# Compression Guide [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io)

MinIO server allows streaming compression to ensure efficient disk space usage.
Compression happens inflight, i.e objects are compressed before being written to disk(s).
MinIO uses [`klauspost/compress/s2`](https://github.com/klauspost/compress/tree/master/s2)
streaming compression due to its stability and performance.

				NewPutObjReader(hr),
				ObjectOptions{
					PreserveETag: part.ETag, // Preserve original ETag to ensure same metadata.
					IndexCB: func() []byte {
						return part.Index // Preserve part Index to ensure decompression works.
					},
					NoAuditLog: true,
				})
			if err != nil {
				return fmt.Errorf("rebalanceObject: PutObjectPart() %w", err)
			}
			parts[i] = CompletePart{
				ETag:       pi.ETag,

func (o *ObjectInfo) IsCompressed() bool {
	_, ok := o.UserDefined[ReservedMetadataPrefix+"compression"]
	return ok
}

// IsCompressedOK returns whether the object is compressed and can be decompressed.
func (o *ObjectInfo) IsCompressedOK() (bool, error) {
	scheme, ok := o.UserDefined[ReservedMetadataPrefix+"compression"]
	if !ok {
		return false, nil
	}
	switch scheme {

				NewPutObjReader(hr),
				ObjectOptions{
					PreserveETag: part.ETag, // Preserve original ETag to ensure same metadata.
					IndexCB: func() []byte {
						return part.Index // Preserve part Index to ensure decompression works.
					},
					NoAuditLog: true,
				})
			if err != nil {
				return fmt.Errorf("decommissionObject: PutObjectPart() %w", err)
			}
			parts[i] = CompletePart{
				ETag:           pi.ETag,

		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidDecompressedSize: {
		Code:           "XMinioInvalidDecompressedSize",
		Description:    "The data provided is unfit for decompression",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrAddUserInvalidArgument: {
		Code:           "XMinioInvalidIAMCredentials",
		Description:    "Credential is not allowed to be same as admin access key",

	"github.com/minio/pkg/v3/env"
)

// Config represents the compression settings.
type Config struct {
	Enabled        bool     `json:"enabled"`
	AllowEncrypted bool     `json:"allow_encryption"`
	Extensions     []string `json:"extensions"`
	MimeTypes      []string `json:"mime-types"`
}

// Compression environment variables
const (
	Extensions     = "extensions"
	AllowEncrypted = "allow_encryption"

		globalActiveCred = cfg.Credential
	}

	// Init compression config. For future migration, Compression config needs to be copied over from previous version.
	switch cfg.Version {
	case "29":
		// V29 -> V30
		cfg.Compression.Enabled = false
		cfg.Compression.Extensions = strings.Split(compress.DefaultExtensions, config.ValueSeparator)
		cfg.Compression.MimeTypes = strings.Split(compress.DefaultMimeTypes, config.ValueSeparator)

* `minimum_size` - Do not GZip responses that are smaller than this minimum size in bytes. Defaults to `500`.
* `compresslevel` - Used during GZip compression. It is an integer ranging from 1 to 9. Defaults to `9`. Lower value results in faster compression but larger file sizes, while higher value results in slower compression but smaller file sizes.

## Other middlewares { #other-middlewares }

There are many other ASGI middlewares.

For example:

					"X-Minio-Internal-compression": "unknown/compression/type",
					"content-type":                 "application/octet-stream",
					"etag":                         "b3ff3ef3789147152fbfbc50efba4bfd-2",
				},
			},
			result: true,
			err:    true,
		},
		3: {
			objInfo: ObjectInfo{
				UserDefined: map[string]string{
					"X-Minio-Internal-compression": compressionAlgorithmV2,

- Parquet API supports columnar compression for  using GZIP, Snappy, LZ4. Whole object compression is not supported for Parquet objects.
- Server-side encryption - The Select API supports querying objects that are protected with server-side encryption.