MySQL按时间维度对亿级数据表进行平滑分表

-- 分析数据时间分布
SELECT 
    DATE_FORMAT(create_time, '%Y-%m') AS month,
    COUNT(*) AS count
FROM original_table
GROUP BY month
ORDER BY month;

-- 创建2023年1月的分表（结构完全相同）
CREATE TABLE original_table_202301 LIKE original_table;

-- 为分表添加同样的索引
ALTER TABLE original_table_202301 ADD INDEX idx_user_id(user_id);

public class DataMigrator {
    private static final int BATCH_SIZE = 5000;
    
    public void migrateByMonth(String month) throws SQLException {
        String sourceTable = "original_table";
        String targetTable = "original_table_" + month;
        
        try (Connection conn = dataSource.getConnection()) {
            long maxId = getMaxId(conn, sourceTable);
            long currentId = 0;
            
            while (currentId < maxId) {
                String sql = String.format(
                    "INSERT INTO %s SELECT * FROM %s " +
                    "WHERE create_time BETWEEN '%s-01' AND '%s-31' " +
                    "AND id > %d ORDER BY id LIMIT %d",
                    targetTable, sourceTable, month, month, currentId, BATCH_SIZE);
                
                try (Statement stmt = conn.createStatement()) {
                    stmt.executeUpdate(sql);
                    currentId = getLastInsertedId(conn, targetTable);
                }
                
                Thread.sleep(100); // 控制迁移速度
            }
        }
    }
}

CREATE VIEW original_table_unified AS
SELECT * FROM original_table_202301 UNION ALL
SELECT * FROM original_table_202302 UNION ALL
...
SELECT * FROM original_table; -- 当前表作为最新数据

-- 创建分表
CREATE TABLE original_table_new LIKE original_table;

-- 创建触发器
DELIMITER //
CREATE TRIGGER tri_original_table_insert
AFTER INSERT ON original_table
FOR EACH ROW
BEGIN
    IF NEW.create_time >= '2023-01-01' THEN
        INSERT INTO original_table_new VALUES (NEW.*);
    END IF;
END//
DELIMITER ;

public class TableRouter {
    private static final DateTimeFormatter MONTH_FORMAT = 
        DateTimeFormatter.ofPattern("yyyyMM");
    
    public static String routeTable(LocalDateTime createTime) {
        String month = createTime.format(MONTH_FORMAT);
        return "original_table_" + month;
    }
}

<select id="queryByTime" resultType="com.example.Entity">
    SELECT * FROM ${tableName}
    WHERE user_id = #{userId}
    AND create_time BETWEEN #{start} AND #{end}
</select>

public List<Entity> queryByTime(Long userId, LocalDate start, LocalDate end) {
    List<String> tableNames = getTableNamesBetween(start, end);
    return tableNames.stream()
        .flatMap(table -> mapper.queryByTime(table, userId, start, end).stream())
        .collect(Collectors.toList());
}

@Intercepts(@Signature(type= StatementHandler.class, 
        method="prepare", args={Connection.class, Integer.class}))
public class TableShardInterceptor implements Interceptor {
    
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        BoundSql boundSql = ((StatementHandler)invocation.getTarget()).getBoundSql();
        String originalSql = boundSql.getSql();
        
        if (originalSql.contains("original_table")) {
            Object param = boundSql.getParameterObject();
            LocalDateTime createTime = getCreateTime(param);
            String newSql = originalSql.replace("original_table", 
                "original_table_" + createTime.format(MONTH_FORMAT));
            
            resetSql(invocation, newSql);
        }
        
        return invocation.proceed();
    }
}

@Scheduled(cron = "0 0 0 1 * ?") // 每月1号执行
public void autoCreateNextMonthTable() {
    LocalDate nextMonth = LocalDate.now().plusMonths(1);
    String tableName = "original_table_" + nextMonth.format(MONTH_FORMAT);
    
    jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + tableName + 
        " LIKE original_table_template");
}

public void archiveOldData(int keepMonths) {
    LocalDate archivePoint = LocalDate.now().minusMonths(keepMonths);
    String archiveTable = "archive_table_" + archivePoint.getYear();
    
    // 创建归档表
    jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + archiveTable + 
        " LIKE original_table_template");
    
    // 迁移数据
    jdbcTemplate.update("INSERT INTO " + archiveTable + 
        " SELECT * FROM original_table WHERE create_time < ?", 
        archivePoint.atStartOfDay());
    
    // 删除原数据
    jdbcTemplate.update("DELETE FROM original_table WHERE create_time < ?", 
        archivePoint.atStartOfDay());
}