ClickHouse/docs/en/engines/table-engines/integrations/s3.md

---
sidebar_position: 7
sidebar_label: S3
---

# S3 Table Engine {#table-engine-s3}

This engine provides integration with [Amazon S3](https://aws.amazon.com/s3/) ecosystem. This engine is similar to the [HDFS](../../../engines/table-engines/special/file.md#table_engines-hdfs) engine, but provides S3-specific features.

## Create Table {#creating-a-table}

``` sql
CREATE TABLE s3_engine_table (name String, value UInt32)
    ENGINE = S3(path, [aws_access_key_id, aws_secret_access_key,] format, [compression])
    [SETTINGS ...]
```

**Engine 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. For more information see [below](#wildcards-in-path).
-   `format` — The [format](../../../interfaces/formats.md#formats) of the file.
-   `aws_access_key_id`, `aws_secret_access_key` - Long-term credentials for the [AWS](https://aws.amazon.com/) account user.  You can use these to authenticate your requests. Parameter is optional. If credentials are not specified, they are used from the configuration file. For more information see [Using S3 for Data Storage](../mergetree-family/mergetree.md#table_engine-mergetree-s3).
-   `compression` — Compression type. Supported values: `none`, `gzip/gz`, `brotli/br`, `xz/LZMA`, `zstd/zst`. Parameter is optional. By default, it will autodetect compression by file extension.

**Example**

``` sql
CREATE TABLE s3_engine_table (name String, value UInt32) 
    ENGINE=S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/test-data.csv.gz', 'CSV', 'gzip')
    SETTINGS input_format_with_names_use_header = 0;

INSERT INTO s3_engine_table VALUES ('one', 1), ('two', 2), ('three', 3);

SELECT * FROM s3_engine_table LIMIT 2;
```

```text
┌─name─┬─value─┐
│ one  │     1 │
│ two  │     2 │
└──────┴───────┘
```
## Virtual columns {#virtual-columns}

-   `_path` — Path to the file.
-   `_file` — Name of the file.

For more information about virtual columns see [here](../../../engines/table-engines/index.md#table_engines-virtual_columns).

## Implementation Details {#implementation-details}

-   Reads and writes can be parallel
-   [Zero-copy](../../../operations/storing-data.md#zero-copy) replication is supported.  
-   Not supported:
    -   `ALTER` and `SELECT...SAMPLE` operations.
    -   Indexes.

## Wildcards In Path {#wildcards-in-path}

`path` argument can specify multiple files using bash-like wildcards. For being processed file should exist and match to the whole path pattern. Listing of files is determined during `SELECT` (not at `CREATE` moment).

-   `*` — 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](../../../sql-reference/table-functions/remote.md) table function.

:::warning    
If the listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
:::

**Example with wildcards 1**

Create table with files named `file-000.csv`, `file-001.csv`, … , `file-999.csv`:

``` sql
CREATE TABLE big_table (name String, value UInt32)
    ENGINE = S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/my_folder/file-{000..999}.csv', 'CSV');
```

**Example with wildcards 2**

Suppose we have several files in CSV format with the following URIs on S3:

-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/some_folder/some_file_1.csv'
-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/some_folder/some_file_2.csv'
-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/some_folder/some_file_3.csv'
-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/another_folder/some_file_1.csv'
-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/another_folder/some_file_2.csv'
-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/another_folder/some_file_3.csv'


There are several ways to make a table consisting of all six files:

1. Specify the range of file postfixes:

``` sql
CREATE TABLE table_with_range (name String, value UInt32)
    ENGINE = S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/{some,another}_folder/some_file_{1..3}', 'CSV');
```

2. Take all files with `some_file_` prefix (there should be no extra files with such prefix in both folders):

``` sql
CREATE TABLE table_with_question_mark (name String, value UInt32)
    ENGINE = S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/{some,another}_folder/some_file_?', 'CSV');
```

3. Take all the files in both folders (all files should satisfy format and schema described in query):

``` sql
CREATE TABLE table_with_asterisk (name String, value UInt32)
    ENGINE = S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/{some,another}_folder/*', 'CSV');
```

## S3-related Settings {#settings}

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

-   `s3_max_single_part_upload_size` — The maximum size of object to upload using singlepart upload to S3. Default value is `64Mb`.
-   `s3_min_upload_part_size` — The minimum size of part to upload during multipart upload to [S3 Multipart upload](https://docs.aws.amazon.com/AmazonS3/latest/dev/uploadobjusingmpu.html). Default value is `512Mb`.
-   `s3_max_redirects` — Max number of S3 redirects hops allowed. Default value is `10`.
-   `s3_single_read_retries` — The maximum number of attempts during single read. Default value is `4`.

Security consideration: if malicious user can specify arbitrary S3 URLs, `s3_max_redirects` must be set to zero to avoid [SSRF](https://en.wikipedia.org/wiki/Server-side_request_forgery) attacks; or alternatively, `remote_host_filter` must be specified in server configuration.

## Endpoint-based Settings {#endpoint-settings}

The following settings can be specified in configuration file for given endpoint (which will be matched by exact prefix of a URL):

-   `endpoint` — Specifies prefix of an endpoint. Mandatory.
-   `access_key_id` and `secret_access_key` — Specifies credentials to use with given endpoint. Optional.
-   `use_environment_credentials` — If set to `true`, S3 client will try to obtain credentials from environment variables and [Amazon EC2](https://en.wikipedia.org/wiki/Amazon_Elastic_Compute_Cloud) metadata for given endpoint. Optional, default value is `false`.
-   `region` — Specifies S3 region name. Optional.
-   `use_insecure_imds_request` — If set to `true`, S3 client will use insecure IMDS request while obtaining credentials from Amazon EC2 metadata. Optional, default value is `false`.
-   `header` —  Adds specified HTTP header to a request to given endpoint. Optional, can be speficied multiple times.
-   `server_side_encryption_customer_key_base64` — If specified, required headers for accessing S3 objects with SSE-C encryption will be set. Optional.
-   `max_single_read_retries` — The maximum number of attempts during single read. Default value is `4`. Optional.

**Example:**

``` xml
<s3>
    <endpoint-name>
        <endpoint>https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/</endpoint>
        <!-- <access_key_id>ACCESS_KEY_ID</access_key_id> -->
        <!-- <secret_access_key>SECRET_ACCESS_KEY</secret_access_key> -->
        <!-- <region>us-west-1</region> -->
        <!-- <use_environment_credentials>false</use_environment_credentials> -->
        <!-- <use_insecure_imds_request>false</use_insecure_imds_request> -->
        <!-- <header>Authorization: Bearer SOME-TOKEN</header> -->
        <!-- <server_side_encryption_customer_key_base64>BASE64-ENCODED-KEY</server_side_encryption_customer_key_base64> -->
        <!-- <max_single_read_retries>4</max_single_read_retries> -->
    </endpoint-name>
</s3>
```

## See also

-  [s3 table function](../../../sql-reference/table-functions/s3.md)

[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/s3/) <!--hide-->