MDEV-17750: Remove dict_index_get_sys_col_pos()

dict_index_t::db_trx_id(): Return the position of DB_TRX_ID.
Only valid for the clustered index.

dict_index_t::db_roll_ptr(): Return the position of DB_ROLL_PTR.
Only valid for the clustered index.

dict_index_get_sys_col_pos(): Remove. This was performing unnecessarily
complex computations, which only made sense for DB_ROW_ID, which would
exist either as the first field in the clustered index or as the last
field in a secondary index (only when a DB_ROW_ID column is materialised).

row_sel_store_row_id_to_prebuilt(): Remove, and replace with simpler code.

row_upd_index_entry_sys_field(): Remove.

btr_cur_log_sys(): Replaces row_upd_write_sys_vals_to_log().

btr_cur_write_sys(): Write DB_TRX_ID,DB_ROLL_PTR to a data tuple.

storage/innobase/btr/btr0cur.cc

@@ -3229,8 +3229,11 @@ btr_cur_ins_lock_and_undo(
 		roll_ptr = roll_ptr_t(1) << ROLL_PTR_INSERT_FLAG_POS;
 		if (!(flags & BTR_KEEP_SYS_FLAG)) {
 upd_sys:
-			row_upd_index_entry_sys_field(entry, index,
-						      DATA_ROLL_PTR, roll_ptr);
+			dfield_t* r = dtuple_get_nth_field(
+				entry, index->db_roll_ptr());
+			ut_ad(r->len == DATA_ROLL_PTR_LEN);
+			trx_write_roll_ptr(static_cast<byte*>(r->data),
+					   roll_ptr);
 		}
 	} else {
 		err = trx_undo_report_row_operation(thr, index, entry,
@@ -3819,6 +3822,50 @@ btr_cur_upd_lock_and_undo(
 		       cmpl_info, rec, offsets, roll_ptr));
 }
 
+/** Copy DB_TRX_ID,DB_ROLL_PTR to the redo log.
+@param[in]	index	clustered index
+@param[in]	trx_id_t	DB_TRX_ID
+@param[in]	roll_ptr	DB_ROLL_PTR
+@param[in,out]	log_ptr		redo log buffer
+@return current end of the redo log buffer */
+static byte*
+btr_cur_log_sys(
+	const dict_index_t*	index,
+	trx_id_t		trx_id,
+	roll_ptr_t		roll_ptr,
+	byte*			log_ptr)
+{
+	log_ptr += mach_write_compressed(log_ptr, index->db_trx_id());
+	/* Yes, we are writing DB_ROLL_PTR,DB_TRX_ID in reverse order,
+	after emitting the position of DB_TRX_ID in the index.
+	This is how row_upd_write_sys_vals_to_log()
+	originally worked, and it is part of the redo log format. */
+	trx_write_roll_ptr(log_ptr, roll_ptr);
+	log_ptr += DATA_ROLL_PTR_LEN;
+	log_ptr += mach_u64_write_compressed(log_ptr, trx_id);
+
+	return log_ptr;
+}
+
+/** Write DB_TRX_ID,DB_ROLL_PTR to a clustered index entry.
+@param[in,out]	entry		clustered index entry
+@param[in]	index		clustered index
+@param[in]	trx_id		DB_TRX_ID
+@param[in]	roll_ptr	DB_ROLL_PTR */
+static void btr_cur_write_sys(
+	dtuple_t*		entry,
+	const dict_index_t*	index,
+	trx_id_t		trx_id,
+	roll_ptr_t		roll_ptr)
+{
+	dfield_t* t = dtuple_get_nth_field(entry, index->db_trx_id());
+	ut_ad(t->len == DATA_TRX_ID_LEN);
+	trx_write_trx_id(static_cast<byte*>(t->data), trx_id);
+	dfield_t* r = dtuple_get_nth_field(entry, index->db_roll_ptr());
+	ut_ad(r->len == DATA_ROLL_PTR_LEN);
+	trx_write_roll_ptr(static_cast<byte*>(r->data), roll_ptr);
+}
+
 /***********************************************************//**
 Writes a redo log record of updating a record in-place. */
 void
@@ -3858,8 +3905,7 @@ btr_cur_update_in_place_log(
 	log_ptr++;
 
 	if (dict_index_is_clust(index)) {
-		log_ptr = row_upd_write_sys_vals_to_log(
-				index, trx_id, roll_ptr, log_ptr, mtr);
+		log_ptr = btr_cur_log_sys(index, trx_id, roll_ptr, log_ptr);
 	} else {
 		/* Dummy system fields for a secondary index */
 		/* TRX_ID Position */
@@ -4532,10 +4578,7 @@ btr_cur_optimistic_update(
 	page_cur_move_to_prev(page_cursor);
 
 	if (!(flags & BTR_KEEP_SYS_FLAG)) {
-		row_upd_index_entry_sys_field(new_entry, index, DATA_ROLL_PTR,
-					      roll_ptr);
-		row_upd_index_entry_sys_field(new_entry, index, DATA_TRX_ID,
-					      trx_id);
+		btr_cur_write_sys(new_entry, index, trx_id, roll_ptr);
 	}
 
 	/* There are no externally stored columns in new_entry */
@@ -4850,10 +4893,7 @@ btr_cur_pessimistic_update(
 	}
 
 	if (!(flags & BTR_KEEP_SYS_FLAG)) {
-		row_upd_index_entry_sys_field(new_entry, index, DATA_ROLL_PTR,
-					      roll_ptr);
-		row_upd_index_entry_sys_field(new_entry, index, DATA_TRX_ID,
-					      trx_id);
+		btr_cur_write_sys(new_entry, index, trx_id, roll_ptr);
 	}
 
 	if (!page_zip) {
@@ -5125,8 +5165,7 @@ btr_cur_del_mark_set_clust_rec_log(
 	*log_ptr++ = 0;
 	*log_ptr++ = 1;
 
-	log_ptr = row_upd_write_sys_vals_to_log(
-		index, trx_id, roll_ptr, log_ptr, mtr);
+	log_ptr = btr_cur_log_sys(index, trx_id, roll_ptr, log_ptr);
 	mach_write_to_2(log_ptr, page_offset(rec));
 	log_ptr += 2;
 

storage/innobase/include/dict0dict.h

@@ -1207,16 +1207,6 @@ dict_table_get_nth_col_pos(
 	ulint			n,	/*!< in: column number */
 	ulint*			prefix_col_pos) /*!< out: col num if prefix */
 	MY_ATTRIBUTE((nonnull(1), warn_unused_result));
-/********************************************************************//**
-Returns the position of a system column in an index.
-@return position, ULINT_UNDEFINED if not contained */
-UNIV_INLINE
-ulint
-dict_index_get_sys_col_pos(
-/*=======================*/
-	const dict_index_t*	index,	/*!< in: index */
-	ulint			type)	/*!< in: DATA_ROW_ID, ... */
-	MY_ATTRIBUTE((nonnull, warn_unused_result));
 /*******************************************************************//**
 Adds a column to index. */
 void

storage/innobase/include/dict0dict.ic

@@ -925,31 +925,6 @@ dict_index_get_nth_field(
 }
 #endif /* UNIV_DEBUG */
 
-/********************************************************************//**
-Returns the position of a system column in an index.
-@return position, ULINT_UNDEFINED if not contained */
-UNIV_INLINE
-ulint
-dict_index_get_sys_col_pos(
-/*=======================*/
-	const dict_index_t*	index,	/*!< in: index */
-	ulint			type)	/*!< in: DATA_ROW_ID, ... */
-{
-	ut_ad(index);
-	ut_ad(index->magic_n == DICT_INDEX_MAGIC_N);
-	ut_ad(!dict_index_is_ibuf(index));
-
-	if (dict_index_is_clust(index)) {
-
-		return(dict_col_get_clust_pos(
-			       dict_table_get_sys_col(index->table, type),
-			       index));
-	}
-
-	return(dict_index_get_nth_col_pos(
-			index, dict_table_get_sys_col_no(index->table, type), NULL));
-}
-
 /*********************************************************************//**
 Gets the field column.
 @return field->col, pointer to the table column */

storage/innobase/include/dict0mem.h

@@ -28,7 +28,6 @@ Created 1/8/1996 Heikki Tuuri
 #ifndef dict0mem_h
 #define dict0mem_h
 
-#include "univ.i"
 #include "dict0types.h"
 #include "data0type.h"
 #include "mem0mem.h"
@@ -50,6 +49,7 @@ Created 1/8/1996 Heikki Tuuri
 #include "ut0new.h"
 #include "fil0fil.h"
 #include "fil0crypt.h"
+#include <sql_const.h>
 #include <set>
 #include <algorithm>
 #include <iterator>
@@ -1103,12 +1103,19 @@ struct dict_index_t {
 	/** @return whether the index includes virtual columns */
 	bool has_virtual() const { return type & DICT_VIRTUAL; }
 
+	/** @return the position of DB_TRX_ID */
+	unsigned db_trx_id() const {
+		DBUG_ASSERT(is_primary());
+		DBUG_ASSERT(n_uniq);
+		DBUG_ASSERT(n_uniq <= MAX_REF_PARTS);
+		return n_uniq;
+	}
+	/** @return the position of DB_ROLL_PTR */
+	unsigned db_roll_ptr() const { return db_trx_id() + 1; }
+
 	/** @return the offset of the metadata BLOB field,
 	or the first user field after the PRIMARY KEY,DB_TRX_ID,DB_ROLL_PTR */
-	unsigned first_user_field() const {
-		ut_ad(is_primary());
-		return n_uniq + 2;
-	}
+	unsigned first_user_field() const { return db_trx_id() + 2; }
 
 	/** @return whether the index is corrupted */
 	inline bool is_corrupted() const;

storage/innobase/include/row0row.ic

 /*****************************************************************************
 
 Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, MariaDB Corporation.
+Copyright (c) 2017, 2018, 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
@@ -39,16 +39,12 @@ row_get_trx_id_offset(
 	const dict_index_t*	index,	/*!< in: clustered index */
 	const ulint*		offsets)/*!< in: record offsets */
 {
-	ulint	pos;
 	ulint	offset;
 	ulint	len;
 
-	ut_ad(dict_index_is_clust(index));
 	ut_ad(rec_offs_validate(NULL, index, offsets));
 
-	pos = dict_index_get_sys_col_pos(index, DATA_TRX_ID);
-
-	offset = rec_get_nth_field_offs(offsets, pos, &len);
+	offset = rec_get_nth_field_offs(offsets, index->db_trx_id(), &len);
 
 	ut_ad(len == DATA_TRX_ID_LEN);
 

storage/innobase/include/row0upd.h

@@ -101,19 +101,6 @@ upd_get_field_by_field_no(
 	bool		is_virtual) /*!< in: if it is a virtual column */
 	MY_ATTRIBUTE((warn_unused_result));
 /*********************************************************************//**
-Writes into the redo log the values of trx id and roll ptr and enough info
-to determine their positions within a clustered index record.
-@return new pointer to mlog */
-byte*
-row_upd_write_sys_vals_to_log(
-/*==========================*/
-	dict_index_t*	index,	/*!< in: clustered index */
-	trx_id_t	trx_id,	/*!< in: transaction id */
-	roll_ptr_t	roll_ptr,/*!< in: roll ptr of the undo log record */
-	byte*		log_ptr,/*!< pointer to a buffer of size > 20 opened
-				in mlog */
-	mtr_t*		mtr);	/*!< in: mtr */
-/*********************************************************************//**
 Updates the trx id and roll ptr field in a clustered index record when
 a row is updated or marked deleted. */
 UNIV_INLINE
@@ -128,18 +115,6 @@ row_upd_rec_sys_fields(
 	const trx_t*	trx,	/*!< in: transaction */
 	roll_ptr_t	roll_ptr);/*!< in: DB_ROLL_PTR to the undo log */
 /*********************************************************************//**
-Sets the trx id or roll ptr field of a clustered index entry. */
-void
-row_upd_index_entry_sys_field(
-/*==========================*/
-	dtuple_t*	entry,	/*!< in/out: index entry, where the memory
-				buffers for sys fields are already allocated:
-				the function just copies the new values to
-				them */
-	dict_index_t*	index,	/*!< in: clustered index */
-	ulint		type,	/*!< in: DATA_TRX_ID or DATA_ROLL_PTR */
-	ib_uint64_t	val);	/*!< in: value to write */
-/*********************************************************************//**
 Creates an update node for a query graph.
 @return own: update node */
 upd_node_t*

storage/innobase/include/row0upd.ic

@@ -167,13 +167,13 @@ row_upd_rec_sys_fields(
 	const trx_t*	trx,	/*!< in: transaction */
 	roll_ptr_t	roll_ptr)/*!< in: DB_ROLL_PTR to the undo log */
 {
-	ut_ad(dict_index_is_clust(index));
+	ut_ad(index->is_primary());
 	ut_ad(rec_offs_validate(rec, index, offsets));
 
-	if (page_zip) {
-		ulint	pos = dict_index_get_sys_col_pos(index, DATA_TRX_ID);
+	if (UNIV_LIKELY_NULL(page_zip)) {
 		page_zip_write_trx_id_and_roll_ptr(page_zip, rec, offsets,
-						   pos, trx->id, roll_ptr);
+						   index->db_trx_id(),
+						   trx->id, roll_ptr);
 	} else {
 		ulint	offset = index->trx_id_offset;
 

storage/innobase/include/trx0undo.h

@@ -79,27 +79,22 @@ trx_undo_trx_id_is_insert(
 /*======================*/
 	const byte*	trx_id)	/*!< in: DB_TRX_ID, followed by DB_ROLL_PTR */
 	MY_ATTRIBUTE((warn_unused_result));
-/*****************************************************************//**
-Writes a roll ptr to an index page. In case that the size changes in
-some future version, this function should be used instead of
-mach_write_... */
-UNIV_INLINE
-void
-trx_write_roll_ptr(
-/*===============*/
-	byte*		ptr,		/*!< in: pointer to memory where
-					written */
-	roll_ptr_t	roll_ptr);	/*!< in: roll ptr */
-/*****************************************************************//**
-Reads a roll ptr from an index page. In case that the roll ptr size
-changes in some future version, this function should be used instead of
-mach_read_...
+/** Write DB_ROLL_PTR.
+@param[out]	ptr		buffer
+@param[in]	roll_ptr	DB_ROLL_PTR value */
+inline void trx_write_roll_ptr(byte* ptr, roll_ptr_t roll_ptr)
+{
+	compile_time_assert(DATA_ROLL_PTR_LEN == 7);
+	mach_write_to_7(ptr, roll_ptr);
+}
+/** Read DB_ROLL_PTR.
+@param[in]	ptr	buffer
 @return roll ptr */
-UNIV_INLINE
-roll_ptr_t
-trx_read_roll_ptr(
-/*==============*/
-	const byte*	ptr);	/*!< in: pointer to memory from where to read */
+inline roll_ptr_t trx_read_roll_ptr(const byte* ptr)
+{
+	compile_time_assert(DATA_ROLL_PTR_LEN == 7);
+	return mach_read_from_7(ptr);
+}
 
 /** Gets an undo log page and x-latches it.
 @param[in]	page_id		page id

storage/innobase/include/trx0undo.ic

@@ -103,37 +103,6 @@ trx_undo_trx_id_is_insert(
 	return bool(trx_id[DATA_TRX_ID_LEN] >> 7);
 }
 
-/*****************************************************************//**
-Writes a roll ptr to an index page. In case that the size changes in
-some future version, this function should be used instead of
-mach_write_... */
-UNIV_INLINE
-void
-trx_write_roll_ptr(
-/*===============*/
-	byte*		ptr,		/*!< in: pointer to memory where
-					written */
-	roll_ptr_t	roll_ptr)	/*!< in: roll ptr */
-{
-	compile_time_assert(DATA_ROLL_PTR_LEN == 7);
-	mach_write_to_7(ptr, roll_ptr);
-}
-
-/*****************************************************************//**
-Reads a roll ptr from an index page. In case that the roll ptr size
-changes in some future version, this function should be used instead of
-mach_read_...
-@return roll ptr */
-UNIV_INLINE
-roll_ptr_t
-trx_read_roll_ptr(
-/*==============*/
-	const byte*	ptr)	/*!< in: pointer to memory from where to read */
-{
-	compile_time_assert(DATA_ROLL_PTR_LEN == 7);
-	return(mach_read_from_7(ptr));
-}
-
 /** Gets an undo log page and x-latches it.
 @param[in]	page_id		page id
 @param[in,out]	mtr		mini-transaction

storage/innobase/page/page0cur.cc

@@ -1787,17 +1787,11 @@ page_cur_insert_rec_zip(
 			columns of free_rec, in case it will not be
 			overwritten by insert_rec. */
 
-			ulint	trx_id_col;
 			ulint	trx_id_offs;
 			ulint	len;
 
-			trx_id_col = dict_index_get_sys_col_pos(index,
-								DATA_TRX_ID);
-			ut_ad(trx_id_col > 0);
-			ut_ad(trx_id_col != ULINT_UNDEFINED);
-
-			trx_id_offs = rec_get_nth_field_offs(foffsets,
-							     trx_id_col, &len);
+			trx_id_offs = rec_get_nth_field_offs(
+				foffsets, index->db_trx_id(), &len);
 			ut_ad(len == DATA_TRX_ID_LEN);
 
 			if (DATA_TRX_ID_LEN + DATA_ROLL_PTR_LEN + trx_id_offs
@@ -1813,7 +1807,7 @@ page_cur_insert_rec_zip(
 
 			ut_ad(free_rec + trx_id_offs + DATA_TRX_ID_LEN
 			      == rec_get_nth_field(free_rec, foffsets,
-						   trx_id_col + 1, &len));
+						   index->db_roll_ptr(), &len));
 			ut_ad(len == DATA_ROLL_PTR_LEN);
 		}
 

storage/innobase/page/page0zip.cc

@@ -1411,10 +1411,7 @@ page_zip_compress(
 	/* Dense page directory and uncompressed columns, if any */
 	if (page_is_leaf(page)) {
 		if (dict_index_is_clust(index)) {
-			trx_id_col = dict_index_get_sys_col_pos(
-				index, DATA_TRX_ID);
-			ut_ad(trx_id_col > 0);
-			ut_ad(trx_id_col != ULINT_UNDEFINED);
+			trx_id_col = index->db_trx_id();
 
 			slot_size = PAGE_ZIP_DIR_SLOT_SIZE
 				+ DATA_TRX_ID_LEN + DATA_ROLL_PTR_LEN;
@@ -1422,8 +1419,6 @@ page_zip_compress(
 		} else {
 			/* Signal the absence of trx_id
 			in page_zip_fields_encode() */
-			ut_ad(dict_index_get_sys_col_pos(
-				      index, DATA_TRX_ID) == ULINT_UNDEFINED);
 			trx_id_col = 0;
 			slot_size = PAGE_ZIP_DIR_SLOT_SIZE;
 		}
@@ -3730,29 +3725,25 @@ page_zip_write_rec(
 		ulint		len;
 
 		if (dict_index_is_clust(index)) {
-			ulint		trx_id_col;
-
-			trx_id_col = dict_index_get_sys_col_pos(index,
-								DATA_TRX_ID);
-			ut_ad(trx_id_col != ULINT_UNDEFINED);
-
 			/* Store separately trx_id, roll_ptr and
 			the BTR_EXTERN_FIELD_REF of each BLOB column. */
 			if (rec_offs_any_extern(offsets)) {
 				data = page_zip_write_rec_ext(
 					page_zip, page,
 					rec, index, offsets, create,
-					trx_id_col, heap_no, storage, data);
+					index->db_trx_id(), heap_no,
+					storage, data);
 			} else {
 				/* Locate trx_id and roll_ptr. */
 				const byte*	src
 					= rec_get_nth_field(rec, offsets,
-							    trx_id_col, &len);
+							    index->db_trx_id(),
+							    &len);
 				ut_ad(len == DATA_TRX_ID_LEN);
 				ut_ad(src + DATA_TRX_ID_LEN
 				      == rec_get_nth_field(
 					      rec, offsets,
-					      trx_id_col + 1, &len));
+					      index->db_roll_ptr(), &len));
 				ut_ad(len == DATA_ROLL_PTR_LEN);
 
 				/* Log the preceding fields. */
@@ -3780,8 +3771,6 @@ page_zip_write_rec(
 		} else {
 			/* Leaf page of a secondary index:
 			no externally stored columns */
-			ut_ad(dict_index_get_sys_col_pos(index, DATA_TRX_ID)
-			      == ULINT_UNDEFINED);
 			ut_ad(!rec_offs_any_extern(offsets));
 
 			/* Log the entire record. */

storage/innobase/rem/rem0rec.cc

@@ -2641,8 +2641,6 @@ rec_get_trx_id(
 	const rec_t*		rec,
 	const dict_index_t*	index)
 {
-	ulint		trx_id_col
-		= dict_index_get_sys_col_pos(index, DATA_TRX_ID);
 	const byte*	trx_id;
 	ulint		len;
 	mem_heap_t*	heap		= NULL;
@@ -2650,15 +2648,10 @@ rec_get_trx_id(
 	rec_offs_init(offsets_);
 	ulint* offsets = offsets_;
 
-	ut_ad(trx_id_col <= MAX_REF_PARTS);
-	ut_ad(dict_index_is_clust(index));
-	ut_ad(trx_id_col > 0);
-	ut_ad(trx_id_col != ULINT_UNDEFINED);
-
 	offsets = rec_get_offsets(rec, index, offsets, true,
-				  trx_id_col + 1, &heap);
+				  index->db_trx_id() + 1, &heap);
 
-	trx_id = rec_get_nth_field(rec, offsets, trx_id_col, &len);
+	trx_id = rec_get_nth_field(rec, offsets, index->db_trx_id(), &len);
 
 	ut_ad(len == DATA_TRX_ID_LEN);
 

storage/innobase/row/row0log.cc

@@ -1244,19 +1244,16 @@ row_log_table_get_pk(
 			ulint	trx_id_offs = index->trx_id_offset;
 
 			if (!trx_id_offs) {
-				ulint	pos = dict_index_get_sys_col_pos(
-					index, DATA_TRX_ID);
 				ulint	len;
-				ut_ad(pos > 0);
 
 				if (!offsets) {
 					offsets = rec_get_offsets(
 						rec, index, NULL, true,
-						pos + 1, heap);
+						index->db_trx_id() + 1, heap);
 				}
 
 				trx_id_offs = rec_get_nth_field_offs(
-					offsets, pos, &len);
+					offsets, index->db_trx_id(), &len);
 				ut_ad(len == DATA_TRX_ID_LEN);
 			}
 

storage/innobase/row/row0mysql.cc

@@ -34,7 +34,6 @@ Created 9/17/2000 Heikki Tuuri
 #include "btr0sea.h"
 #include "dict0boot.h"
 #include "dict0crea.h"
-#include <sql_const.h>
 #include "dict0dict.h"
 #include "dict0load.h"
 #include "dict0priv.h"

storage/innobase/row/row0sel.cc

@@ -2694,44 +2694,6 @@ row_sel_convert_mysql_key_to_innobase(
 	dtuple_set_n_fields(tuple, n_fields);
 }
 
-/**************************************************************//**
-Stores the row id to the prebuilt struct. */
-static
-void
-row_sel_store_row_id_to_prebuilt(
-/*=============================*/
-	row_prebuilt_t*		prebuilt,	/*!< in/out: prebuilt */
-	const rec_t*		index_rec,	/*!< in: record */
-	const dict_index_t*	index,		/*!< in: index of the record */
-	const ulint*		offsets)	/*!< in: rec_get_offsets
-						(index_rec, index) */
-{
-	const byte*	data;
-	ulint		len;
-
-	ut_ad(rec_offs_validate(index_rec, index, offsets));
-
-	data = rec_get_nth_field(
-		index_rec, offsets,
-		dict_index_get_sys_col_pos(index, DATA_ROW_ID), &len);
-
-	if (UNIV_UNLIKELY(len != DATA_ROW_ID_LEN)) {
-
-		ib::error() << "Row id field is wrong length " << len << " in"
-			" index " << index->name
-			<< " of table " << index->table->name
-			<< ", Field number "
-			<< dict_index_get_sys_col_pos(index, DATA_ROW_ID)
-			<< ", record:";
-
-		rec_print_new(stderr, index_rec, offsets);
-		putc('\n', stderr);
-		ut_error;
-	}
-
-	ut_memcpy(prebuilt->row_id, data, len);
-}
-
 /**************************************************************//**
 Stores a non-SQL-NULL field in the MySQL format. The counterpart of this
 function is row_mysql_store_col_in_innobase_format() in row0mysql.cc. */
@@ -5494,11 +5456,19 @@ row_search_mvcc(
 			}
 		}
 
-		if (prebuilt->clust_index_was_generated) {
-			row_sel_store_row_id_to_prebuilt(
-				prebuilt, result_rec,
-				result_rec == rec ? index : clust_index,
-				offsets);
+		if (!prebuilt->clust_index_was_generated) {
+		} else if (result_rec != rec || index->is_primary()) {
+			memcpy(prebuilt->row_id, result_rec, DATA_ROW_ID_LEN);
+		} else {
+			ulint len;
+			const byte* data = rec_get_nth_field(
+				result_rec, offsets, index->n_fields - 1,
+				&len);
+			ut_ad(dict_index_get_nth_col(index,
+						     index->n_fields - 1)
+			      ->prtype == (DATA_ROW_ID | DATA_NOT_NULL));
+			ut_ad(len == DATA_ROW_ID_LEN);
+			memcpy(prebuilt->row_id, data, DATA_ROW_ID_LEN);
 		}
 	}
 

storage/innobase/row/row0upd.cc

@@ -497,39 +497,6 @@ row_upd_rec_sys_fields_in_recovery(
 	}
 }
 
-/*********************************************************************//**
-Sets the trx id or roll ptr field of a clustered index entry. */
-void
-row_upd_index_entry_sys_field(
-/*==========================*/
-	dtuple_t*	entry,	/*!< in/out: index entry, where the memory
-				buffers for sys fields are already allocated:
-				the function just copies the new values to
-				them */
-	dict_index_t*	index,	/*!< in: clustered index */
-	ulint		type,	/*!< in: DATA_TRX_ID or DATA_ROLL_PTR */
-	ib_uint64_t	val)	/*!< in: value to write */
-{
-	dfield_t*	dfield;
-	byte*		field;
-	ulint		pos;
-
-	ut_ad(dict_index_is_clust(index));
-
-	pos = dict_index_get_sys_col_pos(index, type);
-
-	dfield = dtuple_get_nth_field(entry, pos);
-	field = static_cast<byte*>(dfield_get_data(dfield));
-
-	if (type == DATA_TRX_ID) {
-		ut_ad(val > 0);
-		trx_write_trx_id(field, val);
-	} else {
-		ut_ad(type == DATA_ROLL_PTR);
-		trx_write_roll_ptr(field, val);
-	}
-}
-
 /***********************************************************//**
 Returns TRUE if row update changes size of some field in index or if some
 field to be updated is stored externally in rec or update.
@@ -732,35 +699,6 @@ row_upd_rec_in_place(
 	}
 }
 
-/*********************************************************************//**
-Writes into the redo log the values of trx id and roll ptr and enough info
-to determine their positions within a clustered index record.
-@return new pointer to mlog */
-byte*
-row_upd_write_sys_vals_to_log(
-/*==========================*/
-	dict_index_t*	index,	/*!< in: clustered index */
-	trx_id_t	trx_id,	/*!< in: transaction id */
-	roll_ptr_t	roll_ptr,/*!< in: roll ptr of the undo log record */
-	byte*		log_ptr,/*!< pointer to a buffer of size > 20 opened
-				in mlog */
-	mtr_t*		mtr MY_ATTRIBUTE((unused))) /*!< in: mtr */
-{
-	ut_ad(dict_index_is_clust(index));
-	ut_ad(mtr);
-
-	log_ptr += mach_write_compressed(log_ptr,
-					 dict_index_get_sys_col_pos(
-						 index, DATA_TRX_ID));
-
-	trx_write_roll_ptr(log_ptr, roll_ptr);
-	log_ptr += DATA_ROLL_PTR_LEN;
-
-	log_ptr += mach_u64_write_compressed(log_ptr, trx_id);
-
-	return(log_ptr);
-}
-
 /*********************************************************************//**
 Parses the log data of system field values.
 @return log data end or NULL */
@@ -1055,7 +993,6 @@ row_upd_build_difference_binary(
 	ulint		len;
 	upd_t*		update;
 	ulint		n_diff;
-	ulint		trx_id_pos;
 	ulint		i;
 	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
 	ulint		n_fld = dtuple_get_n_fields(entry);
@@ -1070,10 +1007,6 @@ row_upd_build_difference_binary(
 
 	n_diff = 0;
 
-	trx_id_pos = dict_index_get_sys_col_pos(index, DATA_TRX_ID);
-	ut_ad(dict_index_get_sys_col_pos(index, DATA_ROLL_PTR)
-	      == trx_id_pos + 1);
-
 	if (!offsets) {
 		offsets = rec_get_offsets(rec, index, offsets_, true,
 					  ULINT_UNDEFINED, &heap);
@@ -1088,16 +1021,9 @@ row_upd_build_difference_binary(
 
 		/* NOTE: we compare the fields as binary strings!
 		(No collation) */
-		if (no_sys) {
-			/* TRX_ID */
-			if (i == trx_id_pos) {
-				continue;
-			}
-
-			/* DB_ROLL_PTR */
-			if (i == trx_id_pos + 1) {
-				continue;
-			}
+		if (no_sys && (i == index->db_trx_id()
+			       || i == index->db_roll_ptr())) {
+			continue;
 		}
 
 		if (!dfield_is_ext(dfield)
@@ -2761,7 +2687,11 @@ row_upd_clust_rec_by_insert(
 	if (index->is_instant()) entry->trim(*index);
 	ut_ad(dtuple_get_info_bits(entry) == 0);
 
-	row_upd_index_entry_sys_field(entry, index, DATA_TRX_ID, trx->id);
+	{
+		dfield_t* t = dtuple_get_nth_field(entry, index->db_trx_id());
+		ut_ad(t->len == DATA_TRX_ID_LEN);
+		trx_write_trx_id(static_cast<byte*>(t->data), trx->id);
+	}
 
 	switch (node->state) {
 	default:

storage/innobase/trx/trx0rec.cc

@@ -954,9 +954,7 @@ trx_undo_page_report_modify(
 	*ptr++ = (byte) rec_get_info_bits(rec, dict_table_is_comp(table));
 
 	/* Store the values of the system columns */
-	field = rec_get_nth_field(rec, offsets,
-				  dict_index_get_sys_col_pos(
-					  index, DATA_TRX_ID), &flen);
+	field = rec_get_nth_field(rec, offsets, index->db_trx_id(), &flen);
 	ut_ad(flen == DATA_TRX_ID_LEN);
 
 	trx_id = trx_read_trx_id(field);
@@ -970,9 +968,7 @@ trx_undo_page_report_modify(
 	}
 	ptr += mach_u64_write_compressed(ptr, trx_id);
 
-	field = rec_get_nth_field(rec, offsets,
-				  dict_index_get_sys_col_pos(
-					  index, DATA_ROLL_PTR), &flen);
+	field = rec_get_nth_field(rec, offsets, index->db_roll_ptr(), &flen);
 	ut_ad(flen == DATA_ROLL_PTR_LEN);
 	ut_ad(memcmp(field, field_ref_zero, DATA_ROLL_PTR_LEN));
 
@@ -1578,9 +1574,7 @@ trx_undo_update_rec_get_update(
 
 	mach_write_to_6(buf, trx_id);
 
-	upd_field_set_field_no(upd_field,
-			       dict_index_get_sys_col_pos(index, DATA_TRX_ID),
-			       index);
+	upd_field_set_field_no(upd_field, index->db_trx_id(), index);
 	dfield_set_data(&(upd_field->new_val), buf, DATA_TRX_ID_LEN);
 
 	upd_field = upd_get_nth_field(update, n_fields + 1);
@@ -1589,9 +1583,7 @@ trx_undo_update_rec_get_update(
 
 	trx_write_roll_ptr(buf, roll_ptr);
 
-	upd_field_set_field_no(
-		upd_field, dict_index_get_sys_col_pos(index, DATA_ROLL_PTR),
-		index);
+	upd_field_set_field_no(upd_field, index->db_roll_ptr(), index);
 	dfield_set_data(&(upd_field->new_val), buf, DATA_ROLL_PTR_LEN);
 
 	/* Store then the updated ordinary columns to the update vector */