btr0btr.c:

  Improve space utilization if we have 3 kB - 8 kB rows to insert in the order of the primary key
btr0cur.c:
  Fix bug: The row count and key cardinality estimate was grossly too small if each clustered index page only contained one record


innobase/btr/btr0cur.c:
  Fix bug: The row count and key cardinality estimate was grossly too small if each clustered index page only contained one record
innobase/btr/btr0btr.c:
  Improve space utilization if we have 3 kB - 8 kB rows to insert in the order of the primary key

1 files changed, 29 insertions, 32 deletions

diff --git a/innobase/btr/btr0btr.c b/innobase/btr/btr0btr.c
index 71be6d81d7c..1c3e033a8d7 100644
--- a/innobase/btr/btr0btr.c
+++ b/innobase/btr/btr0btr.c
@@ -76,9 +76,6 @@ make them consecutive on disk if possible. From the other file segment
 we allocate pages for the non-leaf levels of the tree.
 */
 
-/* If this many inserts occur sequentially, it affects page split */
-#define BTR_PAGE_SEQ_INSERT_LIMIT	5
-
 /******************************************************************
 Creates a new index page to the tree (not the root, and also not
 used in page reorganization). */
@@ -1086,18 +1083,18 @@ btr_page_get_split_rec_to_left(
 	page = btr_cur_get_page(cursor);
 	insert_point = btr_cur_get_rec(cursor);
 
-	if ((page_header_get_ptr(page, PAGE_LAST_INSERT)
-	    == page_rec_get_next(insert_point))
-	    && (page_header_get_field(page, PAGE_DIRECTION) == PAGE_LEFT)
-	    && ((page_header_get_field(page, PAGE_N_DIRECTION)
-	     	 			>= BTR_PAGE_SEQ_INSERT_LIMIT)
-	     	|| (page_header_get_field(page, PAGE_N_DIRECTION) + 1
-	     	 			>= page_get_n_recs(page)))) {
+	if (page_header_get_ptr(page, PAGE_LAST_INSERT)
+	    == page_rec_get_next(insert_point)) {
 
 	     	infimum = page_get_infimum_rec(page);
-	     	 			
-		if ((infimum != insert_point)
-		    && (page_rec_get_next(infimum) != insert_point)) {
+		
+		/* If the convergence is in the middle of a page, include also
+		the record immediately before the new insert to the upper
+		page. Otherwise, we could repeatedly move from page to page
+		lots of records smaller than the convergence point. */
+
+		if (infimum != insert_point
+		    && page_rec_get_next(infimum) != insert_point) {
 
 			*split_rec = insert_point;
 		} else {
@@ -1131,29 +1128,29 @@ btr_page_get_split_rec_to_right(
 	page = btr_cur_get_page(cursor);
 	insert_point = btr_cur_get_rec(cursor);
 
-	if ((page_header_get_ptr(page, PAGE_LAST_INSERT) == insert_point)
-	    && (page_header_get_field(page, PAGE_DIRECTION) == PAGE_RIGHT)
-	    && ((page_header_get_field(page, PAGE_N_DIRECTION)
-	     	 			>= BTR_PAGE_SEQ_INSERT_LIMIT)
-	     	|| (page_header_get_field(page, PAGE_N_DIRECTION) + 1
-	     	 			>= page_get_n_recs(page)))) {
+	/* We use eager heuristics: if the new insert would be right after
+	the previous insert on the same page, we assume that there is a
+	pattern of sequential inserts here. */
+
+	if (page_header_get_ptr(page, PAGE_LAST_INSERT) == insert_point) {
 
 	     	supremum = page_get_supremum_rec(page);
 	     	 			
-		if ((page_rec_get_next(insert_point) != supremum)
-		    && (page_rec_get_next(page_rec_get_next(insert_point))
-			!= supremum)
-		    && (page_rec_get_next(page_rec_get_next(
-					page_rec_get_next(insert_point)))
-			!= supremum)) {
-
-			/* If there are >= 3 user records up from the insert
-			point, split all but 2 off */
-
-			*split_rec = page_rec_get_next(page_rec_get_next(
-					page_rec_get_next(insert_point)));
+		if (page_rec_get_next(insert_point) != supremum
+		    && page_rec_get_next(page_rec_get_next(insert_point))
+			!= supremum) {
+
+			/* If there are >= 2 user records up from the insert
+			point, split all but 1 off. We want to keep one because
+			then sequential inserts can use the adaptive hash
+			index, as they can do the necessary checks of the right
+			search position just by looking at the records on this
+			page. */
+		
+			*split_rec = page_rec_get_next(
+					page_rec_get_next(insert_point));
 		} else {
-			/* Else split at inserted record */
+			/* Else split at the new record to insert */
 	     		*split_rec = NULL;
 	     	}