Using ClickHouse Distributed Tables (Creation and Management)

== ClickHouse Distributed Tables ==

Introduction

ClickHouse is an open-source distributed database that supports various data models, including relational, graph, and time-series databases.

Creating Distributed Tables

Using the CREATE TABLE command

CREATE TABLE distribution_table (
    id Int64,
    name String
) ENGINE = MergeTree
PARTITION BY hash(id)
ORDER BY (id);

This command creates a distributed table named distribution_table, partitioned by the hash value of id.

Using CREATE TABLE options

CREATE TABLE distribution_table (
    id Int64,
    name String
) ENGINE = MergeTree
PARTITION BY RANGE (id)
ORDER BY (id);

This command creates a distributed table named distribution_table, partitioned by the range of id.

Managing Distributed Tables

Using the EXPLAIN command

EXPLAIN SELECT * FROM distribution_table WHERE id = 1;

This command displays specific information about the partition of id in the distributed table.

Using the ANALYZE TABLE command

ANALYZE TABLE distribution_table;

This command collects statistical information from the distributed table to improve the performance of the optimizer.

Replication and Recovery of Distributed Tables

Using the CREATE MIRROR option

CREATE MIRROR FOR distribution_table TO 'replica1' WITH FORCE;

This command creates a distributed table with a replica target named replica1, forcing replication to that target.

Using the RESTORE TABLE command

RESTORE TABLE distribution_table FROM MASTER;

This command restores the data of the distributed table from the master node.