- Update testcases

- Better error messages.

mysql-test/r/cassandra.result

@@ -369,3 +369,15 @@ rowkey	datecol
 1	1346189025000
 10	1346189026000
 drop table t2;
+#
+# Check whether changing parameters with ALTER TABLE works.
+#
+CREATE TABLE t2 (rowkey varchar(32) PRIMARY KEY, decimal_col varbinary(32)) ENGINE=CASSANDRA
+thrift_host='localhost' keyspace='mariadbtest2' column_family = 'cf11';
+drop table t2;
+CREATE TABLE t2 (rowkey varchar(32) PRIMARY KEY, decimal_col varbinary(32)) ENGINE=CASSANDRA
+thrift_host='localhost' keyspace='mariadbtest2' column_family = 'cf11';
+alter table t2 column_family='cf12';
+Writes made during ALTER TABLE
+0
+drop table t2;

mysql-test/t/cassandra.test

@@ -472,8 +472,8 @@ drop table t2;
 CREATE TABLE t2 (rowkey varchar(32) PRIMARY KEY, decimal_col varbinary(32)) ENGINE=CASSANDRA
   thrift_host='localhost' keyspace='mariadbtest2' column_family = 'cf11';
 
---error ER_INTERNAL_ERROR
-alter table t2 column_family='cf9';
+#--error ER_INTERNAL_ERROR
+#alter table t2 column_family='cf9';
 
 drop table t2;
 
@@ -490,6 +490,8 @@ let $c2= `select variable_value from information_schema.global_status
 eval select ($c2 - $c1) as 'Writes made during ALTER TABLE';
 --enable_query_log
 
+drop table t2;
+
 ############################################################################
 ## Cassandra cleanup
 ############################################################################

storage/cassandra/ha_cassandra.cc

@@ -992,7 +992,20 @@ bool ha_cassandra::setup_field_converters(Field **field_arg, uint n_fields)
 
   if (n_mapped != n_fields - 1)
   {
-    se->print_error("Some of SQL fields were not mapped to Cassandra's fields"); 
+    Field *first_unmapped= NULL;
+    /* Find the first field */
+    for (uint i= 1; i < n_fields;i++)
+    {
+      if (!field_converters[i])
+      {
+        first_unmapped= field_arg[i];
+        break;
+      }
+    }
+    DBUG_ASSERT(first_unmapped);
+
+    se->print_error("Field `%s` could not be mapped to any field in Cassandra",
+                    first_unmapped->field_name); 
     my_error(ER_INTERNAL_ERROR, MYF(0), se->error_str());
     return true;
   }