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selectObjectContent method

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Updated at November 7, 2025

Filters and returns the contents of an Object Storage object using an S3 Select request.

Warning

To be able to make S3 Select requests, contact support. You must also have the s3:GetObject permission. For more information, see Bucket policy.

Features of objects you can query:

  • Objects in CSV, JSON, and Parquet formats are supported.

  • UTF-8 encoded objects are supported.

  • GZIP and BZIP2 compression methods are supported for CSV files. For Parquet files, columnar compression with GZIP, Snappy, and ZSTD is supported.

  • Objects can be protected by server-side encryption.

For objects that are encrypted with managed encryption keys stored in YC Key Management Service (SSE-KMS), server-side encryption is transparent. This means you do not need to specify anything else.

For more information on getting started with the API and the general request format, see How to use the S3 API.

Request

POST /{bucket}/{key}?select&select-type=2 HTTP/2

Path parameters

Parameter Description
bucket Bucket name.
key Object key.

Request parameters

Parameter Description
select Required parameter that indicates the type of operation.
select-type Optional parameter that indicates the type of query.

Headers

Use the appropriate common headers in your request.

Data schema

Request parameters are provided in XML format:

<ListBucketResult
          xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
          <KeyCount>1</KeyCount>
          <Name>my-sample-bucket</Name>
          <Prefix></Prefix>
          <MaxKeys>1000</MaxKeys>
          <IsTruncated>false</IsTruncated>
          <Contents>
              <Key>text.txt</Key>
              <LastModified>2025-05-15T07:23:08.030Z</LastModified>
              <Owner>
                  <ID>ajegtlf2q28a********</ID>
                  <DisplayName>ajegtlf2q28a********</DisplayName>
              </Owner>
              <ETag>&#34;f75a361db63aa4722fb8e083********&#34;</ETag>
              <Size>103</Size>
              <StorageClass>STANDARD</StorageClass>
              <TagSet></TagSet>
          </Contents>
      </ListBucketResult>
Tag Description
SelectObjectContentRequest Root-level tag for providing request parameters.

Required: yes.

Path: /SelectObjectContentRequest.
Expression SQL expression used to query object data.

Data type: string.

Required: yes.

Path: /SelectObjectContentRequest/Expression.
ExpressionType Expression type used for the request.

Data type: string.

Acceptable values: SQL.

Required: yes.

Path: /SelectObjectContentRequest/ExpressionType.
InputSerialization Description of data format in the requested object.

Data type: InputSerialization.

Required: yes.

Path: /SelectObjectContentRequest/InputSerialization.
OutputSerialization Description of the returned data format.

Data type: OutputSerialization.

Required: yes.

Path: /SelectObjectContentRequest/OutputSerialization.
RequestProgress Tag that indicates whether regular notifications on the request progress are enabled.

Data type: RequestProgress.

Required: no.

Path: /SelectObjectContentRequest/RequestProgress.
ScanRange Tag that specifies the byte range of the object to get the records from. A record is processed when its first byte is within the range. It is used only for objects in CSV format.

Data type: ScanRange.

Required: no.

Path: /SelectObjectContentRequest/ScanRange.

Response

Headers

Responses can only contain common headers.

Response codes

For a list of possible responses, see Responses.

A successful response contains additional data in XML format with the schema described below.

Data schema

<ListBucketResult
          xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
          <KeyCount>1</KeyCount>
          <Name>my-sample-bucket</Name>
          <Prefix></Prefix>
          <MaxKeys>1000</MaxKeys>
          <IsTruncated>false</IsTruncated>
          <Contents>
              <Key>text.txt</Key>
              <LastModified>2025-05-15T07:23:08.030Z</LastModified>
              <Owner>
                  <ID>ajegtlf2q28a********</ID>
                  <DisplayName>ajegtlf2q28a********</DisplayName>
              </Owner>
              <ETag>&#34;f75a361db63aa4722fb8e083********&#34;</ETag>
              <Size>103</Size>
              <StorageClass>STANDARD</StorageClass>
              <TagSet></TagSet>
          </Contents>
      </ListBucketResult>
Tag Description
Payload Root-level tag used for providing response parameters.

Path: /Payload.
Cont Message indicating the request is being processed.

Path: /Payload/Cont.
End Message indicating the request has been processed.

Path: /Payload/End.
Progress Information about the request progress.

Path: /Payload/Progress.
Records Request result.
Path: /Payload/Records.
Stats Statistics on the processed data. It is sent once at the end of the request.
Path: /Payload/Stats.

See also

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