Help Center/ MapReduce Service/ Component Operation Guide (LTS) (Ankara Region)/ Using ClickHouse/ Common ClickHouse SQL Syntax/ DROP: Deleting a Table
Updated on 2024-11-29 GMT+08:00
View PDF
Share

DROP: Deleting a Table

This section describes the basic syntax and usage of the SQL statement for deleting a ClickHouse table.

Basic Syntax

DROP [TEMPORARY] TABLE [IF EXISTS] [database_name.]name [ON CLUSTER cluster] [SYNC]

Example

Delete the t1 table.

drop table t1 SYNC;
  • When you delete a replication table, create a path on ZooKeeper to store related data. The default library engine of ClickHouse is the atomic database engine. After a table in the atomic database is deleted, it is not deleted immediately but deleted 480 seconds later. To resolve this issue, when deleting a table, add the SYNC field or set profiles.default.database_atomic_wait_for_drop_and_detach_synchronously to 1, for example, drop table t1 SYNC;.

    To configure this parameter, do the following:

    Log in to FusionInsight Manager and choose Cluster > Services > ClickHouse. Click Configurations then All Configurations, search for database_atomic_wait_for_drop_and_detach_synchronously in the search box in the upper right corner, change the value of profiles.default.database_atomic_wait_for_drop_and_detach_synchronously to 1, and save the configuration. Then, restart the ClickHouse service.

  • This issue does not occur when a local or distributed table is deleted. The SYNC field is not required in your deletion command, for example, drop table t1;.