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:
  1. 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 │
└─────────┘
  1. 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 │
└─────────┘

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

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