mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-27 18:12:02 +00:00
287 lines
7.3 KiB
Markdown
287 lines
7.3 KiB
Markdown
---
|
|
slug: /en/operations/named-collections
|
|
sidebar_position: 69
|
|
sidebar_label: "Named collections"
|
|
---
|
|
|
|
# Storing details for connecting to external sources in configuration files
|
|
|
|
Details for connecting to external sources (dictionaries, tables, table functions) can be saved
|
|
in configuration files and thus simplify the creation of objects and hide credentials
|
|
from users with only SQL access.
|
|
|
|
Parameters can be set in XML `<format>CSV</format>` and overridden in SQL `, format = 'TSV'`.
|
|
The parameters in SQL can be overridden using format `key` = `value`: `compression_method = 'gzip'`.
|
|
|
|
Named collections are stored in the `config.xml` file of the ClickHouse server in the `<named_collections>` section and are applied when ClickHouse starts.
|
|
|
|
Example of configuration:
|
|
```xml
|
|
$ cat /etc/clickhouse-server/config.d/named_collections.xml
|
|
<clickhouse>
|
|
<named_collections>
|
|
...
|
|
</named_collections>
|
|
</clickhouse>
|
|
```
|
|
|
|
## Named collections for accessing S3.
|
|
|
|
The description of parameters see [s3 Table Function](../sql-reference/table-functions/s3.md).
|
|
|
|
Example of configuration:
|
|
```xml
|
|
<clickhouse>
|
|
<named_collections>
|
|
<s3_mydata>
|
|
<access_key_id>AKIAIOSFODNN7EXAMPLE</access_key_id>
|
|
<secret_access_key>wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY</secret_access_key>
|
|
<format>CSV</format>
|
|
<url>https://s3.us-east-1.amazonaws.com/yourbucket/mydata/</url>
|
|
</s3_mydata>
|
|
</named_collections>
|
|
</clickhouse>
|
|
```
|
|
|
|
### Example of using named collections with the s3 function
|
|
|
|
```sql
|
|
INSERT INTO FUNCTION s3(s3_mydata, filename = 'test_file.tsv.gz',
|
|
format = 'TSV', structure = 'number UInt64', compression_method = 'gzip')
|
|
SELECT * FROM numbers(10000);
|
|
|
|
SELECT count()
|
|
FROM s3(s3_mydata, filename = 'test_file.tsv.gz')
|
|
|
|
┌─count()─┐
|
|
│ 10000 │
|
|
└─────────┘
|
|
1 rows in set. Elapsed: 0.279 sec. Processed 10.00 thousand rows, 90.00 KB (35.78 thousand rows/s., 322.02 KB/s.)
|
|
```
|
|
|
|
### Example of using named collections with an S3 table
|
|
|
|
```sql
|
|
CREATE TABLE s3_engine_table (number Int64)
|
|
ENGINE=S3(s3_mydata, url='https://s3.us-east-1.amazonaws.com/yourbucket/mydata/test_file.tsv.gz', format = 'TSV')
|
|
SETTINGS input_format_with_names_use_header = 0;
|
|
|
|
SELECT * FROM s3_engine_table LIMIT 3;
|
|
┌─number─┐
|
|
│ 0 │
|
|
│ 1 │
|
|
│ 2 │
|
|
└────────┘
|
|
```
|
|
|
|
## Named collections for accessing MySQL database
|
|
|
|
The description of parameters see [mysql](../sql-reference/table-functions/mysql.md).
|
|
|
|
Example of configuration:
|
|
```xml
|
|
<clickhouse>
|
|
<named_collections>
|
|
<mymysql>
|
|
<user>myuser</user>
|
|
<password>mypass</password>
|
|
<host>127.0.0.1</host>
|
|
<port>3306</port>
|
|
<database>test</database>
|
|
<connection_pool_size>8</connection_pool_size>
|
|
<on_duplicate_clause>1</on_duplicate_clause>
|
|
<replace_query>1</replace_query>
|
|
</mymysql>
|
|
</named_collections>
|
|
</clickhouse>
|
|
```
|
|
|
|
### Example of using named collections with the mysql function
|
|
|
|
```sql
|
|
SELECT count() FROM mysql(mymysql, table = 'test');
|
|
|
|
┌─count()─┐
|
|
│ 3 │
|
|
└─────────┘
|
|
```
|
|
|
|
### Example of using named collections with an MySQL table
|
|
|
|
```sql
|
|
CREATE TABLE mytable(A Int64) ENGINE = MySQL(mymysql, table = 'test', connection_pool_size=3, replace_query=0);
|
|
SELECT count() FROM mytable;
|
|
|
|
┌─count()─┐
|
|
│ 3 │
|
|
└─────────┘
|
|
```
|
|
|
|
### Example of using named collections with database with engine MySQL
|
|
|
|
```sql
|
|
CREATE DATABASE mydatabase ENGINE = MySQL(mymysql);
|
|
|
|
SHOW TABLES FROM mydatabase;
|
|
|
|
┌─name───┐
|
|
│ source │
|
|
│ test │
|
|
└────────┘
|
|
```
|
|
|
|
### Example of using named collections with a dictionary with source MySQL
|
|
|
|
```sql
|
|
CREATE DICTIONARY dict (A Int64, B String)
|
|
PRIMARY KEY A
|
|
SOURCE(MYSQL(NAME mymysql TABLE 'source'))
|
|
LIFETIME(MIN 1 MAX 2)
|
|
LAYOUT(HASHED());
|
|
|
|
SELECT dictGet('dict', 'B', 2);
|
|
|
|
┌─dictGet('dict', 'B', 2)─┐
|
|
│ two │
|
|
└─────────────────────────┘
|
|
```
|
|
|
|
## Named collections for accessing PostgreSQL database
|
|
|
|
The description of parameters see [postgresql](../sql-reference/table-functions/postgresql.md).
|
|
|
|
Example of configuration:
|
|
```xml
|
|
<clickhouse>
|
|
<named_collections>
|
|
<mypg>
|
|
<user>pguser</user>
|
|
<password>jw8s0F4</password>
|
|
<host>127.0.0.1</host>
|
|
<port>5432</port>
|
|
<database>test</database>
|
|
<schema>test_schema</schema>
|
|
<connection_pool_size>8</connection_pool_size>
|
|
</mypg>
|
|
</named_collections>
|
|
</clickhouse>
|
|
```
|
|
|
|
### Example of using named collections with the postgresql function
|
|
|
|
```sql
|
|
SELECT * FROM postgresql(mypg, table = 'test');
|
|
|
|
┌─a─┬─b───┐
|
|
│ 2 │ two │
|
|
│ 1 │ one │
|
|
└───┴─────┘
|
|
|
|
|
|
SELECT * FROM postgresql(mypg, table = 'test', schema = 'public');
|
|
|
|
┌─a─┐
|
|
│ 1 │
|
|
│ 2 │
|
|
│ 3 │
|
|
└───┘
|
|
```
|
|
|
|
### Example of using named collections with database with engine PostgreSQL
|
|
|
|
```sql
|
|
CREATE TABLE mypgtable (a Int64) ENGINE = PostgreSQL(mypg, table = 'test', schema = 'public');
|
|
|
|
SELECT * FROM mypgtable;
|
|
|
|
┌─a─┐
|
|
│ 1 │
|
|
│ 2 │
|
|
│ 3 │
|
|
└───┘
|
|
```
|
|
|
|
### Example of using named collections with database with engine PostgreSQL
|
|
|
|
```sql
|
|
CREATE DATABASE mydatabase ENGINE = PostgreSQL(mypg);
|
|
|
|
SHOW TABLES FROM mydatabase
|
|
|
|
┌─name─┐
|
|
│ test │
|
|
└──────┘
|
|
```
|
|
|
|
### Example of using named collections with a dictionary with source POSTGRESQL
|
|
|
|
```sql
|
|
CREATE DICTIONARY dict (a Int64, b String)
|
|
PRIMARY KEY a
|
|
SOURCE(POSTGRESQL(NAME mypg TABLE test))
|
|
LIFETIME(MIN 1 MAX 2)
|
|
LAYOUT(HASHED());
|
|
|
|
SELECT dictGet('dict', 'b', 2);
|
|
|
|
┌─dictGet('dict', 'b', 2)─┐
|
|
│ two │
|
|
└─────────────────────────┘
|
|
```
|
|
|
|
## Named collections for accessing remote ClickHouse database
|
|
|
|
The description of parameters see [remote](../sql-reference/table-functions/remote.md/#parameters).
|
|
|
|
Example of configuration:
|
|
|
|
```xml
|
|
<clickhouse>
|
|
<named_collections>
|
|
<remote1>
|
|
<host>localhost</host>
|
|
<port>9000</port>
|
|
<database>system</database>
|
|
<user>foo</user>
|
|
<password>secret</password>
|
|
</remote1>
|
|
</named_collections>
|
|
</clickhouse>
|
|
```
|
|
|
|
### Example of using named collections with the `remote`/`remoteSecure` functions
|
|
|
|
```sql
|
|
SELECT * FROM remote(remote1, table = one);
|
|
┌─dummy─┐
|
|
│ 0 │
|
|
└───────┘
|
|
|
|
SELECT * FROM remote(remote1, database = merge(system, '^one'));
|
|
┌─dummy─┐
|
|
│ 0 │
|
|
└───────┘
|
|
|
|
INSERT INTO FUNCTION remote(remote1, database = default, table = test) VALUES (1,'a');
|
|
|
|
SELECT * FROM remote(remote1, database = default, table = test);
|
|
┌─a─┬─b─┐
|
|
│ 1 │ a │
|
|
└───┴───┘
|
|
```
|
|
|
|
### Example of using named collections with a dictionary with source ClickHouse
|
|
|
|
```sql
|
|
CREATE DICTIONARY dict(a Int64, b String)
|
|
PRIMARY KEY a
|
|
SOURCE(CLICKHOUSE(NAME remote1 TABLE test DB default))
|
|
LIFETIME(MIN 1 MAX 2)
|
|
LAYOUT(HASHED());
|
|
|
|
SELECT dictGet('dict', 'b', 1);
|
|
┌─dictGet('dict', 'b', 1)─┐
|
|
│ a │
|
|
└─────────────────────────┘
|
|
```
|