MXS-1278: Add 'sql_mode' configuration parameter

Using the 'sql_mode' configuration parameter, the initial sql mode
can be specified.

Documentation/Getting-Started/Configuration-Guide.md

@@ -519,6 +519,35 @@ This will log all statements that cannot be parsed completely. This may be
 useful if you suspect that MariaDB MaxScale routes statements to the wrong
 server (e.g. to a slave instead of to a master).
 
+#### `sql_mode`
+
+Specifies whether the query classifier parser should initially expect _MariaDB_
+or _PL/SQL_ kind of SQL.
+
+The allowed values are:
+   `default`: The parser expects regular _MariaDB_ SQL.
+   `oracle` : The parser expects PL/SQL.
+
+```
+sql_mode=oracle
+```
+
+The default value is `default`, which is also used if no value is specified
+or if `sql_mode=` is not present at all. At runtime, MariaDB MaxScale will
+recognize statements like
+```
+set sql_mode=oracle;
+```
+and
+```
+set sql_mode=default;
+```
+and change mode accordingly.
+
+Note that MariaDB MaxScale is **not** explicitly aware of the sql mode of
+the server, so the value of `sql_mode` should reflect the sql mode used
+when the server is started.
+
 ### Service
 
 A service represents the database service that MariaDB MaxScale offers to the

include/maxscale/config.h

@@ -23,6 +23,7 @@
 #include <sys/utsname.h>
 
 #include <maxscale/modinfo.h>
+#include <maxscale/query_classifier.h>
 
 MXS_BEGIN_DECLS
 
@@ -74,6 +75,7 @@ typedef struct
     bool          skip_permission_checks;              /**< Skip service and monitor permission checks */
     char          qc_name[PATH_MAX];                   /**< The name of the query classifier to load */
     char*         qc_args;                             /**< Arguments for the query classifier */
+    qc_sql_mode_t qc_sql_mode;                         /**< The query classifier sql mode */
 } MXS_CONFIG;
 
 /**

server/core/config.c

@@ -13,36 +13,6 @@
 
 /**
  * @file config.c  - Read the gateway.cnf configuration file
- *
- * @verbatim
- * Revision History
- *
- * Date         Who                     Description
- * 21/06/13     Mark Riddoch            Initial implementation
- * 08/07/13     Mark Riddoch            Addition on monitor module support
- * 23/07/13     Mark Riddoch            Addition on default monitor password
- * 06/02/14     Massimiliano Pinto      Added support for enable/disable root user in services
- * 14/02/14     Massimiliano Pinto      Added enable_root_user in the service_params list
- * 11/03/14     Massimiliano Pinto      Added Unix socket support
- * 11/05/14     Massimiliano Pinto      Added version_string support to service
- * 19/05/14     Mark Riddoch            Added unique names from section headers
- * 29/05/14     Mark Riddoch            Addition of filter definition
- * 23/05/14     Massimiliano Pinto      Added automatic set of maxscale-id: first listening ipv4_raw + port + pid
- * 28/05/14     Massimiliano Pinto      Added detect_replication_lag parameter
- * 28/08/14     Massimiliano Pinto      Added detect_stale_master parameter
- * 09/09/14     Massimiliano Pinto      Added localhost_match_wildcard_host parameter
- * 12/09/14     Mark Riddoch            Addition of checks on servers list and
- *                                      internal router suppression of messages
- * 30/10/14     Massimiliano Pinto      Added disable_master_failback parameter
- * 07/11/14     Massimiliano Pinto      Addition of monitor timeouts for connect/read/write
- * 20/02/15     Markus Mäkelä           Added connection_timeout parameter for services
- * 05/03/15     Massimiliano Pinto      Added notification_feedback support
- * 20/04/15     Guillaume Lefranc       Added available_when_donor parameter
- * 22/04/15     Martin Brampton         Added disable_master_role_setting parameter
- * 26/01/16     Martin Brampton         Transfer SSL processing to listener
- * 31/05/16     Martin Brampton         Implement connection throttling, initially no queue
- *
- * @endverbatim
  */
 #include <maxscale/config.h>
 
@@ -1305,6 +1275,22 @@ handle_global_item(const char *name, const char *value)
     {
         gateway.qc_args = MXS_STRDUP_A(value);
     }
+    else if (strcmp(name, "sql_mode") == 0)
+    {
+        if ((*value == 0) || (strcasecmp(value, "default") == 0))
+        {
+            gateway.qc_sql_mode = QC_SQL_MODE_DEFAULT;
+        }
+        else if (strcasecmp(value, "oracle") == 0)
+        {
+            gateway.qc_sql_mode = QC_SQL_MODE_ORACLE;
+        }
+        else
+        {
+            MXS_ERROR("'%s' is not a valid value for '%s'. Allowed values are 'DEFAULT' and "
+                      "'ORACLE'. Using 'DEFAULT' as default.", value, name);
+        }
+    }
     else if (strcmp(name, "log_throttling") == 0)
     {
         if (*value == 0)

server/core/gateway.cc

@@ -1897,7 +1897,7 @@ int main(int argc, char **argv)
     cnf = config_get_global_options();
     ss_dassert(cnf);
 
-    if (!qc_setup(cnf->qc_name, QC_SQL_MODE_DEFAULT, cnf->qc_args))
+    if (!qc_setup(cnf->qc_name, cnf->qc_sql_mode, cnf->qc_args))
     {
         const char* logerr = "Failed to initialise query classifier library.";
         print_log_n_stderr(true, true, logerr, logerr, eno);