MDEV-11487: Remove dict_table_get_n_sys_cols()

In MariaDB, InnoDB tables will always contain DATA_N_SYS_COLS = 3
columns, 2 or 3 of which are present in the clustered index.
We remove the predicate that was added in MySQL 5.7 as part of WL#7682.

storage/innobase/dict/dict0dict.cc

@@ -3044,9 +3044,7 @@ dict_index_build_internal_clust(
 
 	/* Add to new_index non-system columns of table not yet included
 	there */
-	ulint n_sys_cols = dict_table_get_n_sys_cols(table);
-	for (i = 0; i + n_sys_cols < (ulint) table->n_cols; i++) {
-
+	for (i = 0; i + DATA_N_SYS_COLS < ulint(table->n_cols); i++) {
 		dict_col_t*	col = dict_table_get_nth_col(table, i);
 		ut_ad(col->mtype != DATA_SYS);
 
@@ -6422,15 +6420,14 @@ dict_table_schema_check(
 		return(DB_TABLE_NOT_FOUND);
 	}
 
-	ulint n_sys_cols = dict_table_get_n_sys_cols(table);
-	if ((ulint) table->n_def - n_sys_cols != req_schema->n_cols) {
+	if (ulint(table->n_def) - DATA_N_SYS_COLS != req_schema->n_cols) {
 		/* the table has a different number of columns than required */
 		snprintf(errstr, errstr_sz,
 			 "%s has " ULINTPF " columns but should have "
 			 ULINTPF ".",
 			 ut_format_name(req_schema->table_name, buf,
 					sizeof buf),
-			 table->n_def - n_sys_cols,
+			 ulint(table->n_def) - DATA_N_SYS_COLS,
 			 req_schema->n_cols);
 
 		return(DB_ERROR);

storage/innobase/dict/dict0mem.cc

@@ -136,8 +136,7 @@ dict_mem_table_create(
 	table->name.m_name = mem_strdup(name);
 	table->is_system_db = dict_mem_table_is_system(table->name.m_name);
 	table->space = (unsigned int) space;
-	table->n_t_cols = (unsigned int) (n_cols +
-			dict_table_get_n_sys_cols(table));
+	table->n_t_cols = unsigned(n_cols + DATA_N_SYS_COLS);
 	table->n_v_cols = (unsigned int) (n_v_cols);
 	table->n_cols = table->n_t_cols - table->n_v_cols;
 

storage/innobase/handler/handler0alter.cc

@@ -3939,7 +3939,7 @@ innobase_add_virtual_try(
 
 	n_v_col +=  ctx->num_to_add_vcol;
 
-	n_col -= dict_table_get_n_sys_cols(user_table);
+	n_col -= DATA_N_SYS_COLS;
 
 	n_v_col -= ctx->num_to_drop_vcol;
 
@@ -4173,7 +4173,7 @@ innobase_drop_virtual_try(
 
 	n_v_col -=  ctx->num_to_drop_vcol;
 
-	n_col -= dict_table_get_n_sys_cols(user_table);
+	n_col -= DATA_N_SYS_COLS;
 
 	ulint	new_n = dict_table_encode_n_col(n_col, n_v_col)
 			+ ((user_table->flags & DICT_TF_COMPACT) << 31);

storage/innobase/include/data0type.h

 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2018, MariaDB Corporation.
+Copyright (c) 2017, 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -183,8 +183,6 @@ be less than 256 */
 				for shorter VARCHARs MySQL uses only 1 byte */
 #define	DATA_VIRTUAL	8192U	/* Virtual column */
 
-/** Get the number of system columns in a table. */
-#define dict_table_get_n_sys_cols(table) DATA_N_SYS_COLS
 /** Check whether locking is disabled (never). */
 #define dict_table_is_locking_disabled(table) false
 

storage/innobase/include/dict0dict.h

@@ -879,13 +879,11 @@ dict_table_get_sys_col(
 	ulint			sys)	/*!< in: DATA_ROW_ID, ... */
 	MY_ATTRIBUTE((nonnull, warn_unused_result));
 #else /* UNIV_DEBUG */
-#define dict_table_get_nth_col(table, pos)	\
-((table)->cols + (pos))
+#define dict_table_get_nth_col(table, pos)	&(table)->cols[pos]
 #define dict_table_get_sys_col(table, sys)	\
-((table)->cols + (table)->n_cols + (sys)	\
- - (dict_table_get_n_sys_cols(table)))
+	&(table)->cols[(table)->n_cols + (sys) - DATA_N_SYS_COLS]
 /* Get nth virtual columns */
-#define dict_table_get_nth_v_col(table, pos)	((table)->v_cols + (pos))
+#define dict_table_get_nth_v_col(table, pos)	&(table)->v_cols[pos]
 #endif /* UNIV_DEBUG */
 /********************************************************************//**
 Gets the given system column number of a table.

storage/innobase/include/dict0dict.ic

@@ -475,13 +475,11 @@ dict_table_get_sys_col(
 {
 	dict_col_t*	col;
 
-	ut_ad(table);
-	ut_ad(sys < dict_table_get_n_sys_cols(table));
+	ut_ad(sys < DATA_N_SYS_COLS);
 	ut_ad(table->magic_n == DICT_TABLE_MAGIC_N);
 
 	col = dict_table_get_nth_col(table, table->n_cols
-				     - dict_table_get_n_sys_cols(table)
-				     + sys);
+				     + (sys - DATA_N_SYS_COLS));
 	ut_ad(col->mtype == DATA_SYS);
 	ut_ad(col->prtype == (sys | DATA_NOT_NULL));
 
@@ -501,7 +499,7 @@ dict_table_get_sys_col_no(
 {
 	ut_ad(sys < DATA_N_SYS_COLS);
 	ut_ad(table->magic_n == DICT_TABLE_MAGIC_N);
-	return(table->n_cols - dict_table_get_n_sys_cols(table) + sys);
+	return table->n_cols + (sys - DATA_N_SYS_COLS);
 }
 
 /********************************************************************//**