row0mysql.c, dict0dict.c, db0err.h, ha_innobase.cc:

  Heikki will merge to 4.0: Prevent listing the same column twice in an InnoDB index: that will cause index corruption when that col is UPDATEd

innobase/dict/dict0dict.c

@@ -1033,6 +1033,7 @@ dict_index_add_to_cache(
 	ulint		n_ord;
 	ibool		success;
 	ulint		i;
+	ulint		j;
 	
 	ut_ad(index);
 	ut_ad(mutex_own(&(dict_sys->mutex)));
@@ -1063,6 +1064,26 @@ dict_index_add_to_cache(
 		return(FALSE);
 	}
 
+	/* Check that the same column does not appear twice in the index.
+	   InnoDB assumes this in its algorithms, e.g., update of an index
+	   entry */
+
+	for (i = 0; i < dict_index_get_n_fields(index); i++) {
+
+	  for (j = 0; j < i; j++) {
+	    if (dict_index_get_nth_field(index, j)->col
+		== dict_index_get_nth_field(index, i)->col) {
+
+	      fprintf(stderr,
+"InnoDB: Error: column %s appears twice in index %s of table %s\n"
+"InnoDB: This is not allowed in InnoDB.\n"
+"InnoDB: UPDATE can cause such an index to become corrupt in InnoDB.\n",
+		      dict_index_get_nth_field(index, i)->col->name,
+		      index->name, table->name);
+	    }
+	  }
+	}
+	
 	/* Build the cache internal representation of the index,
 	containing also the added system fields */
 

innobase/include/db0err.h

@@ -42,6 +42,8 @@ Created 5/24/1996 Heikki Tuuri
 #define DB_CANNOT_ADD_CONSTRAINT 38	/* adding a foreign key constraint
 					to a table failed */
 
+#define DB_COL_APPEARS_TWICE_IN_INDEX 40
+
 /* The following are partial failure codes */
 #define DB_FAIL 		1000
 #define DB_OVERFLOW 		1001

innobase/row/row0mysql.c

@@ -1393,7 +1393,7 @@ int
 row_create_index_for_mysql(
 /*=======================*/
 					/* out: error number or DB_SUCCESS */
-	dict_index_t*	index,		/* in: index defintion */
+	dict_index_t*	index,		/* in: index definition */
 	trx_t*		trx)		/* in: transaction handle */
 {
 	ind_node_t*	node;
@@ -1402,11 +1402,14 @@ row_create_index_for_mysql(
 	ulint		namelen;
 	ulint		keywordlen;
 	ulint		err;
+	ulint		i;
+	ulint		j;
 	
+	ut_ad(rw_lock_own(&dict_operation_lock, RW_LOCK_EX));
 	ut_ad(mutex_own(&(dict_sys->mutex)));
 	ut_ad(trx->mysql_thread_id == os_thread_get_curr_id());
 	
-	trx->op_info = "creating index";
+	trx->op_info = (char *) "creating index";
 
 	trx_start_if_not_started(trx);
 
@@ -1422,6 +1425,29 @@ row_create_index_for_mysql(
 		return(DB_SUCCESS);
 	}
 
+	/* Check that the same column does not appear twice in the index.
+	InnoDB assumes this in its algorithms, e.g., update of an index
+	entry */
+
+	for (i = 0; i < dict_index_get_n_fields(index); i++) {
+		for (j = 0; j < i; j++) {
+			if (0 == ut_strcmp(
+				dict_index_get_nth_field(index, j)->name,
+				dict_index_get_nth_field(index, i)->name)) {
+
+				fprintf(stderr,
+"InnoDB: Error: column %s appears twice in index %s\n"
+"InnoDB: This is not allowed in InnoDB.\n",
+				dict_index_get_nth_field(index, i)->name,
+				index->name);
+
+				err = DB_COL_APPEARS_TWICE_IN_INDEX;
+
+				goto error_handling;
+			}
+		}
+	}
+
 	heap = mem_heap_create(512);
 
 	trx->dict_operation = TRUE;
@@ -1436,9 +1462,11 @@ row_create_index_for_mysql(
 
  	err = trx->error_state;
 
+	que_graph_free((que_t*) que_node_get_parent(thr));
+
+error_handling:
 	if (err != DB_SUCCESS) {
 		/* We have special error handling here */
-		ut_a(err == DB_OUT_OF_FILE_SPACE);
 		
 		trx->error_state = DB_SUCCESS;
 
@@ -1449,9 +1477,7 @@ row_create_index_for_mysql(
 		trx->error_state = DB_SUCCESS;
 	}
 	
-	que_graph_free((que_t*) que_node_get_parent(thr));
-	
-	trx->op_info = "";
+	trx->op_info = (char *) "";
 
 	return((int) err);
 }

sql/ha_innobase.cc

@@ -237,6 +237,10 @@ convert_error_code_to_mysql(
 
     		return(HA_ERR_CANNOT_ADD_FOREIGN);
 
+        } else if (error == (int) DB_COL_APPEARS_TWICE_IN_INDEX) {
+
+    		return(HA_ERR_WRONG_TABLE_DEF);
+
  	} else if (error == (int) DB_OUT_OF_FILE_SPACE) {
 
     		return(HA_ERR_RECORD_FILE_FULL);