// row. They have an output for each input row.
//
// Some types of a queries are not valid. For example, an aggregation
// function combined with a row function is meaningless ("AVG(s.Age) +
// s.Salary"). Analysis determines if such a scenario exists so an
// error can be returned.

var (
	// Fatal error for query processing.
	errNestedAggregation      = errors.New("Cannot nest aggregations")

    "Accept-Ranges": "bytes",
    "Content-Length": "0",
    "ETag": "4939450d1beec11e10a91ee7700bb593",
    "Server": "MinIO",
    "Strict-Transport-Security": "max-age=31536000; includeSubDomains",
    "Vary": "Origin,Accept-Encoding",
    "X-Amz-Request-Id": "16ABE7A785E7AC2C",
    "X-Amz-Server-Side-Encryption": "aws:kms",
    "X-Amz-Server-Side-Encryption-Aws-Kms-Key-Id": "arn:aws:kms:my-minio-key",

}

// Signature will return a signature that is expected to be the same across all disks.
func (j *xlMetaV2Object) Signature() [4]byte {
	// Shallow copy
	c := *j
	// Zero fields that will vary across disks
	c.ErasureIndex = 0

	// Nil 0 size allownil, so we don't differentiate between nil and 0 len.
	allEmpty := true
	for _, tag := range c.PartETags {
		if len(tag) != 0 {
			allEmpty = false

	OptimizeEnv = "MINIO_STORAGE_CLASS_OPTIMIZE"
	// Inline block indicates the size of the shard
	// that is considered for inlining, remember this
	// shard value is the value per drive shard it
	// will vary based on the parity that is configured
	// for the STANDARD storage_class.
	// inlining means data and metadata are written
	// together in a single file i.e xl.meta
	InlineBlockEnv = "MINIO_STORAGE_CLASS_INLINE_BLOCK"

}

// Tests validate the order of result of ListBuckets.
func testListBucketsOrder(obj ObjectLayer, instanceType string, t TestErrHandler) {
	// if implementation contains a map, order of map keys will vary.
	// this ensures they return in the same order each time.
	// add one and test exists.
	err := obj.MakeBucket(context.Background(), "bucket1", MakeBucketOptions{})
	if err != nil {

	if scParity < 0 {
		scParity = z.serverPools[0].defaultParityCount
	}
	rrSCParity := globalStorageClass.GetParityForSC(storageclass.RRS)

	// Data blocks can vary per pool, but parity is same.
	for i, setDriveCount := range z.SetDriveCounts() {
		b.StandardSCData = append(b.StandardSCData, setDriveCount-scParity)
		b.RRSCData = append(b.RRSCData, setDriveCount-rrSCParity)

		"Content-Disposition",
		"Last-Modified",
		"Content-Language",
		"Cache-Control",
		"Retry-After",
		"X-Amz-Bucket-Region",
		"Expires",
		"X-Amz*",
		"X-Amz*",
		"*",
	}
	expectedMap.Set("Vary", "Origin")

	req, _ := http.NewRequest(http.MethodOptions, s.endPoint, nil)
	req.Header.Set("Origin", "http://foobar.com")
	res, err := s.client.Do(req)
	if err != nil {
		c.Fatal(err)
	}

```
curl http://minio1:9001/minio/health/cluster
HTTP/1.1 503 Service Unavailable
Accept-Ranges: bytes
Content-Length: 0
Server: MinIO
Vary: Origin
X-Amz-Bucket-Region: us-east-1
X-Minio-Write-Quorum: 3
X-Amz-Request-Id: 16239D6AB80EBECF
X-Xss-Protection: 1; mode=block
Date: Tue, 21 Jul 2020 00:36:14 GMT
```

### Cluster-readable probe

	// Note: The size of the security token that STS APIs return is not fixed. We
	// strongly recommend that you make no assumptions about the maximum size. As
	// of this writing, the typical size is less than 4096 bytes, but that can vary.
	// Also, future updates to AWS might require larger sizes.
	Credentials auth.Credentials `xml:",omitempty"`

	// A percentage value that indicates the size of the policy in packed form.