dict_table_t: Rename the integer field max_row_size

to the Boolean field big_rows.  (Bug #20877)

BIG_ROW_SIZE: Move the definition from row0sel.c to dict_table_add_to_cache().

dict/dict0dict.c

@@ -876,23 +876,26 @@ dict_table_add_to_cache(
 #error "DATA_N_SYS_COLS != 3"
 #endif
 
+/* The lower limit for what we consider a "big" row */
+#define BIG_ROW_SIZE 1024
+
 	row_len = 0;
 	for (i = 0; i < table->n_def; i++) {
 		ulint	col_len = dtype_get_max_size
 			(dict_col_get_type(dict_table_get_nth_col(table, i)));
 
+		row_len += col_len;
+
 		/* If we have a single unbounded field, or several gigantic
-		fields, mark the maximum row size as ULINT_MAX. */
-		if (ut_max(col_len, row_len) >= (ULINT_MAX / 2)) {
-			row_len = ULINT_MAX;
+		fields, mark the maximum row size as BIG_ROW_SIZE. */
+		if (row_len >= BIG_ROW_SIZE || col_len >= BIG_ROW_SIZE) {
+			row_len = BIG_ROW_SIZE;
 
 			break;
 		}
-
-		row_len += col_len;
 	}
 
-	table->max_row_size = row_len;
+	table->big_rows = row_len >= BIG_ROW_SIZE;
 
 	/* Look for a table with the same name: error if such exists */
 	{

dict/dict0mem.c

@@ -84,7 +84,7 @@ dict_mem_table_create(
 
 	table->stat_modified_counter = 0;
 
-	table->max_row_size = 0;
+	table->big_rows = 0;
 
 	mutex_create(&table->autoinc_mutex, SYNC_DICT_AUTOINC_MUTEX);
 

include/dict0mem.h

@@ -331,12 +331,6 @@ struct dict_table_struct{
 				had an IX lock on */
 	UT_LIST_BASE_NODE_T(lock_t)
 			locks; /* list of locks on the table */
-	ulint		max_row_size;
-				/* maximum size of a single row in the
-				table, not guaranteed to be especially
-				accurate. it's ULINT_MAX if there are
-				unbounded variable-width fields. initialized
-				in dict_table_add_to_cache. */
 #ifdef UNIV_DEBUG
 	/*----------------------*/
 	ibool		does_not_fit_in_memory;
@@ -350,6 +344,13 @@ struct dict_table_struct{
 				the table definition from disk */
 #endif /* UNIV_DEBUG */
 	/*----------------------*/
+	unsigned	big_rows:1;
+				/* flag: TRUE if the maximum length of
+				a single row exceeds BIG_ROW_SIZE;
+				initialized in dict_table_add_to_cache() */
+	unsigned	stat_initialized:1; /* TRUE if statistics have
+				been calculated the first time
+				after database startup or table creation */
 	ib_longlong	stat_n_rows;
 				/* approximate number of rows in the table;
 				we periodically calculate new estimates */
@@ -358,9 +359,6 @@ struct dict_table_struct{
 				database pages */
 	ulint		stat_sum_of_other_index_sizes;
 				/* other indexes in database pages */
-	ibool		stat_initialized:1; /* TRUE if statistics have
-				been calculated the first time
-				after database startup or table creation */
 	ulint		stat_modified_counter;
 				/* when a row is inserted, updated, or deleted,
 				we add 1 to this number; we calculate new

row/row0sel.c

@@ -45,9 +45,6 @@ to que_run_threads: this is to allow canceling runaway queries */
 
 #define SEL_COST_LIMIT	100
 
-/* The lower limit for what we consider a "big" row */
-#define BIG_ROW_SIZE	1024
-
 /* Flags for search shortcut */
 #define SEL_FOUND	0
 #define	SEL_EXHAUSTED	1
@@ -1247,7 +1244,7 @@ table_loop:
 
 	if (consistent_read && plan->unique_search && !plan->pcur_is_open
 	    && !plan->must_get_clust
-	    && (plan->table->max_row_size < BIG_ROW_SIZE)) {
+	    && !plan->table->big_rows) {
 		if (!search_latch_locked) {
 			rw_lock_s_lock(&btr_search_latch);
 
@@ -1652,7 +1649,7 @@ skip_lock:
 
 	if ((plan->n_rows_fetched <= SEL_PREFETCH_LIMIT)
 	    || plan->unique_search || plan->no_prefetch
-	    || (plan->table->max_row_size >= BIG_ROW_SIZE)) {
+	    || plan->table->big_rows) {
 
 		/* No prefetch in operation: go to the next table */