MDEV-20950 Reduce size of record offsetsbb-10.2-MDEV-20950-stack-offsets

offset_t: this is a type which represents one record offset.
It's unsigned short int.

a lot of functions: replace ulint with offset_t

btr_pcur_restore_position_func(),
page_validate(),
row_ins_scan_sec_index_for_duplicate(),
row_upd_clust_rec_by_insert_inherit_func(),
row_vers_impl_x_locked_low(),
trx_undo_prev_version_build():
  allocate record offsets on the stack instead of waiting for rec_get_offsets()
  to allocate it from mem_heap_t. So, reducing  memory allocations.

RECORD_OFFSET, INDEX_OFFSET:
  now it's less convenient to store pointers in offset_t*
  array. One pointer occupies now several offset_t. And those constant are start
  indexes into array to places where to store pointer values

REC_OFFS_HEADER_SIZE: adjusted for the new reality

REC_OFFS_NORMAL_SIZE:
  increase size from 100 to 300 which means less heap allocations.
  And sizeof(offset_t[REC_OFFS_NORMAL_SIZE]) now is 600 bytes which
  is smaller than previous 800 bytes.

REC_OFFS_SEC_INDEX_SIZE: adjusted for the new reality

rem0rec.h, rem0rec.ic, rem0rec.cc:
  various arguments, return values and local variables types were changed to
  fix numerous integer conversions issues.

enum field_type_t:
  offset types concept was introduces which replaces old offset flags stuff.
  Like in earlier version, 2 upper bits are used to store offset type.
  And this enum represents those types.

REC_OFFS_SQL_NULL, REC_OFFS_MASK: removed

get_type(), set_type(), get_value(), combine():
  these are convenience functions to work with offsets and it's types

rec_offs_base()[0]:
  still uses an old scheme with flags REC_OFFS_COMPACT and REC_OFFS_EXTERNAL

rec_offs_base()[i]:
  these have type offset_t now. Two upper bits contains type.

1 files changed, 22 insertions, 20 deletions

diff --git a/storage/innobase/page/page0page.cc b/storage/innobase/page/page0page.cc
index e316c8b1568..61ebbc3d140 100644
--- a/storage/innobase/page/page0page.cc
+++ b/storage/innobase/page/page0page.cc
@@ -36,6 +36,7 @@ Created 2/2/1994 Heikki Tuuri
 #include "fut0lst.h"
 #include "btr0sea.h"
 #include "trx0sys.h"
+#include <algorithm>
 
 /*			THE INDEX PAGE
 			==============
@@ -582,8 +583,8 @@ page_copy_rec_list_end_no_locks(
 	page_cur_t	cur1;
 	rec_t*		cur2;
 	mem_heap_t*	heap		= NULL;
-	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
-	ulint*		offsets		= offsets_;
+	offset_t	offsets_[REC_OFFS_NORMAL_SIZE];
+	offset_t*	offsets		= offsets_;
 	rec_offs_init(offsets_);
 
 	page_cur_position(rec, block, &cur1);
@@ -814,8 +815,8 @@ page_copy_rec_list_start(
 	rtr_rec_move_t*	rec_move	= NULL;
 	rec_t*		ret
 		= page_rec_get_prev(page_get_supremum_rec(new_page));
-	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
-	ulint*		offsets		= offsets_;
+	offset_t	offsets_[REC_OFFS_NORMAL_SIZE];
+	offset_t*	offsets		= offsets_;
 	rec_offs_init(offsets_);
 
 	/* Here, "ret" may be pointing to a user record or the
@@ -1049,8 +1050,8 @@ page_delete_rec_list_end(
 	page_zip_des_t*	page_zip	= buf_block_get_page_zip(block);
 	page_t*		page		= page_align(rec);
 	mem_heap_t*	heap		= NULL;
-	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
-	ulint*		offsets		= offsets_;
+	offset_t	offsets_[REC_OFFS_NORMAL_SIZE];
+	offset_t*	offsets		= offsets_;
 	rec_offs_init(offsets_);
 
 	ut_ad(size == ULINT_UNDEFINED || size < UNIV_PAGE_SIZE);
@@ -1250,8 +1251,8 @@ page_delete_rec_list_start(
 	mtr_t*		mtr)	/*!< in: mtr */
 {
 	page_cur_t	cur1;
-	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
-	ulint*		offsets		= offsets_;
+	offset_t	offsets_[REC_OFFS_NORMAL_SIZE];
+	offset_t*	offsets		= offsets_;
 	mem_heap_t*	heap		= NULL;
 
 	rec_offs_init(offsets_);
@@ -1738,7 +1739,7 @@ void
 page_rec_print(
 /*===========*/
 	const rec_t*	rec,	/*!< in: physical record */
-	const ulint*	offsets)/*!< in: record descriptor */
+	const offset_t*	offsets)/*!< in: record descriptor */
 {
 	ut_a(!page_rec_is_comp(rec) == !rec_offs_comp(offsets));
 	rec_print_new(stderr, rec, offsets);
@@ -1813,8 +1814,8 @@ page_print_list(
 	ulint		count;
 	ulint		n_recs;
 	mem_heap_t*	heap		= NULL;
-	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
-	ulint*		offsets		= offsets_;
+	offset_t	offsets_[REC_OFFS_NORMAL_SIZE];
+	offset_t*	offsets		= offsets_;
 	rec_offs_init(offsets_);
 
 	ut_a((ibool)!!page_is_comp(page) == dict_table_is_comp(index->table));
@@ -1924,7 +1925,7 @@ ibool
 page_rec_validate(
 /*==============*/
 	const rec_t*	rec,	/*!< in: physical record */
-	const ulint*	offsets)/*!< in: array returned by rec_get_offsets() */
+	const offset_t*	offsets)/*!< in: array returned by rec_get_offsets() */
 {
 	ulint		n_owned;
 	ulint		heap_no;
@@ -2420,8 +2421,13 @@ page_validate(
 	ulint			n_slots;
 	ibool			ret		= FALSE;
 	ulint			i;
-	ulint*			offsets		= NULL;
-	ulint*			old_offsets	= NULL;
+	offset_t		offsets_1[REC_OFFS_NORMAL_SIZE];
+	offset_t		offsets_2[REC_OFFS_NORMAL_SIZE];
+	offset_t*		offsets		= offsets_1;
+	offset_t*		old_offsets	= offsets_2;
+
+	rec_offs_init(offsets_1);
+	rec_offs_init(offsets_2);
 
 #ifdef UNIV_GIS_DEBUG
 	if (dict_index_is_spatial(index)) {
@@ -2644,11 +2650,7 @@ page_validate(
 		}
 
 		/* set old_offsets to offsets; recycle offsets */
-		{
-			ulint* offs = old_offsets;
-			old_offsets = offsets;
-			offsets = offs;
-		}
+		std::swap(old_offsets, offsets);
 	}
 
 	if (page_is_comp(page)) {
@@ -2813,7 +2815,7 @@ page_delete_rec(
 	page_cur_t*		pcur,	/*!< in/out: page cursor on record
 					to delete */
 	page_zip_des_t*		page_zip,/*!< in: compressed page descriptor */
-	const ulint*		offsets)/*!< in: offsets for record */
+	const offset_t*		offsets)/*!< in: offsets for record */
 {
 	bool		no_compress_needed;
 	buf_block_t*	block = pcur->block;