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Delete files outside the mutex.

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Summary:
The compaction process deletes a large number of files. This takes
quite a bit of time and is best done outside the mutex lock.

Test Plan: make check

Differential Revision: https://reviews.facebook.net/D6123
This commit is contained in:
Dhruba Borthakur 2012-10-21 01:49:48 -07:00
parent 5010daa7a8
commit 4c107587ed
2 changed files with 96 additions and 20 deletions
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101
db/db_impl.cc
View File

@ -84,6 +84,22 @@ struct DBImpl::CompactionState {
}
};
struct DBImpl::DeletionState {
// the set of all live files that cannot be deleted
std::set<uint64_t> live;
// a list of all siles that exists in the db directory
std::vector<std::string> allfiles;
// the current filenumber, lognumber and prevlognumber
// that corresponds to the set of files in 'live'.
uint64_t filenumber, lognumber, prevlognumber;
// the list of all files to be evicted from the table cahce
std::vector<uint64_t> files_to_evict;
};
// Fix user-supplied options to be reasonable
template <class T,class V>
static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
@ -248,7 +264,11 @@ void DBImpl::MaybeIgnoreError(Status* s) const {
}
}
void DBImpl::DeleteObsoleteFiles() {
// Returns the list of live files in 'live' and the list
// of all files in the filesystem in 'allfiles'.
void DBImpl::FindObsoleteFiles(DeletionState& deletion_state) {
mutex_.AssertHeld();
// if deletion is disabled, do nothing
if (disable_delete_obsolete_files_) {
return;
@ -267,39 +287,51 @@ void DBImpl::DeleteObsoleteFiles() {
}
// Make a set of all of the live files
std::set<uint64_t> live = pending_outputs_;
versions_->AddLiveFiles(&live);
deletion_state.live = pending_outputs_;
versions_->AddLiveFiles(&deletion_state.live);
std::vector<std::string> filenames;
env_->GetChildren(dbname_, &filenames); // Ignoring errors on purpose
// set of all files in the directory
env_->GetChildren(dbname_, &deletion_state.allfiles); // Ignore errors
// store the current filenum, lognum, etc
deletion_state.filenumber = versions_->ManifestFileNumber();
deletion_state.lognumber = versions_->LogNumber();
deletion_state.prevlognumber = versions_->PrevLogNumber();
}
// Diffs the files listed in filenames and those that do not
// belong to live files are posibly removed. If the removed file
// is a sst file, then it returns the file number in files_to_evict.
// It is not necesary to hold the mutex when invoking this method.
void DBImpl::PurgeObsoleteFiles(DeletionState& state) {
uint64_t number;
FileType type;
std::vector<std::string> old_log_files;
for (size_t i = 0; i < filenames.size(); i++) {
if (ParseFileName(filenames[i], &number, &type)) {
for (size_t i = 0; i < state.allfiles.size(); i++) {
if (ParseFileName(state.allfiles[i], &number, &type)) {
bool keep = true;
switch (type) {
case kLogFile:
keep = ((number >= versions_->LogNumber()) ||
(number == versions_->PrevLogNumber()));
keep = ((number >= state.lognumber) ||
(number == state.prevlognumber));
break;
case kDescriptorFile:
// Keep my manifest file, and any newer incarnations'
// (in case there is a race that allows other incarnations)
keep = (number >= versions_->ManifestFileNumber());
keep = (number >= state.filenumber);
break;
case kTableFile:
keep = (live.find(number) != live.end());
keep = (state.live.find(number) != state.live.end());
break;
case kTempFile:
// Any temp files that are currently being written to must
// be recorded in pending_outputs_, which is inserted into "live"
keep = (live.find(number) != live.end());
keep = (state.live.find(number) != state.live.end());
break;
case kInfoLogFile:
keep = true;
if (number != 0) {
old_log_files.push_back(filenames[i]);
old_log_files.push_back(state.allfiles[i]);
}
break;
case kCurrentFile:
@ -310,12 +342,13 @@ void DBImpl::DeleteObsoleteFiles() {
if (!keep) {
if (type == kTableFile) {
table_cache_->Evict(number);
// record the files to be evicted from the cache
state.files_to_evict.push_back(number);
}
Log(options_.info_log, "Delete type=%d #%lld\n",
int(type),
static_cast<unsigned long long>(number));
Status st = env_->DeleteFile(dbname_ + "/" + filenames[i]);
Status st = env_->DeleteFile(dbname_ + "/" + state.allfiles[i]);
if(!st.ok()) {
Log(options_.info_log, "Delete type=%d #%lld FAILED\n",
int(type),
@ -339,6 +372,25 @@ void DBImpl::DeleteObsoleteFiles() {
}
}
void DBImpl::EvictObsoleteFiles(DeletionState& state) {
mutex_.AssertHeld();
for (unsigned int i = 0; i < state.files_to_evict.size(); i++) {
table_cache_->Evict(state.files_to_evict[i]);
}
}
void DBImpl::DeleteObsoleteFiles() {
mutex_.AssertHeld();
DeletionState deletion_state;
std::set<uint64_t> live;
std::vector<std::string> allfiles;
std::vector<uint64_t> files_to_evict;
uint64_t filenumber, lognumber, prevlognumber;
FindObsoleteFiles(deletion_state);
PurgeObsoleteFiles(deletion_state);
EvictObsoleteFiles(deletion_state);
}
Status DBImpl::Recover(VersionEdit* edit) {
mutex_.AssertHeld();
@ -587,8 +639,10 @@ Status DBImpl::CompactMemTable() {
imm_->Unref();
imm_ = NULL;
has_imm_.Release_Store(NULL);
DeleteObsoleteFiles();
MaybeScheduleLogDBDeployStats();
// we could have deleted obsolete files here, but it is not
// absolutely necessary because it could be also done as part
// of other background compaction
}
return s;
@ -723,10 +777,11 @@ void DBImpl::BGWork(void* db) {
}
void DBImpl::BackgroundCall() {
DeletionState deletion_state;
MutexLock l(&mutex_);
assert(bg_compaction_scheduled_);
if (!shutting_down_.Acquire_Load()) {
Status s = BackgroundCompaction();
Status s = BackgroundCompaction(deletion_state);
if (!s.ok()) {
// Wait a little bit before retrying background compaction in
// case this is an environmental problem and we do not want to
@ -741,6 +796,14 @@ void DBImpl::BackgroundCall() {
}
}
// delete unnecessary files if any, this is done outside the mutex
if (!deletion_state.live.empty()) {
mutex_.Unlock();
PurgeObsoleteFiles(deletion_state);
mutex_.Lock();
EvictObsoleteFiles(deletion_state);
}
bg_compaction_scheduled_ = false;
MaybeScheduleLogDBDeployStats();
@ -751,7 +814,7 @@ void DBImpl::BackgroundCall() {
bg_cv_.SignalAll();
}
Status DBImpl::BackgroundCompaction() {
Status DBImpl::BackgroundCompaction(DeletionState& deletion_state) {
mutex_.AssertHeld();
if (imm_ != NULL) {
@ -801,7 +864,7 @@ Status DBImpl::BackgroundCompaction() {
status = DoCompactionWork(compact);
CleanupCompaction(compact);
c->ReleaseInputs();
DeleteObsoleteFiles();
FindObsoleteFiles(deletion_state);
}
delete c;

15
db/db_impl.h
View File

@ -81,6 +81,7 @@ class DBImpl : public DB {
friend class DB;
struct CompactionState;
struct Writer;
struct DeletionState;
Iterator* NewInternalIterator(const ReadOptions&,
SequenceNumber* latest_snapshot);
@ -123,7 +124,7 @@ class DBImpl : public DB {
void MaybeScheduleCompaction();
static void BGWork(void* db);
void BackgroundCall();
Status BackgroundCompaction();
Status BackgroundCompaction(DeletionState& deletion_state);
void CleanupCompaction(CompactionState* compact);
Status DoCompactionWork(CompactionState* compact);
@ -131,6 +132,18 @@ class DBImpl : public DB {
Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
Status InstallCompactionResults(CompactionState* compact);
// Returns the list of live files in 'live' and the list
// of all files in the filesystem in 'allfiles'.
void FindObsoleteFiles(DeletionState& deletion_state);
// Diffs the files listed in filenames and those that do not
// belong to live files are posibly removed. If the removed file
// is a sst file, then it returns the file number in files_to_evict.
void PurgeObsoleteFiles(DeletionState& deletion_state);
// Removes the file listed in files_to_evict from the table_cache
void EvictObsoleteFiles(DeletionState& deletion_state);
// Constant after construction
Env* const env_;
const InternalKeyComparator internal_comparator_;