res_pjsip_outbound_registration: Fix leak on vector add failure.
[asterisk/asterisk.git] / res / res_odbc.c
index 0b38872..24f63a9 100644 (file)
@@ -1,7 +1,7 @@
 /*
  * Asterisk -- An open source telephony toolkit.
  *
- * Copyright (C) 1999 - 2005, Digium, Inc.
+ * Copyright (C) 1999 - 2012, Digium, Inc.
  *
  * Mark Spencer <markster@digium.com>
  *
  * 
  * \author Mark Spencer <markster@digium.com>
  * \author Anthony Minessale II <anthmct@yahoo.com>
+ * \author Tilghman Lesher <tilghman@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>unixodbc</depend>
+       <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 <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-
 #include "asterisk/file.h"
-#include "asterisk/logger.h"
 #include "asterisk/channel.h"
 #include "asterisk/config.h"
-#include "asterisk/options.h"
 #include "asterisk/pbx.h"
 #include "asterisk/module.h"
 #include "asterisk/cli.h"
 #include "asterisk/lock.h"
 #include "asterisk/res_odbc.h"
+#include "asterisk/time.h"
+#include "asterisk/astobj2.h"
+#include "asterisk/app.h"
+#include "asterisk/strings.h"
+#include "asterisk/threadstorage.h"
 
 struct odbc_class
 {
        AST_LIST_ENTRY(odbc_class) list;
        char name[80];
        char dsn[80];
-       char username[80];
-       char password[80];
-       char sanitysql[256];
+       char *username;
+       char *password;
+       char *sanitysql;
        SQLHENV env;
-       unsigned int haspool:1;         /* Boolean - TDS databases need this */
-       unsigned int limit:10;          /* Gives a limit of 1023 maximum */
-       unsigned int count:10;          /* Running count of pooled connections */
-       unsigned int delme:1;                   /* Purge the class */
-       AST_LIST_HEAD(, odbc_obj) odbc_obj;
+       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 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;
 };
 
-AST_LIST_HEAD_STATIC(odbc_list, odbc_class);
+static struct ao2_container *class_container;
+
+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_register_class(struct odbc_class *class, int connect);
+
+AST_THREADSTORAGE(errors_buf);
+
+struct odbc_txn_frame {
+       AST_LIST_ENTRY(odbc_txn_frame) list;
+       struct ast_channel *owner;
+       struct odbc_obj *obj;        /*!< Database handle within which transacted statements are run */
+       /*!\brief Is this record the current active transaction within the channel?
+        * Note that the active flag is really only necessary for statements which
+        * are triggered from the dialplan, as there isn't a direct correlation
+        * between multiple statements.  Applications wishing to use transactions
+        * may simply perform each statement on the same odbc_obj, which keeps the
+        * transaction persistent.
+        */
+       unsigned int active:1;
+       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 */
+       char name[0];                   /*!< Name of this transaction ID */
+};
 
+const char *ast_odbc_isolation2text(int iso)
+{
+       if (iso == SQL_TXN_READ_COMMITTED) {
+               return "read_committed";
+       } else if (iso == SQL_TXN_READ_UNCOMMITTED) {
+               return "read_uncommitted";
+       } else if (iso == SQL_TXN_SERIALIZABLE) {
+               return "serializable";
+       } else if (iso == SQL_TXN_REPEATABLE_READ) {
+               return "repeatable_read";
+       } else {
+               return "unknown";
+       }
+}
 
-SQLHSTMT ast_odbc_direct_execute(struct odbc_obj *obj, SQLHSTMT (*exec_cb)(struct odbc_obj *obj, void *data), void *data)
+int ast_odbc_text2isolation(const char *txt)
 {
-       int attempt;
-       SQLHSTMT stmt;
+       if (strncasecmp(txt, "read_", 5) == 0) {
+               if (strncasecmp(txt + 5, "c", 1) == 0) {
+                       return SQL_TXN_READ_COMMITTED;
+               } else if (strncasecmp(txt + 5, "u", 1) == 0) {
+                       return SQL_TXN_READ_UNCOMMITTED;
+               } else {
+                       return 0;
+               }
+       } else if (strncasecmp(txt, "ser", 3) == 0) {
+               return SQL_TXN_SERIALIZABLE;
+       } else if (strncasecmp(txt, "rep", 3) == 0) {
+               return SQL_TXN_REPEATABLE_READ;
+       } else {
+               return 0;
+       }
+}
+
+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.
+        */
+       if (class->username) {
+               ast_free(class->username);
+       }
+       if (class->password) {
+               ast_free(class->password);
+       }
+       if (class->sanitysql) {
+               ast_free(class->sanitysql);
+       }
+
+       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)
+{
+       return 0;
+}
+
+static void odbc_obj_destructor(void *data)
+{
+       struct odbc_obj *obj = data;
 
-       for (attempt = 0; attempt < 2; attempt++) {
-               stmt = exec_cb(obj, data);
+       odbc_obj_disconnect(obj);
+}
+
+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);
+}
 
-               if (stmt) {
+/*!
+ * \brief Find or create an entry describing the table specified.
+ * \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)
+{
+       struct odbc_cache_tables *tableptr;
+       struct odbc_cache_columns *entry;
+       char columnname[80];
+       SQLLEN sqlptr;
+       SQLHSTMT stmt = NULL;
+       int res = 0, error = 0;
+       struct odbc_obj *obj;
+
+       AST_RWLIST_RDLOCK(&odbc_tables);
+       AST_RWLIST_TRAVERSE(&odbc_tables, tableptr, list) {
+               if (strcmp(tableptr->connection, database) == 0 && strcmp(tableptr->table, tablename) == 0) {
                        break;
-               } else {
-                       obj->up = 0;
-                       ast_log(LOG_WARNING, "SQL Exec Direct failed.  Attempting a reconnect...\n");
+               }
+       }
+       if (tableptr) {
+               AST_RWLIST_RDLOCK(&tableptr->columns);
+               AST_RWLIST_UNLOCK(&odbc_tables);
+               return tableptr;
+       }
+
+       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;
+       }
+
+       /* Table structure not already cached; build it now. */
+       do {
+               res = SQLAllocHandle(SQL_HANDLE_STMT, obj->con, &stmt);
+               if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
+                       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)) {
+                       SQLFreeHandle(SQL_HANDLE_STMT, stmt);
+                       ast_log(LOG_ERROR, "Unable to query database columns on connection '%s'.\n", database);
+                       break;
+               }
+
+               if (!(tableptr = ast_calloc(sizeof(char), sizeof(*tableptr) + strlen(database) + 1 + strlen(tablename) + 1))) {
+                       ast_log(LOG_ERROR, "Out of memory creating entry for table '%s' on connection '%s'\n", tablename, database);
+                       break;
+               }
+
+               tableptr->connection = (char *)tableptr + sizeof(*tableptr);
+               tableptr->table = (char *)tableptr + sizeof(*tableptr) + strlen(database) + 1;
+               strcpy(tableptr->connection, database); /* SAFE */
+               strcpy(tableptr->table, tablename); /* SAFE */
+               AST_RWLIST_HEAD_INIT(&(tableptr->columns));
+
+               while ((res = SQLFetch(stmt)) != SQL_NO_DATA && res != SQL_ERROR) {
+                       SQLGetData(stmt,  4, SQL_C_CHAR, columnname, sizeof(columnname), &sqlptr);
+
+                       if (!(entry = ast_calloc(sizeof(char), sizeof(*entry) + strlen(columnname) + 1))) {
+                               ast_log(LOG_ERROR, "Out of memory creating entry for column '%s' in table '%s' on connection '%s'\n", columnname, tablename, database);
+                               error = 1;
+                               break;
+                       }
+                       entry->name = (char *)entry + sizeof(*entry);
+                       strcpy(entry->name, columnname);
+
+                       SQLGetData(stmt,  5, SQL_C_SHORT, &entry->type, sizeof(entry->type), NULL);
+                       SQLGetData(stmt,  7, SQL_C_LONG, &entry->size, sizeof(entry->size), NULL);
+                       SQLGetData(stmt,  9, SQL_C_SHORT, &entry->decimals, sizeof(entry->decimals), NULL);
+                       SQLGetData(stmt, 10, SQL_C_SHORT, &entry->radix, sizeof(entry->radix), NULL);
+                       SQLGetData(stmt, 11, SQL_C_SHORT, &entry->nullable, sizeof(entry->nullable), NULL);
+                       SQLGetData(stmt, 16, SQL_C_LONG, &entry->octetlen, sizeof(entry->octetlen), NULL);
+
+                       /* Specification states that the octenlen should be the maximum number of bytes
+                        * returned in a char or binary column, but it seems that some drivers just set
+                        * it to NULL. (Bad Postgres! No biscuit!) */
+                       if (entry->octetlen == 0) {
+                               entry->octetlen = entry->size;
+                       }
 
-                       odbc_obj_disconnect(obj);
-                       odbc_obj_connect(obj);
+                       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);
                }
+               SQLFreeHandle(SQL_HANDLE_STMT, stmt);
+
+               AST_RWLIST_INSERT_TAIL(&odbc_tables, tableptr, list);
+               AST_RWLIST_RDLOCK(&(tableptr->columns));
+               break;
+       } while (1);
+
+       AST_RWLIST_UNLOCK(&odbc_tables);
+
+       if (error) {
+               destroy_table_cache(tableptr);
+               tableptr = NULL;
        }
+       ast_odbc_release_obj(obj);
+       return tableptr;
+}
+
+struct odbc_cache_columns *ast_odbc_find_column(struct odbc_cache_tables *table, const char *colname)
+{
+       struct odbc_cache_columns *col;
+       AST_RWLIST_TRAVERSE(&table->columns, col, list) {
+               if (strcasecmp(col->name, colname) == 0) {
+                       return col;
+               }
+       }
+       return NULL;
+}
+
+int ast_odbc_clear_cache(const char *database, const char *tablename)
+{
+       struct odbc_cache_tables *tableptr;
+
+       AST_RWLIST_WRLOCK(&odbc_tables);
+       AST_RWLIST_TRAVERSE_SAFE_BEGIN(&odbc_tables, tableptr, list) {
+               if (strcmp(tableptr->connection, database) == 0 && strcmp(tableptr->table, tablename) == 0) {
+                       AST_LIST_REMOVE_CURRENT(list);
+                       destroy_table_cache(tableptr);
+                       break;
+               }
+       }
+       AST_RWLIST_TRAVERSE_SAFE_END
+       AST_RWLIST_UNLOCK(&odbc_tables);
+       return tableptr ? 0 : -1;
+}
+
+SQLHSTMT ast_odbc_direct_execute(struct odbc_obj *obj, SQLHSTMT (*exec_cb)(struct odbc_obj *obj, void *data), void *data)
+{
+       SQLHSTMT stmt;
+
+       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;
+       }
 
-                               ast_log(LOG_WARNING, "SQL Execute error %d! Attempting a reconnect...\n", res);
-                               SQLFreeHandle(SQL_HANDLE_STMT, stmt);
-                               stmt = NULL;
+       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");
+               }
 
-                               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;
-                       }
-                       break;
-               } else if (attempt == 0)
-                       ast_odbc_sanity_check(obj);
+               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");
                }
-#if 0
-               /* This is a really bad method of trying to correct a dead connection.  It
-                * only ever really worked with MySQL.  It will not work with any other
-                * database, since most databases prepare their statements on the server,
-                * and if you disconnect, you invalidate the statement handle.  Hence, if
-                * you disconnect, you're going to fail anyway, whether you try to execute
-                * a second time or not.
-                */
-               ast_log(LOG_WARNING, "SQL Execute error %d! Attempting a reconnect...\n", res);
-               ast_mutex_lock(&obj->lock);
-               obj->up = 0;
-               ast_mutex_unlock(&obj->lock);
-               odbc_obj_disconnect(obj);
-               odbc_obj_connect(obj);
-               res = SQLExecute(stmt);
-#endif
        }
-       
+
        return res;
 }
 
-
-int ast_odbc_sanity_check(struct odbc_obj *obj) 
+SQLRETURN ast_odbc_ast_str_SQLGetData(struct ast_str **buf, int pmaxlen, SQLHSTMT StatementHandle, SQLUSMALLINT ColumnNumber, SQLSMALLINT TargetType, SQLLEN *StrLen_or_Ind)
 {
-       char *test_sql = "select 1";
-       SQLHSTMT stmt;
-       int res = 0;
+       SQLRETURN res;
 
-       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;
-                               }
-                       }
+       if (pmaxlen == 0) {
+               if (SQLGetData(StatementHandle, ColumnNumber, TargetType, ast_str_buffer(*buf), 0, StrLen_or_Ind) == SQL_SUCCESS_WITH_INFO) {
+                       ast_str_make_space(buf, *StrLen_or_Ind + 1);
                }
-               SQLFreeHandle (SQL_HANDLE_STMT, stmt);
+       } else if (pmaxlen > 0) {
+               ast_str_make_space(buf, pmaxlen);
        }
+       res = SQLGetData(StatementHandle, ColumnNumber, TargetType, ast_str_buffer(*buf), ast_str_size(*buf), StrLen_or_Ind);
+       ast_str_update(*buf);
 
-       if (!obj->up) { /* Try to reconnect! */
-               ast_log(LOG_WARNING, "Connection is down attempting to reconnect...\n");
-               odbc_obj_disconnect(obj);
-               odbc_obj_connect(obj);
+       return res;
+}
+
+struct ast_str *ast_odbc_print_errors(SQLSMALLINT handle_type, SQLHANDLE handle, const char *operation)
+{
+       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;
+               }
        }
-       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)
@@ -232,15 +476,17 @@ static int load_odbc_config(void)
        static char *cfg = "res_odbc.conf";
        struct ast_config *config;
        struct ast_variable *v;
-       char *cat, *dsn, *username, *password, *sanitysql;
-       int enabled, pooling, limit;
-       int connect = 0, res = 0;
+       char *cat;
+       const char *dsn, *username, *password, *sanitysql;
+       int enabled, bse, conntimeout, forcecommit, isolation, maxconnections;
+       struct timeval ncache = { 0, 0 };
+       int preconnect = 0, res = 0;
        struct ast_flags config_flags = { 0 };
 
        struct odbc_class *new;
 
        config = ast_config_load(cfg, config_flags);
-       if (!config) {
+       if (config == CONFIG_STATUS_FILEMISSING || config == CONFIG_STATUS_FILEINVALID) {
                ast_log(LOG_WARNING, "Unable to load config file res_odbc.conf\n");
                return -1;
        }
@@ -254,27 +500,22 @@ static int load_odbc_config(void)
                        /* Reset all to defaults for each class of odbc connections */
                        dsn = username = password = sanitysql = NULL;
                        enabled = 1;
-                       connect = 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 (!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;
-                                       }
+                               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")) {
-                                       connect = ast_true(v->value);
+                                       preconnect = ast_true(v->value);
                                } else if (!strcasecmp(v->name, "dsn")) {
                                        dsn = v->value;
                                } else if (!strcasecmp(v->name, "username")) {
@@ -283,49 +524,87 @@ static int load_odbc_config(void)
                                        password = v->value;
                                } else if (!strcasecmp(v->name, "sanitysql")) {
                                        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 = 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;
+                                        }
                                }
                        }
 
                        if (enabled && !ast_strlen_zero(dsn)) {
-                               new = ast_calloc(1, sizeof(*new));
+                               new = ao2_alloc(sizeof(*new), odbc_class_destructor);
 
                                if (!new) {
                                        res = -1;
                                        break;
                                }
 
-                               if (cat)
-                                       ast_copy_string(new->name, cat, sizeof(new->name));
-                               if (dsn)
-                                       ast_copy_string(new->dsn, dsn, sizeof(new->dsn));
-                               if (username)
-                                       ast_copy_string(new->username, username, sizeof(new->username));
-                               if (password)
-                                       ast_copy_string(new->password, password, sizeof(new->password));
-                               if (sanitysql)
-                                       ast_copy_string(new->sanitysql, sanitysql, sizeof(new->sanitysql));
-
                                SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &new->env);
                                res = SQLSetEnvAttr(new->env, SQL_ATTR_ODBC_VERSION, (void *) SQL_OV_ODBC3, 0);
 
                                if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
                                        ast_log(LOG_WARNING, "res_odbc: Error SetEnv\n");
-                                       SQLFreeHandle(SQL_HANDLE_ENV, new->env);
+                                       ao2_ref(new, -1);
                                        return res;
                                }
 
-                               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->conntimeout = conntimeout;
+                               new->negative_connection_cache = ncache;
+                               new->maxconnections = maxconnections;
+
+                               if (cat)
+                                       ast_copy_string(new->name, cat, sizeof(new->name));
+                               if (dsn)
+                                       ast_copy_string(new->dsn, dsn, sizeof(new->dsn));
+                               if (username && !(new->username = ast_strdup(username))) {
+                                       ao2_ref(new, -1);
+                                       break;
+                               }
+                               if (password && !(new->password = ast_strdup(password))) {
+                                       ao2_ref(new, -1);
+                                       break;
+                               }
+                               if (sanitysql && !(new->sanitysql = ast_strdup(sanitysql))) {
+                                       ao2_ref(new, -1);
+                                       break;
                                }
 
-                               odbc_register_class(new, connect);
+                               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);
+                               new = NULL;
                        }
                }
        }
@@ -335,8 +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;
        struct odbc_class *class;
-       struct odbc_obj *current;
        int length = 0;
        int which = 0;
        char *ret = NULL;
@@ -353,44 +632,45 @@ 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);
-               AST_LIST_LOCK(&odbc_list);
-               AST_LIST_TRAVERSE(&odbc_list, class, list) {
+               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);
+                       }
+                       ao2_ref(class, -1);
+                       if (ret) {
                                break;
                        }
                }
+               ao2_iterator_destroy(&aoi);
                if (!ret && !strncasecmp(a->word, "all", length) && ++which > a->n) {
                        ret = ast_strdup("all");
                }
-               AST_LIST_UNLOCK(&odbc_list);
                return ret;
        }
 
        ast_cli(a->fd, "\nODBC DSN Settings\n");
-       ast_cli(a->fd, "-----------------\n\n");
-       AST_LIST_LOCK(&odbc_list);
-       AST_LIST_TRAVERSE(&odbc_list, class, list) {
+       ast_cli(a->fd,   "-----------------\n\n");
+       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;
-                       ast_cli(a->fd, "  Name:   %s\n  DSN:    %s\n", class->name, class->dsn);
+                       char timestr[80];
+                       struct ast_tm tm;
 
-                       if (class->haspool) {
-                               ast_cli(a->fd, "  Pooled: Yes\n  Limit:  %d\n  Connections in use: %d\n", class->limit, class->count);
+                       ast_cli(a->fd, "  Name:   %s\n  DSN:    %s\n", class->name, class->dsn);
 
-                               AST_LIST_TRAVERSE(&(class->odbc_obj), current, list) {
-                                       ast_cli(a->fd, "    - Connection %d: %s\n", ++count, current->used ? "in use" : current->up && ast_odbc_sanity_check(current) ? "connected" : "disconnected");
-                               }
-                       } else {
-                               /* Should only ever be one of these */
-                               AST_LIST_TRAVERSE(&(class->odbc_obj), current, list) {
-                                       ast_cli(a->fd, "  Pooled: No\n  Connected: %s\n", current->up && ast_odbc_sanity_check(current) ? "Yes" : "No");
-                               }
+                       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);
        }
-       AST_LIST_UNLOCK(&odbc_list);
+       ao2_iterator_destroy(&aoi);
 
        return CLI_SUCCESS;
 }
@@ -399,129 +679,226 @@ 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 connect)
+static void odbc_register_class(struct odbc_class *class, int preconnect)
 {
        struct odbc_obj *obj;
-       if (class) {
-               AST_LIST_LOCK(&odbc_list);
-               AST_LIST_INSERT_HEAD(&odbc_list, class, list);
-               AST_LIST_UNLOCK(&odbc_list);
-
-               if (connect) {
-                       /* 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. */
+
+       if (!preconnect) {
+               return;
        }
+
+       /* Request and release builds a connection */
+       obj = ast_odbc_request_obj(class->name, 0);
+       if (obj) {
+               ast_odbc_release_obj(obj);
+       }
+
+       return;
 }
 
 void ast_odbc_release_obj(struct odbc_obj *obj)
 {
-       /* For pooled connections, this frees the connection to be
-        * reused.  For non-pooled connections, it does nothing. */
-       obj->used = 0;
+       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)
+{
+       return obj->parent->backslash_is_escape;
 }
 
-struct odbc_obj *ast_odbc_request_obj(const char *name, int check)
+static int aoro2_class_cb(void *obj, void *arg, int flags)
+{
+       struct odbc_class *class = obj;
+       char *name = arg;
+       if (!strcmp(class->name, name) && !class->delme) {
+               return CMP_MATCH | CMP_STOP;
+       }
+       return 0;
+}
+
+unsigned int ast_odbc_get_max_connections(const char *name)
 {
-       struct odbc_obj *obj = NULL;
        struct odbc_class *class;
+       unsigned int max_connections;
 
-       AST_LIST_LOCK(&odbc_list);
-       AST_LIST_TRAVERSE(&odbc_list, class, list) {
-               if (!strcmp(class->name, name))
-                       break;
+       class = ao2_callback(class_container, 0, aoro2_class_cb, (char *) name);
+       if (!class) {
+               return 0;
        }
-       AST_LIST_UNLOCK(&odbc_list);
 
-       if (!class)
+       max_connections = class->maxconnections;
+       ao2_ref(class, -1);
+
+       return max_connections;
+}
+
+/*
+ * \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)
+{
+       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;
+       }
+
+       /* 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;
+       }
+
+       if (!ast_strlen_zero(class->sanitysql)) {
+               test_sql = class->sanitysql;
+       }
+
+       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;
+}
+
+struct odbc_obj *_ast_odbc_request_obj2(const char *name, struct ast_flags flags, const char *file, const char *function, int lineno)
+{
+       struct odbc_obj *obj = NULL;
+       struct odbc_class *class;
+
+       if (!(class = ao2_callback(class_container, 0, aoro2_class_cb, (char *) name))) {
+               ast_debug(1, "Class '%s' not found!\n", name);
                return NULL;
+       }
 
-       AST_LIST_LOCK(&class->odbc_obj);
-       if (class->haspool) {
-               /* Recycle connections before building another */
-               AST_LIST_TRAVERSE(&class->odbc_obj, obj, list) {
-                       if (! obj->used) {
-                               obj->used = 1;
-                               break;
-                       }
-               }
+       ast_mutex_lock(&class->lock);
 
-               if (!obj && (class->count < class->limit)) {
-                       class->count++;
-                       obj = ast_calloc(1, sizeof(*obj));
-                       if (!obj) {
-                               AST_LIST_UNLOCK(&class->odbc_obj);
-                               return NULL;
-                       }
-                       ast_mutex_init(&obj->lock);
-                       obj->parent = class;
-                       if (odbc_obj_connect(obj) == ODBC_FAIL) {
-                               ast_log(LOG_WARNING, "Failed to connect to %s\n", name);
-                               ast_mutex_destroy(&obj->lock);
-                               free(obj);
-                               obj = NULL;
-                               class->count--;
-                       } else {
-                               obj->used = 1;
-                               AST_LIST_INSERT_TAIL(&class->odbc_obj, obj, list);
-                       }
-               }
-       } else {
-               /* Non-pooled connection: multiple modules can use the same connection. */
-               AST_LIST_TRAVERSE(&class->odbc_obj, obj, list) {
-                       /* Non-pooled connection: if there is an entry, return it */
-                       break;
-               }
+       while (!obj) {
+               obj = AST_LIST_REMOVE_HEAD(&class->connections, list);
 
                if (!obj) {
-                       /* No entry: build one */
-                       obj = ast_calloc(1, sizeof(*obj));
-                       if (!obj) {
-                               AST_LIST_UNLOCK(&class->odbc_obj);
-                               return NULL;
-                       }
-                       ast_mutex_init(&obj->lock);
-                       obj->parent = class;
-                       if (odbc_obj_connect(obj) == ODBC_FAIL) {
-                               ast_log(LOG_WARNING, "Failed to connect to %s\n", name);
-                               ast_mutex_destroy(&obj->lock);
-                               ast_free(obj);
-                               obj = NULL;
+                       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;
+                               }
+
+                               obj->parent = ao2_bump(class);
+                               if (odbc_obj_connect(obj) == ODBC_FAIL) {
+                                       ao2_ref(obj->parent, -1);
+                                       ao2_ref(obj, -1);
+                                       obj = NULL;
+                                       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 {
-                               AST_LIST_INSERT_HEAD(&class->odbc_obj, obj, list);
+                               /* 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);
                }
        }
-       AST_LIST_UNLOCK(&class->odbc_obj);
 
-       if (obj && check) {
-               ast_odbc_sanity_check(obj);
-       }
+       ast_mutex_unlock(&class->lock);
+       ao2_ref(class, -1);
+
        return obj;
 }
 
+struct odbc_obj *_ast_odbc_request_obj(const char *name, int check, const char *file, const char *function, int lineno)
+{
+       struct ast_flags flags = { check ? RES_ODBC_SANITY_CHECK : 0 };
+       /* 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);
+}
+
 static odbc_status odbc_obj_disconnect(struct odbc_obj *obj)
 {
        int res;
-       ast_mutex_lock(&obj->lock);
+       SQLINTEGER err;
+       short int mlen;
+       unsigned char msg[200], state[10];
+       SQLHDBC con;
 
-       res = SQLDisconnect(obj->con);
+       /* Nothing to disconnect */
+       if (!obj->con) {
+               return ODBC_SUCCESS;
+       }
 
-       if (res == ODBC_SUCCESS) {
-               ast_log(LOG_WARNING, "res_odbc: disconnected %d from %s [%s]\n", res, obj->parent->name, obj->parent->dsn);
+       con = obj->con;
+       obj->con = NULL;
+       res = SQLDisconnect(con);
+
+       if ((res = SQLFreeHandle(SQL_HANDLE_DBC, con)) == SQL_SUCCESS) {
+               ast_debug(3, "Database handle %p (connection %p) deallocated\n", obj, con);
        } else {
-               ast_log(LOG_WARNING, "res_odbc: %s [%s] already disconnected\n",
-               obj->parent->name, obj->parent->dsn);
+               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;
 }
 
@@ -530,194 +907,90 @@ static odbc_status odbc_obj_connect(struct odbc_obj *obj)
        int res;
        SQLINTEGER err;
        short int mlen;
-       unsigned char msg[200], stat[10];
+       unsigned char msg[200], state[10];
 #ifdef NEEDTRACE
        SQLINTEGER enable = 1;
        char *tracefile = "/tmp/odbc.trace";
 #endif
-       ast_mutex_lock(&obj->lock);
+       SQLHDBC con;
+       long int negative_cache_expiration;
+
+       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(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
 
-       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);
-       }
-
-       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, stat, &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;
+               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 reload(void)
 {
-       static char *cfg = "res_odbc.conf";
-       struct ast_config *config;
-       struct ast_variable *v;
-       char *cat, *dsn, *username, *password, *sanitysql;
-       int enabled, pooling, limit;
-       int connect = 0, res = 0;
-       struct ast_flags config_flags = { CONFIG_FLAG_FILEUNCHANGED };
-
-       struct odbc_class *new, *class;
-       struct odbc_obj *current;
+       struct odbc_cache_tables *table;
+       struct odbc_class *class;
+       struct ao2_iterator aoi = ao2_iterator_init(class_container, 0);
 
        /* First, mark all to be purged */
-       AST_LIST_LOCK(&odbc_list);
-       AST_LIST_TRAVERSE(&odbc_list, class, list) {
+       while ((class = ao2_iterator_next(&aoi))) {
                class->delme = 1;
+               ao2_ref(class, -1);
        }
+       ao2_iterator_destroy(&aoi);
 
-       config = ast_config_load(cfg, config_flags);
-       if (config != NULL && config != CONFIG_STATUS_FILEUNCHANGED) {
-               for (cat = ast_category_browse(config, NULL); cat; cat=ast_category_browse(config, cat)) {
-                       if (!strcasecmp(cat, "ENV")) {
-                               for (v = ast_variable_browse(config, cat); v; v = v->next) {
-                                       setenv(v->name, v->value, 1);
-                                       ast_log(LOG_NOTICE, "Adding ENV var: %s=%s\n", v->name, v->value);
-                               }
-                       } else {
-                               /* Reset all to defaults for each class of odbc connections */
-                               dsn = username = password = sanitysql = NULL;
-                               enabled = 1;
-                               connect = 0;
-                               pooling = 0;
-                               limit = 0;
-                               for (v = ast_variable_browse(config, cat); v; v = v->next) {
-                                       if (!strcasecmp(v->name, "pooling")) {
-                                               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, "enabled")) {
-                                               enabled = ast_true(v->value);
-                                       } else if (!strcasecmp(v->name, "pre-connect")) {
-                                               connect = ast_true(v->value);
-                                       } else if (!strcasecmp(v->name, "dsn")) {
-                                               dsn = v->value;
-                                       } else if (!strcasecmp(v->name, "username")) {
-                                               username = v->value;
-                                       } else if (!strcasecmp(v->name, "password")) {
-                                               password = v->value;
-                                       } else if (!strcasecmp(v->name, "sanitysql")) {
-                                               sanitysql = v->value;
-                                       }
-                               }
-
-                               if (enabled && !ast_strlen_zero(dsn)) {
-                                       /* First, check the list to see if it already exists */
-                                       AST_LIST_TRAVERSE(&odbc_list, class, list) {
-                                               if (!strcmp(class->name, cat)) {
-                                                       class->delme = 0;
-                                                       break;
-                                               }
-                                       }
-
-                                       if (class) {
-                                               new = class;
-                                       } else {
-                                               new = ast_calloc(1, sizeof(*new));
-                                       }
-
-                                       if (!new) {
-                                               res = -1;
-                                               break;
-                                       }
-
-                                       if (cat)
-                                               ast_copy_string(new->name, cat, sizeof(new->name));
-                                       if (dsn)
-                                               ast_copy_string(new->dsn, dsn, sizeof(new->dsn));
-                                       if (username)
-                                               ast_copy_string(new->username, username, sizeof(new->username));
-                                       if (password)
-                                               ast_copy_string(new->password, password, sizeof(new->password));
-                                       if (sanitysql)
-                                               ast_copy_string(new->sanitysql, sanitysql, sizeof(new->sanitysql));
-
-                                       if (!class) {
-                                               SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &new->env);
-                                               res = SQLSetEnvAttr(new->env, SQL_ATTR_ODBC_VERSION, (void *) SQL_OV_ODBC3, 0);
-
-                                               if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
-                                                       ast_log(LOG_WARNING, "res_odbc: Error SetEnv\n");
-                                                       SQLFreeHandle(SQL_HANDLE_ENV, new->env);
-                                                       AST_LIST_UNLOCK(&odbc_list);
-                                                       return res;
-                                               }
-                                       }
+       load_odbc_config();
 
-                                       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;
-                                               }
-                                       }
-
-                                       if (class) {
-                                               ast_log(LOG_NOTICE, "Refreshing ODBC class '%s' dsn->[%s]\n", cat, dsn);
-                                       } else {
-                                               odbc_register_class(new, connect);
-                                               ast_log(LOG_NOTICE, "Registered ODBC class '%s' dsn->[%s]\n", cat, dsn);
-                                       }
-                               }
-                       }
+       aoi = ao2_iterator_init(class_container, 0);
+       while ((class = ao2_iterator_next(&aoi))) {
+               if (class->delme) {
+                       ao2_unlink(class_container, class);
                }
-               ast_config_destroy(config);
+               ao2_ref(class, -1);
        }
+       ao2_iterator_destroy(&aoi);
 
-       /* Purge classes that we know can go away (pooled with 0, only) */
-       AST_LIST_TRAVERSE_SAFE_BEGIN(&odbc_list, class, list) {
-               if (class->delme && class->haspool && class->count == 0) {
-                       while ((current = AST_LIST_REMOVE_HEAD(&class->odbc_obj, list))) {
-                               odbc_obj_disconnect(current);
-                               ast_mutex_destroy(&current->lock);
-                               ast_free(current);
-                       }
-
-                       AST_LIST_REMOVE_CURRENT(list);
-                       ast_free(class);
-               }
+       /* Empty the cache; it will get rebuilt the next time the tables are needed. */
+       AST_RWLIST_WRLOCK(&odbc_tables);
+       while ((table = AST_RWLIST_REMOVE_HEAD(&odbc_tables, list))) {
+               destroy_table_cache(table);
        }
-       AST_LIST_TRAVERSE_SAFE_END;
-       AST_LIST_UNLOCK(&odbc_list);
+       AST_RWLIST_UNLOCK(&odbc_tables);
 
        return 0;
 }
@@ -728,17 +1001,31 @@ 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(load_odbc_config() == -1)
+       if (!(class_container = ao2_container_alloc(1, null_hash_fn, ao2_match_by_addr)))
+               return AST_MODULE_LOAD_DECLINE;
+       if (load_odbc_config() == -1)
                return AST_MODULE_LOAD_DECLINE;
-       ast_cli_register_multiple(cli_odbc, sizeof(cli_odbc) / sizeof(struct ast_cli_entry));
+       ast_cli_register_multiple(cli_odbc, ARRAY_LEN(cli_odbc));
        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,
+);