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WriteUnPrepared: Fix bug in savepoints (#5703)

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Summary:
Fix a bug in write unprepared savepoints. When flushing the write batch according to savepoint boundaries, we were forgetting to flush the last write batch after the last savepoint, meaning that some data was not written to DB.

Also, add a small optimization where we avoid flushing empty batches.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5703

Differential Revision: D16811996

Pulled By: lth

fbshipit-source-id: 600c7e0e520ad7a8fad32d77e11d932453e68e3f
This commit is contained in:
Manuel Ung 2019-08-14 16:08:38 -07:00 committed by Facebook Github Bot
parent 0a97125ec0
commit 7785f61132
2 changed files with 38 additions and 12 deletions
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20
utilities/transactions/write_unprepared_transaction_test.cc
View File

@ -621,6 +621,26 @@ TEST_P(WriteUnpreparedTransactionTest, IterateAndWrite) {
}
}
TEST_P(WriteUnpreparedTransactionTest, SavePoint) {
WriteOptions woptions;
TransactionOptions txn_options;
txn_options.write_batch_flush_threshold = 1;
Transaction* txn = db->BeginTransaction(woptions, txn_options);
txn->SetSavePoint();
ASSERT_OK(txn->Put("a", "a"));
ASSERT_OK(txn->Put("b", "b"));
ASSERT_OK(txn->Commit());
ReadOptions roptions;
std::string value;
ASSERT_OK(txn->Get(roptions, "a", &value));
ASSERT_EQ(value, "a");
ASSERT_OK(txn->Get(roptions, "b", &value));
ASSERT_EQ(value, "b");
delete txn;
}
} // namespace rocksdb
int main(int argc, char** argv) {

30
utilities/transactions/write_unprepared_txn.cc
View File

@ -407,10 +407,13 @@ Status WriteUnpreparedTxn::FlushWriteBatchWithSavePointToDB() {
size_t prev_boundary = WriteBatchInternal::kHeader;
const bool kPrepared = true;
for (size_t i = 0; i < unflushed_save_points_->size(); i++) {
for (size_t i = 0; i < unflushed_save_points_->size() + 1; i++) {
bool trailing_batch = i == unflushed_save_points_->size();
SavePointBatchHandler sp_handler(&write_batch_,
*wupt_db_->GetCFHandleMap().get());
size_t curr_boundary = (*unflushed_save_points_)[i];
size_t curr_boundary = trailing_batch
? wb.GetWriteBatch()->GetDataSize()
: (*unflushed_save_points_)[i];
// Construct the partial write batch up to the savepoint.
//
@ -424,18 +427,22 @@ Status WriteUnpreparedTxn::FlushWriteBatchWithSavePointToDB() {
return s;
}
// Flush the write batch.
s = FlushWriteBatchToDBInternal(!kPrepared);
if (!s.ok()) {
return s;
if (write_batch_.GetWriteBatch()->Count() > 0) {
// Flush the write batch.
s = FlushWriteBatchToDBInternal(!kPrepared);
if (!s.ok()) {
return s;
}
}
if (flushed_save_points_ == nullptr) {
flushed_save_points_.reset(
new autovector<WriteUnpreparedTxn::SavePoint>());
if (!trailing_batch) {
if (flushed_save_points_ == nullptr) {
flushed_save_points_.reset(
new autovector<WriteUnpreparedTxn::SavePoint>());
}
flushed_save_points_->emplace_back(
unprep_seqs_, new ManagedSnapshot(db_impl_, wupt_db_->GetSnapshot()));
}
flushed_save_points_->emplace_back(
unprep_seqs_, new ManagedSnapshot(db_impl_, wupt_db_->GetSnapshot()));
prev_boundary = curr_boundary;
const bool kClear = true;
@ -736,7 +743,6 @@ Status WriteUnpreparedTxn::RollbackToSavePointInternal() {
assert(flushed_save_points_->size() > 0);
WriteUnpreparedTxn::SavePoint& top = flushed_save_points_->back();
assert(top.unprep_seqs_.size() > 0);
assert(save_points_ != nullptr && save_points_->size() > 0);
const TransactionKeyMap& tracked_keys = save_points_->top().new_keys_;