ClickHouse/docs/en/engines/table-engines/integrations/embedded-rocksdb.md

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6	EmbeddedRocksDB

EmbeddedRocksDB Engine

This engine allows integrating ClickHouse with rocksdb.

EmbeddedRocksDB lets you:

Creating a Table

CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
(
    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
    ...
) ENGINE = EmbeddedRocksDB PRIMARY KEY(primary_key_name)

Required parameters:

• primary_key_name – any column name in the column list.

Example:

CREATE TABLE test
(
    `key` String,
    `v1` UInt32,
    `v2` String,
    `v3` Float32,
)
ENGINE = EmbeddedRocksDB
PRIMARY KEY key

Description

• primary key must be specified, it only supports one column in primary key. The primary key will serialized in binary as rocksdb key.
• columns other than the primary key will be serialized in binary as rocksdb value in corresponding order.
• queries with key equals or in filtering will be optimized to multi keys lookup from rocksdb.