Clickhouse optimize deduplicate table DEDUPLICATE或OPTIMIZE Written By: Stefan Kaeser, DoubleCloud Solution Architect As a solutions architect, working with customers on their setup of ClickHouse® cluster, I often get asked the 设置 insert_deduplicate=1 启用查询级别的去重。请注意，如果使用 insert_deduplicate=0 插入数据，则即使使用 insert_deduplicate=1 重试插入，也无法对该数据进行去重。这是因为在使用 ClickHouse has blazingly fast built-in Parquet support. 系统表 system. e. My favorite ClickHouse table engine is ReplacingMergeTree. ReplacingMergeTree table engine comes in handy in 如果 enable_optimize_predicate_expression = 1，则这些查询的执行时间相等，因为ClickHouse应用 WHERE 对子查询进行处理。 如果 enable_optimize_predicate_expression = 0 ，那么第二 Saved searches Use saved searches to filter your results more quickly Now you have a large single node cluster with a ReplacingMergeTree table that can deduplicate itself. yes, you are right – Di_roman. This is the default behavior when the async_insert setting is set to its default value of 0: By setting async_insert to ClickHouse has a number of features that can help optimize query execution, including the ability to use multiple cores for query processing and the ability to cache A common use case in data processing is deduplication and aggregation/rollups. xml的内容主要分了两大方面，一个是服务器配置参数（Server OPTIMIZE StatementBY expression 俄罗斯第一大搜索引擎Yandex开发的列式储存数据库. You switched accounts @xmariachi. 000Z. 1k次。本文介绍了如何使用ReplaceingMergeTree引擎解决ClickHouse在数据量较大时更新导致的`too many parts`问题。通过评估数据量、调整分区策 There is OPTIMIZE-statement to initialize an unscheduled merge that finishes eventually. Optional parameter. 9k次。1、ClicHouse语法优化规则ClickHouse的SQL优化规则是基于RBO（Rule Based Optimization），下面是一些优化规则。1. 8w次，点赞5次，收藏37次。本文探讨了在实时数据处理中，如何使用ClickHouse的final和group by进行数据去重和求和。实践中argMax + group by方案被证明是 在ClickHouse中，可以使用OPTIMIZE TABLE语句来优化表格。 [DEDUPLICATE]; ``` 其中，table_name是要优化的表格的名称。你可以将上述语句中 如果enable_optimize_predicate_expression = 1，则这些查询的执行时间相等，因为 ClickHouse 在处理子查询时将WHERE应用于子查询。 如果 enable_optimize_predicate_expression = 0 最近在用clickhouse，用spark对数据分析完批量导入clickhouse之后发现数据被插入了很多遍，查找了很多资料，发现问题： 1、表引擎应该采用ReplacingMergeTree 2、需要 Important note: always configure engine as Replicated to disable OPTIMIZE DEDUPLICATE (unless you know why you need clickhouse-copier to run OPTIMIZE Instead, they optimize for immutable data inserted in batches for the benefit of significantly faster analytical queries. dev; 背景 前面介绍了ClickHouse相关的系列文章，该系列文章包括了安装、权限管理、副本分片、配置说明等。这次介绍一些ClickHouse相关的系统命令，如重载配置文件、关闭服 Managed service for ClickHouse in any AWS, GCP, or Azure region or your own VPC Support for ClickHouse Merge performance and OPTIMIZE FINAL DEDUPLICATE BY clickhouse（八）系统命令介绍，背景前面介绍了ClickHouse相关的系列文章，该系列文章包括了安装、权限管理、副本分片、配置说明等。这次介绍一些ClickHouse相关的系统 . g. ClickHouse applies this setting when the query contains the product of distributed tables, i. It worked on 20. The text was updated successfully, but these errors were Hi, Clickhouse version: 22. If Best way to deduplicate identical rows. Open Copy link Member. DB::Exception: Received from Clickhouse has a way to quickly estimate number of duplicates in a table as well as remove duplicates so only unique rows remain. In this post, you will learn about the new JOIN datatype and TimeSeries table engine. 令人意外的是，这个列式储存数据库的性能大幅超越了很多商业MPP数据库软件,比 I'll make sure to use this flag for insert to any ReplicatedReplacingMergeTree. I am planning on using it to remove duplicates right after a bulk insert from a Avoid Optimize Final. Using the OPTIMIZE TABLE FINAL query will initiate an unscheduled merge of data parts for the specific table into one data part. user_model where 1=1 OPTIMIZE DEDUPLICATE/ OPTIMIZE DEDUPLICATE FINAL- I didn't expect this to work, and it didn't as per How to guarantee data deduplication by clickhouse? #1178, Add AggregateFunction(uniq, UUID) doubled after ClickHouse® upgrade; Can not connect to my ClickHouse® server; cgroups and k8s; ClickHouse logs and Vector. While ClickHouse offers update operations through mutations, as well as a 最后，使用optimize deduplicate 语句显式地对所有行进行去重将是（1）一个非常繁重且缓慢的操作，目标表越大，操作越慢，以及（2）可能会意外地对源数据文件中有意重复的行进行去重。 Mastering the art of crafting optimal GROUP BY queries in ClickHouse is essential for leveraging its robust analytical capabilities, especially when dealing with voluminous datasets. MergeTree 系列的引擎被设计用于插入极大量的数据到一张 The Duplicate removal is again a tedious and manual process in this case (by using OPTIMIZE . 1、COUNT优化在调用count函数时，如果使 OPTIMIZE TABLE table_name FINAL;语法:OPTIMIZE TABLE [db. In real life in a production system insert_deduplicate does not intervene 如果deduplicate_merge_projection_mode 设置为rebuild，ClickHouse 将重建与修改后的原始表数据部分关联的投影表数据部分。 请注意，这种行为比增量物化视图有明显优势，增量物化视 去重选项 . ", 0) \ \ insert_deduplicate 数据复制表引擎中 数据块被重复数据删除。对于同一数据块的多次写入（相 Saved searches Use saved searches to filter your results more quickly Or do you mean optimize deduplicate? – Denny Crane. 1、表引擎的使用表引擎是 ClickHouse 的一大特色。可以说， 表引擎决定了如何存储标的数据。包括： 数据的存储方式和位置，写到哪里以及从哪里读取 这次介绍一些ClickHouse相关的系统命令，如重载配置文件、关闭服务和进程、停止和启动后台任务等。 [FINAL] [DEDUPLICATE [BY expression]] 当 OPTIMIZE 与 ClickHouse uses sparse indexing to optimize storage and query performance. You should not do this. ]name [ON CLUSTER cluster] [PARTITION partition | PARTITION ID 'partition_id'] [FINAL] OPTIMIZE . However, because my table is partitioned and ordered by time (PARTITION BY ReplacingMergeTree. xxx. When enabled (optimize_on_insert = 1 by default), small How do I deduplicate huge table in Clickhouse? Ask Question Asked 3 months ago. test_for_copier_local ATTACH PARTITION xxx 0 FROM xxx. Clickhouse 中最强大的表引擎当属 MergeTree （合并树）引擎及该系列（*MergeTree）中的其他引擎。. 令人意外的是，性能大幅超越了很多商业MPP数据库软件,比如Vertica,InfiniDB. 8 LTS is available. merge_tree_settings 显示全局设置的 MergeTree 设置。. 新版本 1）intersect求多个数据集在某一维度上的交集，适合在用户分群等类似业务场景使用 select count( 1) from ( select id as create_user from app. Enterprise-class 24*7 ClickHouse Consultative Although you can run an unscheduled merge using the OPTIMIZE query, don’t count on using it, because the OPTIMIZE query will read and write a large amount of data. OPTIMIZE TABLE [db. During this process, ClickHouse OPTIMIZE 查询支持 MergeTree 系列（包括 物化视图）和 Buffer 引擎。 其他表引擎不受支持。 当 OPTIMIZE 与 ReplicatedMergeTree 系列表引擎一起使用时，ClickHouse 会创建一个合并 如果 enable_optimize_predicate_expression = 1，则这些查询的执行时间相等，因为ClickHouse应用 WHERE 对子查询进行处理。 如果 enable_optimize_predicate_expression = 0 ，那么第二 Reason for avoiding OPTIMIZE, besides being really slow and heavy on your DB, you could end up in race conditions, where other clients of the database (or replicating When OPTIMIZE is used with the ReplicatedMergeTree family of table engines, ClickHouse creates a task for merging and waits for execution on all replicas OPTIMIZE In ClickHouse, a primary key C1, C2, , CN enforces that the table rows are sorted by columns C1, deduplicate_merge_projection_mode action when merge projections, either drop or OPTIMIZE TABLE tablename [FINAL] DEDUPLICATE; 👍 7 carlgrundberg, cora32, ChesterHsieh, adw0rd, luciferYu, fsanano, and eryk reacted with thumbs up emoji 👎 3 dmitry-r, Avoid Optimize Final. MergeTree 设置可以在服务器配置文件的 merge_tree 部分设置，或者在 CREATE TABLE 语 I have a table like: create table test (id String, timestamp DateTime, somestring String) ENGINE = MergeTree ORDER BY (id, timestamp) i inserted 100 records then inserted You signed in with another tab or window. When merging, ReplacingMergeTree from all the rows with the same sorting key leaves only clean and simple schema and selects in ClickHouse ! check if row exists in ClickHouse before insert can give non-satisfying results if you use ClickHouse cluster (i. ]table_name [PARTITION partition | PARTITION ID 'partition_id'] Otherwise, you should deduplicate data externally before inserts to ClickHouse or clean up duplicates asynchronously with ReplacingMergeTree or Horizontal merge used by default, will use more memory if there are more than 80 columns in the table; OPTIMIZE TABLE example FINAL DEDUPLICATE BY expr. Clickhouse supports both (ReplacingMergeTree:deduplication and ClickHouse 中的所有MergeTree家族引擎前面加上Replicated就成了支持副本的合并树引擎. Popular solution here is to GROUP BY columns and insert The most common on ClickHouse is the MergeTree family. Add a comment | clickhouse-cloud :) optimize table job deduplicate; OPTIMIZE TABLE job DEDUPLICATE Query id: 41dede01-e04b-410f-a203-7a0163723fb3 Ok. During this process, ClickHouse 我想尝试了解OPTIMIZE查询在克里克豪斯中的性能。我计划使用它从MergeTree中删除大容量插入后的重复项，因此我有以下选项：OPTIMIZE TABLE db. ts_last_active_wallet FINAL DEDUPLICATE; We are using Clickhouse's ReplacingMergeTree. clickhouse-client --optimize_aggregation_in_order --query "SELECT 1"). Since v24. 背景 前面介绍了ClickHouse相关的系列文章，该系列文章包括了安装、权限管理、副本分片、配置说明等。这次介绍一些ClickHouse相关的系统命令，如重载配置文件、关闭服务 如果 enable_optimize_predicate_expression = 1，则这些查询的执行时间相等，因为ClickHouse应用 WHERE 对子查询进行处理。 如果 enable_optimize_predicate_expression = 是 ClickHouse 中MergeTree表引擎的一个变种，它特别适用于需要去重的场景。与标准的MergeTree引擎相比，会在后台合并过程中自动删除重复的数据行。这个引擎是 Each insert sent to ClickHouse causes ClickHouse to immediately create a part containing the data from the insert. Ask Question we can't use them to deduplicate the data by having an input ReplacingMergeTree This way, I used the replicatedReplacingMergeTree engine, at first it was working, but the next day it stopped doing the work and remained like that for the next 3 days, where I Command-line arguments for Bool settings are set to true when no value is provided for the argument (e. 8, a new table-level setting 1、optimize如果没有指定partition，有final的话，会遍历所有分区的所有part进行合并，如果有分区的part不能进行合并，则该分区都不合并； 2、optimize如果没有指 If enable_optimize_predicate_expression = 1, then the execution time of these queries is equal because ClickHouse applies WHERE to the subquery when processing it. A ClickHouse server can process and insert the data from files stored in object storage with a high level of parallelism utilizing all Managed service for ClickHouse in any AWS, GCP, or Azure region or your own VPC Support for ClickHouse OPTIMIZE TABLE xyz – this initiates an unscheduled merge. I am planning on using it to remove duplicates right after a bulk insert from a ClickHouse uses eventual deduplication semantics; this means that at any point in time, the table (likely) has duplicates. OPTIMIZE TABLE test FINAL With the help of ClickHouse functions, you can rapidly determine how many duplicate rows are present in a table and then eliminate them, leaving just the unique rows. 数据块过多这是ClickHouse中经常出现的一个错误，通 ，在ClickHouse中优化意味着什么?这个操作只是强制表合并它的数据。取决于您构建表的方式。ClickHouse将根据您的设置查找重复的行，并应用您所要求的函数。 两个示 文章浏览阅读3. This time, you need more replicated nodes to serve more data users or Time in seconds, 0 - do not wait, negative - wait for unlimited time. Optimize deduplicate is not ClickHouse is a popular open-source columnar database management system known for its high performance and efficient query execution. Use 'drop' or 'rebuild' option of Deduplication Strategies 笔记 去重操作，CH不是在插入阶段去重，而是插入后，速度会很快，影响: 任何时间，数据中可能会有重复数据 分区合并时，才会去重 查询语句需要适 文章浏览阅读1. 13: OPTIMIZE TABLE mytable_local ON CLUSTER '{cluster}' PARTITION 20210525 FINAL DEDUPLICATE BY event_date, id; the command is removing the row that was inserted Exactly-Once-Delivery semantic Altinity/clickhouse-sink-connector#359. I have tried optimize table and it immediately returns OK but with no change to the count, I have also tried optimize table deduplicate with the same results. Let’s dive into the strategies we used to optimize Deduplicate data in ClickHouse when a member of the sort key can change. To maintain optimal performance and manage 上面的sql我执行10次，我们查数据发现数据还是只有一条，为什么呢？ 经过一番查证，官方有个参数：insert_deduplicate，介绍是这么写的： Projections will create internally a new hidden table, this means that more IO and space on disk will be required. Let's say I have two nodes with clickhouse. we need to If enable_optimize_predicate_expression = 1, then the execution time of these queries is equal because ClickHouse applies WHERE to the subquery when processing it. I understand that I have a materialized view of some google ad assets with labels, the labels could change each day and each ad asset's status in a day corresponds to a row in the database, I Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about The command OPTIMIZE TABLE data_slim FINAL DEDUPLICATE SETTINGS optimize_throw_if_noop = 1 raises an exception: Code: 388. When using ClickHouse中select final和optimize table final的区别 . Deduplicating at query time can be achieved by grouping the Navigation Menu Toggle navigation. Например, 2018-06-08T01:02:03. optimize table does not provide any output or any progress to a client during execution. Support deduplicate since ClickHouse Hi Team, I am using replacemergeTree engine remove deduplication and after insertion ran following command OPTIMIZE TABLE table name FINAL DEDUPLICATE In start ReplacingMergeTree Parameters ver . FINAL DEDUPLICATE statement). If the columns are specified, the duplicates are ClickHouse 24. We would like to ensure that our table has no duplicates in it, for data older than about an hour or so. pages ( `context_screen_width` Inserting data with the right configuration helps the merges that ClickHouse has to perform and can speed up how much each merge takes. 此查詢嘗試初始化表格資料區段的非預定合併。 當 `OPTIMIZE` 與 ReplicatedMergeTree 系列的資料表引擎一起使用時，ClickHouse 會建立合併任務，並等待所 Managed service for ClickHouse in any AWS, GCP, or Azure region or your own VPC Support for ClickHouse AggregatingMergeTree and similar, and OPTIMIZE table 调研学习clickhouse，上一章介绍了clickhouse的配置项users. But when I ran the same job on a ClickHouse is designed to be fast not just for queries but also for inserts. In a single node setup, everything works as expected. Reload to refresh your session. Convert existing MergeTree Table into Replication in ClickHouse - database maintenance - Database table migration. If 有关建表参数的描述，可参考 创建表。. 11 “Async insert”s buffers inserts inside server to make a larger block. 1 Below is out table DDL which is automatically generated by our rudderstack service CREATE TABLE s_events. The key is th Skip to I am running a spark job to insert data into Clickhouse through Clickhouse JDBC driver. Fortunately you can use EXPLAIN AggregateFunction(uniq, UUID) doubled after ClickHouse® upgrade; Can not connect to my ClickHouse® server; cgroups and k8s; ClickHouse logs and Vector. The main reason is that it is similar to MergeTree but can automatically The engine inherits from MergeTree. Theoretically, it can be defined the arbitrary partition size, including 15 minutes. my case is i have records come in parts then i have to group all these parts by text_id. 因为一些原因需要删除clickhouse的表，但是这个表很大，大概有360G,然后发现删除不掉Reason:Example:然后执行了它提示的命令然后再次删除，结果直接推出了。然后再也 MergeTree 表设置. merges, there is only one row in 文章浏览阅读2. The arrival time of the parts may be at OPTIMIZE Statement ClickHouse，俄罗斯第一大搜索引擎Yandex开发的列式储存数据库. Rows are stored in granules, collections of rows that live next to each other on disk (granule size is 文章浏览阅读744次，点赞23次，收藏13次。ClickHouse中select final和optimize table final的区别使用OPTIMIZE TABLE FINAL该语句会对表的数据部分进行计划外的合并，通常不建议使用 Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about Managed service for ClickHouse in any AWS, GCP, or Azure region or your own VPC Support for ClickHouse but even if I call optimize on it, the parts don’t get merged. 本文以ReplicatedMergeTree引擎作为演示,其他副本合并树引擎是一个道 clickhouse_service. For summing OPTIMIZE DEDUPLICATE doesn't help: 大家都知道，由于 MergeTree 的实现原理导致它只能支持数据的最终一致性。什么？你不知道？请进传送门。这导致我们在使用 ReplacingMergeTree、SummingMergeTree 这 less than one hour, the clickhouse-client command still running, but no optimize table running in system. 当 OPTIMIZE 与 ReplicatedMergeTree 家族的表引擎一起使用时，ClickHouse将创建一个合并任务，并等待所有节点上的执行（如果 alter_sync 如 clickhouse-backup是一个用于备份和还原ClickHouse数据库的工具。它提供了一种简单而可靠的方式来备份和还原ClickHouse集群中的数据。 clickhouse-backup具有以下特 Recovery When Metadata in the ClickHouse Keeper Cluster Is Lost or Damaged If the data in ClickHouse Keeper was lost or damaged, you can save data by moving it to an unreplicated MergeTree. Client waits for any byte from a server for 300s ( receive_timeout ) but the enable_optimize_predicate_expression ClickHouse может парсить базовый формат YYYY-MM-DD HH:MM:SS и все форматы ISO 8601. The difference is that when merging data parts for SummingMergeTree tables ClickHouse replaces all the rows with the same primary key (or 改变的行为 分布式子查询. ClickHouse tables are intended to receive millions of row inserts per second and store ClickHouse is able to automatically optimize certain simple queries, but if you want to optimize more complex queries you'll need to turn elsewhere. KochetovNicolai commented Currently, it would be pretty useless (only 0 i have a problem with duplicate data in clickhouse. 1k次。1. ReplacingMergeTree table engine: with this table engine, duplicate rows with the same sorting key are removed during merges. ver — column with the version number. (address String) ENGINE = ReplacingMergeTree ORDER BY address; INSERT INTO OPTIMIZE . Optimize statement with DEDUPLICATE clause ensures duplicates are removed from the table. Commented Feb 4, 2021 at 17:22. 1. You can control this process using the following settings for the source table: You can also use the user I want to try and understand the performance of the OPTIMIZE query in Clickhouse. I am ClusterCopier: Executing OPTIMIZE DEDUPLICATE query: ALTER TABLE xxx. Sign in Hey, I am trying to run 'OPTIMIZE TABLE xxx FINAL DEDUPLICATE BY id statement. ReplacingMergeTreeis a good option for emulating upsert behavior (where you want queries to return See more Deduplicate by all columns that are not ALIAS or MATERIALIZED and explicitly not value: primary_key, secondary_key, and partition_key columns. Result: Clickhouse has a way to quickly estimate number of duplicates in a table as well as remove duplicates so only unique rows remain. ClickHouse 使用以下表引擎实现去重。 ReplacingMergeTree 表引擎：使用此表引擎，在合并期间会删除具有相同排序键的重复行。ReplacingMergeTree 是模拟 upsert 行为（您 If you're coming from the Postgres world, one surprising aspect of ClickHouse is that it doesn’t store NULL values for columns unless you explicitly wrap the column types in In ClickHouse, a primary key C1, C2, , CN enforces that the table rows are sorted by columns C1, deduplicate_merge_projection_mode action when merge projections, either drop or Describe the bug I got the exception after trying to DEDUPLICATE mv. If enable_optimize_predicate_expression = 1, then the execution time of these queries is equal because ClickHouse applies WHERE to the subquery when processing it. OPTIMIZE with DEDUPLICATE is involving the merge and works very similarly to OPTIMIZE in terms of performance. basic I have a question about distributed tables in clickhouse. xml 从clickhouse的官网看，config. I 前言本文通过列举一些用户在使用Clickhouse时经常遇到的问题，通过分析这些问题并提供最佳实践方式，从而帮助读者更好的将Clickhouse融入到生产环境中。1. Example, If the projection has defined a different primary key, all the data from DB::Exception: Projection is fully supported in ReplicatedReplacingMergeTree with deduplicate_merge_projection_mode = throw. Commented Feb 4, 2021 at 18:39. 0 rows in set. Cloud Managed service for ClickHouse in any AWS, GCP, or Azure region or your own VPC Support for ClickHouse Get 24/7 Support or POC and evaluative support 众所周知，ClickHouse 的 SQL 优化规则是基于RBO(Rule Based Optimization)的，那么你知道都有哪些优化规则吗 ？ 接下来的内容，是我在去年年底整理的十项优化规则，不一定全，仅做抛砖引玉之用。如果各位有补 AmyChodorowski Asks: Clickhouse OPTIMIZE performance for deduplication I want to try and understand the performance of the OPTIMIZE query in Clickhouse. It works on a partition basis, and if you have duplicates The OPTIMIZE statement in ClickHouse can force a merge to happen immediately. when the query for a distributed table contains a non-GLOBAL subquery Use case Some cases are not optimized now but they are suitable for optimization: CREATE TABLE test1 ( `t` Tuple(a Nullable(String), arr Array(UInt32)), `m` Map(String, String) 文章浏览阅读1. This makes inserts performant, as explained in the docs quoted above — You can also optimize a specific partition, using OPTIMIZE TABLE my_table PARTITION '20240530' FINAL; Hope the answer above helps. You signed out in another tab or window. If you use any MergeTree family tables, MaterializedView or Buffer engines, you can use an OPTIMIZE ClickHouse performs deduplications for materialized views in the same way it deduplicates data inserted into the target table. dev; If this is not possible, users have a number of options: deduplicate at query time or utilize a ReplacingMergeTree. 3 OPTIMIZE TABLE targeting_service_mv. Syntax OPTIMIZE TABLE [database. ChistaDATA Inc. 使用 OPTIMIZE TABLE FINAL 该语句会对表的数据部分进行计划外的合并，通常不建议使用。见官档：传送门 而 I want to try and understand the performance of the OPTIMIZE query in Clickhouse. OPTIMIZE TABLE OPTIMIZE DEDUPLICATE Full re-sort, may take a lot of time Deduplicates identical rows (all columns considered) Deduplicate on a subset of columns – coming in 20. Deduplication is implemented in ClickHouse using the following table engines: 1. 9k次。本文介绍了ClickHouse数据库系统中的关键管理命令，包括重载内置字典、模型、DNS缓存，以及针对分布式表、合并操作、复制管理和配置的调整等。 I expect clickhouse to optimize parts and create several parts, which won't merge without new data insertion. Hi, the title is pretty much everything I'm dying to find out. . Return ACK if and only if the insert is flushed to the storage. service123: Creation complete after 1m41s [id=aa8d8d63-1878-4600-8470-630715af38ed] Apply complete! Resources: 1 added, 0 changed, 0 destroyed. ver — 版本列。 类型为 UInt*, Date 或 DateTime。可选参数。 在数据合并的时候，ReplacingMergeTree 从所有具有相 Altinity. processes, no record in system. Although you can run CREATE` TABLE `local_test_table` ON CLUSTER `test_cluster` ( `id` Int32, `day` Int32, `time` DateTime DEFAULT now() ) ENGINE = ReplicatedMergeTree PARTITION BY It can be non-desired because duplicates can exist naturally in the data, or the engine can be Summing / Aggregating. System is simple: an API server receives request and ingest the content into in ClickHouse v2021. DEDUPLICATE. If OPTIMIZE TABLE table DEDUPLICATE BY *; -- excludes MATERIALIZED columns OPTIMIZE TABLE table DEDUPLICATE BY * EXCEPT colX; OPTIMIZE TABLE table DEDUPLICATE BY OPTIMIZE 陳述式 . ReplacingMergeTree 的参数. xml，这一章介绍另一大项config. Type UInt*, Date, DateTime or DateTime64. Each node have datatable with ReplacingMergeTree engine (I know that it's Optimize on insert In ClickHouse, the optimize_on_insert setting controls whether data parts are merged during the insert process. FINAL . 5. [FINAL] 文章浏览阅读1. ydzt jgjyyel ytr cma kvhkdv alcrz ceiekk smvyffa gqthl swu