Merge a patch from Facebook to fix Bug #53290

commit e759bc64eb5c5eed4f75677ad67246797d486460
Author: Ryan Mack
Date:   3 days ago

    Bugfix for 53290, fast unique index creation fails on duplicate null values

    Summary:
    Bug in the fast index creation code incorrectly considers null
    values to be duplicates during block merging.  Innodb policy is that
    multiple null values are allowed in a unique index.  Null duplicates
    were correctly ignored while sorting individual blocks and with slow
    index creation.

    Test Plan:
    mtr, including new test, load dbs using deferred index creation

    License:
    Copyright (C) 2009-2010 Facebook, Inc.  All Rights Reserved.

    Dual licensed under BSD license and GPLv2.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:
    1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY FACEBOOK, INC. ``AS IS'' AND ANY EXPRESS OR
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
    EVENT SHALL FACEBOOK, INC. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
    OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
    WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
    OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
    ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    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 Foundation; version 2 of the License.

    This program is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
    more details.

    You should have received a copy of the GNU General Public License along with
    this program; if not, write to the Free Software Foundation, Inc., 59 Temple
    Place, Suite 330, Boston, MA  02111-1307  USA

3 files changed, 18 insertions, 6 deletions

diff --git a/storage/innodb_plugin/include/rem0cmp.h b/storage/innodb_plugin/include/rem0cmp.h
index 072f74267ea..2f751a38864 100644
--- a/storage/innodb_plugin/include/rem0cmp.h
+++ b/storage/innodb_plugin/include/rem0cmp.h
@@ -148,7 +148,9 @@ cmp_rec_rec_simple(
 	const rec_t*		rec2,	/*!< in: physical record */
 	const ulint*		offsets1,/*!< in: rec_get_offsets(rec1, ...) */
 	const ulint*		offsets2,/*!< in: rec_get_offsets(rec2, ...) */
-	const dict_index_t*	index);	/*!< in: data dictionary index */
+	const dict_index_t*	index,	/*!< in: data dictionary index */
+	ibool*			null_eq);/*!< out: set to TRUE if
+					found matching null values */
 /*************************************************************//**
 This function is used to compare two physical records. Only the common
 first fields are compared, and if an externally stored field is
diff --git a/storage/innodb_plugin/rem/rem0cmp.c b/storage/innodb_plugin/rem/rem0cmp.c
index e6dab0bc66b..35b67992558 100644
--- a/storage/innodb_plugin/rem/rem0cmp.c
+++ b/storage/innodb_plugin/rem/rem0cmp.c
@@ -706,7 +706,9 @@ cmp_rec_rec_simple(
 	const rec_t*		rec2,	/*!< in: physical record */
 	const ulint*		offsets1,/*!< in: rec_get_offsets(rec1, ...) */
 	const ulint*		offsets2,/*!< in: rec_get_offsets(rec2, ...) */
-	const dict_index_t*	index)	/*!< in: data dictionary index */
+	const dict_index_t*	index,	/*!< in: data dictionary index */
+	ibool*			null_eq)/*!< out: set to TRUE if
+					found matching null values */
 {
 	ulint		rec1_f_len;	/*!< length of current field in rec1 */
 	const byte*	rec1_b_ptr;	/*!< pointer to the current byte
@@ -753,6 +755,9 @@ cmp_rec_rec_simple(
 		    || rec2_f_len == UNIV_SQL_NULL) {
 
 			if (rec1_f_len == rec2_f_len) {
+				if (null_eq) {
+					*null_eq = TRUE;
+				}
 
 				goto next_field;
 
diff --git a/storage/innodb_plugin/row/row0merge.c b/storage/innodb_plugin/row/row0merge.c
index bedad2d1c71..832d29df710 100644
--- a/storage/innodb_plugin/row/row0merge.c
+++ b/storage/innodb_plugin/row/row0merge.c
@@ -1075,11 +1075,14 @@ row_merge_cmp(
 						record to be compared */
 	const ulint*		offsets1,	/*!< in: first record offsets */
 	const ulint*		offsets2,	/*!< in: second record offsets */
-	const dict_index_t*	index)		/*!< in: index */
+	const dict_index_t*	index,		/*!< in: index */
+	ibool*			null_eq)	/*!< out: set to TRUE if
+						found matching null values */
 {
 	int	cmp;
 
-	cmp = cmp_rec_rec_simple(mrec1, mrec2, offsets1, offsets2, index);
+	cmp = cmp_rec_rec_simple(mrec1, mrec2, offsets1, offsets2, index,
+				 null_eq);
 
 #ifdef UNIV_DEBUG
 	if (row_merge_print_cmp) {
@@ -1445,11 +1448,13 @@ corrupt:
 	}
 
 	while (mrec0 && mrec1) {
+		ibool	null_eq = FALSE;
 		switch (row_merge_cmp(mrec0, mrec1,
-				      offsets0, offsets1, index)) {
+				      offsets0, offsets1, index,
+				      &null_eq)) {
 		case 0:
 			if (UNIV_UNLIKELY
-			    (dict_index_is_unique(index))) {
+			    (dict_index_is_unique(index) && !null_eq)) {
 				innobase_rec_to_mysql(table, mrec0,
 						      index, offsets0);
 				mem_heap_free(heap);