Group Replication原理解析与实践经验 徐春阳 MGR原理 MGR vs SEMI-SYNC MRG实践经验 • 支持多节点并发执行事务。如何保证从各个节点并发执行 的事务在每个节点以相同的顺序被应用/执行.------paxos协 议的功能。 • 自动地事务冲突检测。节点之间不能”同时”操作主键相同 记录,如果冲突，只有一个节点成功。------冲突检测。 ���������sql)��! ��sql! mysql_parse! mysql_execute_comma nd! trans_commit_stmt! MYSQL_BIN_LOG::com mit! group_replication_trans_before_commit! waitTicket! ���������� ���������� ���������� ������paxos� ��������� MGR实践经验 Group_replication_bootstrap_group参数须谨慎 DDL操作注意事项 当心secondary节点变成可写节点 规避大事务 Secondary��������! ������Single primary ����secondary����! ��my.cnf�read_only��������! ������stop group_replicaiton������

https://badoo.com/ 26 / 97 ClickHouse in Production: Badoo HTTP Server Aggregation Services HDFS Storage MR Aggregation Old Events Pusher Events Storage Old Events Database PHP API Client Graphs Browser Mobile App 27 / 97 ClickHouse in Production: Badoo HTTP Server Aggregation Services HDFS Storage MR Aggregation Old Events Pusher Events Storage Old Events Database PHP API Client Graphs Browser Mobile App 28 / 97 ClickHouse in Production: Badoo HTTP Server Aggregation Services HDFS Storage MR Aggregation Old Events Pusher Events Storage Old Events Database PHP API Client Graphs

. . . . . . . . . . . . . . . . . . . . . . 295 7.9 In SQLSever and PostgreSQL, why does the aggregation column without alias throw ex‐ ception? . . . . . . . . . . . . . . . . . . . . . . . . . . . name after sharding, or misconducts caused by operations such as pagination, order by or aggregated group by are just the case in point. 3.1. Sharding 10 Apache ShardingSphere document, v5.0.0-beta Cross‐database extract the parsing context, which can include tables, options, ordering items, grouping items, aggregation functions, pagination information, query conditions and placeholders that may be revised. Query

. . . . . . . . . . . . . . . . . . . . . . 257 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308 7.7.20 20. [Other] In SQLSever and PostgreSQL, why does the aggregation column with‐ out alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . t_order CHECK TABLE t_order SET RESOURCE GROUP group_name DROP RESOURCE GROUP group_name CREATE RESOURCE GROUP group_name TYPE = SYSTEM ALTER RESOURCE GROUP rg1 VCPU = 0‐63 4.1. DB Compatibility 19

. . . . . . . . . . . . . . . . . . . . . . 267 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351 7.8.23 [Other] In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . t_order CHECK TABLE t_order SET RESOURCE GROUP group_name DROP RESOURCE GROUP group_name CREATE RESOURCE GROUP group_name TYPE = SYSTEM ALTER RESOURCE GROUP rg1 VCPU = 0‐63 openGauss The unsupported

. . . . . . . . . . . . . . . . . . . . . . 278 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 7.8.23 [Other] In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . t_order CHECK TABLE t_order SET RESOURCE GROUP group_name DROP RESOURCE GROUP group_name CREATE RESOURCE GROUP group_name TYPE = SYSTEM ALTER RESOURCE GROUP rg1 VCPU = 0‐63 Source Codes: https://github

· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2995 15.5.1 Region/peer/Raft group · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2995 15.5.2 Region processing and real-time data analysis in the same system, which greatly saves the cost. • Data aggregation and secondary processing scenarios The application data of most companies are scattered in different MICROSECOND(), MINUTE(), SEC- OND(), SYSDATE() * Type conversion function: CAST(time, real) * Aggregation functions: GROUP_CONCAT(), SUM(enum) – Support 512-bit SIMD – Enhance the cleanup algorithm for outdated

· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2744 15.5.1 Region/peer/Raft group · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2744 15.5.2 Region processing and real-time data analysis in the same system, which greatly saves the cost. • Data aggregation and secondary processing scenarios The application data of most companies are scattered in different partitions #24746 – Fix the potential index out of range error when a SQL statement contains both GROUP BY and UNION #24281 – Fix the issue that the CONCAT function incorrectly handles the collation #24296

· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2847 15.5.1 Region/peer/Raft group · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2847 15.5.2 Region processing and real-time data analysis in the same system, which greatly saves the cost. • Data aggregation and secondary processing scenarios The application data of most companies are scattered in different INET_ATON(), INET6_ATON, INET6_NTOA() – Support Shuffled Hash Join calculation and Shuffled Hash Aggregation calculation in the MPP mode when a new collation is enabled – Optimize basic code to improve MPP

. . . . . . . . . . . . . . . . . . . . . . 382 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 Aggregation Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461 8.6.3 Other In SQLSever and PostgreSQL, why does the aggregation column without alias throw exception? . . . . . . . . . . . . . . . . . . . . . . . . . . . . try to reduce the influence of sharding, in order to let users use horizontal sharding database group like one database. 3.1.4 Application Scenarios Mass data high concurrency in OLTP scenarios Most