[DNM]*: Add a new syntax to randomize the rowid

[shenli]

To avoid single hot-region writing. If the random_scatter option is set. We will use bit-operations to randomize the explicit/implicit auto generated id. For example:

mysql> CREATE TABLE `t` (
    ->   `c` bigint DEFAULT NULL AUTO_INCREMENT KEY
    -> ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin RANDOM_SCATTER=4;
Query OK, 0 rows affected (0.01 sec)

mysql> insert into t values (), (), ();
Query OK, 3 rows affected (0.10 sec)

mysql> select * from t;
+---------------------+
| c                   |
+---------------------+
| 1152921504606846976 |
| 2305843009213693952 |
| 3458764513820540928 |
+---------------------+
3 rows in set (0.00 sec)

mysql> insert into t values (), (), ();
Query OK, 3 rows affected (0.01 sec)

mysql> select * from t;
+---------------------+
| c                   |
+---------------------+
| 1152921504606846976 |
| 2305843009213693952 |
| 3458764513820540928 |
| 4611686018427387904 |
| 5764607523034234880 |
| 6917529027641081856 |
+---------------------+
6 rows in set (0.00 sec)

mysql> insert into t values (), (), ();
Query OK, 3 rows affected (0.00 sec)

mysql> select * from t;
+----------------------+
| c                    |
+----------------------+
| -9223372036854775808 |
| -8070450532247928832 |
|  1152921504606846976 |
|  2305843009213693952 |
|  3458764513820540928 |
|  4611686018427387904 |
|  5764607523034234880 |
|  6917529027641081856 |
|  8070450532247928832 |
+----------------------+
9 rows in set (0.00 sec)

[winoros]

This will make AUTO_INCREMENT meaningless.

[winkyao]

how about add a RANDOM KEY syntax , and replace AUTO_INCREMENT KEY with it?

[shenli]

Duplicate with #5513