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Merge branch 'master' into columnfamilies

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This commit is contained in:
Igor Canadi 2014-01-07 11:05:03 -08:00
commit d3a2ba9c64
2 changed files with 44 additions and 34 deletions
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71
db/db_impl.cc
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@ -247,6 +247,7 @@ DBImpl::DBImpl(const Options& options, const std::string& dbname)
super_version_(nullptr),
tmp_batch_(),
bg_compaction_scheduled_(0),
bg_manual_only_(0),
bg_flush_scheduled_(0),
bg_logstats_scheduled_(false),
manual_compaction_(nullptr),
@ -1605,45 +1606,44 @@ void DBImpl::TEST_CompactRange(int level, const Slice* begin,const Slice* end) {
MutexLock l(&mutex_);
// When a manual compaction arrives, temporarily throttle down
// the number of background compaction threads to 1. This is
// needed to ensure that this manual compaction can compact
// any range of keys/files. We artificialy increase
// bg_compaction_scheduled_ by a large number, this causes
// the system to have a single background thread. Now,
// this manual compaction can progress without stomping
// on any other concurrent compactions.
const int LargeNumber = 10000000;
const int newvalue = options_.max_background_compactions-1;
bg_compaction_scheduled_ += LargeNumber;
while (bg_compaction_scheduled_ > LargeNumber) {
Log(options_.info_log, "Manual compaction request waiting for background threads to fall below 1");
// When a manual compaction arrives, temporarily disable scheduling of
// non-manual compactions and wait until the number of scheduled compaction
// jobs drops to zero. This is needed to ensure that this manual compaction
// can compact any range of keys/files.
//
// bg_manual_only_ is non-zero when at least one thread is inside
// TEST_CompactRange(), i.e. during that time no other compaction will
// get scheduled (see MaybeScheduleFlushOrCompaction).
//
// Note that the following loop doesn't stop more that one thread calling
// TEST_CompactRange() from getting to the second while loop below.
// However, only one of them will actually schedule compaction, while
// others will wait on a condition variable until it completes.
++bg_manual_only_;
while (bg_compaction_scheduled_ > 0) {
Log(options_.info_log,
"Manual compaction waiting for all other scheduled background "
"compactions to finish");
bg_cv_.Wait();
}
Log(options_.info_log, "Manual compaction starting");
while (!manual.done) {
while (manual_compaction_ != nullptr) {
bg_cv_.Wait();
}
manual_compaction_ = &manual;
if (bg_compaction_scheduled_ == LargeNumber) {
bg_compaction_scheduled_ = newvalue;
}
MaybeScheduleFlushOrCompaction();
while (manual_compaction_ == &manual) {
while (!manual.done && !shutting_down_.Acquire_Load() && bg_error_.ok()) {
assert(bg_manual_only_ > 0);
if (manual_compaction_ != nullptr) {
// Running either this or some other manual compaction
bg_cv_.Wait();
} else {
manual_compaction_ = &manual;
MaybeScheduleFlushOrCompaction();
}
}
assert(!manual.in_progress);
// wait till there are no background threads scheduled
bg_compaction_scheduled_ += LargeNumber;
while (bg_compaction_scheduled_ > LargeNumber + newvalue) {
Log(options_.info_log, "Manual compaction resetting background threads");
bg_cv_.Wait();
}
bg_compaction_scheduled_ = 0;
assert(!manual.in_progress);
assert(bg_manual_only_ > 0);
--bg_manual_only_;
}
Status DBImpl::FlushMemTable(const FlushOptions& options) {
@ -1708,11 +1708,16 @@ void DBImpl::MaybeScheduleFlushOrCompaction() {
env_->Schedule(&DBImpl::BGWorkFlush, this, Env::Priority::HIGH);
}
// Schedule BGWorkCompaction if there's a compaction pending (or a memtable
// flush, but the HIGH pool is not enabled). Do it only if
// max_background_compactions hasn't been reached and, in case
// bg_manual_only_ > 0, if it's a manual compaction.
if ((manual_compaction_ ||
versions_->NeedsCompaction() ||
(is_flush_pending && (options_.max_background_flushes <= 0))) &&
bg_compaction_scheduled_ < options_.max_background_compactions) {
// compaction needed, or memtable flush needed but HIGH pool not enabled.
bg_compaction_scheduled_ < options_.max_background_compactions &&
(!bg_manual_only_ || manual_compaction_)) {
bg_compaction_scheduled_++;
env_->Schedule(&DBImpl::BGWorkCompaction, this, Env::Priority::LOW);
}

7
db/db_impl.h
View File

@ -425,9 +425,14 @@ class DBImpl : public DB {
// part of ongoing compactions.
std::set<uint64_t> pending_outputs_;
// count how many background compaction been scheduled or is running?
// count how many background compactions are running or have been scheduled
int bg_compaction_scheduled_;
// If non-zero, MaybeScheduleFlushOrCompaction() will only schedule manual
// compactions (if manual_compaction_ is not null). This mechanism enables
// manual compactions to wait until all other compactions are finished.
int bg_manual_only_;
// number of background memtable flush jobs, submitted to the HIGH pool
int bg_flush_scheduled_;