bool PessimisticTxnManager::PerformRead(const oid_t &tile_group_id,
const oid_t &tuple_id) {
LOG_TRACE("Perform read");
auto &manager = catalog::Manager::GetInstance();
auto tile_group = manager.GetTileGroup(tile_group_id);
auto tile_group_header = tile_group->GetHeader();
auto &rw_set = current_txn->GetRWSet();
auto tuple_map = rw_set.find(tile_group_id);
if (tuple_map != rw_set.end()) {
if (tuple_map->second.find(tuple_id) != tuple_map->second.end()) {
// It was already accessed, don't acquire read lock again
return true;
}
}
if (IsOwner(tile_group_header, tuple_id)) {
return true;
}
// Try to acquire read lock.
auto old_txn_id = tile_group_header->GetTransactionId(tuple_id);
// No one is holding the write lock
if (EXTRACT_TXNID(old_txn_id) == INITIAL_TXN_ID) {
LOG_TRACE("No one holding the lock");
while (true) {
LOG_TRACE("Current read count is %lu", EXTRACT_READ_COUNT(old_txn_id));
auto new_read_count = EXTRACT_READ_COUNT(old_txn_id) + 1;
// Try add read count
auto new_txn_id = PACK_TXNID(INITIAL_TXN_ID, new_read_count);
LOG_TRACE("New txn id %lx", new_txn_id);
txn_id_t real_txn_id = tile_group_header->SetAtomicTransactionId(
tuple_id, old_txn_id, new_txn_id);
if (real_txn_id != old_txn_id) {
// See if there's writer
if (EXTRACT_TXNID(real_txn_id) != INITIAL_TXN_ID) return false;
} else {
break;
}
}
} else {
// SetTransactionResult(RESULT_FAILURE);
return false;
}
current_txn->RecordRead(tile_group_id, tuple_id);
return true;
}
bool IndexScanExecutor::ExecPrimaryIndexLookup() {
PL_ASSERT(!done_);
std::vector<ItemPointer *> tuple_location_ptrs;
PL_ASSERT(index_->GetIndexType() == INDEX_CONSTRAINT_TYPE_PRIMARY_KEY);
if (0 == key_column_ids_.size()) {
index_->ScanAllKeys(tuple_location_ptrs);
} else {
index_->Scan(values_, key_column_ids_, expr_types_,
SCAN_DIRECTION_TYPE_FORWARD, tuple_location_ptrs);
}
if (tuple_location_ptrs.size() == 0) return false;
auto &transaction_manager =
concurrency::TransactionManagerFactory::GetInstance();
std::map<oid_t, std::vector<oid_t>> visible_tuples;
std::vector<ItemPointer> garbage_tuples;
// for every tuple that is found in the index.
for (auto tuple_location_ptr : tuple_location_ptrs) {
ItemPointer tuple_location = *tuple_location_ptr;
auto &manager = catalog::Manager::GetInstance();
auto tile_group = manager.GetTileGroup(tuple_location.block);
auto tile_group_header = tile_group.get()->GetHeader();
size_t chain_length = 0;
while (true) {
++chain_length;
// if the tuple is visible.
if (transaction_manager.IsVisible(tile_group_header,
tuple_location.offset)) {
LOG_TRACE("traverse chain length : %lu", chain_length);
LOG_TRACE("perform read: %u, %u", tuple_location.block,
tuple_location.offset);
// perform predicate evaluation.
if (predicate_ == nullptr) {
visible_tuples[tuple_location.block].push_back(tuple_location.offset);
auto res = transaction_manager.PerformRead(tuple_location);
if (!res) {
transaction_manager.SetTransactionResult(RESULT_FAILURE);
return res;
}
} else {
expression::ContainerTuple<storage::TileGroup> tuple(
tile_group.get(), tuple_location.offset);
auto eval =
predicate_->Evaluate(&tuple, nullptr, executor_context_).IsTrue();
if (eval == true) {
visible_tuples[tuple_location.block]
.push_back(tuple_location.offset);
auto res = transaction_manager.PerformRead(tuple_location);
if (!res) {
transaction_manager.SetTransactionResult(RESULT_FAILURE);
return res;
}
}
}
break;
}
// if the tuple is not visible.
else {
ItemPointer old_item = tuple_location;
cid_t old_end_cid = tile_group_header->GetEndCommitId(old_item.offset);
tuple_location = tile_group_header->GetNextItemPointer(old_item.offset);
// there must exist a visible version.
// FIXME: currently, only speculative read transaction manager **may** see a null version
// it's a potential bug
if(tuple_location.IsNull()) {
transaction_manager.SetTransactionResult(RESULT_FAILURE);
// FIXME: this cause unnecessary abort when we have delete operations
return false;
}
// FIXME: Is this always true? what if we have a deleted tuple? --jiexi
PL_ASSERT(tuple_location.IsNull() == false);
cid_t max_committed_cid = transaction_manager.GetMaxCommittedCid();
// check whether older version is garbage.
if (old_end_cid <= max_committed_cid) {
PL_ASSERT(tile_group_header->GetTransactionId(old_item.offset) == INITIAL_TXN_ID ||
tile_group_header->GetTransactionId(old_item.offset) == INVALID_TXN_ID);
if (tile_group_header->SetAtomicTransactionId(old_item.offset, INVALID_TXN_ID) == true) {
// atomically swap item pointer held in the index bucket.
AtomicUpdateItemPointer(tuple_location_ptr, tuple_location);
// currently, let's assume only primary index exists.
// gc::GCManagerFactory::GetInstance().RecycleTupleSlot(
// table_->GetOid(), old_item.block, old_item.offset,
// transaction_manager.GetNextCommitId());
garbage_tuples.push_back(old_item);
tile_group = manager.GetTileGroup(tuple_location.block);
tile_group_header = tile_group.get()->GetHeader();
tile_group_header->SetPrevItemPointer(tuple_location.offset, INVALID_ITEMPOINTER);
} else {
tile_group = manager.GetTileGroup(tuple_location.block);
tile_group_header = tile_group.get()->GetHeader();
}
} else {
tile_group = manager.GetTileGroup(tuple_location.block);
tile_group_header = tile_group.get()->GetHeader();
}
}
}
}
// Add all garbage tuples to GC manager
if(garbage_tuples.size() != 0) {
cid_t garbage_timestamp = transaction_manager.GetNextCommitId();
for (auto garbage : garbage_tuples) {
gc::GCManagerFactory::GetInstance().RecycleTupleSlot(
table_->GetOid(), garbage.block, garbage.offset, garbage_timestamp);
}
}
// Construct a logical tile for each block
for (auto tuples : visible_tuples) {
auto &manager = catalog::Manager::GetInstance();
auto tile_group = manager.GetTileGroup(tuples.first);
std::unique_ptr<LogicalTile> logical_tile(LogicalTileFactory::GetTile());
// Add relevant columns to logical tile
logical_tile->AddColumns(tile_group, full_column_ids_);
logical_tile->AddPositionList(std::move(tuples.second));
if (column_ids_.size() != 0) {
logical_tile->ProjectColumns(full_column_ids_, column_ids_);
}
result_.push_back(logical_tile.release());
}
done_ = true;
LOG_TRACE("Result tiles : %lu", result_.size());
return true;
}
bool HybridScanExecutor::ExecPrimaryIndexLookup() {
assert(!index_done_);
std::vector<ItemPointer *> tuple_location_ptrs;
assert(index_->GetIndexType() == INDEX_CONSTRAINT_TYPE_PRIMARY_KEY);
if (0 == key_column_ids_.size()) {
index_->ScanAllKeys(tuple_location_ptrs);
} else {
index_->Scan(values_, key_column_ids_, expr_types_,
SCAN_DIRECTION_TYPE_FORWARD, tuple_location_ptrs);
}
LOG_INFO("Tuple_locations.size(): %lu", tuple_location_ptrs.size());
auto &transaction_manager =
concurrency::TransactionManagerFactory::GetInstance();
if (tuple_location_ptrs.size() == 0) {
index_done_ = true;
return false;
}
//std::set<oid_t> oid_ts;
std::map<oid_t, std::vector<oid_t>> visible_tuples;
// for every tuple that is found in the index.
for (auto tuple_location_ptr : tuple_location_ptrs) {
ItemPointer tuple_location = *tuple_location_ptr;
if (type_ == planner::HYBRID &&
tuple_location.block >= (block_threshold)) {
item_pointers_.insert(tuple_location);
// oid_ts.insert(tuple_location.block);
}
auto &manager = catalog::Manager::GetInstance();
auto tile_group = manager.GetTileGroup(tuple_location.block);
auto tile_group_header = tile_group.get()->GetHeader();
// perform transaction read
size_t chain_length = 0;
while (true) {
++chain_length;
if (transaction_manager.IsVisible(tile_group_header,
tuple_location.offset)) {
visible_tuples[tuple_location.block].push_back(tuple_location.offset);
auto res = transaction_manager.PerformRead(tuple_location);
if (!res) {
transaction_manager.SetTransactionResult(RESULT_FAILURE);
return res;
}
break;
} else {
ItemPointer old_item = tuple_location;
cid_t old_end_cid = tile_group_header->GetEndCommitId(old_item.offset);
tuple_location = tile_group_header->GetNextItemPointer(old_item.offset);
// there must exist a visible version.
assert(tuple_location.IsNull() == false);
cid_t max_committed_cid = transaction_manager.GetMaxCommittedCid();
// check whether older version is garbage.
if (old_end_cid < max_committed_cid) {
assert(tile_group_header->GetTransactionId(old_item.offset) == INITIAL_TXN_ID ||
tile_group_header->GetTransactionId(old_item.offset) == INVALID_TXN_ID);
if (tile_group_header->SetAtomicTransactionId(old_item.offset, INVALID_TXN_ID) == true) {
// atomically swap item pointer held in the index bucket.
AtomicUpdateItemPointer(tuple_location_ptr, tuple_location);
// currently, let's assume only primary index exists.
//gc::GCManagerFactory::GetInstance().RecycleTupleSlot(
// table_->GetOid(), old_item.block, old_item.offset,
// max_committed_cid);
}
}
tile_group = manager.GetTileGroup(tuple_location.block);
tile_group_header = tile_group.get()->GetHeader();
}
}
}
// Construct a logical tile for each block
for (auto tuples : visible_tuples) {
auto &manager = catalog::Manager::GetInstance();
auto tile_group = manager.GetTileGroup(tuples.first);
std::unique_ptr<LogicalTile> logical_tile(LogicalTileFactory::GetTile());
// Add relevant columns to logical tile
logical_tile->AddColumns(tile_group, full_column_ids_);
logical_tile->AddPositionList(std::move(tuples.second));
if (column_ids_.size() != 0) {
logical_tile->ProjectColumns(full_column_ids_, column_ids_);
}
result_.push_back(logical_tile.release());
}
index_done_ = true;
LOG_TRACE("Result tiles : %lu", result_.size());
return true;
}
bool HybridScanExecutor::ExecPrimaryIndexLookup() {
PL_ASSERT(index_done_ == false);
const planner::HybridScanPlan &node = GetPlanNode<planner::HybridScanPlan>();
bool acquire_owner = GetPlanNode<planner::AbstractScan>().IsForUpdate();
auto key_column_ids_ = node.GetKeyColumnIds();
auto expr_type_ = node.GetExprTypes();
std::vector<ItemPointer *> tuple_location_ptrs;
PL_ASSERT(index_->GetIndexType() == INDEX_CONSTRAINT_TYPE_PRIMARY_KEY);
if (0 == key_column_ids_.size()) {
LOG_TRACE("Scan all keys");
index_->ScanAllKeys(tuple_location_ptrs);
} else {
LOG_TRACE("Scan");
index_->Scan(values_,
key_column_ids_,
expr_type_,
SCAN_DIRECTION_TYPE_FORWARD,
tuple_location_ptrs,
&node.GetIndexPredicate().GetConjunctionList()[0]);
}
LOG_TRACE("Result tuple count: %lu", tuple_location_ptrs.size());
auto &transaction_manager =
concurrency::TransactionManagerFactory::GetInstance();
auto current_txn = executor_context_->GetTransaction();
if (tuple_location_ptrs.size() == 0) {
index_done_ = true;
return false;
}
std::map<oid_t, std::vector<oid_t>> visible_tuples;
// for every tuple that is found in the index.
for (auto tuple_location_ptr : tuple_location_ptrs) {
ItemPointer tuple_location = *tuple_location_ptr;
if (type_ == HYBRID_SCAN_TYPE_HYBRID &&
tuple_location.block >= (block_threshold)) {
item_pointers_.insert(tuple_location);
}
auto &manager = catalog::Manager::GetInstance();
auto tile_group = manager.GetTileGroup(tuple_location.block);
auto tile_group_header = tile_group.get()->GetHeader();
// perform transaction read
size_t chain_length = 0;
while (true) {
++chain_length;
auto visibility = transaction_manager.IsVisible(current_txn, tile_group_header, tuple_location.offset);
if (visibility == VISIBILITY_OK) {
visible_tuples[tuple_location.block].push_back(tuple_location.offset);
auto res = transaction_manager.PerformRead(current_txn, tuple_location, acquire_owner);
if (!res) {
transaction_manager.SetTransactionResult(current_txn, RESULT_FAILURE);
return res;
}
break;
} else {
ItemPointer old_item = tuple_location;
cid_t old_end_cid = tile_group_header->GetEndCommitId(old_item.offset);
tuple_location = tile_group_header->GetNextItemPointer(old_item.offset);
// there must exist a visible version.
assert(tuple_location.IsNull() == false);
cid_t max_committed_cid = transaction_manager.GetMaxCommittedCid();
// check whether older version is garbage.
if (old_end_cid < max_committed_cid) {
assert(tile_group_header->GetTransactionId(old_item.offset) ==
INITIAL_TXN_ID ||
tile_group_header->GetTransactionId(old_item.offset) ==
INVALID_TXN_ID);
if (tile_group_header->SetAtomicTransactionId(
old_item.offset, INVALID_TXN_ID) == true) {
// atomically swap item pointer held in the index bucket.
AtomicUpdateItemPointer(tuple_location_ptr, tuple_location);
}
}
tile_group = manager.GetTileGroup(tuple_location.block);
tile_group_header = tile_group.get()->GetHeader();
}
}
}
// Construct a logical tile for each block
for (auto tuples : visible_tuples) {
auto &manager = catalog::Manager::GetInstance();
auto tile_group = manager.GetTileGroup(tuples.first);
std::unique_ptr<LogicalTile> logical_tile(LogicalTileFactory::GetTile());
// Add relevant columns to logical tile
logical_tile->AddColumns(tile_group, full_column_ids_);
logical_tile->AddPositionList(std::move(tuples.second));
if (column_ids_.size() != 0) {
logical_tile->ProjectColumns(full_column_ids_, column_ids_);
}
result_.push_back(logical_tile.release());
}
index_done_ = true;
LOG_TRACE("Result tiles : %lu", result_.size());
return true;
}
