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MDEV-17614 INSERT on dup key update is replication unsafe

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Problem:-
When mysql executes INSERT ON DUPLICATE KEY INSERT, the storage engine checks
if the inserted row would generate a duplicate key error. If yes, it returns
the existing row to mysql, mysql updates it and sends it back to the storage
engine.When the table has more than one unique or primary key, this statement
is sensitive to the order in which the storage engines checks the keys.
Depending on this order, the storage engine may determine different rows
to mysql, and hence mysql can update different rows.The order that the
storage engine checks keys is not deterministic. For example, InnoDB checks
keys in an order that depends on the order in which indexes were added to
the table. The first added index is checked first. So if master and slave
have added indexes in different orders, then slave may go out of sync.

Solution:-
Make INSERT...ON DUPLICATE KEY UPDATE unsafe while using stmt or mixed format
When there is more then one unique key.
Although there is two exception.
  1. Auto Increment key is not counted because Innodb will get gap lock for
    failed Insert and concurrent insert will get a next increment value. But if
    user supplies auto inc value it can be unsafe.
  2. Count only unique keys for which insertion is performed.

So this patch also addresses the bug id #72921
This commit is contained in:
Sachin
2019-07-17 15:56:29 +05:30
parent 47f8a18fec
commit 284c72eacf
9 changed files with 294 additions and 74 deletions
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5
mysql-test/suite/rpl/r/rpl_unsafe_statements.result
View File

@@ -1,5 +1,6 @@
include/master-slave.inc
[connection master]
call mtr.add_suppression("Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT");
CREATE TABLE t1(id INT AUTO_INCREMENT, i INT, PRIMARY KEY (id)) ENGINE=INNODB;
CREATE TABLE t2(id INT AUTO_INCREMENT, i INT, PRIMARY KEY (id)) ENGINE=INNODB;
CREATE TRIGGER trig1 AFTER INSERT ON t1
@@ -43,9 +44,13 @@ include/diff_tables.inc [master:t1, slave:t1]
DROP TABLE t1;
CREATE TABLE t1(i INT, j INT, UNIQUE KEY(i), UNIQUE KEY(j)) ENGINE=INNODB;
INSERT INTO t1 (i,j) VALUES (1,2) ON DUPLICATE KEY UPDATE j=j+1;
Warnings:
Note 1592 Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. INSERT... ON DUPLICATE KEY UPDATE on a table with more than one UNIQUE KEY is unsafe
START TRANSACTION;
LOCK TABLES t1 WRITE;
INSERT INTO t1 (i,j) VALUES (1,2) ON DUPLICATE KEY UPDATE j=j+1;
Warnings:
Note 1592 Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. INSERT... ON DUPLICATE KEY UPDATE on a table with more than one UNIQUE KEY is unsafe
UNLOCK TABLES;
COMMIT;
include/diff_tables.inc [master:t1, slave:t1]