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FASTERImpl.cs
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FASTERImpl.cs
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// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license.
#define CPR
using System;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
namespace FASTER.core
{
public unsafe partial class FasterKV<Key, Value> : FasterBase, IFasterKV<Key, Value>
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private bool InVersionNew<Input, Output, Context>(ref HashBucketEntry entry, FasterExecutionContext<Input, Output, Context> sessionCtx)
{
// A version shift can only in an address after the checkpoint starts, as v_new threads RCU entries to the tail.
if (entry.Address < _hybridLogCheckpoint.info.startLogicalAddress) return false;
// Otherwise, check if the version suffix of the entry matches v_new.
return GetLatestRecordVersion(ref entry, sessionCtx.version) == RecordInfo.GetShortVersion(currentSyncStateMachine.ToVersion());
}
internal enum LatchOperation : byte
{
None,
Shared,
Exclusive
}
#region Read Operation
/// <summary>
/// Read operation. Computes the 'output' from 'input' and current value corresponding to 'key'.
/// When the read operation goes pending, once the record is retrieved from disk, InternalContinuePendingRead
/// function is used to complete the operation.
/// </summary>
/// <param name="key">Key of the record.</param>
/// <param name="input">Input required to compute output from value.</param>
/// <param name="output">Location to store output computed from input and value.</param>
/// <param name="startAddress">If not Constants.kInvalidAddress, this is the address to start at instead of a hash table lookup</param>
/// <param name="userContext">User context for the operation, in case it goes pending.</param>
/// <param name="pendingContext">Pending context used internally to store the context of the operation.</param>
/// <param name="fasterSession">Callback functions.</param>
/// <param name="sessionCtx">Session context</param>
/// <param name="lsn">Operation serial number</param>
/// <returns>
/// <list type="table">
/// <listheader>
/// <term>Value</term>
/// <term>Description</term>
/// </listheader>
/// <item>
/// <term>SUCCESS</term>
/// <term>The output has been computed using current value of 'key' and 'input'; and stored in 'output'.</term>
/// </item>
/// <item>
/// <term>RECORD_ON_DISK</term>
/// <term>The record corresponding to 'key' is on disk and the operation.</term>
/// </item>
/// <item>
/// <term>CPR_SHIFT_DETECTED</term>
/// <term>A shift in version has been detected. Synchronize immediately to avoid violating CPR consistency.</term>
/// </item>
/// </list>
/// </returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal OperationStatus InternalRead<Input, Output, Context, Functions>(
ref Key key,
ref Input input,
ref Output output,
long startAddress,
ref Context userContext,
ref PendingContext<Input, Output, Context> pendingContext,
Functions fasterSession,
FasterExecutionContext<Input, Output, Context> sessionCtx,
long lsn)
where Functions : IFasterSession<Key, Value, Input, Output, Context>
{
var bucket = default(HashBucket*);
var slot = default(int);
var physicalAddress = default(long);
var heldOperation = LatchOperation.None;
var hash = comparer.GetHashCode64(ref key);
var tag = (ushort)((ulong)hash >> Constants.kHashTagShift);
if (sessionCtx.phase != Phase.REST)
HeavyEnter(hash, sessionCtx, fasterSession);
#region Trace back for record in in-memory HybridLog
HashBucketEntry entry = default;
OperationStatus status;
long logicalAddress;
var usePreviousAddress = startAddress != Constants.kInvalidAddress;
bool tagExists;
if (!usePreviousAddress)
{
tagExists = FindTag(hash, tag, ref bucket, ref slot, ref entry);
}
else
{
tagExists = startAddress >= hlog.BeginAddress;
entry.Address = startAddress;
}
if (tagExists)
{
logicalAddress = entry.Address;
if (UseReadCache)
{
if (pendingContext.SkipReadCache || pendingContext.NoKey)
{
SkipReadCache(ref logicalAddress);
}
else if (ReadFromCache(ref key, ref logicalAddress, ref physicalAddress))
{
if (sessionCtx.phase == Phase.PREPARE && InVersionNew(ref entry, sessionCtx))
{
status = OperationStatus.CPR_SHIFT_DETECTED;
goto CreatePendingContext; // Pivot thread
}
// This is not called when looking up by address, so we do not set pendingContext.recordInfo.
// ReadCache addresses are not valid for indexing etc. so pass kInvalidAddress.
fasterSession.SingleReader(ref key, ref input, ref readcache.GetValue(physicalAddress), ref output, Constants.kInvalidAddress);
return OperationStatus.SUCCESS;
}
}
if (logicalAddress >= hlog.HeadAddress)
{
physicalAddress = hlog.GetPhysicalAddress(logicalAddress);
if (!pendingContext.NoKey)
{
if (!comparer.Equals(ref key, ref hlog.GetKey(physicalAddress)))
{
logicalAddress = hlog.GetInfo(physicalAddress).PreviousAddress;
TraceBackForKeyMatch(ref key,
logicalAddress,
hlog.HeadAddress,
out logicalAddress,
out physicalAddress);
}
} else
{
// If NoKey, we do not have the key in the call and must use the key from the record.
key = ref hlog.GetKey(physicalAddress);
}
}
}
else
{
// no tag found
return OperationStatus.NOTFOUND;
}
#endregion
if (sessionCtx.phase == Phase.PREPARE && InVersionNew(ref entry, sessionCtx))
{
status = OperationStatus.CPR_SHIFT_DETECTED;
goto CreatePendingContext; // Pivot thread
}
#region Normal processing
// Mutable region (even fuzzy region is included here)
if (logicalAddress >= hlog.SafeReadOnlyAddress)
{
ref RecordInfo recordInfo = ref hlog.GetInfo(physicalAddress);
pendingContext.recordInfo = recordInfo;
if (!pendingContext.recordInfo.Tombstone)
{
fasterSession.ConcurrentReader(ref key, ref input, ref hlog.GetValue(physicalAddress), ref output, ref recordInfo, logicalAddress);
return OperationStatus.SUCCESS;
}
return OperationStatus.NOTFOUND;
}
// Immutable region
else if (logicalAddress >= hlog.HeadAddress)
{
pendingContext.recordInfo = hlog.GetInfo(physicalAddress);
if (!pendingContext.recordInfo.Tombstone)
{
fasterSession.SingleReader(ref key, ref input, ref hlog.GetValue(physicalAddress), ref output, logicalAddress);
if (CopyReadsToTail == CopyReadsToTail.FromReadOnly)
{
var container = hlog.GetValueContainer(ref hlog.GetValue(physicalAddress));
InternalTryCopyToTail(ref key, ref container.Get(), ref pendingContext.recordInfo, logicalAddress, fasterSession, sessionCtx);
container.Dispose();
}
return OperationStatus.SUCCESS;
}
return OperationStatus.NOTFOUND;
}
// On-Disk Region
else if (logicalAddress >= hlog.BeginAddress)
{
if (hlog.IsNullDevice)
return OperationStatus.NOTFOUND;
status = OperationStatus.RECORD_ON_DISK;
if (sessionCtx.phase == Phase.PREPARE)
{
Debug.Assert(heldOperation != LatchOperation.Exclusive);
if (usePreviousAddress)
{
Debug.Assert(heldOperation == LatchOperation.None);
}
else if (heldOperation == LatchOperation.Shared || HashBucket.TryAcquireSharedLatch(bucket))
{
heldOperation = LatchOperation.Shared;
}
else
{
status = OperationStatus.CPR_SHIFT_DETECTED;
}
if (RelaxedCPR) // don't hold on to shared latched during IO
{
if (heldOperation == LatchOperation.Shared)
HashBucket.ReleaseSharedLatch(bucket);
heldOperation = LatchOperation.None;
}
}
goto CreatePendingContext;
}
// No record found
else
{
return OperationStatus.NOTFOUND;
}
#endregion
#region Create pending context
CreatePendingContext:
{
pendingContext.type = OperationType.READ;
if (!pendingContext.NoKey && pendingContext.key == default) // If this is true, we don't have a valid key
pendingContext.key = hlog.GetKeyContainer(ref key);
if (pendingContext.input == default) pendingContext.input = fasterSession.GetHeapContainer(ref input);
pendingContext.output = output;
if (pendingContext.output is IHeapConvertible heapConvertible)
heapConvertible.ConvertToHeap();
pendingContext.userContext = userContext;
pendingContext.entry.word = entry.word;
pendingContext.logicalAddress = logicalAddress;
pendingContext.version = sessionCtx.version;
pendingContext.serialNum = lsn;
pendingContext.heldLatch = heldOperation;
pendingContext.recordInfo.PreviousAddress = startAddress;
}
#endregion
return status;
}
#endregion
#region Upsert Operation
private enum LatchDestination
{
CreateNewRecord,
CreatePendingContext,
NormalProcessing
}
/// <summary>
/// Upsert operation. Replaces the value corresponding to 'key' with provided 'value', if one exists
/// else inserts a new record with 'key' and 'value'.
/// </summary>
/// <param name="key">key of the record.</param>
/// <param name="value">value to be updated to (or inserted if key does not exist).</param>
/// <param name="userContext">User context for the operation, in case it goes pending.</param>
/// <param name="pendingContext">Pending context used internally to store the context of the operation.</param>
/// <param name="fasterSession">Callback functions.</param>
/// <param name="sessionCtx">Session context</param>
/// <param name="lsn">Operation serial number</param>
/// <returns>
/// <list type="table">
/// <listheader>
/// <term>Value</term>
/// <term>Description</term>
/// </listheader>
/// <item>
/// <term>SUCCESS</term>
/// <term>The value has been successfully replaced(or inserted)</term>
/// </item>
/// <item>
/// <term>RETRY_LATER</term>
/// <term>Cannot be processed immediately due to system state. Add to pending list and retry later</term>
/// </item>
/// <item>
/// <term>CPR_SHIFT_DETECTED</term>
/// <term>A shift in version has been detected. Synchronize immediately to avoid violating CPR consistency.</term>
/// </item>
/// </list>
/// </returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal OperationStatus InternalUpsert<Input, Output, Context, FasterSession>(
ref Key key, ref Value value,
ref Context userContext,
ref PendingContext<Input, Output, Context> pendingContext,
FasterSession fasterSession,
FasterExecutionContext<Input, Output, Context> sessionCtx,
long lsn)
where FasterSession : IFasterSession<Key, Value, Input, Output, Context>
{
var bucket = default(HashBucket*);
var slot = default(int);
var status = default(OperationStatus);
var latchOperation = LatchOperation.None;
var latchDestination = LatchDestination.NormalProcessing;
var hash = comparer.GetHashCode64(ref key);
var tag = (ushort)((ulong)hash >> Constants.kHashTagShift);
if (sessionCtx.phase != Phase.REST)
HeavyEnter(hash, sessionCtx, fasterSession);
#region Trace back for record in in-memory HybridLog
var entry = default(HashBucketEntry);
FindOrCreateTag(hash, tag, ref bucket, ref slot, ref entry, hlog.BeginAddress);
var logicalAddress = entry.Address;
var physicalAddress = default(long);
if (UseReadCache)
SkipAndInvalidateReadCache(ref logicalAddress, ref key);
var latestLogicalAddress = logicalAddress;
if (logicalAddress >= hlog.ReadOnlyAddress)
{
physicalAddress = hlog.GetPhysicalAddress(logicalAddress);
if (!comparer.Equals(ref key, ref hlog.GetKey(physicalAddress)))
{
logicalAddress = hlog.GetInfo(physicalAddress).PreviousAddress;
TraceBackForKeyMatch(ref key,
logicalAddress,
hlog.ReadOnlyAddress,
out logicalAddress,
out physicalAddress);
}
}
#endregion
// Optimization for the most common case
if (sessionCtx.phase == Phase.REST && logicalAddress >= hlog.ReadOnlyAddress)
{
ref RecordInfo recordInfo = ref hlog.GetInfo(physicalAddress);
if (!recordInfo.Tombstone
&& fasterSession.ConcurrentWriter(ref key, ref value, ref hlog.GetValue(physicalAddress), ref recordInfo, logicalAddress))
{
hlog.MarkPage(logicalAddress, sessionCtx.version);
return OperationStatus.SUCCESS;
}
goto CreateNewRecord;
}
#region Entry latch operation
if (sessionCtx.phase != Phase.REST)
{
latchDestination = AcquireLatchUpsert(sessionCtx, bucket, ref status, ref latchOperation, ref entry);
}
#endregion
#region Normal processing
// Mutable Region: Update the record in-place
if (latchDestination == LatchDestination.NormalProcessing)
{
if (logicalAddress >= hlog.ReadOnlyAddress)
{
ref RecordInfo recordInfo = ref hlog.GetInfo(physicalAddress);
if (!recordInfo.Tombstone
&& fasterSession.ConcurrentWriter(ref key, ref value, ref hlog.GetValue(physicalAddress), ref recordInfo, logicalAddress))
{
if (sessionCtx.phase == Phase.REST) hlog.MarkPage(logicalAddress, sessionCtx.version);
else hlog.MarkPageAtomic(logicalAddress, sessionCtx.version);
status = OperationStatus.SUCCESS;
goto LatchRelease; // Release shared latch (if acquired)
}
}
}
// All other regions: Create a record in the mutable region
#endregion
#region Create new record in the mutable region
CreateNewRecord:
if (latchDestination != LatchDestination.CreatePendingContext)
{
// Immutable region or new record
status = CreateNewRecordUpsert(ref key, ref value, ref pendingContext, fasterSession, sessionCtx, bucket, slot, tag, entry, latestLogicalAddress);
if (status != OperationStatus.ALLOCATE_FAILED)
goto LatchRelease;
latchDestination = LatchDestination.CreatePendingContext;
}
#endregion
#region Create pending context
Debug.Assert(latchDestination == LatchDestination.CreatePendingContext, $"Upsert CreatePendingContext encountered latchDest == {latchDestination}");
{
pendingContext.type = OperationType.UPSERT;
if (pendingContext.key == default) pendingContext.key = hlog.GetKeyContainer(ref key);
if (pendingContext.value == default) pendingContext.value = hlog.GetValueContainer(ref value);
pendingContext.userContext = userContext;
pendingContext.entry.word = entry.word;
pendingContext.logicalAddress = logicalAddress;
pendingContext.version = sessionCtx.version;
pendingContext.serialNum = lsn;
}
#endregion
#region Latch release
LatchRelease:
{
switch (latchOperation)
{
case LatchOperation.Shared:
HashBucket.ReleaseSharedLatch(bucket);
break;
case LatchOperation.Exclusive:
HashBucket.ReleaseExclusiveLatch(bucket);
break;
default:
break;
}
}
#endregion
return status;
}
private LatchDestination AcquireLatchUpsert<Input, Output, Context>(FasterExecutionContext<Input, Output, Context> sessionCtx, HashBucket* bucket, ref OperationStatus status,
ref LatchOperation latchOperation, ref HashBucketEntry entry)
{
switch (sessionCtx.phase)
{
case Phase.PREPARE:
{
if (HashBucket.TryAcquireSharedLatch(bucket))
{
// Set to release shared latch (default)
latchOperation = LatchOperation.Shared;
if (InVersionNew(ref entry, sessionCtx))
{
status = OperationStatus.CPR_SHIFT_DETECTED;
return LatchDestination.CreatePendingContext; // Pivot Thread
}
break; // Normal Processing
}
else
{
status = OperationStatus.CPR_SHIFT_DETECTED;
return LatchDestination.CreatePendingContext; // Pivot Thread
}
}
case Phase.IN_PROGRESS:
{
if (!InVersionNew(ref entry, sessionCtx))
{
if (HashBucket.TryAcquireExclusiveLatch(bucket))
{
// Set to release exclusive latch (default)
latchOperation = LatchOperation.Exclusive;
return LatchDestination.CreateNewRecord; // Create a (v+1) record
}
else
{
status = OperationStatus.RETRY_LATER;
return LatchDestination.CreatePendingContext; // Go Pending
}
}
break; // Normal Processing
}
case Phase.WAIT_PENDING:
{
if (!InVersionNew(ref entry, sessionCtx))
{
if (HashBucket.NoSharedLatches(bucket))
{
return LatchDestination.CreateNewRecord; // Create a (v+1) record
}
else
{
status = OperationStatus.RETRY_LATER;
return LatchDestination.CreatePendingContext; // Go Pending
}
}
break; // Normal Processing
}
case Phase.WAIT_FLUSH:
{
if (!InVersionNew(ref entry, sessionCtx))
{
return LatchDestination.CreateNewRecord; // Create a (v+1) record
}
break; // Normal Processing
}
default:
break;
}
return LatchDestination.NormalProcessing;
}
private OperationStatus CreateNewRecordUpsert<Input, Output, Context, FasterSession>(ref Key key, ref Value value, ref PendingContext<Input, Output, Context> pendingContext, FasterSession fasterSession,
FasterExecutionContext<Input, Output, Context> sessionCtx, HashBucket* bucket, int slot, ushort tag, HashBucketEntry entry,
long latestLogicalAddress)
where FasterSession : IFasterSession<Key, Value, Input, Output, Context>
{
var (actualSize, allocateSize) = hlog.GetRecordSize(ref key, ref value);
BlockAllocate(allocateSize, out long newLogicalAddress, sessionCtx, fasterSession, pendingContext.IsAsync);
if (newLogicalAddress == 0)
return OperationStatus.ALLOCATE_FAILED;
var newPhysicalAddress = hlog.GetPhysicalAddress(newLogicalAddress);
RecordInfo.WriteInfo(ref hlog.GetInfo(newPhysicalAddress),
sessionCtx.version,
tombstone: false, invalidBit: false,
latestLogicalAddress);
hlog.Serialize(ref key, newPhysicalAddress);
fasterSession.SingleWriter(ref key, ref value,
ref hlog.GetValue(newPhysicalAddress, newPhysicalAddress + actualSize));
var updatedEntry = default(HashBucketEntry);
updatedEntry.Tag = tag;
updatedEntry.Address = newLogicalAddress & Constants.kAddressMask;
updatedEntry.Pending = entry.Pending;
updatedEntry.Tentative = false;
var foundEntry = default(HashBucketEntry);
foundEntry.word = Interlocked.CompareExchange(ref bucket->bucket_entries[slot], updatedEntry.word, entry.word);
if (foundEntry.word == entry.word)
{
pendingContext.logicalAddress = newLogicalAddress;
return OperationStatus.SUCCESS;
}
// CAS failed - let user dispose similar to a deleted record
ref RecordInfo insertedRecordInfo = ref hlog.GetInfo(newPhysicalAddress);
ref Value insertedValue = ref hlog.GetValue(newPhysicalAddress);
ref Key insertedKey = ref hlog.GetKey(newPhysicalAddress);
// First set Invalid to true so that ConcurrentDeleter knows to dispose key as well
insertedRecordInfo.Invalid = true;
fasterSession.ConcurrentDeleter(ref insertedKey, ref insertedValue, ref insertedRecordInfo, newLogicalAddress);
if (WriteDefaultOnDelete)
{
insertedKey = default;
insertedValue = default;
}
return OperationStatus.RETRY_NOW;
}
#endregion
#region RMW Operation
/// <summary>
/// Read-Modify-Write Operation. Updates value of 'key' using 'input' and current value.
/// Pending operations are processed either using InternalRetryPendingRMW or
/// InternalContinuePendingRMW.
/// </summary>
/// <param name="key">key of the record.</param>
/// <param name="input">input used to update the value.</param>
/// <param name="output">Location to store output computed from input and value.</param>
/// <param name="userContext">user context corresponding to operation used during completion callback.</param>
/// <param name="pendingContext">pending context created when the operation goes pending.</param>
/// <param name="fasterSession">Callback functions.</param>
/// <param name="sessionCtx">Session context</param>
/// <param name="lsn">Operation serial number</param>
/// <returns>
/// <list type="table">
/// <listheader>
/// <term>Value</term>
/// <term>Description</term>
/// </listheader>
/// <item>
/// <term>SUCCESS</term>
/// <term>The value has been successfully updated(or inserted).</term>
/// </item>
/// <item>
/// <term>RECORD_ON_DISK</term>
/// <term>The record corresponding to 'key' is on disk. Issue async IO to retrieve record and retry later.</term>
/// </item>
/// <item>
/// <term>RETRY_LATER</term>
/// <term>Cannot be processed immediately due to system state. Add to pending list and retry later.</term>
/// </item>
/// <item>
/// <term>CPR_SHIFT_DETECTED</term>
/// <term>A shift in version has been detected. Synchronize immediately to avoid violating CPR consistency.</term>
/// </item>
/// </list>
/// </returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal OperationStatus InternalRMW<Input, Output, Context, FasterSession>(
ref Key key, ref Input input, ref Output output,
ref Context userContext,
ref PendingContext<Input, Output, Context> pendingContext,
FasterSession fasterSession,
FasterExecutionContext<Input, Output, Context> sessionCtx,
long lsn)
where FasterSession : IFasterSession<Key, Value, Input, Output, Context>
{
var bucket = default(HashBucket*);
var slot = default(int);
var physicalAddress = default(long);
var status = default(OperationStatus);
var latchOperation = LatchOperation.None;
var heldOperation = LatchOperation.None;
var latchDestination = LatchDestination.NormalProcessing;
var hash = comparer.GetHashCode64(ref key);
var tag = (ushort)((ulong)hash >> Constants.kHashTagShift);
if (sessionCtx.phase != Phase.REST)
HeavyEnter(hash, sessionCtx, fasterSession);
#region Trace back for record in in-memory HybridLog
var entry = default(HashBucketEntry);
FindOrCreateTag(hash, tag, ref bucket, ref slot, ref entry, hlog.BeginAddress);
var logicalAddress = entry.Address;
// For simplicity, we don't let RMW operations use read cache
if (UseReadCache)
SkipReadCache(ref logicalAddress);
var latestLogicalAddress = logicalAddress;
if (logicalAddress >= hlog.HeadAddress)
{
physicalAddress = hlog.GetPhysicalAddress(logicalAddress);
if (!comparer.Equals(ref key, ref hlog.GetKey(physicalAddress)))
{
logicalAddress = hlog.GetInfo(physicalAddress).PreviousAddress;
TraceBackForKeyMatch(ref key,
logicalAddress,
hlog.HeadAddress,
out logicalAddress,
out physicalAddress);
}
}
#endregion
// Optimization for the most common case
if (sessionCtx.phase == Phase.REST && logicalAddress >= hlog.ReadOnlyAddress)
{
ref RecordInfo recordInfo = ref hlog.GetInfo(physicalAddress);
if (!recordInfo.Tombstone
&& fasterSession.InPlaceUpdater(ref key, ref input, ref hlog.GetValue(physicalAddress), ref output, ref recordInfo, logicalAddress))
{
hlog.MarkPage(logicalAddress, sessionCtx.version);
return OperationStatus.SUCCESS;
}
goto CreateNewRecord;
}
#region Entry latch operation
if (sessionCtx.phase != Phase.REST)
{
latchDestination = AcquireLatchRMW(pendingContext, sessionCtx, bucket, ref status, ref latchOperation, ref entry, logicalAddress);
}
#endregion
#region Normal processing
// Mutable Region: Update the record in-place
if (latchDestination == LatchDestination.NormalProcessing)
{
if (logicalAddress >= hlog.ReadOnlyAddress)
{
ref RecordInfo recordInfo = ref hlog.GetInfo(physicalAddress);
if (!recordInfo.Tombstone)
{
if (FoldOverSnapshot)
{
Debug.Assert(recordInfo.Version == sessionCtx.version);
}
if (fasterSession.InPlaceUpdater(ref key, ref input, ref hlog.GetValue(physicalAddress), ref output, ref recordInfo, logicalAddress))
{
if (sessionCtx.phase == Phase.REST) hlog.MarkPage(logicalAddress, sessionCtx.version);
else hlog.MarkPageAtomic(logicalAddress, sessionCtx.version);
status = OperationStatus.SUCCESS;
goto LatchRelease; // Release shared latch (if acquired)
}
}
}
// Fuzzy Region: Must go pending due to lost-update anomaly
else if (logicalAddress >= hlog.SafeReadOnlyAddress && !hlog.GetInfo(physicalAddress).Tombstone)
{
status = OperationStatus.RETRY_LATER;
// Do not retain latch for pendings ops in relaxed CPR
if (!RelaxedCPR)
{
// Retain the shared latch (if acquired)
if (latchOperation == LatchOperation.Shared)
{
heldOperation = latchOperation;
latchOperation = LatchOperation.None;
}
}
latchDestination = LatchDestination.CreatePendingContext; // Go pending
}
// Safe Read-Only Region: Create a record in the mutable region
else if (logicalAddress >= hlog.HeadAddress)
{
goto CreateNewRecord;
}
// Disk Region: Need to issue async io requests
else if (logicalAddress >= hlog.BeginAddress)
{
status = OperationStatus.RECORD_ON_DISK;
// Do not retain latch for pendings ops in relaxed CPR
if (!RelaxedCPR)
{
// Retain the shared latch (if acquired)
if (latchOperation == LatchOperation.Shared)
{
heldOperation = latchOperation;
latchOperation = LatchOperation.None;
}
}
latchDestination = LatchDestination.CreatePendingContext; // Go pending
}
// No record exists - create new
else
{
goto CreateNewRecord;
}
}
#endregion
#region Create new record
CreateNewRecord:
if (latchDestination != LatchDestination.CreatePendingContext)
{
status = CreateNewRecordRMW(ref key, ref input, ref output, ref pendingContext, fasterSession, sessionCtx, bucket, slot, logicalAddress, physicalAddress, tag, entry, latestLogicalAddress);
if (status != OperationStatus.ALLOCATE_FAILED)
goto LatchRelease;
latchDestination = LatchDestination.CreatePendingContext;
}
#endregion
#region Create failure context
Debug.Assert(latchDestination == LatchDestination.CreatePendingContext, $"RMW CreatePendingContext encountered latchDest == {latchDestination}");
{
pendingContext.type = OperationType.RMW;
if (pendingContext.key == default) pendingContext.key = hlog.GetKeyContainer(ref key);
if (pendingContext.input == default) pendingContext.input = fasterSession.GetHeapContainer(ref input);
pendingContext.output = output;
if (pendingContext.output is IHeapConvertible heapConvertible)
heapConvertible.ConvertToHeap();
pendingContext.userContext = userContext;
pendingContext.entry.word = entry.word;
pendingContext.logicalAddress = logicalAddress;
pendingContext.version = sessionCtx.version;
pendingContext.serialNum = lsn;
pendingContext.heldLatch = heldOperation;
}
#endregion
#region Latch release
LatchRelease:
{
switch (latchOperation)
{
case LatchOperation.Shared:
HashBucket.ReleaseSharedLatch(bucket);
break;
case LatchOperation.Exclusive:
HashBucket.ReleaseExclusiveLatch(bucket);
break;
default:
break;
}
}
#endregion
return status;
}
private LatchDestination AcquireLatchRMW<Input, Output, Context>(PendingContext<Input, Output, Context> pendingContext, FasterExecutionContext<Input, Output, Context> sessionCtx,
HashBucket* bucket, ref OperationStatus status, ref LatchOperation latchOperation, ref HashBucketEntry entry, long logicalAddress)
{
switch (sessionCtx.phase)
{
case Phase.PREPARE:
{
Debug.Assert(pendingContext.heldLatch != LatchOperation.Exclusive);
if (pendingContext.heldLatch == LatchOperation.Shared || HashBucket.TryAcquireSharedLatch(bucket))
{
// Set to release shared latch (default)
latchOperation = LatchOperation.Shared;
if (InVersionNew(ref entry, sessionCtx))
{
status = OperationStatus.CPR_SHIFT_DETECTED;
return LatchDestination.CreatePendingContext; // Pivot Thread
}
break; // Normal Processing
}
else
{
status = OperationStatus.CPR_SHIFT_DETECTED;
return LatchDestination.CreatePendingContext; // Pivot Thread
}
}
case Phase.IN_PROGRESS:
{
if (!InVersionNew(ref entry, sessionCtx))
{
Debug.Assert(pendingContext.heldLatch != LatchOperation.Shared);
if (pendingContext.heldLatch == LatchOperation.Exclusive || HashBucket.TryAcquireExclusiveLatch(bucket))
{
// Set to release exclusive latch (default)
latchOperation = LatchOperation.Exclusive;
if (logicalAddress >= hlog.HeadAddress)
return LatchDestination.CreateNewRecord; // Create a (v+1) record
}
else
{
status = OperationStatus.RETRY_LATER;
return LatchDestination.CreatePendingContext; // Go Pending
}
}
break; // Normal Processing
}
case Phase.WAIT_PENDING:
{
if (!InVersionNew(ref entry, sessionCtx))
{
if (HashBucket.NoSharedLatches(bucket))
{
if (logicalAddress >= hlog.HeadAddress)
return LatchDestination.CreateNewRecord; // Create a (v+1) record
}
else
{
status = OperationStatus.RETRY_LATER;
return LatchDestination.CreatePendingContext; // Go Pending
}
}
break; // Normal Processing
}
case Phase.WAIT_FLUSH:
{
if (!InVersionNew(ref entry, sessionCtx))
{
if (logicalAddress >= hlog.HeadAddress)
return LatchDestination.CreateNewRecord; // Create a (v+1) record
}
break; // Normal Processing
}
default:
break;
}
return LatchDestination.NormalProcessing;
}
private OperationStatus CreateNewRecordRMW<Input, Output, Context, FasterSession>(ref Key key, ref Input input, ref Output output, ref PendingContext<Input, Output, Context> pendingContext, FasterSession fasterSession,
FasterExecutionContext<Input, Output, Context> sessionCtx, HashBucket* bucket, int slot, long logicalAddress,
long physicalAddress, ushort tag, HashBucketEntry entry, long latestLogicalAddress)
where FasterSession : IFasterSession<Key, Value, Input, Output, Context>
{
if (logicalAddress >= hlog.HeadAddress && !hlog.GetInfo(physicalAddress).Tombstone)
{
if (!fasterSession.NeedCopyUpdate(ref key, ref input, ref hlog.GetValue(physicalAddress), ref output))
return OperationStatus.SUCCESS;
}
var (actualSize, allocatedSize) = (logicalAddress < hlog.BeginAddress) ?
hlog.GetInitialRecordSize(ref key, ref input, fasterSession) :
hlog.GetRecordSize(physicalAddress, ref input, fasterSession);
BlockAllocate(allocatedSize, out long newLogicalAddress, sessionCtx, fasterSession, pendingContext.IsAsync);
if (newLogicalAddress == 0)
return OperationStatus.ALLOCATE_FAILED;
var newPhysicalAddress = hlog.GetPhysicalAddress(newLogicalAddress);
RecordInfo.WriteInfo(ref hlog.GetInfo(newPhysicalAddress), sessionCtx.version,
tombstone: false, invalidBit: false,
latestLogicalAddress);
hlog.Serialize(ref key, newPhysicalAddress);
OperationStatus status;
if (logicalAddress < hlog.BeginAddress)
{
fasterSession.InitialUpdater(ref key, ref input, ref hlog.GetValue(newPhysicalAddress, newPhysicalAddress + actualSize), ref output);
status = OperationStatus.NOTFOUND;
}
else if (logicalAddress >= hlog.HeadAddress)
{
if (hlog.GetInfo(physicalAddress).Tombstone)
{
fasterSession.InitialUpdater(ref key, ref input, ref hlog.GetValue(newPhysicalAddress, newPhysicalAddress + actualSize), ref output);
status = OperationStatus.NOTFOUND;
}
else
{
fasterSession.CopyUpdater(ref key, ref input, ref hlog.GetValue(physicalAddress),
ref hlog.GetValue(newPhysicalAddress, newPhysicalAddress + actualSize),
ref output);
status = OperationStatus.SUCCESS;
}
}
else
{
// ah, old record slipped onto disk
hlog.GetInfo(newPhysicalAddress).Invalid = true;
return OperationStatus.RETRY_NOW;
}
var updatedEntry = default(HashBucketEntry);
updatedEntry.Tag = tag;
updatedEntry.Address = newLogicalAddress & Constants.kAddressMask;
updatedEntry.Pending = entry.Pending;
updatedEntry.Tentative = false;
var foundEntry = default(HashBucketEntry);
foundEntry.word = Interlocked.CompareExchange(ref bucket->bucket_entries[slot], updatedEntry.word, entry.word);
if (foundEntry.word == entry.word)
{
pendingContext.logicalAddress = newLogicalAddress;
}
else
{
// CAS failed
hlog.GetInfo(newPhysicalAddress).Invalid = true;
status = OperationStatus.RETRY_NOW;
}
return status;
}
#endregion
#region Delete Operation
/// <summary>
/// Delete operation. Replaces the value corresponding to 'key' with tombstone.
/// If at head, tries to remove item from hash chain
/// </summary>
/// <param name="key">Key of the record to be deleted.</param>
/// <param name="userContext">User context for the operation, in case it goes pending.</param>
/// <param name="pendingContext">Pending context used internally to store the context of the operation.</param>
/// <param name="fasterSession">Callback functions.</param>
/// <param name="sessionCtx">Session context</param>
/// <param name="lsn">Operation serial number</param>
/// <returns>
/// <list type="table">
/// <listheader>
/// <term>Value</term>
/// <term>Description</term>
/// </listheader>
/// <item>
/// <term>SUCCESS</term>
/// <term>The value has been successfully deleted</term>
/// </item>
/// <item>
/// <term>RETRY_LATER</term>
/// <term>Cannot be processed immediately due to system state. Add to pending list and retry later</term>
/// </item>
/// <item>
/// <term>CPR_SHIFT_DETECTED</term>
/// <term>A shift in version has been detected. Synchronize immediately to avoid violating CPR consistency.</term>
/// </item>
/// </list>
/// </returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal OperationStatus InternalDelete<Input, Output, Context, FasterSession>(
ref Key key,
ref Context userContext,
ref PendingContext<Input, Output, Context> pendingContext,
FasterSession fasterSession,
FasterExecutionContext<Input, Output, Context> sessionCtx,
long lsn)
where FasterSession : IFasterSession<Key, Value, Input, Output, Context>
{
var status = default(OperationStatus);
var bucket = default(HashBucket*);
var slot = default(int);
var logicalAddress = Constants.kInvalidAddress;