Structure the eighth operation of the combat battalion module

Table name design

date _topic_ Table No , Such as 20220729_topic_00001, The date is the date of the day , Create new tables every day ;topic Subject the message ; The serial number of the table is the number of tables created on that day , Each table has a fixed capacity , Such as 1000 Line ten thousand , Beyond that, you need to create a new table .

Field design

（1）seq_no, Message is currently topic The serial number in ;

（2）data,varchar type , Store message data ;

Index design

Each table has seq_no Index for primary key , Incremental 1;

Design thinking

（1） Try to operate the disks sequentially ;

（2） Every topic Reasons for creating separate tables , When a subscriber wants something topic Data time , The database is read sequentially , Good performance ; Each table has a fixed capacity , When you want some serial number data, you can easily determine which table it is in ;

（3） The reason why the table name is dated , When old data needs to be deleted , Directly according to the date of the table name drop Just watch , Efficient ;

（4） Message writing library design , The application server caches a certain amount of messages plus timeout logic , Write in batches , according to topic Write in bulk , In this way, the disk can be written sequentially , Good performance ; But the business needs to be able to tolerate the main point of downtime , The data cached in the application server that has not been written to the library in batch is lost . The timeout can be set shorter , The maximum cache size can also be set less , According to the nature of the business ;

（5）seq_no The reason for the quotation , When subscribers want to subscribe to messages after a certain serial number , You can quickly locate the data location of the desired sequence number through the index , Avoid full table scanning .