// and not continuously try to update.
	// Should not be combined with ReturnLastGood.
	CacheError bool

	// If NoWait is set, Get() will return the last good value,
	// if TTL has expired but 2x TTL has not yet passed,
	// but will fetch a new value in the background.
	NoWait bool
}

// Cache contains a synchronized value that is considered valid
// for a specific amount of time.

package clause

const (
	LockingStrengthUpdate    = "UPDATE"
	LockingStrengthShare     = "SHARE"
	LockingOptionsSkipLocked = "SKIP LOCKED"
	LockingOptionsNoWait     = "NOWAIT"
)

type Locking struct {
	Strength string
	Table    Table
	Options  string
}

// Name where clause name
func (locking Locking) Name() string {
	return "FOR"
}

// Build build where clause
func (locking Locking) Build(builder Builder) {

		},
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Locking{Strength: clause.LockingStrengthUpdate, Options: clause.LockingOptionsNoWait}},
			"SELECT * FROM `users` FOR UPDATE NOWAIT", nil,
		},
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Locking{Strength: clause.LockingStrengthUpdate, Options: clause.LockingOptionsSkipLocked}},
			"SELECT * FROM `users` FOR UPDATE SKIP LOCKED", nil,

		return map[string]uint64{}, nil
	}

	cache := dataUsageCache{}

	prefixUsageCache.InitOnce(30*time.Second,
		// No need to fail upon Update() error, fallback to old value.
		cachevalue.Opts{ReturnLastGood: true, NoWait: true},
		func() (map[string]uint64, error) {
			m := make(map[string]uint64)
			for _, pool := range z.serverPools {
				for _, er := range pool.sets {
					// Load bucket usage prefixes

var bucketStorageCache = cachevalue.New[DataUsageInfo]()

// Init initialize bucket quota.
func (sys *BucketQuotaSys) Init(objAPI ObjectLayer) {
	bucketStorageCache.InitOnce(10*time.Second,
		cachevalue.Opts{ReturnLastGood: true, NoWait: true},
		func() (DataUsageInfo, error) {
			ctx, done := context.WithTimeout(context.Background(), 2*time.Second)
			defer done()

			return loadDataUsageFromBackend(ctx, objAPI)
		},
	)
}