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Fix CRC16 Hashslot Calculation (#399)
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* fix bug and refactor crc16 to HashSlotUtils

* fix migration tests

* add tests for cluster keyslot

* fix formatting errors
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vazois authored May 20, 2024
1 parent 78d6ad7 commit 8ef45f9
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Showing 15 changed files with 255 additions and 222 deletions.
4 changes: 2 additions & 2 deletions libs/cluster/Server/ClusterManagerSlotState.cs
Original file line number Diff line number Diff line change
Expand Up @@ -463,7 +463,7 @@ public static unsafe void DeleteKeysInSlotsFromMainStore(BasicGarnetApi BasicGar
while (iter.GetNext(out _))
{
ref SpanByte key = ref iter.GetKey();
var s = NumUtils.HashSlot(key.ToPointer(), key.Length);
var s = HashSlotUtils.HashSlot(key.ToPointer(), key.Length);
if (slots.Contains(s))
_ = BasicGarnetApi.DELETE(ref key, StoreType.Main);
}
Expand All @@ -481,7 +481,7 @@ public static unsafe void DeleteKeysInSlotsFromObjectStore(BasicGarnetApi BasicG
{
ref var key = ref iterObject.GetKey();
ref var value = ref iterObject.GetValue();
var s = NumUtils.HashSlot(key);
var s = HashSlotUtils.HashSlot(key);
if (slots.Contains(s))
_ = BasicGarnetApi.DELETE(key, StoreType.Object);
}
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ internal MainStoreMigrateSlots(MigrateSession session, HashSet<int> slots)
public bool SingleReader(ref SpanByte key, ref SpanByte value, RecordMetadata recordMetadata, long numberOfRecords, out CursorRecordResult cursorRecordResult)
{
cursorRecordResult = CursorRecordResult.Accept; // default; not used here
var s = NumUtils.HashSlot(key.ToPointer(), key.Length);
var s = HashSlotUtils.HashSlot(key.ToPointer(), key.Length);

if (slots.Contains(s) && !ClusterSession.Expired(ref value) && !session.WriteOrSendMainStoreKeyValuePair(ref key, ref value))
return false;
Expand All @@ -54,7 +54,7 @@ internal ObjectStoreMigrateSlots(MigrateSession session, HashSet<int> slots)
public bool SingleReader(ref byte[] key, ref IGarnetObject value, RecordMetadata recordMetadata, long numberOfRecords, out CursorRecordResult cursorRecordResult)
{
cursorRecordResult = CursorRecordResult.Accept; // default; not used here
var slot = NumUtils.HashSlot(key);
var slot = HashSlotUtils.HashSlot(key);

if (slots.Contains(slot) && !ClusterSession.Expired(ref value))
{
Expand Down Expand Up @@ -85,7 +85,7 @@ internal MainStoreDeleteKeysInSlot(ClientSession<SpanByte, SpanByte, SpanByte, S
public bool SingleReader(ref SpanByte key, ref SpanByte value, RecordMetadata recordMetadata, long numberOfRecords, out CursorRecordResult cursorRecordResult)
{
cursorRecordResult = CursorRecordResult.Accept; // default; not used here
var s = NumUtils.HashSlot(key.ToPointer(), key.Length);
var s = HashSlotUtils.HashSlot(key.ToPointer(), key.Length);
if (slots.Contains(s))
session.Delete(key);
return true;
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8 changes: 4 additions & 4 deletions libs/cluster/Session/ClusterKeyIterationFunctions.cs
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ internal struct MainStoreCountKeys : IScanIteratorFunctions<SpanByte, SpanByte>
public bool SingleReader(ref SpanByte key, ref SpanByte value, RecordMetadata recordMetadata, long numberOfRecords, out CursorRecordResult cursorRecordResult)
{
cursorRecordResult = CursorRecordResult.Accept; // default; not used here
if (NumUtils.HashSlot(key.ToPointer(), key.LengthWithoutMetadata) == slot && !Expired(ref value))
if (HashSlotUtils.HashSlot(key.ToPointer(), key.LengthWithoutMetadata) == slot && !Expired(ref value))
keyCount++;
return true;
}
Expand All @@ -46,7 +46,7 @@ public bool SingleReader(ref byte[] key, ref IGarnetObject value, RecordMetadata
cursorRecordResult = CursorRecordResult.Accept; // default; not used here , out CursorRecordResult cursorRecordResult
fixed (byte* keyPtr = key)
{
if (NumUtils.HashSlot(keyPtr, key.Length) == slot && !Expired(ref value))
if (HashSlotUtils.HashSlot(keyPtr, key.Length) == slot && !Expired(ref value))
keyCount++;
}
return true;
Expand All @@ -73,7 +73,7 @@ internal MainStoreGetKeysInSlot(List<byte[]> keys, int slot, int maxKeyCount)
public bool SingleReader(ref SpanByte key, ref SpanByte value, RecordMetadata recordMetadata, long numberOfRecords, out CursorRecordResult cursorRecordResult)
{
cursorRecordResult = CursorRecordResult.Accept; // default; not used here, out CursorRecordResult cursorRecordResult
if (NumUtils.HashSlot(key.ToPointer(), key.LengthWithoutMetadata) == slot && !Expired(ref value))
if (HashSlotUtils.HashSlot(key.ToPointer(), key.LengthWithoutMetadata) == slot && !Expired(ref value))
keys.Add(key.ToByteArray());
return keys.Count < maxKeyCount;
}
Expand All @@ -100,7 +100,7 @@ public bool SingleReader(ref byte[] key, ref IGarnetObject value, RecordMetadata
cursorRecordResult = CursorRecordResult.Accept; // default; not used here
fixed (byte* keyPtr = key)
{
if (NumUtils.HashSlot(keyPtr, key.Length) == slot && !Expired(ref value))
if (HashSlotUtils.HashSlot(keyPtr, key.Length) == slot && !Expired(ref value))
keys.Add(key);
}
return true;
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4 changes: 2 additions & 2 deletions libs/cluster/Session/ClusterSlotVerify.cs
Original file line number Diff line number Diff line change
Expand Up @@ -133,7 +133,7 @@ static ClusterSlotVerificationResult ArrayCrosslotVerify(int keyCount, ref byte*
if (!RespReadUtils.ReadPtrWithLengthHeader(ref valPtr, ref vsize, ref ptr, endPtr))
return new(SlotVerifiedState.OK, 0);

var slot = NumUtils.HashSlot(keyPtr, ksize);
var slot = HashSlotUtils.HashSlot(keyPtr, ksize);

for (var c = 1; c < keyCount; c++)
{
Expand All @@ -148,7 +148,7 @@ static ClusterSlotVerificationResult ArrayCrosslotVerify(int keyCount, ref byte*
if (!RespReadUtils.ReadPtrWithLengthHeader(ref valPtr, ref vsize, ref ptr, endPtr))
return new(SlotVerifiedState.OK, 0);

var _slot = NumUtils.HashSlot(keyPtr, ksize);
var _slot = HashSlotUtils.HashSlot(keyPtr, ksize);
crossSlot |= (_slot != slot);
}

Expand Down
2 changes: 1 addition & 1 deletion libs/cluster/Session/MigrateCommand.cs
Original file line number Diff line number Diff line change
Expand Up @@ -151,7 +151,7 @@ private bool TryMIGRATE(int count, byte* ptr)
if (pstate != MigrateCmdParseState.SUCCESS) continue;

// Check if all keys are local R/W because we migrate keys and need to be able to delete them
var slot = NumUtils.HashSlot(keyPtr, ksize);
var slot = HashSlotUtils.HashSlot(keyPtr, ksize);
if (!current.IsLocal(slot, readCommand: false))
{
pstate = MigrateCmdParseState.SLOTNOTLOCAL;
Expand Down
4 changes: 2 additions & 2 deletions libs/cluster/Session/RespClusterMigrateCommands.cs
Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,7 @@ private bool NetworkClusterMigrate(ReadOnlySpan<byte> bufSpan, int count, out bo
continue;
}

var slot = NumUtils.HashSlot(key.ToPointer(), key.LengthWithoutMetadata);
var slot = HashSlotUtils.HashSlot(key.ToPointer(), key.LengthWithoutMetadata);
if (!currentConfig.IsImportingSlot(slot))//Slot is not in importing state
{
migrateState = 1;
Expand Down Expand Up @@ -119,7 +119,7 @@ private bool NetworkClusterMigrate(ReadOnlySpan<byte> bufSpan, int count, out bo
if (migrateState > 0)
continue;

var slot = NumUtils.HashSlot(key);
var slot = HashSlotUtils.HashSlot(key);
if (!currentConfig.IsImportingSlot(slot))//Slot is not in importing state
{
migrateState = 1;
Expand Down
2 changes: 1 addition & 1 deletion libs/cluster/Session/RespClusterSlotManagementCommands.cs
Original file line number Diff line number Diff line change
Expand Up @@ -471,7 +471,7 @@ private bool NetworkClusterKeySlot(int count, out bool invalidParameters)
return false;
readHead = (int)(ptr - recvBufferPtr);

int slot = NumUtils.HashSlot(keyPtr, ksize);
int slot = HashSlotUtils.HashSlot(keyPtr, ksize);
while (!RespWriteUtils.WriteInteger(slot, ref dcurr, dend))
SendAndReset();

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121 changes: 121 additions & 0 deletions libs/common/HashSlotUtils.cs
Original file line number Diff line number Diff line change
@@ -0,0 +1,121 @@
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.

using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace Garnet.common
{
public static unsafe class HashSlotUtils
{
/// <summary>
/// This table is based on the CRC-16-CCITT polynomial (0x1021)
/// </summary>
#pragma warning disable IDE0300 // Simplify collection initialization. Ignored to avoid dotnet-format bug, see https://github.com/dotnet/sdk/issues/39898
#if NET7_0_OR_GREATER
private static ReadOnlySpan<ushort> Crc16Table => new ushort[256]
#else
private static readonly ushort[] Crc16Table = new ushort[256]
#endif
{
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
};
#pragma warning restore IDE0300 // Simplify collection initialization

/// <summary>
/// Generate a ushort hash value using the CRC16 algorithm
/// </summary>
/// <param name="data">Pointer to head of data byte sequence</param>
/// <param name="len">Length of byte sequence</param>
/// <returns></returns>
internal static unsafe ushort Hash(byte* data, int len)
{
ushort result = 0;

#if NET7_0_OR_GREATER
ref var crc16Base = ref MemoryMarshal.GetReference(Crc16Table);
#else
ref var crc16Base = ref MemoryMarshal.GetArrayDataReference(Crc16Table);
#endif
var end = data + len;
while (data < end)
{
var index = (nuint)(uint)((result >> 8) ^ *data++) & 0xff;
result = (ushort)(Unsafe.Add(ref crc16Base, index) ^ (result << 8));
}
return result;
}

/// <summary>
/// Compute hash slot of given data
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public static unsafe ushort HashSlot(byte[] key)
{
fixed (byte* keyPtr = key)
return HashSlot(keyPtr, key.Length);
}

/// <summary>
/// Compute hash slot of given data
/// </summary>
/// <param name="keyPtr"></param>
/// <param name="ksize"></param>
/// <returns></returns>
public static unsafe ushort HashSlot(byte* keyPtr, int ksize)
{
var startPtr = keyPtr;
var end = keyPtr + ksize;

// Find first occurence of '{'
while (startPtr < end && *startPtr != '{') { startPtr++; };

// Return early if did not find '{'
if (startPtr == end) return (ushort)(Hash(keyPtr, ksize) & 16383);

var endPtr = startPtr + 1;

// Find first occurence of '}'
while (endPtr < end && *endPtr != '}') { endPtr++; }

// Return early if did not find '}' after '{'
if (endPtr == end || endPtr == startPtr + 1) return (ushort)(Hash(keyPtr, ksize) & 16383);

// Return hash for byte sequence between brackets
return (ushort)(Hash(startPtr + 1, (int)(endPtr - startPtr - 1)) & 16383);
}
}
}
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