ClickHouse/docs/en/sql-reference/table-functions/s3.md

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45	s3

s3

Provides table-like interface to select/insert files in S3. This table function is similar to hdfs.

s3(path, [aws_access_key_id, aws_secret_access_key,] format, structure, [compression])

Input parameters

• path — Bucket url with path to file. Supports following wildcards in readonly mode: *, ?, {abc,def} and {N..M} where N, M — numbers, `’abc’, ‘def’ — strings.
• format — The format of the file.
• structure — Structure of the table. Format 'column1_name column1_type, column2_name column2_type, ...'.
• compression — Parameter is optional. Supported values: none, gzip/gz, brotli/br, xz/LZMA, zstd/zst. By default, it will autodetect compression by file extension.

Returned value

A table with the specified structure for reading or writing data in the specified file.

Example

Table from S3 file https://storage.yandexcloud.net/my-test-bucket-768/data.csv and selection of the first two rows from it:

SELECT *
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/data.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32')
LIMIT 2

┌─column1─┬─column2─┬─column3─┐
│       1 │       2 │       3 │
│       3 │       2 │       1 │
└─────────┴─────────┴─────────┘

The similar but from file with gzip compression:

SELECT *
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/data.csv.gz', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32', 'gzip')
LIMIT 2

┌─column1─┬─column2─┬─column3─┐
│       1 │       2 │       3 │
│       3 │       2 │       1 │
└─────────┴─────────┴─────────┘

Globs in path

Multiple path components can have globs. For being processed file should exists and matches to the whole path pattern (not only suffix or prefix).

• * — Substitutes any number of any characters except / including empty string.
• ? — Substitutes any single character.
• {some_string,another_string,yet_another_one} — Substitutes any of strings 'some_string', 'another_string', 'yet_another_one'.
• {N..M} — Substitutes any number in range from N to M including both borders. N and M can have leading zeroes e.g. 000..078.

Constructions with {} are similar to the remote table function).

Example

1. Suppose that we have several files with following URIs on S3:

• ‘https://storage.yandexcloud.net/my-test-bucket-768/some_prefix/some_file_1.csv’
• ‘https://storage.yandexcloud.net/my-test-bucket-768/some_prefix/some_file_2.csv’
• ‘https://storage.yandexcloud.net/my-test-bucket-768/some_prefix/some_file_3.csv’
• ‘https://storage.yandexcloud.net/my-test-bucket-768/some_prefix/some_file_4.csv’
• ‘https://storage.yandexcloud.net/my-test-bucket-768/another_prefix/some_file_1.csv’
• ‘https://storage.yandexcloud.net/my-test-bucket-768/another_prefix/some_file_2.csv’
• ‘https://storage.yandexcloud.net/my-test-bucket-768/another_prefix/some_file_3.csv’
• ‘https://storage.yandexcloud.net/my-test-bucket-768/another_prefix/some_file_4.csv’

2. Query the amount of rows in files end with number from 1 to 3:

SELECT count(*)
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/{some,another}_prefix/some_file_{1..3}.csv', 'CSV', 'name String, value UInt32')

┌─count()─┐
│      18 │
└─────────┘

3. Query the amount of rows in all files of these two directories:

SELECT count(*)
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/{some,another}_prefix/*', 'CSV', 'name String, value UInt32')

┌─count()─┐
│      24 │
└─────────┘

!!! warning "Warning" If your listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use ?.

Example

Query the data from files named file-000.csv, file-001.csv, … , file-999.csv:

SELECT count(*)
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/big_prefix/file-{000..999}.csv', 'CSV', 'name String, value UInt32')

┌─count()─┐
│      12 │
└─────────┘

Data insert

The S3 table function may be used for data insert as well.

Example

Insert a data into file test-data.csv.gz:

INSERT INTO s3('https://storage.yandexcloud.net/my-test-bucket-768/test-data.csv.gz', 'CSV', 'name String, value UInt32', 'gzip')
VALUES ('test-data', 1), ('test-data-2', 2)

Insert a data into file test-data.csv.gz from existing table:

INSERT INTO s3('https://storage.yandexcloud.net/my-test-bucket-768/test-data.csv.gz', 'CSV', 'name String, value UInt32', 'gzip')
SELECT name, value FROM existing_table

Virtual Columns

• _path — Path to the file.
• _file — Name of the file.

S3-related settings

The following settings can be set before query execution or placed into configuration file.

• s3_max_single_part_upload_size — Default value is 64Mb. The maximum size of object to upload using singlepart upload to S3.
• s3_min_upload_part_size — Default value is 512Mb. The minimum size of part to upload during multipart upload to S3 Multipart upload.
• s3_max_redirects — Default value is 10. Max number of S3 redirects hops allowed.

Security consideration: if malicious user can specify arbitrary S3 URLs, s3_max_redirects must be set to zero to avoid SSRF attacks; or alternatively, remote_host_filter must be specified in server configuration.

See Also

• Virtual columns

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