mirror of
https://github.com/seaweedfs/seaweedfs.git
synced 2026-08-28 11:56:07 +00:00
Chris LuandGitHub
f09e8345c6
A master decides nothing from it. Every caller that read it was asking whether a volume is remote, which the backend name answers, and the value itself is reported on demand by the server holding the volume, through the volume info in ReadVolumeFileStatus. It is also the one string here that cannot be shared: unique per volume, so unlike the collection and backend names it carries its own characters for every volume a master tracks. VolumeInfo goes from 136 bytes to 120. 800k volumes registered from a heartbeat that has been over the wire go from 214 to 163 B/volume when tiered. The volume server's own status page keeps showing the key, now read from the volume it holds rather than relayed through a master, which is also where the other volume server implementation reads it. The heartbeat digest drops it on the same grounds: a change to something the master does not hold cannot make its copy stale. Both implementations and their shared vectors move together, and the field-coverage test now names what is deliberately not retained rather than being loosened.
50 lines
1.8 KiB
Go
50 lines
1.8 KiB
Go
package storage
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import (
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"encoding/binary"
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"github.com/cespare/xxhash/v2"
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)
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// ReportHash digests everything a volume server reports about a volume, so the
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// two ends of a heartbeat can agree on whether the master's copy is current
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// without shipping the volume list.
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//
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// It must cover every field of VolumeInformationMessage: a change the hash
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// misses is a change the master would never be told about. Volume servers hash
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// the message they are about to send, masters hash what they already hold, and
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// the two match only when the master is up to date.
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func (vi VolumeInfo) ReportHash() uint64 {
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var buf [57]byte
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binary.LittleEndian.PutUint32(buf[0:], uint32(vi.Id))
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binary.LittleEndian.PutUint64(buf[4:], vi.Size)
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binary.LittleEndian.PutUint64(buf[12:], uint64(vi.FileCount))
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binary.LittleEndian.PutUint64(buf[20:], uint64(vi.DeleteCount))
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binary.LittleEndian.PutUint64(buf[28:], vi.DeletedByteCount)
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binary.LittleEndian.PutUint32(buf[36:], uint32(vi.ReplicaPlacement.Byte()))
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binary.LittleEndian.PutUint32(buf[40:], uint32(vi.Version))
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binary.LittleEndian.PutUint32(buf[44:], vi.Ttl.ToUint32())
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binary.LittleEndian.PutUint32(buf[48:], vi.CompactRevision)
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binary.LittleEndian.PutUint32(buf[52:], vi.DiskId)
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if vi.ReadOnly {
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buf[56] = 1
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}
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h := xxhash.Sum64(buf[:])
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var modified [8]byte
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binary.LittleEndian.PutUint64(modified[:], uint64(vi.ModifiedAtSecond))
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h = foldReportHash(h, xxhash.Sum64(modified[:]))
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h = foldReportHash(h, xxhash.Sum64String(vi.Collection))
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h = foldReportHash(h, xxhash.Sum64String(vi.DiskType))
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h = foldReportHash(h, xxhash.Sum64String(vi.RemoteStorageName))
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return h
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}
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// foldReportHash combines two hashes order-dependently, so swapping two string
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// fields is not invisible.
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func foldReportHash(h, x uint64) uint64 {
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h ^= x
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h *= 0x9E3779B97F4A7C15
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return h ^ (h >> 29)
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}
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