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storage: rename intent to update in MVCC intent resolution functions
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Rename the intent argument to the mvccResolveWriteIntent,
MVCCResolveWriteIntent, and MVCCResolveWriteIntentRange functions to
make it clear that it refers to the state passed in via ResolveIntent,
and not the current value of the stored intent.

Informs: #117553

Release note: None
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@miraradeva
miraradeva committed Jan 9, 2024
1 parent 5bf97e5 commit c5adf13
Showing 1 changed file with 58 additions and 59 deletions.
117 changes: 58 additions & 59 deletions pkg/storage/mvcc.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4959,17 +4959,17 @@ func MVCCResolveWriteIntent(
ctx context.Context,
rw ReadWriter,
ms *enginepb.MVCCStats,
intent roachpb.LockUpdate,
update roachpb.LockUpdate,
opts MVCCResolveWriteIntentOptions,
) (ok bool, numBytes int64, resumeSpan *roachpb.Span, replLocksReleased bool, err error) {
if len(intent.Key) == 0 {
if len(update.Key) == 0 {
return false, 0, nil, false, emptyKeyError()
}
if len(intent.EndKey) > 0 {
if len(update.EndKey) > 0 {
return false, 0, nil, false, errors.Errorf("can't resolve range intent as point intent")
}
if opts.TargetBytes < 0 {
return false, 0, &roachpb.Span{Key: intent.Key}, false, nil
return false, 0, &roachpb.Span{Key: update.Key}, false, nil
}

// Production code will use a buffered writer, which makes the numBytes
Expand All @@ -4978,10 +4978,10 @@ func MVCCResolveWriteIntent(
// the database.
beforeBytes := rw.BufferedSize()

// Iterate over all locks held by intent.Txn on this key.
// Iterate over all locks held by update.Txn on this key.
ltIter, err := NewLockTableIterator(ctx, rw, LockTableIteratorOptions{
Prefix: true,
MatchTxnID: intent.Txn.ID,
MatchTxnID: update.Txn.ID,
ReadCategory: IntentResolutionReadCategory,
})
if err != nil {
Expand All @@ -4993,11 +4993,11 @@ func MVCCResolveWriteIntent(

var ltSeekKey EngineKey
ltSeekKey, buf.ltKeyBuf = LockTableKey{
Key: intent.Key,
Key: update.Key,
// lock.Intent is the first locking strength in the lock-table. As a
// minor performance optimization, we seek to this version and iterate
// instead of iterating from the beginning of the version prefix (i.e.
// keys.LockTableSingleKey(intent.Key)). This can seek past half of the
// keys.LockTableSingleKey(update.Key)). This can seek past half of the
// LSM tombstones on this key in cases like those described in d1c91e0e
// where intents are repeatedly written and removed on a specific key so
// an intent is surrounded by a large number of tombstones during its
Expand All @@ -5014,7 +5014,7 @@ func MVCCResolveWriteIntent(
// a single seek and step in cases where only an intent is present. We
// chose not to pessimize the common case to optimize the uncommon case.
Strength: lock.Intent,
TxnUUID: intent.Txn.ID,
TxnUUID: update.Txn.ID,
}.ToEngineKey(buf.ltKeyBuf)

for valid, err := ltIter.SeekEngineKeyGE(ltSeekKey); ; valid, err = ltIter.NextEngineKey() {
Expand All @@ -5027,9 +5027,9 @@ func MVCCResolveWriteIntent(
if err != nil {
return false, 0, nil, false, errors.Wrap(err, "decoding lock table key version")
}
if txnID != intent.Txn.ID {
if txnID != update.Txn.ID {
return false, 0, nil, false, errors.AssertionFailedf(
"unexpected txnID %v != %v while scanning lock table", txnID, intent.Txn.ID)
"unexpected txnID %v != %v while scanning lock table", txnID, update.Txn.ID)
}
if err := ltIter.ValueProto(&buf.meta); err != nil {
return false, 0, nil, false, errors.Wrap(err, "unmarshaling lock table value")
Expand All @@ -5050,9 +5050,9 @@ func MVCCResolveWriteIntent(
}
defer iter.Close()
}
outcome, err = mvccResolveWriteIntent(ctx, rw, iter, ms, intent, &buf.meta, buf)
outcome, err = mvccResolveWriteIntent(ctx, rw, iter, ms, update, &buf.meta, buf)
} else {
outcome, err = mvccReleaseLockInternal(ctx, rw, ms, intent, str, &buf.meta, buf)
outcome, err = mvccReleaseLockInternal(ctx, rw, ms, update, str, &buf.meta, buf)
replLocksReleased = replLocksReleased || outcome != lockNoop
}
if err != nil {
Expand Down Expand Up @@ -5173,58 +5173,57 @@ const (
// provided intent was resolved (a no-op, rewriting the intent, writing a
// SingleDelete key, or writing a Delete key).
//
// REQUIRES: intent and meta refer to the same intent on the same key.
// REQUIRES: update and meta refer to the same intent on the same key.
// REQUIRES: iter surfaces range keys via IterKeyTypePointsAndRanges.
func mvccResolveWriteIntent(
ctx context.Context,
writer Writer,
iter MVCCIterator,
ms *enginepb.MVCCStats,
// TODO(nvanbenschoten): rename this field to "update".
intent roachpb.LockUpdate,
update roachpb.LockUpdate,
meta *enginepb.MVCCMetadata,
buf *putBuffer,
) (outcome lockResolutionOutcome, err error) {
if meta.Txn == nil || meta.Txn.ID != intent.Txn.ID {
return lockNoop, errors.Errorf("txn does not match: %v != %v", meta.Txn, intent.Txn)
if meta.Txn == nil || meta.Txn.ID != update.Txn.ID {
return lockNoop, errors.Errorf("txn does not match: %v != %v", meta.Txn, update.Txn)
}

metaKey := MakeMVCCMetadataKey(intent.Key)
metaKey := MakeMVCCMetadataKey(update.Key)
origMetaKeySize := int64(metaKey.EncodedSize())
origMetaValSize := int64(meta.Size())
metaTimestamp := meta.Timestamp.ToTimestamp()
canSingleDelHelper := singleDelOptimizationHelper{
_didNotUpdateMeta: meta.TxnDidNotUpdateMeta,
_hasIgnoredSeqs: len(intent.IgnoredSeqNums) > 0,
_hasIgnoredSeqs: len(update.IgnoredSeqNums) > 0,
// NB: the value is only used if epochs match, so it doesn't
// matter if we use the one from meta or incoming request here.
_epoch: intent.Txn.Epoch,
_epoch: update.Txn.Epoch,
}

// A commit with a newer epoch than the intent effectively means that we
// An update with a newer epoch than the intent effectively means that we
// wrote this intent before an earlier retry, but didn't write it again
// after. We treat such intents as uncommitted.
//
// A commit with a newer timestamp than the intent means that our timestamp
// An update with a newer timestamp than the intent means that our timestamp
// was pushed during the course of an epoch. We treat such intents as
// committed after moving their timestamp forward. This is possible if a
// transaction writes an intent and then successfully refreshes its
// timestamp to avoid a restart.
//
// A commit with an older epoch than the intent should never happen because
// An update with an older epoch than the intent should never happen because
// epoch increments require client action. This means that they can't be
// caused by replays.
//
// A commit with an older timestamp than the intent should not happen under
// An update with an older timestamp than the intent should not happen under
// normal circumstances because a client should never bump its timestamp
// after issuing an EndTxn request. Replays of intent writes that are pushed
// forward due to WriteTooOld errors without client action combined with
// replays of intent resolution make this configuration a possibility. We
// treat such intents as uncommitted.
epochsMatch := meta.Txn.Epoch == intent.Txn.Epoch
timestampsValid := metaTimestamp.LessEq(intent.Txn.WriteTimestamp)
timestampChanged := metaTimestamp.Less(intent.Txn.WriteTimestamp)
commit := intent.Status == roachpb.COMMITTED && epochsMatch && timestampsValid
epochsMatch := meta.Txn.Epoch == update.Txn.Epoch
timestampsValid := metaTimestamp.LessEq(update.Txn.WriteTimestamp)
timestampChanged := metaTimestamp.Less(update.Txn.WriteTimestamp)
commit := update.Status == roachpb.COMMITTED && epochsMatch && timestampsValid

// Note the small difference to commit epoch handling here: We allow
// a push from a previous epoch to move a newer intent. That's not
Expand All @@ -5251,9 +5250,9 @@ func mvccResolveWriteIntent(
// used for resolving), but that costs latency.
// TODO(tschottdorf): various epoch-related scenarios here deserve more
// testing.
inProgress := !intent.Status.IsFinalized() && meta.Txn.Epoch >= intent.Txn.Epoch
inProgress := !update.Status.IsFinalized() && meta.Txn.Epoch >= update.Txn.Epoch
pushed := inProgress && timestampChanged
latestKey := MVCCKey{Key: intent.Key, Timestamp: metaTimestamp}
latestKey := MVCCKey{Key: update.Key, Timestamp: metaTimestamp}

// Handle partial txn rollbacks. If the current txn sequence
// is part of a rolled back (ignored) seqnum range, we're going
Expand All @@ -5265,7 +5264,7 @@ func mvccResolveWriteIntent(
var rolledBackVal *MVCCValue
buf.newMeta = *meta
newMeta := &buf.newMeta
if len(intent.IgnoredSeqNums) > 0 {
if len(update.IgnoredSeqNums) > 0 {
// NOTE: mvccMaybeRewriteIntentHistory mutates its meta argument.
// TODO(nvanbenschoten): this is an awkward interface. We shouldn't
// be mutating meta and we shouldn't be restoring the previous value
Expand All @@ -5276,7 +5275,7 @@ func mvccResolveWriteIntent(
// intact and corresponding to the stats in ms to ensure that later on (in
// updateStatsOnResolve) the stats will be updated correctly based on the
// old meta (meta) and the new meta (newMeta).
removeIntent, rolledBackVal, err = mvccMaybeRewriteIntentHistory(ctx, writer, intent.IgnoredSeqNums, newMeta, latestKey)
removeIntent, rolledBackVal, err = mvccMaybeRewriteIntentHistory(ctx, writer, update.IgnoredSeqNums, newMeta, latestKey)
if err != nil {
return lockNoop, err
}
Expand All @@ -5296,7 +5295,7 @@ func mvccResolveWriteIntent(
// If we need to update the intent to roll back part of its intent
// history, make sure that we don't regress its timestamp, even if the
// caller provided an outdated timestamp.
intent.Txn.WriteTimestamp.Forward(metaTimestamp)
update.Txn.WriteTimestamp.Forward(metaTimestamp)
}
}

Expand All @@ -5320,7 +5319,7 @@ func mvccResolveWriteIntent(
if commit || pushed || rolledBackVal != nil {
// The intent might be committing at a higher timestamp, or it might be
// getting pushed.
newTimestamp := intent.Txn.WriteTimestamp
newTimestamp := update.Txn.WriteTimestamp

// Assert that the intent timestamp never regresses. The logic above should
// not allow this, regardless of the input to this function.
Expand Down Expand Up @@ -5380,7 +5379,7 @@ func mvccResolveWriteIntent(
// to the observed timestamp.
newValue := oldValue
newValue.LocalTimestamp = oldValue.GetLocalTimestamp(oldKey.Timestamp)
newValue.LocalTimestamp.Forward(intent.ClockWhilePending.Timestamp)
newValue.LocalTimestamp.Forward(update.ClockWhilePending.Timestamp)
if !newValue.LocalTimestampNeeded(newKey.Timestamp) || !writer.ShouldWriteLocalTimestamps(ctx) {
newValue.LocalTimestamp = hlc.ClockTimestamp{}
}
Expand Down Expand Up @@ -5459,7 +5458,7 @@ func mvccResolveWriteIntent(

// Update stat counters related to resolving the intent.
if ms != nil {
ms.Add(updateStatsOnResolve(intent.Key, prevIsValue, prevValSize, origMetaKeySize, origMetaValSize,
ms.Add(updateStatsOnResolve(update.Key, prevIsValue, prevValSize, origMetaKeySize, origMetaValSize,
metaKeySize, metaValSize, meta, newMeta, commit))
}

Expand All @@ -5469,9 +5468,9 @@ func mvccResolveWriteIntent(
logicalOp = MVCCUpdateIntentOpType
}
writer.LogLogicalOp(logicalOp, MVCCLogicalOpDetails{
Txn: intent.Txn,
Key: intent.Key,
Timestamp: intent.Txn.WriteTimestamp,
Txn: update.Txn,
Key: update.Key,
Timestamp: update.Txn.WriteTimestamp,
})
// outcome is set up above.
return outcome, nil
Expand All @@ -5481,7 +5480,7 @@ func mvccResolveWriteIntent(
// MVCCMetadata.
//
// Note that we have to support a somewhat unintuitive case - an ABORT with
// intent.Txn.Epoch < meta.Txn.Epoch:
// update.Txn.Epoch < meta.Txn.Epoch:
// - writer1 writes key0 at epoch 0
// - writer2 with higher priority encounters intent at key0 (epoch 0)
// - writer1 restarts, now at epoch one (txn record not updated)
Expand All @@ -5499,8 +5498,8 @@ func mvccResolveWriteIntent(

// Log the logical MVCC operation.
writer.LogLogicalOp(MVCCAbortIntentOpType, MVCCLogicalOpDetails{
Txn: intent.Txn,
Key: intent.Key,
Txn: update.Txn,
Key: update.Key,
})

ok := false
Expand Down Expand Up @@ -5575,7 +5574,7 @@ func mvccResolveWriteIntent(
// Clear stat counters attributable to the intent we're aborting.
if ms != nil {
ms.Add(updateStatsOnClear(
intent.Key, origMetaKeySize, origMetaValSize, 0, 0, meta, nil, 0))
update.Key, origMetaKeySize, origMetaValSize, 0, 0, meta, nil, 0))
}
// outcome is set above before the clearLockMeta call.
return outcome, nil
Expand Down Expand Up @@ -5603,7 +5602,7 @@ func mvccResolveWriteIntent(

// Update stat counters with older version.
if ms != nil {
ms.Add(updateStatsOnClear(intent.Key, origMetaKeySize, origMetaValSize, metaKeySize,
ms.Add(updateStatsOnClear(update.Key, origMetaKeySize, origMetaValSize, metaKeySize,
metaValSize, meta, &buf.newMeta, unsafeNextKey.Timestamp.WallTime))
}
// outcome is set above before the clearLockMeta call.
Expand Down Expand Up @@ -5684,7 +5683,7 @@ func MVCCResolveWriteIntentRange(
ctx context.Context,
rw ReadWriter,
ms *enginepb.MVCCStats,
intent roachpb.LockUpdate,
update roachpb.LockUpdate,
opts MVCCResolveWriteIntentRangeOptions,
) (
numKeys, numBytes int64,
Expand All @@ -5696,7 +5695,7 @@ func MVCCResolveWriteIntentRange(
keysExceeded := opts.MaxKeys < 0
bytesExceeded := opts.TargetBytes < 0
if keysExceeded || bytesExceeded {
resumeSpan := intent.Span // don't inline or `intent` would escape to heap
resumeSpan := update.Span // don't inline or `update` would escape to heap
if keysExceeded {
resumeReason = kvpb.RESUME_KEY_LIMIT
} else if bytesExceeded {
Expand All @@ -5705,12 +5704,12 @@ func MVCCResolveWriteIntentRange(
return 0, 0, &resumeSpan, resumeReason, false, nil
}

ltStart, _ := keys.LockTableSingleKey(intent.Key, nil)
ltEnd, _ := keys.LockTableSingleKey(intent.EndKey, nil)
ltStart, _ := keys.LockTableSingleKey(update.Key, nil)
ltEnd, _ := keys.LockTableSingleKey(update.EndKey, nil)
ltIter, err := NewLockTableIterator(ctx, rw, LockTableIteratorOptions{
LowerBound: ltStart,
UpperBound: ltEnd,
MatchTxnID: intent.Txn.ID,
MatchTxnID: update.Txn.ID,
ReadCategory: IntentResolutionReadCategory,
})
if err != nil {
Expand All @@ -5720,8 +5719,8 @@ func MVCCResolveWriteIntentRange(
var mvccIter MVCCIterator
iterOpts := IterOptions{
KeyTypes: IterKeyTypePointsAndRanges,
LowerBound: intent.Key,
UpperBound: intent.EndKey,
LowerBound: update.Key,
UpperBound: update.EndKey,
ReadCategory: IntentResolutionReadCategory,
}
if rw.ConsistentIterators() {
Expand All @@ -5738,8 +5737,8 @@ func MVCCResolveWriteIntentRange(
buf := newPutBuffer()
defer buf.release()

intentEndKey := intent.EndKey
intent.EndKey = nil
intentEndKey := update.EndKey
update.EndKey = nil

var lastResolvedKey roachpb.Key
var lastResolvedKeyOk bool
Expand Down Expand Up @@ -5789,20 +5788,20 @@ func MVCCResolveWriteIntentRange(
lastResolvedKey = append(lastResolvedKey[:0], ltKey.Key...)
lastResolvedKeyOk = false
}
if ltKey.TxnUUID != intent.Txn.ID {
if ltKey.TxnUUID != update.Txn.ID {
return 0, 0, nil, 0, false, errors.AssertionFailedf(
"unexpected txnID %v != %v while scanning lock table", ltKey.TxnUUID, intent.Txn.ID)
"unexpected txnID %v != %v while scanning lock table", ltKey.TxnUUID, update.Txn.ID)
}
intent.Key = ltKey.Key
update.Key = ltKey.Key
if err := ltIter.ValueProto(&buf.meta); err != nil {
return 0, 0, nil, 0, false, errors.Wrap(err, "unmarshaling lock table value")
}
beforeBytes := rw.BufferedSize()
var outcome lockResolutionOutcome
if ltKey.Strength == lock.Intent {
outcome, err = mvccResolveWriteIntent(ctx, rw, mvccIter, ms, intent, &buf.meta, buf)
outcome, err = mvccResolveWriteIntent(ctx, rw, mvccIter, ms, update, &buf.meta, buf)
} else {
outcome, err = mvccReleaseLockInternal(ctx, rw, ms, intent, ltKey.Strength, &buf.meta, buf)
outcome, err = mvccReleaseLockInternal(ctx, rw, ms, update, ltKey.Strength, &buf.meta, buf)
replLocksReleased = replLocksReleased || outcome != lockNoop
}
if err != nil {
Expand Down

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