diff --git a/mysql-test/include/deadlock.inc b/mysql-test/include/deadlock.inc
index abf217aea75..362d456e3f2 100644
--- a/mysql-test/include/deadlock.inc
+++ b/mysql-test/include/deadlock.inc
@@ -103,7 +103,6 @@ connection con2;
 
 # The following query should hang because con1 is locking the record
 update t2 set a=2 where b = 0;
-select * from t2;
 --send
 update t1 set x=2 where id = 0;
 --sleep 2
diff --git a/mysql-test/include/innodb_rollback_on_timeout.inc b/mysql-test/include/innodb_rollback_on_timeout.inc
index 274bbe12566..883b0820589 100644
--- a/mysql-test/include/innodb_rollback_on_timeout.inc
+++ b/mysql-test/include/innodb_rollback_on_timeout.inc
@@ -22,7 +22,6 @@ select * from t1;
 connection con1;
 begin work;
 insert into t1 values (5);
-select * from t1;
 # Lock wait timeout set to 2 seconds in <THIS TEST>-master.opt; this
 # statement will time out; in 5.0.13+, it will not roll back transaction.
 --error ER_LOCK_WAIT_TIMEOUT
diff --git a/mysql-test/main/deadlock_innodb.result b/mysql-test/main/deadlock_innodb.result
index 09958bf0413..9236f21c22b 100644
--- a/mysql-test/main/deadlock_innodb.result
+++ b/mysql-test/main/deadlock_innodb.result
@@ -89,11 +89,6 @@ id	x
 300	300
 connection con2;
 update t2 set a=2 where b = 0;
-select * from t2;
-b	a
-0	2
-1	20
-2	30
 update t1 set x=2 where id = 0;
 connection con1;
 update t1 set x=1 where id = 0;
diff --git a/mysql-test/main/mysqld--help.result b/mysql-test/main/mysqld--help.result
index 8a60f262554..79c0d7005f2 100644
--- a/mysql-test/main/mysqld--help.result
+++ b/mysql-test/main/mysqld--help.result
@@ -1837,7 +1837,7 @@ slave-run-triggers-for-rbr NO
 slave-skip-errors OFF
 slave-sql-verify-checksum TRUE
 slave-transaction-retries 10
-slave-transaction-retry-errors 1158,1159,1160,1161,1205,1213,1429,2013,12701
+slave-transaction-retry-errors 1158,1159,1160,1161,1205,1213,1020,1429,2013,12701
 slave-transaction-retry-interval 0
 slave-type-conversions 
 slow-launch-time 2
diff --git a/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result b/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
index 63ea5b1d418..505afb9b923 100644
--- a/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
+++ b/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
@@ -96,11 +96,8 @@ a	b	c
 DROP TABLE t1;
 CREATE TABLE t1 (a INT, b INT, c INT GENERATED ALWAYS AS(a+b));
 INSERT INTO t1(a, b) VALUES (1, 1), (2, 2), (3, 3), (4, 4);
-connection con1;
-# disable purge
-BEGIN;
-SELECT * FROM t0;
-a
+connect  stop_purge,localhost,root,,;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
 connection default;
 DELETE FROM t1 WHERE a = 1;
 UPDATE t1 SET a = 2, b = 2 WHERE a = 5;
@@ -109,10 +106,11 @@ SET DEBUG_SYNC= 'inplace_after_index_build SIGNAL uncommitted WAIT_FOR purged';
 ALTER TABLE t1 ADD INDEX idx (c), ALGORITHM=INPLACE, LOCK=NONE;
 connection con1;
 SET DEBUG_SYNC= 'now WAIT_FOR uncommitted';
+BEGIN;
 DELETE FROM t1 WHERE a = 3;
 UPDATE t1 SET a = 7, b = 7 WHERE a = 4;
 INSERT INTO t1(a, b) VALUES (8, 8);
-# enable purge
+disconnect stop_purge;
 COMMIT;
 # wait for purge to process the deleted/updated records.
 InnoDB		2 transactions not purged
diff --git a/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test b/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
index 09fba0285c7..7966953535c 100644
--- a/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
+++ b/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
@@ -131,9 +131,8 @@ CREATE TABLE t1 (a INT, b INT, c INT GENERATED ALWAYS AS(a+b));
 
 INSERT INTO t1(a, b) VALUES (1, 1), (2, 2), (3, 3), (4, 4);
 
-connection con1;
---echo # disable purge
-BEGIN; SELECT * FROM t0;
+connect (stop_purge,localhost,root,,);
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
 
 connection default;
 DELETE FROM t1 WHERE a = 1;
@@ -148,13 +147,14 @@ send ALTER TABLE t1 ADD INDEX idx (c), ALGORITHM=INPLACE, LOCK=NONE;
 connection con1;
 SET DEBUG_SYNC= 'now WAIT_FOR uncommitted';
 
+BEGIN;
 DELETE FROM t1 WHERE a = 3;
 
 UPDATE t1 SET a = 7, b = 7 WHERE a = 4;
 
 INSERT INTO t1(a, b) VALUES (8, 8);
 
---echo # enable purge
+disconnect stop_purge;
 COMMIT;
 
 --echo # wait for purge to process the deleted/updated records.
diff --git a/mysql-test/suite/innodb/r/innodb_mysql.result b/mysql-test/suite/innodb/r/innodb_mysql.result
index d142c0e499e..9d8ead7a165 100644
--- a/mysql-test/suite/innodb/r/innodb_mysql.result
+++ b/mysql-test/suite/innodb/r/innodb_mysql.result
@@ -431,10 +431,6 @@ a
 connection con1;
 begin work;
 insert into t1 values (5);
-select * from t1;
-a
-1
-5
 insert into t1 values (2);
 ERROR HY000: Lock wait timeout exceeded; try restarting transaction
 select * from t1;
@@ -509,10 +505,6 @@ a
 connection con1;
 begin work;
 insert into t1 values (5);
-select * from t1;
-a
-1
-5
 insert into t1 values (2);
 ERROR HY000: Lock wait timeout exceeded; try restarting transaction
 select * from t1;
@@ -1217,10 +1209,6 @@ a
 connection con1;
 begin work;
 insert into t1 values (5);
-select * from t1;
-a
-1
-5
 insert into t1 values (2);
 ERROR HY000: Lock wait timeout exceeded; try restarting transaction
 select * from t1;
diff --git a/mysql-test/suite/innodb/r/innodb_timeout_rollback.result b/mysql-test/suite/innodb/r/innodb_timeout_rollback.result
index 30db5a21a4d..e8fc89e55ba 100644
--- a/mysql-test/suite/innodb/r/innodb_timeout_rollback.result
+++ b/mysql-test/suite/innodb/r/innodb_timeout_rollback.result
@@ -17,10 +17,6 @@ a
 connection con1;
 begin work;
 insert into t1 values (5);
-select * from t1;
-a
-1
-5
 insert into t1 values (2);
 ERROR HY000: Lock wait timeout exceeded; try restarting transaction
 select * from t1;
diff --git a/mysql-test/suite/innodb/r/lock_isolation.result b/mysql-test/suite/innodb/r/lock_isolation.result
new file mode 100644
index 00000000000..88a2ad9326e
--- /dev/null
+++ b/mysql-test/suite/innodb/r/lock_isolation.result
@@ -0,0 +1,108 @@
+#
+# MDEV-26642 Weird SELECT view when a record is
+#            modified to the same value by two transactions
+# MDEV-32898 Phantom rows caused by updates of PRIMARY KEY
+#
+CREATE TABLE t(a INT PRIMARY KEY, b INT) ENGINE=InnoDB;
+INSERT INTO t VALUES (1,1),(2,2);
+BEGIN;
+SELECT * FROM t LOCK IN SHARE MODE;
+a	b
+1	1
+2	2
+connect con_weird,localhost,root;
+BEGIN;
+SELECT * FROM t;
+a	b
+1	1
+2	2
+connect consistent,localhost,root;
+SET innodb_snapshot_isolation=ON;
+BEGIN;
+SELECT * FROM t;
+a	b
+1	1
+2	2
+connection default;
+UPDATE t SET a=3 WHERE b=2;
+COMMIT;
+connection consistent;
+UPDATE t SET b=3;
+ERROR HY000: Record has changed since last read in table 't'
+SELECT * FROM t;
+a	b
+1	1
+3	2
+COMMIT;
+connection con_weird;
+UPDATE t SET b=3;
+SELECT * FROM t;
+a	b
+1	3
+2	2
+3	3
+COMMIT;
+connection default;
+SELECT * FROM t;
+a	b
+1	3
+3	3
+DROP TABLE t;
+#
+# MDEV-26643 Inconsistent behaviors of UPDATE under
+#            READ UNCOMMITTED and READ COMMITTED isolation level
+#
+CREATE TABLE t(a INT, b INT) ENGINE=InnoDB;
+INSERT INTO t VALUES(NULL, 1), (2, 2);
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+BEGIN;
+UPDATE t SET a = 10;
+connection consistent;
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+UPDATE t SET b = 20 WHERE a;
+connection default;
+COMMIT;
+connection consistent;
+SELECT * FROM t;
+a	b
+10	20
+10	20
+connection default;
+TRUNCATE TABLE t;
+INSERT INTO t VALUES(NULL, 1), (2, 2);
+BEGIN;
+UPDATE t SET a = 10;
+connection consistent;
+SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
+UPDATE t SET b = 20 WHERE a;
+connection default;
+COMMIT;
+connection consistent;
+SELECT * FROM t;
+a	b
+10	20
+10	20
+disconnect consistent;
+connection default;
+TRUNCATE TABLE t;
+INSERT INTO t VALUES(NULL, 1), (2, 2);
+BEGIN;
+UPDATE t SET a = 10;
+connection con_weird;
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+UPDATE t SET b = 20 WHERE a;
+connection default;
+SELECT * FROM t;
+a	b
+10	1
+10	2
+COMMIT;
+connection con_weird;
+COMMIT;
+disconnect con_weird;
+connection default;
+SELECT * FROM t;
+a	b
+10	1
+10	20
+DROP TABLE t;
diff --git a/mysql-test/suite/innodb/t/lock_isolation.test b/mysql-test/suite/innodb/t/lock_isolation.test
new file mode 100644
index 00000000000..30d2978f4f2
--- /dev/null
+++ b/mysql-test/suite/innodb/t/lock_isolation.test
@@ -0,0 +1,110 @@
+--source include/have_innodb.inc
+
+--echo #
+--echo # MDEV-26642 Weird SELECT view when a record is
+--echo #            modified to the same value by two transactions
+--echo # MDEV-32898 Phantom rows caused by updates of PRIMARY KEY
+--echo #
+
+CREATE TABLE t(a INT PRIMARY KEY, b INT) ENGINE=InnoDB;
+INSERT INTO t VALUES (1,1),(2,2);
+BEGIN; SELECT * FROM t LOCK IN SHARE MODE;
+--connect con_weird,localhost,root
+BEGIN;
+SELECT * FROM t;
+--connect consistent,localhost,root
+SET innodb_snapshot_isolation=ON;
+BEGIN;
+SELECT * FROM t;
+--connection default
+UPDATE t SET a=3 WHERE b=2;
+COMMIT;
+--connection consistent
+--error ER_CHECKREAD
+UPDATE t SET b=3;
+SELECT * FROM t;
+COMMIT;
+--connection con_weird
+UPDATE t SET b=3;
+SELECT * FROM t;
+COMMIT;
+--connection default
+SELECT * FROM t;
+DROP TABLE t;
+
+--echo #
+--echo # MDEV-26643 Inconsistent behaviors of UPDATE under
+--echo #            READ UNCOMMITTED and READ COMMITTED isolation level
+--echo #
+
+CREATE TABLE t(a INT, b INT) ENGINE=InnoDB;
+INSERT INTO t VALUES(NULL, 1), (2, 2);
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+BEGIN; UPDATE t SET a = 10;
+
+--connection consistent
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+--send UPDATE t SET b = 20 WHERE a
+
+--connection default
+let $wait_condition=
+  select count(*) = 1 from information_schema.processlist
+  where state = 'Updating'
+  and info = 'UPDATE t SET b = 20 WHERE a';
+--source include/wait_condition.inc
+
+COMMIT;
+
+--connection consistent
+--reap
+SELECT * FROM t;
+
+--connection default
+TRUNCATE TABLE t;
+INSERT INTO t VALUES(NULL, 1), (2, 2);
+BEGIN; UPDATE t SET a = 10;
+
+--connection consistent
+SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
+--send UPDATE t SET b = 20 WHERE a
+
+--connection default
+let $wait_condition=
+  select count(*) = 1 from information_schema.processlist
+  where info = 'UPDATE t SET b = 20 WHERE a';
+--source include/wait_condition.inc
+
+COMMIT;
+
+--connection consistent
+--reap
+SELECT * FROM t;
+--disconnect consistent
+
+--connection default
+TRUNCATE TABLE t;
+INSERT INTO t VALUES(NULL, 1), (2, 2);
+BEGIN; UPDATE t SET a = 10;
+
+--connection con_weird
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+send UPDATE t SET b = 20 WHERE a;
+
+--connection default
+let $wait_condition=
+  select count(*) = 1 from information_schema.processlist
+  where state = 'Updating'
+  and info = 'UPDATE t SET b = 20 WHERE a';
+--source include/wait_condition.inc
+
+SELECT * FROM t;
+COMMIT;
+
+--connection con_weird
+--reap
+COMMIT;
+--disconnect con_weird
+
+--connection default
+SELECT * FROM t;
+DROP TABLE t;
diff --git a/mysql-test/suite/sys_vars/r/slave_transaction_retry_errors.result b/mysql-test/suite/sys_vars/r/slave_transaction_retry_errors.result
index 72b4041599a..43988a81f4f 100644
--- a/mysql-test/suite/sys_vars/r/slave_transaction_retry_errors.result
+++ b/mysql-test/suite/sys_vars/r/slave_transaction_retry_errors.result
@@ -1,20 +1,20 @@
 select @@global.slave_transaction_retry_errors;
 @@global.slave_transaction_retry_errors
-1158,1159,1160,1161,1205,1213,1429,2013,12701,10,20,5000,400
+1158,1159,1160,1161,1205,1213,1020,1429,2013,12701,10,20,5000,400
 select @@session.slave_transaction_retry_errors;
 ERROR HY000: Variable 'slave_transaction_retry_errors' is a GLOBAL variable
 show global variables like 'slave_transaction_retry_errors';
 Variable_name	Value
-slave_transaction_retry_errors	1158,1159,1160,1161,1205,1213,1429,2013,12701,10,20,5000,400
+slave_transaction_retry_errors	1158,1159,1160,1161,1205,1213,1020,1429,2013,12701,10,20,5000,400
 show session variables like 'slave_transaction_retry_errors';
 Variable_name	Value
-slave_transaction_retry_errors	1158,1159,1160,1161,1205,1213,1429,2013,12701,10,20,5000,400
+slave_transaction_retry_errors	1158,1159,1160,1161,1205,1213,1020,1429,2013,12701,10,20,5000,400
 select * from information_schema.global_variables where variable_name='slave_transaction_retry_errors';
 VARIABLE_NAME	VARIABLE_VALUE
-SLAVE_TRANSACTION_RETRY_ERRORS	1158,1159,1160,1161,1205,1213,1429,2013,12701,10,20,5000,400
+SLAVE_TRANSACTION_RETRY_ERRORS	1158,1159,1160,1161,1205,1213,1020,1429,2013,12701,10,20,5000,400
 select * from information_schema.session_variables where variable_name='slave_transaction_retry_errors';
 VARIABLE_NAME	VARIABLE_VALUE
-SLAVE_TRANSACTION_RETRY_ERRORS	1158,1159,1160,1161,1205,1213,1429,2013,12701,10,20,5000,400
+SLAVE_TRANSACTION_RETRY_ERRORS	1158,1159,1160,1161,1205,1213,1020,1429,2013,12701,10,20,5000,400
 set global slave_transaction_retry_errors=1;
 ERROR HY000: Variable 'slave_transaction_retry_errors' is a read only variable
 set session slave_transaction_retry_errors=1;
diff --git a/mysql-test/suite/sys_vars/r/sysvars_innodb.result b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
index 8cc23f696b1..148ec4f9c9b 100644
--- a/mysql-test/suite/sys_vars/r/sysvars_innodb.result
+++ b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
@@ -1411,6 +1411,18 @@ NUMERIC_BLOCK_SIZE	0
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	OPTIONAL
+VARIABLE_NAME	INNODB_SNAPSHOT_ISOLATION
+SESSION_VALUE	OFF
+DEFAULT_VALUE	OFF
+VARIABLE_SCOPE	SESSION
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	Use snapshot isolation (write-write conflict detection).
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	NO
+COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	INNODB_SORT_BUFFER_SIZE
 SESSION_VALUE	NULL
 DEFAULT_VALUE	1048576
diff --git a/sql/slave.cc b/sql/slave.cc
index 1e73b9c2612..63346d29bbb 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -858,7 +858,7 @@ static void make_slave_transaction_retry_errors_printable(void)
 }
 
 
-#define DEFAULT_SLAVE_RETRY_ERRORS 9
+static constexpr uint DEFAULT_SLAVE_RETRY_ERRORS= 10;
 
 bool init_slave_transaction_retry_errors(const char* arg)
 {
@@ -900,9 +900,10 @@ bool init_slave_transaction_retry_errors(const char* arg)
   slave_transaction_retry_errors[3]= ER_NET_WRITE_INTERRUPTED;
   slave_transaction_retry_errors[4]= ER_LOCK_WAIT_TIMEOUT;
   slave_transaction_retry_errors[5]= ER_LOCK_DEADLOCK;
-  slave_transaction_retry_errors[6]= ER_CONNECT_TO_FOREIGN_DATA_SOURCE;
-  slave_transaction_retry_errors[7]= 2013; /* CR_SERVER_LOST */
-  slave_transaction_retry_errors[8]= 12701; /* ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM */
+  slave_transaction_retry_errors[6]= ER_CHECKREAD;
+  slave_transaction_retry_errors[7]= ER_CONNECT_TO_FOREIGN_DATA_SOURCE;
+  slave_transaction_retry_errors[8]= 2013; /* CR_SERVER_LOST */
+  slave_transaction_retry_errors[9]= 12701; /* ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM */
 
   /* Add user codes after this */
   for (p= arg, i= DEFAULT_SLAVE_RETRY_ERRORS; *p; )
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 474e5669222..c13cb55f805 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -881,6 +881,10 @@ static MYSQL_THDVAR_BOOL(table_locks, PLUGIN_VAR_OPCMDARG,
   /* check_func */ NULL, /* update_func */ NULL,
   /* default */ TRUE);
 
+static MYSQL_THDVAR_BOOL(snapshot_isolation, PLUGIN_VAR_OPCMDARG,
+  "Use snapshot isolation (write-write conflict detection).",
+  NULL, NULL, FALSE);
+
 static MYSQL_THDVAR_BOOL(strict_mode, PLUGIN_VAR_OPCMDARG,
   "Use strict mode when evaluating create options.",
   NULL, NULL, TRUE);
@@ -2238,6 +2242,9 @@ convert_error_code_to_mysql(
 
 		return(HA_ERR_LOCK_DEADLOCK);
 
+	case DB_RECORD_CHANGED:
+		return HA_ERR_RECORD_CHANGED;
+
 	case DB_LOCK_WAIT_TIMEOUT:
 		/* Starting from 5.0.13, we let MySQL just roll back the
 		latest SQL statement in a lock wait timeout. Previously, we
@@ -2881,6 +2888,8 @@ innobase_trx_init(
 
 	trx->check_unique_secondary = !thd_test_options(
 		thd, OPTION_RELAXED_UNIQUE_CHECKS);
+	trx->snapshot_isolation = THDVAR(thd, snapshot_isolation) & 1;
+
 #ifdef WITH_WSREP
 	trx->wsrep = wsrep_on(thd);
 #endif
@@ -4431,7 +4440,7 @@ innobase_start_trx_and_assign_read_view(
 	Do this only if transaction is using REPEATABLE READ isolation
 	level. */
 	trx->isolation_level = innobase_map_isolation_level(
-		thd_get_trx_isolation(thd));
+		thd_get_trx_isolation(thd)) & 3;
 
 	if (trx->isolation_level == TRX_ISO_REPEATABLE_READ) {
 		trx->read_view.open(trx);
@@ -15376,7 +15385,7 @@ ha_innobase::check(
 	}
 
 	/* Restore the original isolation level */
-	m_prebuilt->trx->isolation_level = old_isolation_level;
+	m_prebuilt->trx->isolation_level = old_isolation_level & 3;
 #ifdef BTR_CUR_HASH_ADAPT
 # if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
 	/* We validate the whole adaptive hash index for all tables
@@ -16431,7 +16440,7 @@ ha_innobase::store_lock(
 	if (lock_type != TL_IGNORE
 	    && trx->n_mysql_tables_in_use == 0) {
 		trx->isolation_level = innobase_map_isolation_level(
-			(enum_tx_isolation) thd_tx_isolation(thd));
+			(enum_tx_isolation) thd_tx_isolation(thd)) & 3;
 
 		if (trx->isolation_level <= TRX_ISO_READ_COMMITTED) {
 
@@ -19802,6 +19811,7 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
   MYSQL_SYSVAR(ft_server_stopword_table),
   MYSQL_SYSVAR(ft_user_stopword_table),
   MYSQL_SYSVAR(disable_sort_file_cache),
+  MYSQL_SYSVAR(snapshot_isolation),
   MYSQL_SYSVAR(stats_on_metadata),
   MYSQL_SYSVAR(stats_transient_sample_pages),
   MYSQL_SYSVAR(stats_persistent),
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index f278c428d62..96c03891679 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -864,6 +864,9 @@ my_error_innodb(
 	case DB_DEADLOCK:
 		my_error(ER_LOCK_DEADLOCK, MYF(0));
 		break;
+	case DB_RECORD_CHANGED:
+		my_error(ER_CHECKREAD, MYF(0), table);
+		break;
 	case DB_LOCK_WAIT_TIMEOUT:
 		my_error(ER_LOCK_WAIT_TIMEOUT, MYF(0));
 		break;
diff --git a/storage/innobase/include/db0err.h b/storage/innobase/include/db0err.h
index 64182aabc38..960ec3905eb 100644
--- a/storage/innobase/include/db0err.h
+++ b/storage/innobase/include/db0err.h
@@ -32,23 +32,25 @@ Created 5/24/1996 Heikki Tuuri
 enum dberr_t {
 	DB_SUCCESS,
 
-	DB_SUCCESS_LOCKED_REC = 9,	/*!< like DB_SUCCESS, but a new
+	DB_SUCCESS_LOCKED_REC= 9,		/*!< like DB_SUCCESS, but a new
 					explicit record lock was created */
 
 	/* The following are error codes */
-	DB_ERROR = 11,
+	DB_RECORD_CHANGED,
+	DB_ERROR,
 	DB_INTERRUPTED,
 	DB_OUT_OF_MEMORY,
 	DB_OUT_OF_FILE_SPACE,
 	DB_LOCK_WAIT,
 	DB_DEADLOCK,
-	DB_ROLLBACK,
 	DB_DUPLICATE_KEY,
 	DB_MISSING_HISTORY,		/*!< required history data has been
 					deleted due to lack of space in
 					rollback segment */
-	DB_CLUSTER_NOT_FOUND = 30,
-	DB_TABLE_NOT_FOUND,
+#ifdef WITH_WSREP
+	DB_ROLLBACK,
+#endif
+	DB_TABLE_NOT_FOUND= 31,
 	DB_TOO_BIG_RECORD,		/*!< a record in an index would not fit
 					on a compressed page, or it would
 					become bigger than 1/2 free space in
diff --git a/storage/innobase/include/row0row.h b/storage/innobase/include/row0row.h
index a1350740e2a..7056c77f2e6 100644
--- a/storage/innobase/include/row0row.h
+++ b/storage/innobase/include/row0row.h
@@ -370,6 +370,12 @@ row_search_index_entry(
 	mtr_t*		mtr)	/*!< in: mtr */
 	MY_ATTRIBUTE((nonnull, warn_unused_result));
 
+/** Get the byte offset of the DB_TRX_ID column
+@param[in]	rec	clustered index record
+@param[in]	index	clustered index
+@return	the byte offset of DB_TRX_ID, from the start of rec */
+ulint row_trx_id_offset(const rec_t* rec, const dict_index_t* index);
+
 #define ROW_COPY_DATA		1
 #define ROW_COPY_POINTERS	2
 
diff --git a/storage/innobase/include/trx0trx.h b/storage/innobase/include/trx0trx.h
index d5638778079..361d58f5663 100644
--- a/storage/innobase/include/trx0trx.h
+++ b/storage/innobase/include/trx0trx.h
@@ -739,13 +739,19 @@ public:
 	const char*	op_info;	/*!< English text describing the
 					current operation, or an empty
 					string */
-	uint		isolation_level;/*!< TRX_ISO_REPEATABLE_READ, ... */
-	bool		check_foreigns;	/*!< normally TRUE, but if the user
-					wants to suppress foreign key checks,
-					(in table imports, for example) we
-					set this FALSE */
+  /** TRX_ISO_REPEATABLE_READ, ... */
+  unsigned isolation_level:2;
+  /** when set, REPEATABLE READ will actually be Snapshot Isolation, due to
+  detecting write/write conflicts and disabling "semi-consistent read" */
+  unsigned snapshot_isolation:1;
+  /** normally set; "SET foreign_key_checks=0" can be issued to suppress
+  foreign key checks, in table imports, for example */
+  unsigned check_foreigns:1;
+  /** normally set; "SET unique_checks=0, foreign_key_checks=0"
+  enables bulk insert into an empty table */
+  unsigned check_unique_secondary:1;
   /** whether an insert into an empty table is active */
-  bool bulk_insert;
+  unsigned bulk_insert:1;
 	/*------------------------------*/
 	/* MySQL has a transaction coordinator to coordinate two phase
 	commit between multiple storage engines and the binary log. When
@@ -759,13 +765,6 @@ public:
 	/** whether this is holding the prepare mutex */
 	bool		active_commit_ordered;
 	/*------------------------------*/
-	bool		check_unique_secondary;
-					/*!< normally TRUE, but if the user
-					wants to speed up inserts by
-					suppressing unique key checks
-					for secondary indexes when we decide
-					if we can use the insert buffer for
-					them, we set this FALSE */
 	bool		flush_log_later;/* In 2PC, we hold the
 					prepare_commit mutex across
 					both phases. In that case, we
diff --git a/storage/innobase/lock/lock0lock.cc b/storage/innobase/lock/lock0lock.cc
index daef137db29..27209f71795 100644
--- a/storage/innobase/lock/lock0lock.cc
+++ b/storage/innobase/lock/lock0lock.cc
@@ -5949,6 +5949,14 @@ lock_clust_rec_read_check_and_lock(
 		return DB_SUCCESS;
 	}
 
+	if (heap_no > PAGE_HEAP_NO_SUPREMUM && gap_mode != LOCK_GAP
+            && trx->snapshot_isolation
+	    && trx->read_view.is_open()
+	    && !trx->read_view.changes_visible(
+		trx_read_trx_id(rec + row_trx_id_offset(rec, index)))) {
+		return DB_RECORD_CHANGED;
+	}
+
 	dberr_t err = lock_rec_lock(false, gap_mode | mode,
 				    block, heap_no, index, thr);
 
diff --git a/storage/innobase/row/row0mysql.cc b/storage/innobase/row/row0mysql.cc
index 6a518cddadf..b12100be7b5 100644
--- a/storage/innobase/row/row0mysql.cc
+++ b/storage/innobase/row/row0mysql.cc
@@ -695,6 +695,7 @@ handle_new_error:
 		DBUG_RETURN(true);
 
 	case DB_DEADLOCK:
+	case DB_RECORD_CHANGED:
 	case DB_LOCK_TABLE_FULL:
 	rollback:
 		/* Roll back the whole transaction; this resolution was added
diff --git a/storage/innobase/row/row0sel.cc b/storage/innobase/row/row0sel.cc
index 58684ebf20d..6886ca1ae5d 100644
--- a/storage/innobase/row/row0sel.cc
+++ b/storage/innobase/row/row0sel.cc
@@ -865,6 +865,11 @@ row_sel_build_committed_vers_for_mysql(
 					column version if any */
 	mtr_t*		mtr)		/*!< in: mtr */
 {
+	if (prebuilt->trx->snapshot_isolation) {
+		*old_vers = rec;
+		return;
+	}
+
 	if (prebuilt->old_vers_heap) {
 		mem_heap_empty(prebuilt->old_vers_heap);
 	} else {
diff --git a/storage/innobase/row/row0umod.cc b/storage/innobase/row/row0umod.cc
index a01eaea516a..52f54443911 100644
--- a/storage/innobase/row/row0umod.cc
+++ b/storage/innobase/row/row0umod.cc
@@ -190,7 +190,7 @@ row_undo_mod_clust_low(
 @param[in]	rec	clustered index record
 @param[in]	index	clustered index
 @return	the byte offset of DB_TRX_ID, from the start of rec */
-static ulint row_trx_id_offset(const rec_t* rec, const dict_index_t* index)
+ulint row_trx_id_offset(const rec_t* rec, const dict_index_t* index)
 {
 	ut_ad(index->n_uniq <= MAX_REF_PARTS);
 	ulint trx_id_offset = index->trx_id_offset;
diff --git a/storage/innobase/trx/trx0trx.cc b/storage/innobase/trx/trx0trx.cc
index 58e36726bbc..59685e21cfb 100644
--- a/storage/innobase/trx/trx0trx.cc
+++ b/storage/innobase/trx/trx0trx.cc
@@ -412,12 +412,12 @@ void trx_t::free()
 #endif
   read_view.mem_noaccess();
   MEM_NOACCESS(&lock, sizeof lock);
-  MEM_NOACCESS(&op_info, sizeof op_info);
-  MEM_NOACCESS(&isolation_level, sizeof isolation_level);
-  MEM_NOACCESS(&check_foreigns, sizeof check_foreigns);
+  MEM_NOACCESS(&op_info, sizeof op_info +
+               sizeof(unsigned) /* isolation_level, snapshot_isolation,
+                                   check_foreigns, check_unique_secondary,
+                                   bulk_insert */);
   MEM_NOACCESS(&is_registered, sizeof is_registered);
   MEM_NOACCESS(&active_commit_ordered, sizeof active_commit_ordered);
-  MEM_NOACCESS(&check_unique_secondary, sizeof check_unique_secondary);
   MEM_NOACCESS(&flush_log_later, sizeof flush_log_later);
   MEM_NOACCESS(&duplicates, sizeof duplicates);
   MEM_NOACCESS(&dict_operation, sizeof dict_operation);
diff --git a/storage/innobase/ut/ut0ut.cc b/storage/innobase/ut/ut0ut.cc
index 7f4d2da2089..3cdc49c4b32 100644
--- a/storage/innobase/ut/ut0ut.cc
+++ b/storage/innobase/ut/ut0ut.cc
@@ -312,14 +312,16 @@ ut_strerr(
 		return("Lock wait");
 	case DB_DEADLOCK:
 		return("Deadlock");
+	case DB_RECORD_CHANGED:
+		return("Record changed");
+#ifdef WITH_WSREP
 	case DB_ROLLBACK:
 		return("Rollback");
+#endif
 	case DB_DUPLICATE_KEY:
 		return("Duplicate key");
 	case DB_MISSING_HISTORY:
 		return("Required history data has been deleted");
-	case DB_CLUSTER_NOT_FOUND:
-		return("Cluster not found");
 	case DB_TABLE_NOT_FOUND:
 		return("Table not found");
 	case DB_TOO_BIG_RECORD:
diff --git a/storage/spider/mysql-test/spider/bugfix/r/slave_transaction_retry_errors_5digit.result b/storage/spider/mysql-test/spider/bugfix/r/slave_transaction_retry_errors_5digit.result
index f2cab6b0a95..c8b1de982eb 100644
--- a/storage/spider/mysql-test/spider/bugfix/r/slave_transaction_retry_errors_5digit.result
+++ b/storage/spider/mysql-test/spider/bugfix/r/slave_transaction_retry_errors_5digit.result
@@ -9,7 +9,7 @@ for slave1_1
 connection slave1_1;
 SHOW VARIABLES LIKE 'slave_transaction_retry_errors';
 Variable_name	Value
-slave_transaction_retry_errors	1158,1159,1160,1161,1205,1213,1429,2013,12701,10000,20000,30000
+slave_transaction_retry_errors	1158,1159,1160,1161,1205,1213,1020,1429,2013,12701,10000,20000,30000
 connection slave1_1;
 for slave1_1
 for master_1
diff --git a/storage/spider/mysql-test/spider/feature/r/slave_transaction_retry_errors.result b/storage/spider/mysql-test/spider/feature/r/slave_transaction_retry_errors.result
index 0a147c0356a..1de1ba04528 100644
--- a/storage/spider/mysql-test/spider/feature/r/slave_transaction_retry_errors.result
+++ b/storage/spider/mysql-test/spider/feature/r/slave_transaction_retry_errors.result
@@ -9,7 +9,7 @@ for slave1_1
 connection slave1_1;
 SHOW VARIABLES LIKE 'slave_transaction_retry_errors';
 Variable_name	Value
-slave_transaction_retry_errors	1158,1159,1160,1161,1205,1213,1429,2013,12701
+slave_transaction_retry_errors	1158,1159,1160,1161,1205,1213,1020,1429,2013,12701
 connection slave1_1;
 for slave1_1
 for master_1