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Re: About AUTO-INC In different mode (1,2 or 3)
Posted by: five small
Date: April 21, 2021 11:50PM

So sorry i can't understand, let me put an example,and this is from MySQL official

mysql> CREATE TABLE t1 (
-> c1 INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
-> c2 CHAR(1)
-> ) ENGINE = INNODB;

-------------------------------------------------------------------------------
innodb_autoinc_lock_mode = 1

there are two transactions:
tx1:insert into t1 values(1,"a"),(null,"b"),(3,"c"),(null,"d");
tx2:insert into t1 values(5,"a"),(null,"b"),(7,"c"),(null,"d");

I want to know whether there are Auto-Inc locks for "Mixed-insert"? And in this situation ,Is statement-based replication repeatable?
-------------------------------------------------------------------------------
innodb_autoinc_lock_mode = 2

there are two transactions:
tx1:insert into t1 values(1,"a"),(null,"b"),(3,"c"),(null,"d");
tx2:insert into t1 values(5,"a"),(null,"b"),(7,"c"),(null,"d");

and according to MySQL offical,my tx1 may be like this:

mysql> SELECT c1, c2 FROM t1 ORDER BY c2;
+-----+------+
| c1 | c2 |
+-----+------+
| 1 | a |
| x | b |
| 3 | c |
| y | d |
+-----+------+
The values of x and y are unique and larger than any previously generated rows. However, the specific values of x and y depend on the number of auto-increment values generated by concurrently executing statements.

So I want to know what's difference between mode=1 and mode=2 ?

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Re: About AUTO-INC In different mode (1,2 or 3)
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April 21, 2021 11:50PM


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