1. The scenario in which the problem occurs 1. Network delay, or use the FD tool to simulate requests sql select time form order where uid= 15 order by time desc limit 0 br > if (current time-time < 15) { exit (do not request frequently); } INS...
the company uses Aliyun s ECS server, which used to be a server (centos7) + a disk, and the environment and code were all put together. Once, when configuring the environment, the system file was deleted by mistake, so that the system could not boot. L...
Multi-table management, because the sum operation is used, so even if there is no data mybatis query will become one. The result is that null, if the default value is set on the sum, such as 0, it will return a piece of data that only the field sum is 0....