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authorSergei Petrunia <psergey@askmonty.org>2015-03-27 23:44:06 +0300
committerSergei Petrunia <psergey@askmonty.org>2015-03-27 23:44:06 +0300
commit9b8f86f8958116030de5a4e6ab75011cca251dfc (patch)
treeff440968f401ff811215cbbca94c257c36e58569 /sql/sql_select.h
parent47c26d5aeeae79276142746128c4b28f6693553d (diff)
downloadmariadb-git-9b8f86f8958116030de5a4e6ab75011cca251dfc.tar.gz
Better comments
Diffstat (limited to 'sql/sql_select.h')
-rw-r--r--sql/sql_select.h17
1 files changed, 16 insertions, 1 deletions
diff --git a/sql/sql_select.h b/sql/sql_select.h
index 0557e328ea0..94ca52471e0 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -1039,7 +1039,20 @@ public:
table_map outer_join;
/* Bitmap of tables used in the select list items */
table_map select_list_used_tables;
- ha_rows send_records,found_records,examined_rows,row_limit, select_limit;
+ ha_rows send_records,found_records,examined_rows;
+
+ /*
+ LIMIT for the JOIN operation. When not using aggregation or DISITNCT, this
+ is the same as select's LIMIT clause specifies.
+ Note that this doesn't take sql_calc_found_rows into account.
+ */
+ ha_rows row_limit;
+
+ /*
+ How many output rows should be produced after GROUP BY.
+ (if sql_calc_found_rows is used, LIMIT is ignored)
+ */
+ ha_rows select_limit;
/**
Used to fetch no more than given amount of rows per one
fetch operation of server side cursor.
@@ -1048,8 +1061,10 @@ public:
- fetch_limit= HA_POS_ERROR if there is no cursor.
- when we open a cursor, we set fetch_limit to 0,
- on each fetch iteration we add num_rows to fetch to fetch_limit
+ NOTE: currently always HA_POS_ERROR.
*/
ha_rows fetch_limit;
+
/* Finally picked QEP. This is result of join optimization */
POSITION *best_positions;