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Update DB::AddFile() to have less restrictions

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Summary:
Update DB::AddFile() restrictions to be
  - Key range in loaded table file don't overlap with existing keys or tombstones in DB.
  - No other writes happen during AddFile call.

The updated AddFile() will verify that the file key range don't overlap with any keys or tombstones in the DB, and then add the file to L0

Test Plan: unit tests

Reviewers: igor, rven, anthony, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: adsharma, ameyag, dhruba

Differential Revision: https://reviews.facebook.net/D49233
This commit is contained in:
Islam AbdelRahman 2015-10-30 16:38:10 -07:00
parent 11c71a365a
commit ff4499e297
4 changed files with 175 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
db/db_impl.cc
View File

@ -3274,10 +3274,6 @@ Status DBImpl::AddFile(ColumnFamilyHandle* column_family,
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
ColumnFamilyData* cfd = cfh->cfd();
if (cfd->NumberLevels() <= 1) {
return Status::NotSupported(
"AddFile requires a database with at least 2 levels");
}
if (file_info->version != 1) {
return Status::InvalidArgument("Generated table version is not supported");
}
@ -3324,48 +3320,44 @@ Status DBImpl::AddFile(ColumnFamilyHandle* column_family,
WriteThread::Writer w;
write_thread_.EnterUnbatched(&w, &mutex_);
// Make sure memtables are empty
if (!cfd->mem()->IsEmpty() || cfd->imm()->NumNotFlushed() > 0) {
// Cannot add the file since the keys in memtable
// will hide the keys in file
status = Status::NotSupported("Memtable is not empty");
if (!snapshots_.empty()) {
// Check that no snapshots are being held
status =
Status::NotSupported("Cannot add a file while holding snapshots");
}
// Make sure last sequence number is 0, if there are existing files then
// they should have sequence number = 0
if (status.ok() && versions_->LastSequence() > 0) {
status = Status::NotSupported("Last Sequence number is not zero");
}
auto* vstorage = cfd->current()->storage_info();
if (status.ok()) {
// Make sure that the key range in the file we will add does not overlap
// with previously added files
Slice smallest_user_key = meta.smallest.user_key();
Slice largest_user_key = meta.largest.user_key();
for (int level = 0; level < vstorage->num_non_empty_levels(); level++) {
if (vstorage->OverlapInLevel(level, &smallest_user_key,
&largest_user_key)) {
status = Status::NotSupported("Cannot add overlapping files");
break;
// Verify that added file key range dont overlap with any keys in DB
SuperVersion* sv = cfd->GetSuperVersion()->Ref();
Arena arena;
ReadOptions ro;
ro.total_order_seek = true;
ScopedArenaIterator iter(NewInternalIterator(ro, cfd, sv, &arena));
InternalKey range_start(file_info->smallest_key, kMaxSequenceNumber,
kTypeValue);
iter->Seek(range_start.Encode());
status = iter->status();
if (status.ok() && iter->Valid()) {
ParsedInternalKey seek_result;
if (ParseInternalKey(iter->key(), &seek_result)) {
auto* vstorage = cfd->current()->storage_info();
if (vstorage->InternalComparator()->user_comparator()->Compare(
seek_result.user_key, file_info->largest_key) <= 0) {
status = Status::NotSupported("Cannot add overlapping range");
}
} else {
status = Status::Corruption("DB have corrupted keys");
}
}
}
if (status.ok()) {
// We add the file to the last level
int target_level = cfd->NumberLevels() - 1;
if (cfd->ioptions()->level_compaction_dynamic_level_bytes == false) {
// If we are using dynamic level compaction we add the file to
// last level with files
target_level = vstorage->num_non_empty_levels() - 1;
if (target_level <= 0) {
target_level = 1;
}
}
// Add file to L0
VersionEdit edit;
edit.SetColumnFamily(cfd->GetID());
edit.AddFile(target_level, meta.fd.GetNumber(), meta.fd.GetPathId(),
edit.AddFile(0, meta.fd.GetNumber(), meta.fd.GetPathId(),
meta.fd.GetFileSize(), meta.smallest, meta.largest,
meta.smallest_seqno, meta.largest_seqno,
meta.marked_for_compaction);

148
db/db_test.cc
View File

@ -9602,9 +9602,15 @@ TEST_F(DBTest, AddExternalSstFile) {
ASSERT_EQ(Get(Key(k)), Key(k) + "_val");
}
// Add file using file info
s = db_->AddFile(&file2_info);
ASSERT_TRUE(s.ok()) << s.ToString();
// Add file while holding a snapshot will fail
const Snapshot* s1 = db_->GetSnapshot();
if (s1 != nullptr) {
ASSERT_NOK(db_->AddFile(&file2_info));
db_->ReleaseSnapshot(s1);
}
// We can add the file after releaseing the snapshot
ASSERT_OK(db_->AddFile(&file2_info));
ASSERT_EQ(db_->GetLatestSequenceNumber(), 0U);
for (int k = 0; k < 200; k++) {
ASSERT_EQ(Get(Key(k)), Key(k) + "_val");
@ -9624,9 +9630,8 @@ TEST_F(DBTest, AddExternalSstFile) {
}
ASSERT_NE(db_->GetLatestSequenceNumber(), 0U);
// DB have values in memtable now, we cannot add files anymore
s = db_->AddFile(file5);
ASSERT_FALSE(s.ok()) << s.ToString();
// Key range of file5 (400 => 499) dont overlap with any keys in DB
ASSERT_OK(db_->AddFile(file5));
// Make sure values are correct before and after flush/compaction
for (int i = 0; i < 2; i++) {
@ -9637,13 +9642,37 @@ TEST_F(DBTest, AddExternalSstFile) {
}
ASSERT_EQ(Get(Key(k)), value);
}
for (int k = 400; k < 500; k++) {
std::string value = Key(k) + "_val";
ASSERT_EQ(Get(Key(k)), value);
}
ASSERT_OK(Flush());
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
}
// DB sequence number is not zero, cannot add files anymore
s = db_->AddFile(file5);
ASSERT_FALSE(s.ok()) << s.ToString();
Close();
options.disable_auto_compactions = true;
Reopen(options);
// Delete keys in range (400 => 499)
for (int k = 400; k < 500; k++) {
ASSERT_OK(Delete(Key(k)));
}
// We deleted range (400 => 499) but cannot add file5 because
// of the range tombstones
ASSERT_NOK(db_->AddFile(file5));
// Compacting the DB will remove the tombstones
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
// Now we can add the file
ASSERT_OK(db_->AddFile(file5));
// Verify values of file5 in DB
for (int k = 400; k < 500; k++) {
std::string value = Key(k) + "_val";
ASSERT_EQ(Get(Key(k)), value);
}
} while (ChangeOptions(kSkipPlainTable | kSkipUniversalCompaction |
kSkipFIFOCompaction));
}
@ -9816,6 +9845,107 @@ TEST_F(DBTest, AddExternalSstFileMultiThreaded) {
} while (ChangeOptions(kSkipPlainTable | kSkipUniversalCompaction |
kSkipFIFOCompaction));
}
TEST_F(DBTest, AddExternalSstFileOverlappingRanges) {
std::string sst_files_folder = test::TmpDir(env_) + "/sst_files/";
Random rnd(301);
do {
env_->CreateDir(sst_files_folder);
Options options = CurrentOptions();
DestroyAndReopen(options);
const ImmutableCFOptions ioptions(options);
SstFileWriter sst_file_writer(EnvOptions(), ioptions, options.comparator);
printf("Option config = %d\n", option_config_);
std::vector<std::pair<int, int>> key_ranges;
for (int i = 0; i < 500; i++) {
int range_start = rnd.Uniform(20000);
int keys_per_range = 10 + rnd.Uniform(41);
key_ranges.emplace_back(range_start, range_start + keys_per_range);
}
int memtable_add = 0;
int success_add_file = 0;
int failed_add_file = 0;
std::map<std::string, std::string> true_data;
for (size_t i = 0; i < key_ranges.size(); i++) {
int range_start = key_ranges[i].first;
int range_end = key_ranges[i].second;
Status s;
std::string range_val = "range_" + ToString(i);
// For 20% of ranges we use DB::Put, for 80% we use DB::AddFile
if (i && i % 5 == 0) {
// Use DB::Put to insert range (insert into memtable)
range_val += "_put";
for (int k = range_start; k <= range_end; k++) {
s = Put(Key(k), range_val);
ASSERT_OK(s);
}
memtable_add++;
} else {
// Use DB::AddFile to insert range
range_val += "_add_file";
// Generate the file containing the range
std::string file_name = sst_files_folder + env_->GenerateUniqueId();
ASSERT_OK(sst_file_writer.Open(file_name));
for (int k = range_start; k <= range_end; k++) {
s = sst_file_writer.Add(Key(k), range_val);
ASSERT_OK(s);
}
ExternalSstFileInfo file_info;
s = sst_file_writer.Finish(&file_info);
ASSERT_OK(s);
// Insert the generated file
s = db_->AddFile(&file_info);
auto it = true_data.lower_bound(Key(range_start));
if (it != true_data.end() && it->first <= Key(range_end)) {
// This range overlap with data already exist in DB
ASSERT_NOK(s);
failed_add_file++;
} else {
ASSERT_OK(s);
success_add_file++;
}
}
if (s.ok()) {
// Update true_data map to include the new inserted data
for (int k = range_start; k <= range_end; k++) {
true_data[Key(k)] = range_val;
}
}
// Flush / Compact the DB
if (i && i % 50 == 0) {
Flush();
}
if (i && i % 75 == 0) {
db_->CompactRange(CompactRangeOptions(), nullptr, nullptr);
}
}
printf(
"Total: %zu ranges\n"
"AddFile()|Success: %d ranges\n"
"AddFile()|RangeConflict: %d ranges\n"
"Put(): %d ranges\n",
key_ranges.size(), success_add_file, failed_add_file, memtable_add);
// Verify the correctness of the data
for (const auto& kv : true_data) {
ASSERT_EQ(Get(kv.first), kv.second);
}
printf("keys/values verified\n");
} while (ChangeOptions(kSkipPlainTable | kSkipUniversalCompaction |
kSkipFIFOCompaction));
}
#endif // ROCKSDB_LITE
// 1 Create some SST files by inserting K-V pairs into DB

5
db/version_builder.cc
View File

@ -136,7 +136,10 @@ class VersionBuilder::Rep {
auto f2 = level_files[i];
if (level == 0) {
assert(level_zero_cmp_(f1, f2));
assert(f1->largest_seqno > f2->largest_seqno);
assert(f1->largest_seqno > f2->largest_seqno ||
// We can have multiple files with seqno = 0 as a result of
// using DB::AddFile()
(f1->largest_seqno == 0 && f2->largest_seqno == 0));
} else {
assert(level_nonzero_cmp_(f1, f2));

10
include/rocksdb/db.h
View File

@ -679,13 +679,11 @@ class DB {
// move the file instead of copying it.
//
// Current Requirements:
// (1) Memtable is empty.
// (2) All existing files (if any) have sequence number = 0.
// (3) Key range in loaded table file don't overlap with existing
// files key ranges.
// (4) No other writes happen during AddFile call, otherwise
// (1) Key range in loaded table file don't overlap with
// existing keys or tombstones in DB.
// (2) No other writes happen during AddFile call, otherwise
// DB may get corrupted.
// (5) Database have at least 2 levels.
// (3) No snapshots are held.
virtual Status AddFile(ColumnFamilyHandle* column_family,
const std::string& file_path,
bool move_file = false) = 0;