Make sure that CompactFiles does not run two parallel Level 0 compactions

Summary:
Since level 0 files can overlap, two level 0 compactions cannot
run in parallel. Compact files needs to check this before running a
compaction.

Test Plan: CompactFilesTest.L0ConflictsFiles

Reviewers: igor, IslamAbdelRahman, anthony, sdong, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D50079
This commit is contained in:
Venkatesh Radhakrishnan 2015-11-13 12:01:00 -08:00
parent d781da8164
commit 2ae4d7d708
4 changed files with 81 additions and 5 deletions

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@ -12,6 +12,7 @@
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "util/string_util.h"
#include "util/sync_point.h"
#include "util/testharness.h"
namespace rocksdb {
@ -53,6 +54,62 @@ class FlushedFileCollector : public EventListener {
std::mutex mutex_;
};
TEST_F(CompactFilesTest, L0ConflictsFiles) {
Options options;
// to trigger compaction more easily
const int kWriteBufferSize = 10000;
const int kLevel0Trigger = 2;
options.create_if_missing = true;
options.compaction_style = kCompactionStyleLevel;
// Small slowdown and stop trigger for experimental purpose.
options.level0_slowdown_writes_trigger = 20;
options.level0_stop_writes_trigger = 20;
options.level0_stop_writes_trigger = 20;
options.write_buffer_size = kWriteBufferSize;
options.level0_file_num_compaction_trigger = kLevel0Trigger;
options.compression = kNoCompression;
DB* db = nullptr;
DestroyDB(db_name_, options);
Status s = DB::Open(options, db_name_, &db);
assert(s.ok());
assert(db);
rocksdb::SyncPoint::GetInstance()->LoadDependency({
{"CompactFilesImpl:0", "BackgroundCallCompaction:0"},
{"BackgroundCallCompaction:1", "CompactFilesImpl:1"},
});
rocksdb::SyncPoint::GetInstance()->EnableProcessing();
// create couple files
// Background compaction starts and waits in BackgroundCallCompaction:0
for (int i = 0; i < kLevel0Trigger * 4; ++i) {
db->Put(WriteOptions(), ToString(i), "");
db->Put(WriteOptions(), ToString(100 - i), "");
db->Flush(FlushOptions());
}
rocksdb::ColumnFamilyMetaData meta;
db->GetColumnFamilyMetaData(&meta);
std::string file1;
for (auto& file : meta.levels[0].files) {
ASSERT_EQ(0, meta.levels[0].level);
if (file1 == "") {
file1 = file.db_path + "/" + file.name;
} else {
std::string file2 = file.db_path + "/" + file.name;
// Another thread starts a compact files and creates an L0 compaction
// The background compaction then notices that there is an L0 compaction
// already in progress and doesn't do an L0 compaction
// Once the background compaction finishes, the compact files finishes
ASSERT_OK(
db->CompactFiles(rocksdb::CompactionOptions(), {file1, file2}, 0));
break;
}
}
delete db;
}
TEST_F(CompactFilesTest, ObsoleteFiles) {
Options options;
// to trigger compaction more easily

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@ -255,16 +255,30 @@ Compaction* CompactionPicker::FormCompaction(
const CompactionOptions& compact_options,
const std::vector<CompactionInputFiles>& input_files, int output_level,
VersionStorageInfo* vstorage, const MutableCFOptions& mutable_cf_options,
uint32_t output_path_id) const {
uint32_t output_path_id) {
uint64_t max_grandparent_overlap_bytes =
output_level + 1 < vstorage->num_levels() ?
mutable_cf_options.MaxGrandParentOverlapBytes(output_level + 1) :
std::numeric_limits<uint64_t>::max();
assert(input_files.size());
return new Compaction(
// TODO(rven ): we might be able to run concurrent level 0 compaction
// if the key ranges of the two compactions do not overlap, but for now
// we do not allow it.
if ((input_files[0].level == 0) && !level0_compactions_in_progress_.empty()) {
return nullptr;
}
auto c = new Compaction(
vstorage, mutable_cf_options, input_files, output_level,
compact_options.output_file_size_limit, max_grandparent_overlap_bytes,
output_path_id, compact_options.compression, /* grandparents */ {}, true);
// If it's level 0 compaction, make sure we don't execute any other level 0
// compactions in parallel
if ((c != nullptr) && (input_files[0].level == 0)) {
level0_compactions_in_progress_.insert(c);
}
return c;
}
Status CompactionPicker::GetCompactionInputsFromFileNumbers(

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@ -94,7 +94,7 @@ class CompactionPicker {
const CompactionOptions& compact_options,
const std::vector<CompactionInputFiles>& input_files, int output_level,
VersionStorageInfo* vstorage, const MutableCFOptions& mutable_cf_options,
uint32_t output_path_id) const;
uint32_t output_path_id);
// Converts a set of compaction input file numbers into
// a list of CompactionInputFiles.

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@ -1772,7 +1772,9 @@ Status DBImpl::CompactFilesImpl(
c.reset(cfd->compaction_picker()->FormCompaction(
compact_options, input_files, output_level, version->storage_info(),
*cfd->GetLatestMutableCFOptions(), output_path_id));
assert(c);
if (!c) {
return Status::Aborted("Another Level 0 compaction is running");
}
c->SetInputVersion(version);
// deletion compaction currently not allowed in CompactFiles.
assert(!c->deletion_compaction());
@ -1801,6 +1803,8 @@ Status DBImpl::CompactFilesImpl(
compaction_job.Prepare();
mutex_.Unlock();
TEST_SYNC_POINT("CompactFilesImpl:0");
TEST_SYNC_POINT("CompactFilesImpl:1");
compaction_job.Run();
mutex_.Lock();
@ -2559,7 +2563,7 @@ void DBImpl::BackgroundCallFlush() {
void DBImpl::BackgroundCallCompaction() {
bool made_progress = false;
JobContext job_context(next_job_id_.fetch_add(1), true);
TEST_SYNC_POINT("BackgroundCallCompaction:0");
MaybeDumpStats();
LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, db_options_.info_log.get());
{
@ -2571,6 +2575,7 @@ void DBImpl::BackgroundCallCompaction() {
assert(bg_compaction_scheduled_);
Status s = BackgroundCompaction(&made_progress, &job_context, &log_buffer);
TEST_SYNC_POINT("BackgroundCallCompaction:1");
if (!s.ok() && !s.IsShutdownInProgress()) {
// Wait a little bit before retrying background compaction in
// case this is an environmental problem and we do not want to