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Fix an issue of manual / auto compaction data race

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Summary:
A data race between a manual and an auto compaction can cause a scheduled automatic compaction to be cancelled and never rescheduled again. This may cause a condition of hanging forever. Fix this by always making sure the cancelled compaction is put back to the compaction queue.
Closes https://github.com/facebook/rocksdb/pull/2238

Differential Revision: D4984591

Pulled By: siying

fbshipit-source-id: 3ab153886403c7b991896dcb2158b96cac12f227
This commit is contained in:
Siying Dong 2017-05-02 15:01:07 -07:00 committed by Yi Wu
parent b634fd7162
commit dc0bbf78f7
2 changed files with 52 additions and 6 deletions
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41
db/db_compaction_test.cc
View File

@ -1884,6 +1884,47 @@ TEST_F(DBCompactionTest, L0_CompactionBug_Issue44_b) {
} while (ChangeCompactOptions());
}
TEST_F(DBCompactionTest, ManualAutoRace) {
CreateAndReopenWithCF({"pikachu"}, CurrentOptions());
rocksdb::SyncPoint::GetInstance()->LoadDependency(
{{"DBImpl::BGWorkCompaction", "DBCompactionTest::ManualAutoRace:1"},
{"DBImpl::RunManualCompaction:WaitScheduled",
"BackgroundCallCompaction:0"}});
rocksdb::SyncPoint::GetInstance()->EnableProcessing();
Put(1, "foo", "");
Put(1, "bar", "");
Flush(1);
Put(1, "foo", "");
Put(1, "bar", "");
// Generate four files in CF 0, which should trigger an auto compaction
Put("foo", "");
Put("bar", "");
Flush();
Put("foo", "");
Put("bar", "");
Flush();
Put("foo", "");
Put("bar", "");
Flush();
Put("foo", "");
Put("bar", "");
Flush();
// The auto compaction is scheduled but waited until here
TEST_SYNC_POINT("DBCompactionTest::ManualAutoRace:1");
// The auto compaction will wait until the the manual compaction is registerd
// before processing so that it will be cancelled.
dbfull()->CompactRange(CompactRangeOptions(), handles_[1], nullptr, nullptr);
ASSERT_EQ("0,1", FilesPerLevel(1));
// Eventually the cancelled compaction will be rescheduled and executed.
dbfull()->TEST_WaitForCompact();
ASSERT_EQ("0,1", FilesPerLevel(0));
rocksdb::SyncPoint::GetInstance()->DisableProcessing();
}
TEST_P(DBCompactionTestWithParam, ManualCompaction) {
Options options = CurrentOptions();
options.max_subcompactions = max_subcompactions_;

17
db/db_impl_compaction_flush.cc
View File

@ -826,6 +826,7 @@ Status DBImpl::RunManualCompaction(ColumnFamilyData* cfd, int input_level,
TEST_SYNC_POINT_CALLBACK("DBImpl::RunManualCompaction:NotScheduled", &mutex_);
if (exclusive) {
while (bg_compaction_scheduled_ > 0) {
TEST_SYNC_POINT("DBImpl::RunManualCompaction:WaitScheduled");
ROCKS_LOG_INFO(
immutable_db_options_.info_log,
"[%s] Manual compaction waiting for all other scheduled background "
@ -1392,6 +1393,16 @@ Status DBImpl::BackgroundCompaction(bool* made_progress,
: m->manual_end->DebugString().c_str()));
}
} else if (!compaction_queue_.empty()) {
if (HaveManualCompaction(compaction_queue_.front())) {
// Can't compact right now, but try again later
TEST_SYNC_POINT("DBImpl::BackgroundCompaction()::Conflict");
// Stay in the compaciton queue.
unscheduled_compactions_++;
return Status::OK();
}
// cfd is referenced here
auto cfd = PopFirstFromCompactionQueue();
// We unreference here because the following code will take a Ref() on
@ -1406,12 +1417,6 @@ Status DBImpl::BackgroundCompaction(bool* made_progress,
return Status::OK();
}
if (HaveManualCompaction(cfd)) {
// Can't compact right now, but try again later
TEST_SYNC_POINT("DBImpl::BackgroundCompaction()::Conflict");
return Status::OK();
}
// Pick up latest mutable CF Options and use it throughout the
// compaction job
// Compaction makes a copy of the latest MutableCFOptions. It should be used