uint32_t TransactionRuntime::PerformVectorizedRead(
concurrency::TransactionContext &txn, storage::TileGroup &tile_group,
uint32_t *selection_vector, uint32_t end_idx, bool is_for_update) {
// Get the transaction manager
auto &txn_manager = concurrency::TransactionManagerFactory::GetInstance();
// Get the tile group header
auto tile_group_header = tile_group.GetHeader();
uint32_t tile_group_idx = tile_group.GetTileGroupId();
// Perform a read operation for every visible tuple we found
uint32_t out_idx = 0;
for (uint32_t idx = 0; idx < end_idx; idx++) {
// Construct the item location
ItemPointer location{tile_group_idx, selection_vector[idx]};
// Perform the read
bool can_read = txn_manager.PerformRead(&txn, location, tile_group_header,
is_for_update);
// Update the selection vector and output position
selection_vector[out_idx] = selection_vector[idx];
out_idx += static_cast<uint32_t>(can_read);
}
return out_idx;
}
// Perform a read operation for all tuples in the tile group in the given range
// TODO: Right now, we split this check into two loops: a visibility check and
// the actual reading. Can this be merged?
uint32_t TransactionRuntime::PerformVectorizedRead(
concurrency::TransactionContext &txn, storage::TileGroup &tile_group,
uint32_t tid_start, uint32_t tid_end, uint32_t *selection_vector) {
// Get the transaction manager
auto &txn_manager = concurrency::TransactionManagerFactory::GetInstance();
// Get the tile group header
auto tile_group_header = tile_group.GetHeader();
// Check visibility of tuples in the range [tid_start, tid_end), storing all
// visible tuple IDs in the provided selection vector
uint32_t out_idx = 0;
for (uint32_t i = tid_start; i < tid_end; i++) {
// Perform the visibility check
auto visibility = txn_manager.IsVisible(&txn, tile_group_header, i);
// Update the output position
selection_vector[out_idx] = i;
out_idx += (visibility == VisibilityType::OK);
}
uint32_t tile_group_idx = tile_group.GetTileGroupId();
// Perform a read operation for every visible tuple we found
uint32_t end_idx = out_idx;
out_idx = 0;
for (uint32_t idx = 0; idx < end_idx; idx++) {
// Construct the item location
ItemPointer location{tile_group_idx, selection_vector[idx]};
// Perform the read
bool can_read = txn_manager.PerformRead(&txn, location);
// Update the selection vector and output position
selection_vector[out_idx] = selection_vector[idx];
out_idx += static_cast<uint32_t>(can_read);
}
return out_idx;
}