       struct ast_tm tm;
+
                        ast_cli(a->fd, "  Name:   %s\n  DSN:    %s\n", class->name, class->dsn);
 
-                       if (class->haspool) {
-                               struct ao2_iterator aoi2 = ao2_iterator_init(class->obj_container, 0);
-
-                               ast_cli(a->fd, "  Pooled: Yes\n  Limit:  %d\n  Connections in use: %d\n", class->limit, class->count);
-
-                               while ((current = ao2_iterator_next(&aoi2))) {
-                                       ast_mutex_lock(&current->lock);
-#ifdef DEBUG_THREADS
-                                       ast_cli(a->fd, "    - Connection %d: %s (%s:%d %s)\n", ++count,
-                                               current->used ? "in use" :
-                                               current->up && ast_odbc_sanity_check(current) ? "connected" : "disconnected",
-                                               current->file, current->lineno, current->function);
-#else
-                                       ast_cli(a->fd, "    - Connection %d: %s\n", ++count,
-                                               current->used ? "in use" :
-                                               current->up && ast_odbc_sanity_check(current) ? "connected" : "disconnected");
-#endif
-                                       ast_mutex_unlock(&current->lock);
-                                       ao2_ref(current, -1);
-                               }
-                       } else {
-                               /* Should only ever be one of these (unless there are transactions) */
-                               struct ao2_iterator aoi2 = ao2_iterator_init(class->obj_container, 0);
-                               while ((current = ao2_iterator_next(&aoi2))) {
-                                       ast_cli(a->fd, "  Pooled: No\n  Connected: %s\n", current->used ? "In use" :
-                                               current->up && ast_odbc_sanity_check(current) ? "Yes" : "No");
-                                       ao2_ref(current, -1);
-                               }
+                       if (class->last_negative_connect.tv_sec > 0) {
+                               ast_localtime(&class->last_negative_connect, &tm, NULL);
+                               ast_strftime(timestr, sizeof(timestr), "%Y-%m-%d %T", &tm);
+                               ast_cli(a->fd, "    Last fail connection attempt: %s\n", timestr);
                        }
+
+                       ast_cli(a->fd, "    Number of active connections: %zd (out of %d)\n", class->connection_cnt, class->maxconnections);
                        ast_cli(a->fd, "\n");
                }
                ao2_ref(class, -1);
        }
+       ao2_iterator_destroy(&aoi);
 
        return CLI_SUCCESS;
 }
@@ -952,91 +679,47 @@ static struct ast_cli_entry cli_odbc[] = {
        AST_CLI_DEFINE(handle_cli_odbc_show, "List ODBC DSN(s)")
 };
 
-static int odbc_register_class(struct odbc_class *class, int preconnect)
+static void odbc_register_class(struct odbc_class *class, int preconnect)
 {
        struct odbc_obj *obj;
-       if (class) {
-               ao2_link(class_container, class);
-               /* I still have a reference in the caller, so a deref is NOT missing here. */
-
-               if (preconnect) {
-                       /* Request and release builds a connection */
-                       obj = ast_odbc_request_obj(class->name, 0);
-                       if (obj) {
-                               ast_odbc_release_obj(obj);
-                       }
-               }
 
-               return 0;
-       } else {
-               ast_log(LOG_WARNING, "Attempted to register a NULL class?\n");
-               return -1;
-       }
-}
+       ao2_link(class_container, class);
+       /* I still have a reference in the caller, so a deref is NOT missing here. */
 
-static void odbc_release_obj2(struct odbc_obj *obj, struct odbc_txn_frame *tx)
-{
-       SQLINTEGER nativeerror=0, numfields=0;
-       SQLSMALLINT diagbytes=0, i;
-       unsigned char state[10], diagnostic[256];
-
-       ast_debug(2, "odbc_release_obj2(%p) called (obj->txf = %p)\n", obj, obj->txf);
-       if (tx) {
-               ast_debug(1, "called on a transactional handle with %s\n", tx->forcecommit ? "COMMIT" : "ROLLBACK");
-               if (SQLEndTran(SQL_HANDLE_DBC, obj->con, tx->forcecommit ? SQL_COMMIT : SQL_ROLLBACK) == SQL_ERROR) {
-                       /* Handle possible transaction commit failure */
-                       SQLGetDiagField(SQL_HANDLE_DBC, obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                       for (i = 0; i < numfields; i++) {
-                               SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                               ast_log(LOG_WARNING, "SQLEndTran returned an error: %s: %s\n", state, diagnostic);
-                               if (!strcmp((char *)state, "25S02") || !strcmp((char *)state, "08007")) {
-                                       /* These codes mean that a commit failed and a transaction
-                                        * is still active. We must rollback, or things will get
-                                        * very, very weird for anybody using the handle next. */
-                                       SQLEndTran(SQL_HANDLE_DBC, obj->con, SQL_ROLLBACK);
-                               }
-                               if (i > 10) {
-                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                                       break;
-                               }
-                       }
-               }
-
-               /* Transaction is done, reset autocommit */
-               if (SQLSetConnectAttr(obj->con, SQL_ATTR_AUTOCOMMIT, (void *)SQL_AUTOCOMMIT_ON, 0) == SQL_ERROR) {
-                       SQLGetDiagField(SQL_HANDLE_DBC, obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                       for (i = 0; i < numfields; i++) {
-                               SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                               ast_log(LOG_WARNING, "SetConnectAttr (Autocommit) returned an error: %s: %s\n", state, diagnostic);
-                               if (i > 10) {
-                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                                       break;
-                               }
-                       }
-               }
+       if (!preconnect) {
+               return;
        }
 
-#ifdef DEBUG_THREADS
-       obj->file[0] = '\0';
-       obj->function[0] = '\0';
-       obj->lineno = 0;
-#endif
-
-       /* For pooled connections, this frees the connection to be
-        * reused.  For non-pooled connections, it does nothing. */
-       obj->used = 0;
-       if (obj->txf) {
-               /* Prevent recursion -- transaction is already closed out. */
-               obj->txf->obj = NULL;
-               obj->txf = release_transaction(obj->txf);
+       /* Request and release builds a connection */
+       obj = ast_odbc_request_obj(class->name, 0);
+       if (obj) {
+               ast_odbc_release_obj(obj);
        }
-       ao2_ref(obj, -1);
+
+       return;
 }
 
 void ast_odbc_release_obj(struct odbc_obj *obj)
 {
-       struct odbc_txn_frame *tx = find_transaction(NULL, obj, NULL, 0);
-       odbc_release_obj2(obj, tx);
+       struct odbc_class *class = obj->parent;
+
+       ast_debug(2, "Releasing ODBC handle %p into pool\n", obj);
+
+       /* The odbc_obj only holds a reference to the class when it is
+        * actively being used. This guarantees no circular reference
+        * between odbc_class and odbc_obj. Since it is being released
+        * we also release our class reference. If a reload occurred before
+        * the class will go away automatically once all odbc_obj are
+        * released back.
+        */
+       obj->parent = NULL;
+
+       ast_mutex_lock(&class->lock);
+       AST_LIST_INSERT_HEAD(&class->connections, obj, list);
+       ast_cond_signal(&class->cond);
+       ast_mutex_unlock(&class->lock);
+
+       ao2_ref(class, -1);
 }
 
 int ast_odbc_backslash_is_escape(struct odbc_obj *obj)
@@ -1044,326 +727,152 @@ int ast_odbc_backslash_is_escape(struct odbc_obj *obj)
        return obj->parent->backslash_is_escape;
 }
 
-static int commit_exec(struct ast_channel *chan, void *data)
+static int aoro2_class_cb(void *obj, void *arg, int flags)
 {
-       struct odbc_txn_frame *tx;
-       SQLINTEGER nativeerror=0, numfields=0;
-       SQLSMALLINT diagbytes=0, i;
-       unsigned char state[10], diagnostic[256];
-
-       if (ast_strlen_zero(data)) {
-               tx = find_transaction(chan, NULL, NULL, 1);
-       } else {
-               tx = find_transaction(chan, NULL, data, 0);
-       }
-
-       pbx_builtin_setvar_helper(chan, "COMMIT_RESULT", "OK");
-
-       if (tx) {
-               if (SQLEndTran(SQL_HANDLE_DBC, tx->obj->con, SQL_COMMIT) == SQL_ERROR) {
-                       struct ast_str *errors = ast_str_thread_get(&errors_buf, 16);
-                       ast_str_reset(errors);
-
-                       /* Handle possible transaction commit failure */
-                       SQLGetDiagField(SQL_HANDLE_DBC, tx->obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                       for (i = 0; i < numfields; i++) {
-                               SQLGetDiagRec(SQL_HANDLE_DBC, tx->obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                               ast_str_append(&errors, 0, "%s%s", ast_str_strlen(errors) ? "," : "", state);
-                               ast_log(LOG_WARNING, "SQLEndTran returned an error: %s: %s\n", state, diagnostic);
-                               if (i > 10) {
-                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                                       break;
-                               }
-                       }
-                       pbx_builtin_setvar_helper(chan, "COMMIT_RESULT", ast_str_buffer(errors));
-               }
+       struct odbc_class *class = obj;
+       char *name = arg;
+       if (!strcmp(class->name, name) && !class->delme) {
+               return CMP_MATCH | CMP_STOP;
        }
        return 0;
 }
 
-static int rollback_exec(struct ast_channel *chan, void *data)
+unsigned int ast_odbc_get_max_connections(const char *name)
 {
-       struct odbc_txn_frame *tx;
-       SQLINTEGER nativeerror=0, numfields=0;
-       SQLSMALLINT diagbytes=0, i;
-       unsigned char state[10], diagnostic[256];
+       struct odbc_class *class;
+       unsigned int max_connections;
 
-       if (ast_strlen_zero(data)) {
-               tx = find_transaction(chan, NULL, NULL, 1);
-       } else {
-               tx = find_transaction(chan, NULL, data, 0);
+       class = ao2_callback(class_container, 0, aoro2_class_cb, (char *) name);
+       if (!class) {
+               return 0;
        }
 
-       pbx_builtin_setvar_helper(chan, "ROLLBACK_RESULT", "OK");
-
-       if (tx) {
-               if (SQLEndTran(SQL_HANDLE_DBC, tx->obj->con, SQL_ROLLBACK) == SQL_ERROR) {
-                       struct ast_str *errors = ast_str_thread_get(&errors_buf, 16);
-                       ast_str_reset(errors);
-
-                       /* Handle possible transaction commit failure */
-                       SQLGetDiagField(SQL_HANDLE_DBC, tx->obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                       for (i = 0; i < numfields; i++) {
-                               SQLGetDiagRec(SQL_HANDLE_DBC, tx->obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                               ast_str_append(&errors, 0, "%s%s", ast_str_strlen(errors) ? "," : "", state);
-                               ast_log(LOG_WARNING, "SQLEndTran returned an error: %s: %s\n", state, diagnostic);
-                               if (i > 10) {
-                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                                       break;
-                               }
-                       }
-                       pbx_builtin_setvar_helper(chan, "ROLLBACK_RESULT", ast_str_buffer(errors));
-               }
-       }
-       return 0;
+       max_connections = class->maxconnections;
+       ao2_ref(class, -1);
+
+       return max_connections;
 }
 
-static int aoro2_class_cb(void *obj, void *arg, int flags)
+/*
+ * \brief Determine if the connection has died.
+ *
+ * \param connection The connection to check
+ * \param class The ODBC class
+ * \retval 1 Yep, it's dead
+ * \retval 0 It's alive and well
+ */
+static int connection_dead(struct odbc_obj *connection, struct odbc_class *class)
 {
-       struct odbc_class *class = obj;
-       char *name = arg;
-       if (!strcmp(class->name, name) && !class->delme) {
-               return CMP_MATCH | CMP_STOP;
+       char *test_sql = "select 1";
+       SQLINTEGER dead;
+       SQLRETURN res;
+       SQLHSTMT stmt;
+
+       res = SQLGetConnectAttr(connection->con, SQL_ATTR_CONNECTION_DEAD, &dead, 0, 0);
+       if (SQL_SUCCEEDED(res)) {
+               return dead == SQL_CD_TRUE ? 1 : 0;
        }
-       return 0;
-}
 
-#define USE_TX (void *)(long)1
-#define NO_TX  (void *)(long)2
-#define EOR_TX (void *)(long)3
+       /* If the Driver doesn't support SQL_ATTR_CONNECTION_DEAD do a
+        * probing query instead
+        */
+       res = SQLAllocHandle(SQL_HANDLE_STMT, connection->con, &stmt);
+       if (!SQL_SUCCEEDED(res)) {
+               return 1;
+       }
 
-static int aoro2_obj_cb(void *vobj, void *arg, int flags)
-{
-       struct odbc_obj *obj = vobj;
-       ast_mutex_lock(&obj->lock);
-       if ((arg == NO_TX && !obj->tx) || (arg == EOR_TX && !obj->used) || (arg == USE_TX && obj->tx && !obj->used)) {
-               obj->used = 1;
-               ast_mutex_unlock(&obj->lock);
-               return CMP_MATCH | CMP_STOP;
+       if (!ast_strlen_zero(class->sanitysql)) {
+               test_sql = class->sanitysql;
        }
-       ast_mutex_unlock(&obj->lock);
-       return 0;
+
+       res = SQLPrepare(stmt, (unsigned char *)test_sql, SQL_NTS);
+       if (!SQL_SUCCEEDED(res)) {
+               SQLFreeHandle(SQL_HANDLE_STMT, stmt);
+               return 1;
+       }
+
+       res = SQLExecute(stmt);
+       SQLFreeHandle(SQL_HANDLE_STMT, stmt);
+
+       return SQL_SUCCEEDED(res) ? 0 : 1;
 }
 
-#ifdef DEBUG_THREADS
 struct odbc_obj *_ast_odbc_request_obj2(const char *name, struct ast_flags flags, const char *file, const char *function, int lineno)
-#else
-struct odbc_obj *ast_odbc_request_obj2(const char *name, struct ast_flags flags)
-#endif
 {
        struct odbc_obj *obj = NULL;
        struct odbc_class *class;
-       SQLINTEGER nativeerror=0, numfields=0;
-       SQLSMALLINT diagbytes=0, i;
-       unsigned char state[10], diagnostic[256];
 
        if (!(class = ao2_callback(class_container, 0, aoro2_class_cb, (char *) name))) {
+               ast_debug(1, "Class '%s' not found!\n", name);
                return NULL;
        }
 
-       ast_assert(ao2_ref(class, 0) > 1);
+       ast_mutex_lock(&class->lock);
 
-       if (class->haspool) {
-               /* Recycle connections before building another */
-               obj = ao2_callback(class->obj_container, 0, aoro2_obj_cb, EOR_TX);
-
-               if (obj) {
-                       ast_assert(ao2_ref(obj, 0) > 1);
-               }
-
-               if (!obj && (class->count < class->limit)) {
-                       obj = ao2_alloc(sizeof(*obj), odbc_obj_destructor);
-                       if (!obj) {
-                               ao2_ref(class, -1);
-                               return NULL;
-                       }
-                       ast_assert(ao2_ref(obj, 0) == 1);
-                       ast_mutex_init(&obj->lock);
-                       /* obj inherits the outstanding reference to class */
-                       obj->parent = class;
-                       class = NULL;
-                       if (odbc_obj_connect(obj) == ODBC_FAIL) {
-                               ast_log(LOG_WARNING, "Failed to connect to %s\n", name);
-                               ao2_ref(obj, -1);
-                               ast_assert(ao2_ref(class, 0) > 0);
-                               obj = NULL;
-                       } else {
-                               obj->used = 1;
-                               ao2_link(obj->parent->obj_container, obj);
-                               ast_atomic_fetchadd_int(&obj->parent->count, +1);
-                       }
-               } else {
-                       /* Object is not constructed, so delete outstanding reference to class. */
-                       ao2_ref(class, -1);
-                       class = NULL;
-               }
-
-               if (obj && ast_test_flag(&flags, RES_ODBC_INDEPENDENT_CONNECTION)) {
-                       /* Ensure this connection has autocommit turned off. */
-                       if (SQLSetConnectAttr(obj->con, SQL_ATTR_AUTOCOMMIT, (void *)SQL_AUTOCOMMIT_OFF, 0) == SQL_ERROR) {
-                               SQLGetDiagField(SQL_HANDLE_DBC, obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                               for (i = 0; i < numfields; i++) {
-                                       SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                                       ast_log(LOG_WARNING, "SQLSetConnectAttr (Autocommit) returned an error: %s: %s\n", state, diagnostic);
-                                       if (i > 10) {
-                                               ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                                               break;
-                                       }
-                               }
-                       }
-               }
-       } else if (ast_test_flag(&flags, RES_ODBC_INDEPENDENT_CONNECTION)) {
-               /* Non-pooled connections -- but must use a separate connection handle */
-               if (!(obj = ao2_callback(class->obj_container, 0, aoro2_obj_cb, USE_TX))) {
-                       obj = ao2_alloc(sizeof(*obj), odbc_obj_destructor);
-                       if (!obj) {
-                               ao2_ref(class, -1);
-                               return NULL;
-                       }
-                       ast_mutex_init(&obj->lock);
-                       /* obj inherits the outstanding reference to class */
-                       obj->parent = class;
-                       class = NULL;
-                       if (odbc_obj_connect(obj) == ODBC_FAIL) {
-                               ast_log(LOG_WARNING, "Failed to connect to %s\n", name);
-                               ao2_ref(obj, -1);
-                               obj = NULL;
-                       } else {
-                               obj->used = 1;
-                               ao2_link(obj->parent->obj_container, obj);
-                               ast_atomic_fetchadd_int(&obj->parent->count, +1);
-                       }
-               }
+       while (!obj) {
+               obj = AST_LIST_REMOVE_HEAD(&class->connections, list);
 
-               if (obj && SQLSetConnectAttr(obj->con, SQL_ATTR_AUTOCOMMIT, (void *)SQL_AUTOCOMMIT_OFF, 0) == SQL_ERROR) {
-                       SQLGetDiagField(SQL_HANDLE_DBC, obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                       for (i = 0; i < numfields; i++) {
-                               SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                               ast_log(LOG_WARNING, "SetConnectAttr (Autocommit) returned an error: %s: %s\n", state, diagnostic);
-                               if (i > 10) {
-                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
+               if (!obj) {
+                       if (class->connection_cnt < class->maxconnections) {
+                               /* If no connection is immediately available establish a new
+                                * one if allowed. If we try and fail we give up completely as
+                                * we could go into an infinite loop otherwise.
+                                */
+                               obj = ao2_alloc(sizeof(*obj), odbc_obj_destructor);
+                               if (!obj) {
                                        break;
                                }
-                       }
-               }
-       } else {
-               /* Non-pooled connection: multiple modules can use the same connection. */
-               if ((obj = ao2_callback(class->obj_container, 0, aoro2_obj_cb, NO_TX))) {
-                       /* Object is not constructed, so delete outstanding reference to class. */
-                       ast_assert(ao2_ref(class, 0) > 1);
-                       ao2_ref(class, -1);
-                       class = NULL;
-               } else {
-                       /* No entry: build one */
-                       if (!(obj = ao2_alloc(sizeof(*obj), odbc_obj_destructor))) {
-                               ast_assert(ao2_ref(class, 0) > 1);
-                               ao2_ref(class, -1);
-                               return NULL;
-                       }
-                       ast_mutex_init(&obj->lock);
-                       /* obj inherits the outstanding reference to class */
-                       obj->parent = class;
-                       class = NULL;
-                       if (odbc_obj_connect(obj) == ODBC_FAIL) {
-                               ast_log(LOG_WARNING, "Failed to connect to %s\n", name);
-                               ao2_ref(obj, -1);
-                               obj = NULL;
-                       } else {
-                               ao2_link(obj->parent->obj_container, obj);
-                               ast_assert(ao2_ref(obj, 0) > 1);
-                       }
-               }
 
-               if (obj && SQLSetConnectAttr(obj->con, SQL_ATTR_AUTOCOMMIT, (void *)SQL_AUTOCOMMIT_ON, 0) == SQL_ERROR) {
-                       SQLGetDiagField(SQL_HANDLE_DBC, obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                       for (i = 0; i < numfields; i++) {
-                               SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                               ast_log(LOG_WARNING, "SetConnectAttr (Autocommit) returned an error: %s: %s\n", state, diagnostic);
-                               if (i > 10) {
-                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
+                               obj->parent = ao2_bump(class);
+                               if (odbc_obj_connect(obj) == ODBC_FAIL) {
+                                       ao2_ref(obj->parent, -1);
+                                       ao2_ref(obj, -1);
+                                       obj = NULL;
                                        break;
                                }
-                       }
-               }
-       }
 
-       /* Set the isolation property */
-       if (obj && SQLSetConnectAttr(obj->con, SQL_ATTR_TXN_ISOLATION, (void *)(long)obj->parent->isolation, 0) == SQL_ERROR) {
-               SQLGetDiagField(SQL_HANDLE_DBC, obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-               for (i = 0; i < numfields; i++) {
-                       SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                       ast_log(LOG_WARNING, "SetConnectAttr (Txn isolation) returned an error: %s: %s\n", state, diagnostic);
-                       if (i > 10) {
-                               ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                               break;
+                               class->connection_cnt++;
+                               ast_debug(2, "Created ODBC handle %p on class '%s', new count is %zd\n", obj,
+                                       name, class->connection_cnt);
+                       } else {
+                               /* Otherwise if we're not allowed to create a new one we
+                                * wait for another thread to give up the connection they
+                                * own.
+                                */
+                               ast_cond_wait(&class->cond, &class->lock);
                        }
+               } else if (connection_dead(obj, class)) {
+                       /* If the connection is dead try to grab another functional one from the
+                        * pool instead of trying to resurrect this one.
+                        */
+                       ao2_ref(obj, -1);
+                       obj = NULL;
+                       class->connection_cnt--;
+                       ast_debug(2, "ODBC handle %p dead - removing from class '%s', new count is %zd\n",
+                               obj, name, class->connection_cnt);
+               } else {
+                       /* We successfully grabbed a connection from the pool and all is well!
+                        */
+                       obj->parent = ao2_bump(class);
+                       ast_debug(2, "Reusing ODBC handle %p from class '%s'\n", obj, name);
                }
        }
 
-       if (obj && ast_test_flag(&flags, RES_ODBC_SANITY_CHECK)) {
-               ast_odbc_sanity_check(obj);
-       } else if (obj && obj->parent->idlecheck > 0 && ast_tvdiff_sec(ast_tvnow(), obj->last_used) > obj->parent->idlecheck)
-               odbc_obj_connect(obj);
-
-#ifdef DEBUG_THREADS
-       if (obj) {
-               ast_copy_string(obj->file, file, sizeof(obj->file));
-               ast_copy_string(obj->function, function, sizeof(obj->function));
-               obj->lineno = lineno;
-       }
-#endif
-       ast_assert(class == NULL);
+       ast_mutex_unlock(&class->lock);
+       ao2_ref(class, -1);
 
-       if (obj) {
-               ast_assert(ao2_ref(obj, 0) > 1);
-       }
        return obj;
 }
 
-#ifdef DEBUG_THREADS
 struct odbc_obj *_ast_odbc_request_obj(const char *name, int check, const char *file, const char *function, int lineno)
-#else
-struct odbc_obj *ast_odbc_request_obj(const char *name, int check)
-#endif
 {
        struct ast_flags flags = { check ? RES_ODBC_SANITY_CHECK : 0 };
-#ifdef DEBUG_THREADS
+       /* XXX New flow means that the "check" parameter doesn't do anything. We're requesting
+        * a connection from ODBC. We'll either get a new one, which obviously is already connected, or
+        * we'll get one from the ODBC connection pool. In that case, it will ensure to only give us a
+        * live connection
+        */
        return _ast_odbc_request_obj2(name, flags, file, function, lineno);
-#else
-       return ast_odbc_request_obj2(name, flags);
-#endif
-}
-
-struct odbc_obj *ast_odbc_retrieve_transaction_obj(struct ast_channel *chan, const char *objname)
-{
-       struct ast_datastore *txn_store;
-       AST_LIST_HEAD(, odbc_txn_frame) *oldlist;
-       struct odbc_txn_frame *txn = NULL;
-
-       if (!chan) {
-               /* No channel == no transaction */
-               return NULL;
-       }
-
-       ast_channel_lock(chan);
-       if ((txn_store = ast_channel_datastore_find(chan, &txn_info, NULL))) {
-               oldlist = txn_store->data;
-       } else {
-               ast_channel_unlock(chan);
-               return NULL;
-       }
-
-       AST_LIST_LOCK(oldlist);
-       ast_channel_unlock(chan);
-
-       AST_LIST_TRAVERSE(oldlist, txn, list) {
-               if (txn->obj && txn->obj->parent && !strcmp(txn->obj->parent->name, objname)) {
-                       AST_LIST_UNLOCK(oldlist);
-                       return txn->obj;
-               }
-       }
-       AST_LIST_UNLOCK(oldlist);
-       return NULL;
 }
 
 static odbc_status odbc_obj_disconnect(struct odbc_obj *obj)
@@ -1372,34 +881,24 @@ static odbc_status odbc_obj_disconnect(struct odbc_obj *obj)
        SQLINTEGER err;
        short int mlen;
        unsigned char msg[200], state[10];
+       SQLHDBC con;
 
        /* Nothing to disconnect */
        if (!obj->con) {
                return ODBC_SUCCESS;
        }
 
-       ast_mutex_lock(&obj->lock);
-
-       res = SQLDisconnect(obj->con);
+       con = obj->con;
+       obj->con = NULL;
+       res = SQLDisconnect(con);
 
-       if (obj->parent) {
-               if (res == SQL_SUCCESS || res == SQL_SUCCESS_WITH_INFO) {
-                       ast_log(LOG_DEBUG, "Disconnected %d from %s [%s]\n", res, obj->parent->name, obj->parent->dsn);
-               } else {
-                       ast_log(LOG_DEBUG, "res_odbc: %s [%s] already disconnected\n", obj->parent->name, obj->parent->dsn);
-               }
-       }
-
-       if ((res = SQLFreeHandle(SQL_HANDLE_DBC, obj->con) == SQL_SUCCESS)) {
-               obj->con = NULL;
-               ast_log(LOG_DEBUG, "Database handle deallocated\n");
+       if ((res = SQLFreeHandle(SQL_HANDLE_DBC, con)) == SQL_SUCCESS) {
+               ast_debug(3, "Database handle %p (connection %p) deallocated\n", obj, con);
        } else {
-               SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, 1, state, &err, msg, 100, &mlen);
-               ast_log(LOG_WARNING, "Unable to deallocate database handle? %d errno=%d %s\n", res, (int)err, msg);
+               SQLGetDiagRec(SQL_HANDLE_DBC, con, 1, state, &err, msg, 100, &mlen);
+               ast_log(LOG_WARNING, "Unable to deallocate database handle %p? %d errno=%d %s\n", con, res, (int)err, msg);
        }
 
-       obj->up = 0;
-       ast_mutex_unlock(&obj->lock);
        return ODBC_SUCCESS;
 }
 
@@ -1413,194 +912,59 @@ static odbc_status odbc_obj_connect(struct odbc_obj *obj)
        SQLINTEGER enable = 1;
        char *tracefile = "/tmp/odbc.trace";
 #endif
-       ast_mutex_lock(&obj->lock);
+       SQLHDBC con;
+       long int negative_cache_expiration;
 
-       if (obj->up) {
-               odbc_obj_disconnect(obj);
-               ast_log(LOG_NOTICE, "Re-connecting %s\n", obj->parent->name);
-       } else {
-               ast_log(LOG_NOTICE, "Connecting %s\n", obj->parent->name);
+       ast_assert(obj->con == NULL);
+       ast_debug(3, "Connecting %s(%p)\n", obj->parent->name, obj);
+
+       /* Dont connect while server is marked as unreachable via negative_connection_cache */
+       negative_cache_expiration = obj->parent->last_negative_connect.tv_sec + obj->parent->negative_connection_cache.tv_sec;
+       if (time(NULL) < negative_cache_expiration) {
+               ast_log(LOG_WARNING, "Not connecting to %s. Negative connection cache for %ld seconds\n", obj->parent->name, negative_cache_expiration - time(NULL));
+               return ODBC_FAIL;
        }
 
-       res = SQLAllocHandle(SQL_HANDLE_DBC, obj->parent->env, &obj->con);
+       res = SQLAllocHandle(SQL_HANDLE_DBC, obj->parent->env, &con);
 
        if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
                ast_log(LOG_WARNING, "res_odbc: Error AllocHDB %d\n", res);
-               ast_mutex_unlock(&obj->lock);
+               obj->parent->last_negative_connect = ast_tvnow();
                return ODBC_FAIL;
        }
-       SQLSetConnectAttr(obj->con, SQL_LOGIN_TIMEOUT, (SQLPOINTER *) 10, 0);
-       SQLSetConnectAttr(obj->con, SQL_ATTR_CONNECTION_TIMEOUT, (SQLPOINTER *) 10, 0);
+       SQLSetConnectAttr(con, SQL_LOGIN_TIMEOUT, (SQLPOINTER *)(long) obj->parent->conntimeout, 0);
+       SQLSetConnectAttr(con, SQL_ATTR_CONNECTION_TIMEOUT, (SQLPOINTER *)(long) obj->parent->conntimeout, 0);
 #ifdef NEEDTRACE
-       SQLSetConnectAttr(obj->con, SQL_ATTR_TRACE, &enable, SQL_IS_INTEGER);
-       SQLSetConnectAttr(obj->con, SQL_ATTR_TRACEFILE, tracefile, strlen(tracefile));
+       SQLSetConnectAttr(con, SQL_ATTR_TRACE, &enable, SQL_IS_INTEGER);
+       SQLSetConnectAttr(con, SQL_ATTR_TRACEFILE, tracefile, strlen(tracefile));
 #endif
 
-       res = SQLConnect(obj->con,
+       res = SQLConnect(con,
                   (SQLCHAR *) obj->parent->dsn, SQL_NTS,
                   (SQLCHAR *) obj->parent->username, SQL_NTS,
                   (SQLCHAR *) obj->parent->password, SQL_NTS);
 
        if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
-               SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, 1, state, &err, msg, 100, &mlen);
-               ast_mutex_unlock(&obj->lock);
+               SQLGetDiagRec(SQL_HANDLE_DBC, con, 1, state, &err, msg, 100, &mlen);
+               obj->parent->last_negative_connect = ast_tvnow();
                ast_log(LOG_WARNING, "res_odbc: Error SQLConnect=%d errno=%d %s\n", res, (int)err, msg);
+               if ((res = SQLFreeHandle(SQL_HANDLE_DBC, con)) != SQL_SUCCESS) {
+                       SQLGetDiagRec(SQL_HANDLE_DBC, con, 1, state, &err, msg, 100, &mlen);
+                       ast_log(LOG_WARNING, "Unable to deallocate database handle %p? %d errno=%d %s\n", con, res, (int)err, msg);
+               }
                return ODBC_FAIL;
        } else {
-               ast_log(LOG_NOTICE, "res_odbc: Connected to %s [%s]\n", obj->parent->name, obj->parent->dsn);
-               obj->up = 1;
-               obj->last_used = ast_tvnow();
+               ast_debug(3, "res_odbc: Connected to %s [%s (%p)]\n", obj->parent->name, obj->parent->dsn, obj);
        }
 
-       ast_mutex_unlock(&obj->lock);
+       obj->con = con;
        return ODBC_SUCCESS;
 }
 
-static int acf_transaction_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
-{
-       AST_DECLARE_APP_ARGS(args,
-               AST_APP_ARG(property);
-               AST_APP_ARG(opt);
-       );
-       struct odbc_txn_frame *tx;
-
-       AST_STANDARD_APP_ARGS(args, data);
-       if (strcasecmp(args.property, "transaction") == 0) {
-               if ((tx = find_transaction(chan, NULL, NULL, 1))) {
-                       ast_copy_string(buf, tx->name, len);
-                       return 0;
-               }
-       } else if (strcasecmp(args.property, "isolation") == 0) {
-               if (!ast_strlen_zero(args.opt)) {
-                       tx = find_transaction(chan, NULL, args.opt, 0);
-               } else {
-                       tx = find_transaction(chan, NULL, NULL, 1);
-               }
-               if (tx) {
-                       ast_copy_string(buf, isolation2text(tx->isolation), len);
-                       return 0;
-               }
-       } else if (strcasecmp(args.property, "forcecommit") == 0) {
-               if (!ast_strlen_zero(args.opt)) {
-                       tx = find_transaction(chan, NULL, args.opt, 0);
-               } else {
-                       tx = find_transaction(chan, NULL, NULL, 1);
-               }
-               if (tx) {
-                       ast_copy_string(buf, tx->forcecommit ? "1" : "0", len);
-                       return 0;
-               }
-       }
-       return -1;
-}
-
-static int acf_transaction_write(struct ast_channel *chan, const char *cmd, char *s, const char *value)
-{
-       AST_DECLARE_APP_ARGS(args,
-               AST_APP_ARG(property);
-               AST_APP_ARG(opt);
-       );
-       struct odbc_txn_frame *tx;
-       SQLINTEGER nativeerror=0, numfields=0;
-       SQLSMALLINT diagbytes=0, i;
-       unsigned char state[10], diagnostic[256];
-
-       AST_STANDARD_APP_ARGS(args, s);
-       if (strcasecmp(args.property, "transaction") == 0) {
-               /* Set active transaction */
-               struct odbc_obj *obj;
-               if ((tx = find_transaction(chan, NULL, value, 0))) {
-                       mark_transaction_active(chan, tx);
-               } else {
-                       /* No such transaction, create one */
-                       struct ast_flags flags = { RES_ODBC_INDEPENDENT_CONNECTION };
-                       if (ast_strlen_zero(args.opt) || !(obj = ast_odbc_request_obj2(args.opt, flags))) {
-                               ast_log(LOG_ERROR, "Could not create transaction: invalid database specification '%s'\n", S_OR(args.opt, ""));
-                               pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "INVALID_DB");
-                               return -1;
-                       }
-                       if (!(tx = find_transaction(chan, obj, value, 0))) {
-                               pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "FAILED_TO_CREATE");
-                               return -1;
-                       }
-                       obj->tx = 1;
-               }
-               pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "OK");
-               return 0;
-       } else if (strcasecmp(args.property, "forcecommit") == 0) {
-               /* Set what happens when an uncommitted transaction ends without explicit Commit or Rollback */
-               if (ast_strlen_zero(args.opt)) {
-                       tx = find_transaction(chan, NULL, NULL, 1);
-               } else {
-                       tx = find_transaction(chan, NULL, args.opt, 0);
-               }
-               if (!tx) {
-                       pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "FAILED_TO_CREATE");
-                       return -1;
-               }
-               if (ast_true(value)) {
-                       tx->forcecommit = 1;
-               } else if (ast_false(value)) {
-                       tx->forcecommit = 0;
-               } else {
-                       ast_log(LOG_ERROR, "Invalid value for forcecommit: '%s'\n", S_OR(value, ""));
-                       pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "INVALID_VALUE");
-                       return -1;
-               }
-
-               pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "OK");
-               return 0;
-       } else if (strcasecmp(args.property, "isolation") == 0) {
-               /* How do uncommitted transactions affect reads? */
-               int isolation = text2isolation(value);
-               if (ast_strlen_zero(args.opt)) {
-                       tx = find_transaction(chan, NULL, NULL, 1);
-               } else {
-                       tx = find_transaction(chan, NULL, args.opt, 0);
-               }
-               if (!tx) {
-                       pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "FAILED_TO_CREATE");
-                       return -1;
-               }
-               if (isolation == 0) {
-                       pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "INVALID_VALUE");
-                       ast_log(LOG_ERROR, "Invalid isolation specification: '%s'\n", S_OR(value, ""));
-               } else if (SQLSetConnectAttr(tx->obj->con, SQL_ATTR_TXN_ISOLATION, (void *)(long)isolation, 0) == SQL_ERROR) {
-                       pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "SQL_ERROR");
-                       SQLGetDiagField(SQL_HANDLE_DBC, tx->obj->con, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
-                       for (i = 0; i < numfields; i++) {
-                               SQLGetDiagRec(SQL_HANDLE_DBC, tx->obj->con, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
-                               ast_log(LOG_WARNING, "SetConnectAttr (Txn isolation) returned an error: %s: %s\n", state, diagnostic);
-                               if (i > 10) {
-                                       ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
-                                       break;
-                               }
-                       }
-               } else {
-                       pbx_builtin_setvar_helper(chan, "ODBC_RESULT", "OK");
-                       tx->isolation = isolation;
-               }
-               return 0;
-       } else {
-               ast_log(LOG_ERROR, "Unknown property: '%s'\n", args.property);
-               return -1;
-       }
-}
-
-static struct ast_custom_function odbc_function = {
-       .name = "ODBC",
-       .read = acf_transaction_read,
-       .write = acf_transaction_write,
-};
-
-static const char *app_commit = "ODBC_Commit";
-static const char *app_rollback = "ODBC_Rollback";
-
 static int reload(void)
 {
        struct odbc_cache_tables *table;
        struct odbc_class *class;
-       struct odbc_obj *current;
        struct ao2_iterator aoi = ao2_iterator_init(class_container, 0);
 
        /* First, mark all to be purged */
@@ -1608,54 +972,18 @@ static int reload(void)
                class->delme = 1;
                ao2_ref(class, -1);
        }
+       ao2_iterator_destroy(&aoi);
 
        load_odbc_config();
 
-       /* Purge remaining classes */
-
-       /* Note on how this works; this is a case of circular references, so we
-        * explicitly do NOT want to use a callback here (or we wind up in
-        * recursive hell).
-        *
-        * 1. Iterate through all the classes.  Note that the classes will currently
-        * contain two classes of the same name, one of which is marked delme and
-        * will be purged when all remaining objects of the class are released, and
-        * the other, which was created above when we re-parsed the config file.
-        * 2. On each class, there is a reference held by the master container and
-        * a reference held by each connection object.  There are two cases for
-        * destruction of the class, noted below.  However, in all cases, all O-refs
-        * (references to objects) will first be freed, which will cause the C-refs
-        * (references to classes) to be decremented (but never to 0, because the
-        * class container still has a reference).
-        *    a) If the class has outstanding objects, the C-ref by the class
-        *    container will then be freed, which leaves only C-refs by any
-        *    outstanding objects.  When the final outstanding object is released
-        *    (O-refs held by applications and dialplan functions), it will in turn
-        *    free the final C-ref, causing class destruction.
-        *    b) If the class has no outstanding objects, when the class container
-        *    removes the final C-ref, the class will be destroyed.
-        */
        aoi = ao2_iterator_init(class_container, 0);
-       while ((class = ao2_iterator_next(&aoi))) { /* C-ref++ (by iterator) */
+       while ((class = ao2_iterator_next(&aoi))) {
                if (class->delme) {
-                       struct ao2_iterator aoi2 = ao2_iterator_init(class->obj_container, 0);
-                       while ((current = ao2_iterator_next(&aoi2))) { /* O-ref++ (by iterator) */
-                               ao2_unlink(class->obj_container, current); /* unlink O-ref from class (reference handled implicitly) */
-                               ao2_ref(current, -1); /* O-ref-- (by iterator) */
-                               /* At this point, either
-                                * a) there's an outstanding O-ref, or
-                                * b) the object has already been destroyed.
-                                */
-                       }
-                       ao2_unlink(class_container, class); /* unlink C-ref from container (reference handled implicitly) */
-                       /* At this point, either
-                        * a) there's an outstanding O-ref, which holds an outstanding C-ref, or
-                        * b) the last remaining C-ref is held by the iterator, which will be
-                        * destroyed in the next step.
-                        */
+                       ao2_unlink(class_container, class);
                }
-               ao2_ref(class, -1); /* C-ref-- (by iterator) */
+               ao2_ref(class, -1);
        }
+       ao2_iterator_destroy(&aoi);
 
        /* Empty the cache; it will get rebuilt the next time the tables are needed. */
        AST_RWLIST_WRLOCK(&odbc_tables);
@@ -1673,6 +1001,16 @@ static int unload_module(void)
        return -1;
 }
 
+/*!
+ * \brief Load the module
+ *
+ * Module loading including tests for configuration or dependencies.
+ * This function can return AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_DECLINE,
+ * or AST_MODULE_LOAD_SUCCESS. If a dependency or environment variable fails
+ * tests return AST_MODULE_LOAD_FAILURE. If the module can not load the 
+ * configuration file or other non-critical problem return 
+ * AST_MODULE_LOAD_DECLINE. On success return AST_MODULE_LOAD_SUCCESS.
+ */
 static int load_module(void)
 {
        if (!(class_container = ao2_container_alloc(1, null_hash_fn, ao2_match_by_addr)))
@@ -1680,15 +1018,14 @@ static int load_module(void)
        if (load_odbc_config() == -1)
                return AST_MODULE_LOAD_DECLINE;
        ast_cli_register_multiple(cli_odbc, ARRAY_LEN(cli_odbc));
-       ast_register_application_xml(app_commit, commit_exec);
-       ast_register_application_xml(app_rollback, rollback_exec);
-       ast_custom_function_register(&odbc_function);
        ast_log(LOG_NOTICE, "res_odbc loaded.\n");
        return 0;
 }
 
-AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS, "ODBC resource",
-               .load = load_module,
-               .unload = unload_module,
-               .reload = reload,
-              );
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "ODBC resource",
+       .support_level = AST_MODULE_SUPPORT_CORE,
+       .load = load_module,
+       .unload = unload_module,
+       .reload = reload,
+       .load_pri = AST_MODPRI_REALTIME_DEPEND,
+);