Have a way for compaction filter to ignore snapshots

Summary:
Provide an API for compaction filter to specify that it needs
to be applied even if there are snapshots.

Test Plan: DBTestCompactionFilter.CompactionFilterIgnoreSnapshot

Reviewers: yhchiang, IslamAbdelRahman, sdong, anthony

Reviewed By: anthony

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51087
This commit is contained in:
Venkatesh Radhakrishnan 2015-11-20 15:57:26 -08:00
parent 88e0527724
commit 81be49c755
5 changed files with 117 additions and 1 deletions

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@ -2,6 +2,7 @@
## Unreleased
### New Features
* CompactionFilter has new member function called IgnoreSnapshots which allows CompactionFilter to be called even if there are snapshots later than the key.
* RocksDB will now persist options under the same directory as the RocksDB database on successful DB::Open, CreateColumnFamily, DropColumnFamily, and SetOptions.
* Introduce LoadLatestOptions() in rocksdb/utilities/options_util.h. This function can construct the latest DBOptions / ColumnFamilyOptions used by the specified RocksDB intance.
* Introduce CheckOptionsCompatibility() in rocksdb/utilities/options_util.h. This function checks whether the input set of options is able to open the specified DB successfully.

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@ -42,6 +42,11 @@ CompactionIterator::CompactionIterator(
earliest_snapshot_ = snapshots_->at(0);
latest_snapshot_ = snapshots_->back();
}
if (compaction_filter_ != nullptr && compaction_filter_->IgnoreSnapshots()) {
ignore_snapshots_ = true;
} else {
ignore_snapshots_ = false;
}
}
void CompactionIterator::ResetRecordCounts() {
@ -140,7 +145,8 @@ void CompactionIterator::NextFromInput() {
current_user_key_snapshot_ = 0;
// apply the compaction filter to the first occurrence of the user key
if (compaction_filter_ != nullptr && ikey_.type == kTypeValue &&
(visible_at_tip_ || ikey_.sequence > latest_snapshot_)) {
(visible_at_tip_ || ikey_.sequence > latest_snapshot_ ||
ignore_snapshots_)) {
// If the user has specified a compaction filter and the sequence
// number is greater than any external snapshot, then invoke the
// filter. If the return value of the compaction filter is true,
@ -170,6 +176,9 @@ void CompactionIterator::NextFromInput() {
} else {
// Update the current key to reflect the new sequence number/type without
// copying the user key.
// TODO(rven): Compaction filter does not process keys in this path
// Need to have the compaction filter process multiple versions
// if we have versions on both sides of a snapshot
current_key_.UpdateInternalKey(ikey_.sequence, ikey_.type);
key_ = current_key_.GetKey();
ikey_.user_key = current_key_.GetUserKey();

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@ -98,6 +98,7 @@ class CompactionIterator {
SequenceNumber visible_at_tip_;
SequenceNumber earliest_snapshot_;
SequenceNumber latest_snapshot_;
bool ignore_snapshots_;
// State
//

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@ -47,6 +47,24 @@ class DeleteFilter : public CompactionFilter {
virtual const char* Name() const override { return "DeleteFilter"; }
};
class DeleteISFilter : public CompactionFilter {
public:
virtual bool Filter(int level, const Slice& key, const Slice& value,
std::string* new_value,
bool* value_changed) const override {
cfilter_count++;
int i = std::stoi(key.ToString());
if (i > 5 && i <= 105) {
return true;
}
return false;
}
virtual bool IgnoreSnapshots() const override { return true; }
virtual const char* Name() const override { return "DeleteFilter"; }
};
class DelayFilter : public CompactionFilter {
public:
explicit DelayFilter(DBTestBase* d) : db_test(d) {}
@ -141,6 +159,21 @@ class DeleteFilterFactory : public CompactionFilterFactory {
virtual const char* Name() const override { return "DeleteFilterFactory"; }
};
// Delete Filter Factory which ignores snapshots
class DeleteISFilterFactory : public CompactionFilterFactory {
public:
virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
const CompactionFilter::Context& context) override {
if (context.is_manual_compaction) {
return std::unique_ptr<CompactionFilter>(new DeleteISFilter());
} else {
return std::unique_ptr<CompactionFilter>(nullptr);
}
}
virtual const char* Name() const override { return "DeleteFilterFactory"; }
};
class DelayFilterFactory : public CompactionFilterFactory {
public:
explicit DelayFilterFactory(DBTestBase* d) : db_test(d) {}
@ -620,6 +653,68 @@ TEST_F(DBTestCompactionFilter, CompactionFilterSnapshot) {
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
ASSERT_EQ(0U, CountLiveFiles());
}
// Compaction filters should only be applied to records that are newer than the
// latest snapshot. However, if the compaction filter asks to ignore snapshots
// records newer than the snapshot will also be processed
TEST_F(DBTestCompactionFilter, CompactionFilterIgnoreSnapshot) {
std::string five = ToString(5);
Options options;
options.compaction_filter_factory = std::make_shared<DeleteISFilterFactory>();
options.disable_auto_compactions = true;
options.create_if_missing = true;
options = CurrentOptions(options);
DestroyAndReopen(options);
// Put some data.
const Snapshot* snapshot = nullptr;
for (int table = 0; table < 4; ++table) {
for (int i = 0; i < 10; ++i) {
Put(ToString(table * 100 + i), "val");
}
Flush();
if (table == 0) {
snapshot = db_->GetSnapshot();
}
}
assert(snapshot != nullptr);
cfilter_count = 0;
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
// The filter should delete 40 records.
ASSERT_EQ(40U, cfilter_count);
{
// Scan the entire database as of the snapshot to ensure
// that nothing is left
ReadOptions read_options;
read_options.snapshot = snapshot;
std::unique_ptr<Iterator> iter(db_->NewIterator(read_options));
iter->SeekToFirst();
int count = 0;
while (iter->Valid()) {
count++;
iter->Next();
}
ASSERT_EQ(count, 6);
read_options.snapshot = 0;
std::unique_ptr<Iterator> iter1(db_->NewIterator(read_options));
iter1->SeekToFirst();
count = 0;
while (iter1->Valid()) {
count++;
iter1->Next();
}
// We have deleted 10 keys from 40 using the compaction filter
// Keys 6-9 before the snapshot and 100-105 after the snapshot
ASSERT_EQ(count, 30);
}
// Release the snapshot and compact again -> now all records should be
// removed.
db_->ReleaseSnapshot(snapshot);
}
#endif // ROCKSDB_LITE
} // namespace rocksdb

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@ -98,6 +98,16 @@ class CompactionFilter {
return false;
}
// By default, compaction will only call Filter() on keys written after the
// most recent call to GetSnapshot(). However, if the compaction filter
// overrides IgnoreSnapshots to make it return false, the compaction filter
// will be called even if the keys were written before the last snapshot.
// This behavior is to be used only when we want to delete a set of keys
// irrespective of snapshots. In particular, care should be taken
// to understand that the values of thesekeys will change even if we are
// using a snapshot.
virtual bool IgnoreSnapshots() const { return false; }
// Returns a name that identifies this compaction filter.
// The name will be printed to LOG file on start up for diagnosis.
virtual const char* Name() const = 0;