aleesa-bot/aleesa-jabber-go
0
Fork 0
Code Activity

Update deps

Browse Source
This commit is contained in:
eleksir
2024-04-19 21:30:16 +03:00
parent 3b6dd3fdef
commit 442142291c
585 changed files with 21099 additions and 15328 deletions
Download Patch File Download Diff File Expand all files Collapse all files

534
vendor/github.com/cockroachdb/pebble/compaction_iter.go generated vendored
View File

@@ -15,9 +15,9 @@ import (
"github.com/cockroachdb/errors"
"github.com/cockroachdb/pebble/internal/base"
"github.com/cockroachdb/pebble/internal/bytealloc"
"github.com/cockroachdb/pebble/internal/invariants"
"github.com/cockroachdb/pebble/internal/keyspan"
"github.com/cockroachdb/pebble/internal/rangekey"
"github.com/cockroachdb/redact"
)
// compactionIter provides a forward-only iterator that encapsulates the logic
@@ -256,10 +256,12 @@ type compactionIter struct {
// The fragmented range keys.
rangeKeys []keyspan.Span
// Byte allocator for the tombstone keys.
alloc bytealloc.A
allowZeroSeqNum bool
elideTombstone func(key []byte) bool
elideRangeTombstone func(start, end []byte) bool
alloc bytealloc.A
allowZeroSeqNum bool
elideTombstone func(key []byte) bool
elideRangeTombstone func(start, end []byte) bool
ineffectualSingleDeleteCallback func(userKey []byte)
singleDeleteInvariantViolationCallback func(userKey []byte)
// The on-disk format major version. This informs the types of keys that
// may be written to disk during a compaction.
formatVersion FormatMajorVersion
@@ -281,20 +283,24 @@ func newCompactionIter(
allowZeroSeqNum bool,
elideTombstone func(key []byte) bool,
elideRangeTombstone func(start, end []byte) bool,
ineffectualSingleDeleteCallback func(userKey []byte),
singleDeleteInvariantViolationCallback func(userKey []byte),
formatVersion FormatMajorVersion,
) *compactionIter {
i := &compactionIter{
equal: equal,
merge: merge,
iter: iter,
snapshots: snapshots,
frontiers: frontiers{cmp: cmp},
rangeDelFrag: rangeDelFrag,
rangeKeyFrag: rangeKeyFrag,
allowZeroSeqNum: allowZeroSeqNum,
elideTombstone: elideTombstone,
elideRangeTombstone: elideRangeTombstone,
formatVersion: formatVersion,
equal: equal,
merge: merge,
iter: iter,
snapshots: snapshots,
frontiers: frontiers{cmp: cmp},
rangeDelFrag: rangeDelFrag,
rangeKeyFrag: rangeKeyFrag,
allowZeroSeqNum: allowZeroSeqNum,
elideTombstone: elideTombstone,
elideRangeTombstone: elideRangeTombstone,
ineffectualSingleDeleteCallback: ineffectualSingleDeleteCallback,
singleDeleteInvariantViolationCallback: singleDeleteInvariantViolationCallback,
formatVersion: formatVersion,
}
i.rangeDelFrag.Cmp = cmp
i.rangeDelFrag.Format = formatKey
@@ -333,7 +339,7 @@ func (i *compactionIter) Next() (*InternalKey, []byte) {
return nil, nil
}
// Prior to this call to `Next()` we are in one of three situations with
// Prior to this call to `Next()` we are in one of four situations with
// respect to `iterKey` and related state:
//
// - `!skip && pos == iterPosNext`: `iterKey` is already at the next key.
@@ -342,12 +348,34 @@ func (i *compactionIter) Next() (*InternalKey, []byte) {
// snapshot stripe.
// - `skip && pos == iterPosCurForward`: We are at the key that has been returned.
// To move forward we skip skippable entries in the stripe.
// - `skip && pos == iterPosNext && i.iterStripeChange == sameStripeNonSkippable`:
// This case may occur when skipping within a snapshot stripe and we
// encounter either:
// a) an invalid key kind; The previous call will have returned
// whatever key it was processing and deferred handling of the
// invalid key to this invocation of Next(). We're responsible for
// ignoring skip=true and falling into the invalid key kind case
// down below.
// b) an interleaved range delete; This is a wart of the current code
// structure. While skipping within a snapshot stripe, a range
// delete interleaved at its start key and sequence number
// interrupts the sequence of point keys. After we return the range
// delete to the caller, we need to pick up skipping at where we
// left off, so we preserve skip=true.
// TODO(jackson): This last case is confusing and can be removed if we
// interleave range deletions at the maximal sequence number using the
// keyspan interleaving iterator. This is the treatment given to range
// keys today.
if i.pos == iterPosCurForward {
if i.skip {
i.skipInStripe()
} else {
i.nextInStripe()
}
} else if i.skip {
if i.iterStripeChange != sameStripeNonSkippable {
panic(errors.AssertionFailedf("compaction iterator has skip=true, but iterator is at iterPosNext"))
}
}
i.pos = iterPosCurForward
@@ -401,6 +429,10 @@ func (i *compactionIter) Next() (*InternalKey, []byte) {
return &i.key, i.value
}
// TODO(sumeer): we could avoid calling Covers if i.iterStripeChange ==
// sameStripeSameKey since that check has already been done in
// nextInStripeHelper. However, we also need to handle the case of
// CoversInvisibly below.
if cover := i.rangeDelFrag.Covers(*i.iterKey, i.curSnapshotSeqNum); cover == keyspan.CoversVisibly {
// A pending range deletion deletes this key. Skip it.
i.saveKey()
@@ -429,7 +461,17 @@ func (i *compactionIter) Next() (*InternalKey, []byte) {
// If we're at the last snapshot stripe and the tombstone
// can be elided skip skippable keys in the same stripe.
i.saveKey()
i.skipInStripe()
if i.key.Kind() == InternalKeyKindSingleDelete {
i.skipDueToSingleDeleteElision()
} else {
i.skipInStripe()
if !i.skip && i.iterStripeChange != newStripeNewKey {
panic(errors.AssertionFailedf("pebble: skipInStripe in last stripe disabled skip without advancing to new key"))
}
}
if i.iterStripeChange == newStripeSameKey {
panic(errors.AssertionFailedf("pebble: skipInStripe in last stripe found a new stripe within the same key"))
}
continue
} else {
// We're not at the last snapshot stripe, so the tombstone
@@ -456,8 +498,14 @@ func (i *compactionIter) Next() (*InternalKey, []byte) {
case InternalKeyKindSingleDelete:
if i.singleDeleteNext() {
return &i.key, i.value
} else if i.err != nil {
return nil, nil
}
continue
default:
panic(errors.AssertionFailedf(
"unexpected kind %s", redact.SafeString(i.iterKey.Kind().String())))
}
case InternalKeyKindSet, InternalKeyKindSetWithDelete:
@@ -467,6 +515,9 @@ func (i *compactionIter) Next() (*InternalKey, []byte) {
// preserving the original value, and potentially mutating the key
// kind.
i.setNext()
if i.err != nil {
return nil, nil
}
return &i.key, i.value
case InternalKeyKindMerge:
@@ -483,7 +534,15 @@ func (i *compactionIter) Next() (*InternalKey, []byte) {
if i.err == nil {
// includesBase is true whenever we've transformed the MERGE record
// into a SET.
includesBase := i.key.Kind() == InternalKeyKindSet
var includesBase bool
switch i.key.Kind() {
case InternalKeyKindSet, InternalKeyKindSetWithDelete:
includesBase = true
case InternalKeyKindMerge:
default:
panic(errors.AssertionFailedf(
"unexpected kind %s", redact.SafeString(i.key.Kind().String())))
}
i.value, needDelete, i.valueCloser, i.err = finishValueMerger(valueMerger, includesBase)
}
if i.err == nil {
@@ -512,6 +571,8 @@ func (i *compactionIter) Next() (*InternalKey, []byte) {
}
if i.err != nil {
i.valid = false
// TODO(sumeer): why is MarkCorruptionError only being called for
// MERGE?
i.err = base.MarkCorruptionError(i.err)
}
return nil, nil
@@ -551,10 +612,16 @@ func snapshotIndex(seq uint64, snapshots []uint64) (int, uint64) {
return index, snapshots[index]
}
// skipInStripe skips over skippable keys in the same stripe and user key.
// skipInStripe skips over skippable keys in the same stripe and user key. It
// may set i.err, in which case i.iterKey will be nil.
func (i *compactionIter) skipInStripe() {
i.skip = true
// TODO(sumeer): we can avoid the overhead of calling i.rangeDelFrag.Covers,
// in this case of nextInStripe, since we are skipping all of them anyway.
for i.nextInStripe() == sameStripeSkippable {
if i.err != nil {
panic(i.err)
}
}
// Reset skip if we landed outside the original stripe. Otherwise, we landed
// in the same stripe on a non-skippable key. In that case we should preserve
@@ -592,11 +659,17 @@ const (
// nextInStripe advances the iterator and returns one of the above const ints
// indicating how its state changed.
//
// All sameStripeSkippable keys that are covered by a RANGEDEL will be skipped
// and not returned.
//
// Calls to nextInStripe must be preceded by a call to saveKey to retain a
// temporary reference to the original key, so that forward iteration can
// proceed with a reference to the original key. Care should be taken to avoid
// overwriting or mutating the saved key or value before they have been returned
// to the caller of the exported function (i.e. the caller of Next, First, etc.)
//
// nextInStripe may set i.err, in which case the return value will be
// newStripeNewKey, and i.iterKey will be nil.
func (i *compactionIter) nextInStripe() stripeChangeType {
i.iterStripeChange = i.nextInStripeHelper()
return i.iterStripeChange
@@ -605,58 +678,72 @@ func (i *compactionIter) nextInStripe() stripeChangeType {
// nextInStripeHelper is an internal helper for nextInStripe; callers should use
// nextInStripe and not call nextInStripeHelper.
func (i *compactionIter) nextInStripeHelper() stripeChangeType {
if !i.iterNext() {
return newStripeNewKey
}
key := i.iterKey
origSnapshotIdx := i.curSnapshotIdx
for {
if !i.iterNext() {
return newStripeNewKey
}
key := i.iterKey
// NB: The below conditional is an optimization to avoid a user key
// comparison in many cases. Internal keys with the same user key are
// ordered in (strictly) descending order by trailer. If the new key has a
// greater or equal trailer, or the previous key had a zero sequence number,
// the new key must have a new user key.
//
// A couple things make these cases common:
// - Sequence-number zeroing ensures ~all of the keys in L6 have a zero
// sequence number.
// - Ingested sstables' keys all adopt the same sequence number.
if i.keyTrailer <= base.InternalKeyZeroSeqnumMaxTrailer || key.Trailer >= i.keyTrailer {
if invariants.Enabled && i.equal(i.key.UserKey, key.UserKey) {
if !i.equal(i.key.UserKey, key.UserKey) {
i.curSnapshotIdx, i.curSnapshotSeqNum = snapshotIndex(key.SeqNum(), i.snapshots)
return newStripeNewKey
}
// If i.key and key have the same user key, then
// 1. i.key must not have had a zero sequence number (or it would've be the last
// key with its user key).
// 2. i.key must have a strictly larger sequence number
// There's an exception in that either key may be a range delete. Range
// deletes may share a sequence number with a point key if the keys were
// ingested together. Range keys may also share the sequence number if they
// were ingested, but range keys are interleaved into the compaction
// iterator's input iterator at the maximal sequence number so their
// original sequence number will not be observed here.
if prevSeqNum := base.SeqNumFromTrailer(i.keyTrailer); (prevSeqNum == 0 || prevSeqNum <= key.SeqNum()) &&
i.key.Kind() != InternalKeyKindRangeDelete && key.Kind() != InternalKeyKindRangeDelete {
prevKey := i.key
prevKey.Trailer = i.keyTrailer
panic(fmt.Sprintf("pebble: invariant violation: %s and %s out of order", key, prevKey))
panic(errors.AssertionFailedf("pebble: invariant violation: %s and %s out of order", prevKey, key))
}
i.curSnapshotIdx, i.curSnapshotSeqNum = snapshotIndex(key.SeqNum(), i.snapshots)
return newStripeNewKey
} else if !i.equal(i.key.UserKey, key.UserKey) {
i.curSnapshotIdx, i.curSnapshotSeqNum = snapshotIndex(key.SeqNum(), i.snapshots)
return newStripeNewKey
}
origSnapshotIdx := i.curSnapshotIdx
i.curSnapshotIdx, i.curSnapshotSeqNum = snapshotIndex(key.SeqNum(), i.snapshots)
switch key.Kind() {
case InternalKeyKindRangeDelete:
// Range tombstones need to be exposed by the compactionIter to the upper level
// `compaction` object, so return them regardless of whether they are in the same
// snapshot stripe.
if i.curSnapshotIdx == origSnapshotIdx {
return sameStripeNonSkippable
switch key.Kind() {
case InternalKeyKindRangeDelete:
// Range tombstones need to be exposed by the compactionIter to the upper level
// `compaction` object, so return them regardless of whether they are in the same
// snapshot stripe.
if i.curSnapshotIdx == origSnapshotIdx {
return sameStripeNonSkippable
}
return newStripeSameKey
case InternalKeyKindRangeKeySet, InternalKeyKindRangeKeyUnset, InternalKeyKindRangeKeyDelete:
// Range keys are interleaved at the max sequence number for a given user
// key, so we should not see any more range keys in this stripe.
panic("unreachable")
case InternalKeyKindInvalid:
if i.curSnapshotIdx == origSnapshotIdx {
return sameStripeNonSkippable
}
return newStripeSameKey
case InternalKeyKindDelete, InternalKeyKindSet, InternalKeyKindMerge, InternalKeyKindSingleDelete,
InternalKeyKindSetWithDelete, InternalKeyKindDeleteSized:
// Fall through
default:
i.iterKey = nil
i.err = base.CorruptionErrorf("invalid internal key kind: %d", errors.Safe(i.iterKey.Kind()))
i.valid = false
return newStripeNewKey
}
return newStripeSameKey
case InternalKeyKindRangeKeySet, InternalKeyKindRangeKeyUnset, InternalKeyKindRangeKeyDelete:
// Range keys are interleaved at the max sequence number for a given user
// key, so we should not see any more range keys in this stripe.
panic("unreachable")
case InternalKeyKindInvalid:
if i.curSnapshotIdx == origSnapshotIdx {
return sameStripeNonSkippable
// Same snapshot.
if i.rangeDelFrag.Covers(*i.iterKey, i.curSnapshotSeqNum) == keyspan.CoversVisibly {
continue
}
return sameStripeSkippable
}
return newStripeSameKey
}
if i.curSnapshotIdx == origSnapshotIdx {
return sameStripeSkippable
}
return newStripeSameKey
}
func (i *compactionIter) setNext() {
@@ -682,6 +769,10 @@ func (i *compactionIter) setNext() {
// Else, we continue to loop through entries in the stripe looking for a
// DEL. Note that we may stop *before* encountering a DEL, if one exists.
//
// NB: nextInStripe will skip sameStripeSkippable keys that are visibly
// covered by a RANGEDEL. This can include DELs -- this is fine since such
// DELs don't need to be combined with SET to make SETWITHDEL.
for {
switch i.nextInStripe() {
case newStripeNewKey, newStripeSameKey:
@@ -732,12 +823,16 @@ func (i *compactionIter) setNext() {
// We're still in the same stripe. If this is a
// DEL/SINGLEDEL/DELSIZED, we stop looking and emit a SETWITHDEL.
// Subsequent keys are eligible for skipping.
if i.iterKey.Kind() == InternalKeyKindDelete ||
i.iterKey.Kind() == InternalKeyKindSingleDelete ||
i.iterKey.Kind() == InternalKeyKindDeleteSized {
switch i.iterKey.Kind() {
case InternalKeyKindDelete, InternalKeyKindSingleDelete, InternalKeyKindDeleteSized:
i.key.SetKind(InternalKeyKindSetWithDelete)
i.skip = true
return
case InternalKeyKindSet, InternalKeyKindMerge, InternalKeyKindSetWithDelete:
// Do nothing
default:
i.err = base.CorruptionErrorf("invalid internal key kind: %d", errors.Safe(i.iterKey.Kind()))
i.valid = false
}
default:
panic("pebble: unexpected stripeChangeType: " + strconv.Itoa(int(i.iterStripeChange)))
@@ -757,13 +852,24 @@ func (i *compactionIter) mergeNext(valueMerger ValueMerger) stripeChangeType {
i.pos = iterPosNext
return i.iterStripeChange
}
if i.err != nil {
panic(i.err)
}
// NB: MERGE#10+RANGEDEL#9 stays a MERGE, since nextInStripe skips
// sameStripeSkippable keys that are visibly covered by a RANGEDEL. There
// may be MERGE#7 that is invisibly covered and will be preserved, but
// there is no risk that MERGE#10 and MERGE#7 will get merged in the
// future as the RANGEDEL still exists and will be used in user-facing
// reads that see MERGE#10, and will also eventually cause MERGE#7 to be
// deleted in a compaction.
key := i.iterKey
switch key.Kind() {
case InternalKeyKindDelete, InternalKeyKindSingleDelete, InternalKeyKindDeleteSized:
// We've hit a deletion tombstone. Return everything up to this point and
// then skip entries until the next snapshot stripe. We change the kind
// of the result key to a Set so that it shadows keys in lower
// levels. That is, MERGE+DEL -> SET.
// levels. That is, MERGE+DEL -> SETWITHDEL.
//
// We do the same for SingleDelete since SingleDelete is only
// permitted (with deterministic behavior) for keys that have been
// set once since the last SingleDelete/Delete, so everything
@@ -776,21 +882,11 @@ func (i *compactionIter) mergeNext(valueMerger ValueMerger) stripeChangeType {
// single Set, and then merge in any following Sets, but that is
// complicated wrt code and unnecessary given the narrow permitted
// use of SingleDelete.
i.key.SetKind(InternalKeyKindSet)
i.key.SetKind(InternalKeyKindSetWithDelete)
i.skip = true
return sameStripeSkippable
case InternalKeyKindSet, InternalKeyKindSetWithDelete:
if i.rangeDelFrag.Covers(*key, i.curSnapshotSeqNum) == keyspan.CoversVisibly {
// We change the kind of the result key to a Set so that it shadows
// keys in lower levels. That is, MERGE+RANGEDEL -> SET. This isn't
// strictly necessary, but provides consistency with the behavior of
// MERGE+DEL.
i.key.SetKind(InternalKeyKindSet)
i.skip = true
return sameStripeSkippable
}
// We've hit a Set or SetWithDel value. Merge with the existing
// value and return. We change the kind of the resulting key to a
// Set so that it shadows keys in lower levels. That is:
@@ -805,16 +901,6 @@ func (i *compactionIter) mergeNext(valueMerger ValueMerger) stripeChangeType {
return sameStripeSkippable
case InternalKeyKindMerge:
if i.rangeDelFrag.Covers(*key, i.curSnapshotSeqNum) == keyspan.CoversVisibly {
// We change the kind of the result key to a Set so that it shadows
// keys in lower levels. That is, MERGE+RANGEDEL -> SET. This isn't
// strictly necessary, but provides consistency with the behavior of
// MERGE+DEL.
i.key.SetKind(InternalKeyKindSet)
i.skip = true
return sameStripeSkippable
}
// We've hit another Merge value. Merge with the existing value and
// continue looping.
i.err = valueMerger.MergeOlder(i.iterValue)
@@ -831,6 +917,16 @@ func (i *compactionIter) mergeNext(valueMerger ValueMerger) stripeChangeType {
}
}
// singleDeleteNext processes a SingleDelete point tombstone. A SingleDelete, or
// SINGLEDEL, is unique in that it deletes exactly 1 internal key. It's a
// performance optimization when the client knows a user key has not been
// overwritten, allowing the elision of the tombstone earlier, avoiding write
// amplification.
//
// singleDeleteNext returns a boolean indicating whether or not the caller
// should yield the SingleDelete key to the consumer of the compactionIter. If
// singleDeleteNext returns false, the caller may consume/elide the
// SingleDelete.
func (i *compactionIter) singleDeleteNext() bool {
// Save the current key.
i.saveKey()
@@ -839,26 +935,85 @@ func (i *compactionIter) singleDeleteNext() bool {
// Loop until finds a key to be passed to the next level.
for {
// If we find a key that can't be skipped, return true so that the
// caller yields the SingleDelete to the caller.
if i.nextInStripe() != sameStripeSkippable {
// This defers additional error checking regarding single delete
// invariants to the compaction where the keys with the same user key as
// the single delete are in the same stripe.
i.pos = iterPosNext
return true
return i.err == nil
}
if i.err != nil {
panic(i.err)
}
// INVARIANT: sameStripeSkippable.
key := i.iterKey
switch key.Kind() {
case InternalKeyKindDelete, InternalKeyKindMerge, InternalKeyKindSetWithDelete, InternalKeyKindDeleteSized:
// We've hit a Delete, DeleteSized, Merge, SetWithDelete, transform
kind := key.Kind()
switch kind {
case InternalKeyKindDelete, InternalKeyKindSetWithDelete, InternalKeyKindDeleteSized:
if (kind == InternalKeyKindDelete || kind == InternalKeyKindDeleteSized) &&
i.ineffectualSingleDeleteCallback != nil {
i.ineffectualSingleDeleteCallback(i.key.UserKey)
}
// We've hit a Delete, DeleteSized, SetWithDelete, transform
// the SingleDelete into a full Delete.
i.key.SetKind(InternalKeyKindDelete)
i.skip = true
return true
case InternalKeyKindSet:
i.nextInStripe()
case InternalKeyKindSet, InternalKeyKindMerge:
// This SingleDelete deletes the Set/Merge, and we can now elide the
// SingleDel as well. We advance past the Set and return false to
// indicate to the main compaction loop that we should NOT yield the
// current SingleDel key to the compaction loop.
//
// NB: singleDeleteNext was called with i.pos == iterPosCurForward, and
// after the call to nextInStripe, we are still at iterPosCurForward,
// since we are at the key after the Set/Merge that was single deleted.
change := i.nextInStripe()
switch change {
case sameStripeSkippable, newStripeSameKey:
// On the same user key.
nextKind := i.iterKey.Kind()
switch nextKind {
case InternalKeyKindSet, InternalKeyKindSetWithDelete, InternalKeyKindMerge:
if i.singleDeleteInvariantViolationCallback != nil {
// sameStripeSkippable keys returned by nextInStripe() are already
// known to not be covered by a RANGEDEL, so it is an invariant
// violation. The rare case is newStripeSameKey, where it is a
// violation if not covered by a RANGEDEL.
if change == sameStripeSkippable ||
i.rangeDelFrag.Covers(*i.iterKey, i.curSnapshotSeqNum) == keyspan.NoCover {
i.singleDeleteInvariantViolationCallback(i.key.UserKey)
}
}
case InternalKeyKindDelete, InternalKeyKindDeleteSized, InternalKeyKindSingleDelete,
InternalKeyKindRangeDelete:
default:
panic(errors.AssertionFailedf(
"unexpected internal key kind: %d", errors.Safe(i.iterKey.Kind())))
}
case sameStripeNonSkippable:
// No ability to check whether there is another Set/Merge below with
// the same user key.
//
// TODO(sumeer): once range deletions are interleaved at the maximal
// sequence number, this case will go away.
case newStripeNewKey:
default:
panic("unreachable")
}
i.valid = false
return false
case InternalKeyKindSingleDelete:
// Two single deletes met in a compaction. The first single delete is
// ineffectual.
if i.ineffectualSingleDeleteCallback != nil {
i.ineffectualSingleDeleteCallback(i.key.UserKey)
}
// Continue to apply the second single delete.
continue
default:
@@ -869,6 +1024,135 @@ func (i *compactionIter) singleDeleteNext() bool {
}
}
// skipDueToSingleDeleteElision is called when the SingleDelete is being
// elided because it is in the final snapshot stripe and there are no keys
// with the same user key in lower levels in the LSM (below the files in this
// compaction).
//
// TODO(sumeer): the only difference between singleDeleteNext and
// skipDueToSingleDeleteElision is the fact that the caller knows it will be
// eliding the single delete in the latter case. There are some similar things
// happening in both implementations. My first attempt at combining them into
// a single method was hard to comprehend. Try again.
func (i *compactionIter) skipDueToSingleDeleteElision() {
for {
stripeChange := i.nextInStripe()
if i.err != nil {
panic(i.err)
}
switch stripeChange {
case newStripeNewKey:
// The single delete is only now being elided, meaning it did not elide
// any keys earlier in its descent down the LSM. We stepped onto a new
// user key, meaning that even now at its moment of elision, it still
// hasn't elided any other keys. The single delete was ineffectual (a
// no-op).
if i.ineffectualSingleDeleteCallback != nil {
i.ineffectualSingleDeleteCallback(i.key.UserKey)
}
i.skip = false
return
case newStripeSameKey:
// This should be impossible. If we're eliding a single delete, we
// determined that the tombstone is in the final snapshot stripe, but we
// stepped into a new stripe of the same key.
panic(errors.AssertionFailedf("eliding single delete followed by same key in new stripe"))
case sameStripeNonSkippable:
// There's a key that we cannot skip. There are two possible cases:
// a. The key is invalid. This is an error.
// b. The key is a range deletion.
// The second case may also be an ineffectual single delete. However, it
// is possible that there is a SET that is at the same seqnum as the
// RANGEDEL, and so is not deleted by that RANGEDEL, and will be deleted
// by this single delete. So we cannot be certain that this is an
// ineffectual single delete.
//
// TODO(sumeer): the existing todo to interleave range deletions at the
// maximal sequence number will allow us to address this ambiguity.
//
// TODO(sumeer): by setting skip to true, the compactionIter is making a
// single delete stronger (like a del), which will hide bugs in the use of
// single delete.
i.skip = true
return
case sameStripeSkippable:
kind := i.iterKey.Kind()
switch kind {
case InternalKeyKindDelete, InternalKeyKindDeleteSized, InternalKeyKindSingleDelete:
if i.ineffectualSingleDeleteCallback != nil {
i.ineffectualSingleDeleteCallback(i.key.UserKey)
}
switch kind {
case InternalKeyKindDelete, InternalKeyKindDeleteSized:
i.skipInStripe()
return
case InternalKeyKindSingleDelete:
// Repeat the same with this SingleDelete. We don't want to simply
// call skipInStripe(), since it increases the strength of the
// SingleDel, which hides bugs in the use of single delete.
continue
default:
panic(errors.AssertionFailedf(
"unexpected internal key kind: %d", errors.Safe(i.iterKey.Kind())))
}
case InternalKeyKindSetWithDelete:
// The SingleDelete should behave like a Delete.
i.skipInStripe()
return
case InternalKeyKindSet, InternalKeyKindMerge:
// This SingleDelete deletes the Set/Merge, and we are eliding the
// SingleDel as well. Step to the next key (this is not deleted by the
// SingleDelete).
//
// NB: skipDueToSingleDeleteElision was called with i.pos ==
// iterPosCurForward, and after the call to nextInStripe, we are still
// at iterPosCurForward, since we are at the key after the Set/Merge
// that was single deleted.
change := i.nextInStripe()
if i.err != nil {
panic(i.err)
}
switch change {
case newStripeSameKey:
panic(errors.AssertionFailedf("eliding single delete followed by same key in new stripe"))
case newStripeNewKey:
case sameStripeSkippable:
// On the same key.
nextKind := i.iterKey.Kind()
switch nextKind {
case InternalKeyKindSet, InternalKeyKindSetWithDelete, InternalKeyKindMerge:
if i.singleDeleteInvariantViolationCallback != nil {
i.singleDeleteInvariantViolationCallback(i.key.UserKey)
}
case InternalKeyKindDelete, InternalKeyKindDeleteSized, InternalKeyKindSingleDelete,
InternalKeyKindRangeDelete:
default:
panic(errors.AssertionFailedf(
"unexpected internal key kind: %d", errors.Safe(i.iterKey.Kind())))
}
case sameStripeNonSkippable:
// No ability to check whether there is another Set/Merge below with
// the same user key.
//
// TODO(sumeer): once range deletions are interleaved at the maximal
// sequence number, this case will go away.
default:
panic("unreachable")
}
// Whether in same stripe or new stripe, this key is not consumed by
// the SingleDelete.
i.skip = false
return
default:
panic(errors.AssertionFailedf(
"unexpected internal key kind: %d", errors.Safe(i.iterKey.Kind())))
}
default:
panic("unreachable")
}
}
}
// deleteSizedNext processes a DELSIZED point tombstone. Unlike ordinary DELs,
// these tombstones carry a value that's a varint indicating the size of the
// entry (len(key)+len(value)) that the tombstone is expected to delete.
@@ -894,8 +1178,11 @@ func (i *compactionIter) deleteSizedNext() (*base.InternalKey, []byte) {
// Loop through all the keys within this stripe that are skippable.
i.pos = iterPosNext
for i.nextInStripe() == sameStripeSkippable {
if i.err != nil {
panic(i.err)
}
switch i.iterKey.Kind() {
case InternalKeyKindDelete, InternalKeyKindDeleteSized:
case InternalKeyKindDelete, InternalKeyKindDeleteSized, InternalKeyKindSingleDelete:
// We encountered a tombstone (DEL, or DELSIZED) that's deleted by
// the original DELSIZED tombstone. This can happen in two cases:
//
@@ -917,8 +1204,8 @@ func (i *compactionIter) deleteSizedNext() (*base.InternalKey, []byte) {
// We can differentiate these two cases by examining the length of
// the DELSIZED's value. A DELSIZED's value holds the size of both
// the user key and value that it intends to delete. For any user
// key with a length > 1, a DELSIZED that has not deleted a key must
// have a value with a length > 1.
// key with a length > 0, a DELSIZED that has not deleted a key must
// have a value with a length > 0.
//
// We treat both cases the same functionally, adopting the identity
// of the lower-sequence numbered tombstone. However in the second
@@ -930,20 +1217,28 @@ func (i *compactionIter) deleteSizedNext() (*base.InternalKey, []byte) {
}
i.valueBuf = append(i.valueBuf[:0], i.iterValue...)
i.value = i.valueBuf
if i.iterKey.Kind() == InternalKeyKindDelete {
// Convert the DELSIZED to a DEL—The DEL we're eliding may not
// have deleted the key(s) it was intended to yet. The ordinary
// DEL compaction heuristics are better suited at that, plus we
// don't want to count it as a missized DEL. We early exit in
// this case, after skipping the remainder of the snapshot
// stripe.
i.key.SetKind(i.iterKey.Kind())
if i.iterKey.Kind() != InternalKeyKindDeleteSized {
// Convert the DELSIZED to a DEL—The DEL/SINGLEDEL we're eliding
// may not have deleted the key(s) it was intended to yet. The
// ordinary DEL compaction heuristics are better suited at that,
// plus we don't want to count it as a missized DEL. We early
// exit in this case, after skipping the remainder of the
// snapshot stripe.
i.key.SetKind(InternalKeyKindDelete)
// NB: We skipInStripe now, rather than returning leaving
// i.skip=true and returning early, because Next() requires
// that i.skip=true only if i.iterPos = iterPosCurForward.
//
// Ignore any error caused by skipInStripe since it does not affect
// the key/value being returned here, and the next call to Next() will
// expose it.
i.skipInStripe()
return &i.key, i.value
}
// Continue, in case we uncover another DELSIZED or a key this
// DELSIZED deletes.
default:
case InternalKeyKindSet, InternalKeyKindMerge, InternalKeyKindSetWithDelete:
// If the DELSIZED is value-less, it already deleted the key that it
// was intended to delete. This is possible with a sequence like:
//
@@ -955,6 +1250,13 @@ func (i *compactionIter) deleteSizedNext() (*base.InternalKey, []byte) {
// the snapshot stripe and return.
if len(i.value) == 0 {
i.key.SetKind(InternalKeyKindDelete)
// NB: We skipInStripe now, rather than returning leaving
// i.skip=true and returning early, because Next() requires
// that i.skip=true only if i.iterPos = iterPosCurForward.
//
// Ignore any error caused by skipInStripe since it does not affect
// the key/value being returned here, and the next call to Next() will
// expose it.
i.skipInStripe()
return &i.key, i.value
}
@@ -982,13 +1284,28 @@ func (i *compactionIter) deleteSizedNext() (*base.InternalKey, []byte) {
// We opt for (4) under the rationale that we can't rely on the
// user-provided size for accuracy, so ordinary DEL heuristics
// are safer.
i.key.SetKind(InternalKeyKindDelete)
i.stats.countMissizedDels++
i.key.SetKind(InternalKeyKindDelete)
i.value = i.valueBuf[:0]
// NB: We skipInStripe now, rather than returning leaving
// i.skip=true and returning early, because Next() requires
// that i.skip=true only if i.iterPos = iterPosCurForward.
//
// Ignore any error caused by skipInStripe since it does not affect
// the key/value being returned here, and the next call to Next() will
// expose it.
i.skipInStripe()
return &i.key, i.value
}
// NB: We remove the value regardless of whether the key was sized
// appropriately. The size encoded is 'consumed' the first time it
// meets a key that it deletes.
i.value = i.valueBuf[:0]
default:
i.err = base.CorruptionErrorf("invalid internal key kind: %d", errors.Safe(i.iterKey.Kind()))
i.valid = false
return nil, nil
}
}
// Reset skip if we landed outside the original stripe. Otherwise, we landed
@@ -998,6 +1315,9 @@ func (i *compactionIter) deleteSizedNext() (*base.InternalKey, []byte) {
if i.iterStripeChange == newStripeNewKey || i.iterStripeChange == newStripeSameKey {
i.skip = false
}
if i.err != nil {
return nil, nil
}
return &i.key, i.value
}