Description:
Hello, dear verification team:
I created a table with UK, and I inserted one record into the table. Then I tested replace staments, and I made sure that the PRIMARY KEY of the only record is not changed. But as a result, I found that sometimes I got 1 rows affected from the replace statement, and sometimes 2 rows affected. The problem is that, I have only 1 record in the table.
However, it's the implementation of replace_stmt that leads to this inconsistency, but I think it's not proper because I have only 1 record in the table. For replace_stmt, it will act as a insert if there is no same record, and act as a update if there is a record with same key. No matter I execute an insert_stmt or update_stmt for 1 record, I will always get at most 1 rows affected.
Sql statements are placed in `How to repear` section.
How to repeat:
mysql> create database dbagent;
Query OK, 1 row affected (0.01 sec)
mysql> use dbagent
Database changed
mysql> create table heartbeat(serverid bigint primary key, hb_time timestamp); Query OK, 0 rows affected (0.74 sec)
mysql> insert into dbagent.heartbeat values (1, "2021-03-12 09:18:37");
Query OK, 1 row affected (0.01 sec)
mysql> replace into dbagent.heartbeat values (1, "2021-03-12 09:18:37");
Query OK, 1 row affected (0.00 sec)
mysql> replace into dbagent.heartbeat values (1, "2021-03-12 09:18:37");
Query OK, 1 row affected (0.01 sec)
mysql> replace into dbagent.heartbeat values (1, "2021-03-12 09:18:38");
Query OK, 2 rows affected (0.00 sec)
mysql> replace into dbagent.heartbeat values (1, "2021-03-12 09:18:39");
Query OK, 2 rows affected (0.00 sec)
