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PolarDB 列存索引解决上亿级数量统计问题 添加列存索引 创建表： CREATE TABLE t10( col1 INT COMMENT 'COLUMNAR=1', col2 DATETIME COMMENT 'COLUMNAR=1', col3 VARCHAR(200) ) ENGINE InnoDB; 查看最后执行SQL -- 查看最后执行SQL 阈值 SHOW STATUS LIKE 'Last_query_cost'; -- 查询cost阈值 SHOW VARIABLES LIKE 'imci_ap_threshold'; 查看表是否列存索引 SELECT * FROM INFORMATION_SCHEMA.IMCI_INDEXES WHERE TABLE_NAME LIKE '%by_wechat_message%'; 检查执行SQL 字段缺少列存索引 CALL dbms_imci.check_columnar_index(' SELECT domain, subject_id AS subjectId, SUM(question_num) AS questionNum , SUM(tk_question_num) AS tkQuestionNum FROM ask_question_statistic WHERE dt >= 20230501 AND dt 强制执行列存查询 SELECT /*+ SET_VAR(cost_threshold_for_imci=0) */ domain, subject_id AS subjectId, SUM(question_num) AS questionNum , SUM(tk_question_num) AS tkQuestionNum FROM ask_question_statistic WHERE dt >= 20230501 AND dt 设置并列索引 =16 -- 后台控制 innodb_polar_parallel_ddl_threads = 16; -- 查看是否开启并列查询 SHOW VARIABLES LIKE 'innodb_polar_parallel_ddl_threads' 查看列存索引创建状态 -- 表中查看索引的状态信息； SELECT * FROM INFORMATION_SCHEMA.IMCI_INDEXES; -- 表中查看索引的写入速度； SELECT * FROM INFORMATION_SCHEMA.IMCI_INDEX_STATS; -- 参见查看DDL执行速度和进度 SELECT * FROM INFORMATION_SCHEMA.IMCI_ASYNC_DDL_STATS;

感谢阿里云,特别棒的平台

Java 和redis 的游戏排名demo private static final String REDIS_HOST = 'xxxx'; private static final int REDIS_PORT = 6379; private static final String REDIS_PASSWORD = 'xxxx'; // 替换为实际的密码 private static final String RANKING_KEY = 'game_ranking'; public static void main(String[] args) { // 连接到Redis服务器 Jedis jedis = new Jedis(REDIS_HOST, REDIS_PORT); jedis.auth(REDIS_PASSWORD); // 设置初始玩家分数 jedis.zadd(RANKING_KEY, 100, 'Player1'); jedis.zadd(RANKING_KEY, 250, 'Player2'); jedis.zadd(RANKING_KEY, 180, 'Player3'); jedis.zadd(RANKING_KEY, 400, 'Player4'); // 获取排名前三的玩家 Set topPlayers = jedis.zrevrangeWithScores(RANKING_KEY, 0, 2); int rank = 1; System.out.println('排名\t玩家\t分数'); for (Tuple tuple : topPlayers) { System.out.println(rank++ + '\t' + tuple.getElement() + '\t' + tuple.getScore()); } // 增加玩家分数 jedis.zincrby(RANKING_KEY, 150, 'Player1'); // 获取更新后的排名前三的玩家 topPlayers = jedis.zrevrangeWithScores(RANKING_KEY, 0, 2); rank = 1; System.out.println('更新后的排名\t玩家\t分数'); for (Tuple tuple : topPlayers) { System.out.println(rank++ + '\t' + tuple.getElement() + '\t' + tuple.getScore()); } // 关闭Redis连接 jedis.close(); }