v22.4 开始在单机 MergeTree 上支持事务,需要 "Begin Transaction" 和 "Commit/Rollback"。只支持 insert, update, delete 语句。 v22.7 增加参数implicit transaction,设为 true 时,事务无需 "Begin", "Commit/Rollback" 包裹,单条语句自动在事务中执行。 最新的 lts 版本 v22.8 已包含以上两个功能。 目前仍...
通过执行语句set implicit_transaction='true';,可以使用会话级别的隐式事务。ClickHouse目前没有alter queries中断机制,所以alter queries(如:lightweight delete)执行过程中被中断之后,即便开启隐式事务能力,也无法回滚,与开源保持一致。 分布式表事务性插入使用方法: ...
自从2016年6月15日开源后,从 ClickHouse 1.1.54245(2017-07-04)发布支持分布式DDL、复制查询、字典引擎等功能,到2018年期间支持 MySQL引擎、支持 HDFS引擎、支持JDBC引擎、支持Kafka引擎使用多个消费者、支持JOIN ON 语法、支持表中存储多维数组和元组、支持format格式化查询、支持clickhouse-copier(测试版)及系统库下各...
timezone() timezone, version() version, toUInt8(ifnull((select value from system.settings where name = 'readonly'), '0')) as readonly, toInt8(ifnull((select value from system.settings where name = 'throw_on_unsupported_query_inside_transaction'), '-1')) as...
A simple SELECT query can be written with implicit SELECT to enable calculator-style expressions, e.g., ch "1 + 2". This is controlled by a new setting, implicit_select. #68502 (Alexey Milovidov). Support the --copy mode for clickhouse local as a shortcut for format conversion #6850...
[86fe010]: improve implicit transaction support and error handling (Zhichun Wu)#1008 [9633bf8]: Improve error message as suggested in#1010(Zhichun Wu)#1008 [d7a6f77]: Roll back unnecessary changes (Zhichun Wu)#1008 [33cf266]: Enable repeat_on_session_lock to test CI (Zhichun Wu)#1008...
(select value from system.settings where name = 'implicit_transaction'), '-1')) as implicit_transaction, toUInt64(ifnull((select value from system.settings where name = 'max_insert_block_size'), '0')) as max_insert_block_size, toInt8(ifnull((select value from system.settings where ...
Adds new setting implicit_transaction to run standalone queries inside a transaction. It handles both creation and closing (via COMMIT if the query succeeded or ROLLBACK if it didn't) of the transaction automatically. #38344 (Raúl Marín). ...
Note that for CPU efficiency, the query language must be declarative (SQL or MDX), or at least a vector (J, K). The query should only contain implicit loops, allowing for optimization. 典型问题场景 使用原生的 ClickHouse,在大数据量的时候会发生很多问题: ...
Note that for CPU efficiency, the query language must be declarative (SQL or MDX), or at least a vector (J, K). The query should only contain implicit loops, allowing for optimization. 典型问题场景 使用原生的 ClickHouse,在大数据量的时候会发生很多问题: ...