// Check whether need to recovery, if yes, reset fseek to the right place.
bool WriteBehindFrontendLogger::NeedRecovery(void) {
// Otherwise, read the last transaction record
fseek(log_file, -TransactionRecord::GetTransactionRecordSize(), SEEK_END);
// Get its type
auto log_record_type = GetNextLogRecordType(log_file, log_file_size);
// Check if the previous transaction run is broken
if (log_record_type == LOGRECORD_TYPE_TRANSACTION_COMMIT) {
TransactionRecord txn_record(LOGRECORD_TYPE_TRANSACTION_COMMIT);
// read the last written out transaction log record
if (ReadTransactionRecordHeader(txn_record, log_file, log_file_size) ==
false) {
return false;
}
// Peloton log records items have fixed size.
// Compute log offset based on txn_id
size_t tuple_log_record_count = txn_record.GetTransactionId();
size_t rollback_offset =
tuple_log_record_count * TupleRecord::GetTupleRecordSize() +
TransactionRecord::GetTransactionRecordSize();
// Rollback to the computed offset
fseek(log_file, -rollback_offset, SEEK_END);
return true;
} else {
return false;
}
}
/**
* @brief Add new txn to recovery table
*/
void AriesFrontendLogger::AddTransactionToRecoveryTable() {
// read transaction information from the log file
TransactionRecord txn_record(LOGRECORD_TYPE_TRANSACTION_BEGIN);
// Check for torn log write
if (ReadTransactionRecordHeader(txn_record, log_file, log_file_size) ==
false) {
return;
}
auto txn_id = txn_record.GetTransactionId();
// create the new txn object and added it into recovery recovery_txn_table
concurrency::Transaction *txn =
new concurrency::Transaction(txn_id, INVALID_CID);
recovery_txn_table.insert(std::make_pair(txn_id, txn));
LOG_TRACE("Added txd id %d object in table", (int)txn_id);
}
/**
* @brief abort tuple
*/
void AriesFrontendLogger::AbortTuplesFromRecoveryTable() {
// read transaction information from the log file
TransactionRecord txn_record(LOGRECORD_TYPE_TRANSACTION_ABORT);
// Check for torn log write
if (ReadTransactionRecordHeader(txn_record, log_file, log_file_size) ==
false) {
return;
}
auto txn_id = txn_record.GetTransactionId();
// Get info about the transaction from recovery table
if (recovery_txn_table.find(txn_id) != recovery_txn_table.end()) {
auto txn = recovery_txn_table.at(txn_id);
AbortTuples(txn);
LOG_INFO("Abort txd id %d object in table", (int)txn_id);
} else {
LOG_INFO("Abort txd id %d not found in recovery txn table", (int)txn_id);
}
}
/**
* @brief move tuples from current txn to recovery txn so that we can commit
* them later
* @param recovery txn
*/
void AriesFrontendLogger::MoveCommittedTuplesToRecoveryTxn(
concurrency::Transaction *recovery_txn) {
// read transaction information from the log file
TransactionRecord txn_record(LOGRECORD_TYPE_TRANSACTION_COMMIT);
// Check for torn log write
if (ReadTransactionRecordHeader(txn_record, log_file, log_file_size) ==
false) {
return;
}
// Get info about the transaction from recovery table
auto txn_id = txn_record.GetTransactionId();
if (recovery_txn_table.find(txn_id) != recovery_txn_table.end()) {
auto txn = recovery_txn_table.at(txn_id);
// Copy inserted/deleted tuples to recovery transaction
MoveTuples(recovery_txn, txn);
LOG_TRACE("Commit txd id %d object in table", (int)txn_id);
} else {
LOG_TRACE("Commit txd id %d not found in recovery txn table", (int)txn_id);
}
}
/**
* @brief Remove txn from recovery table
*/
void AriesFrontendLogger::RemoveTransactionFromRecoveryTable() {
// read transaction information from the log file
TransactionRecord txn_record(LOGRECORD_TYPE_TRANSACTION_END);
// Check for torn log write
if (ReadTransactionRecordHeader(txn_record, log_file, log_file_size) ==
false) {
return;
}
auto txn_id = txn_record.GetTransactionId();
// remove txn from recovery txn table
if (recovery_txn_table.find(txn_id) != recovery_txn_table.end()) {
auto txn = recovery_txn_table.at(txn_id);
recovery_txn_table.erase(txn_id);
// drop the txn as well
delete txn;
LOG_TRACE("Erase txd id %d object in table", (int)txn_id);
} else {
LOG_TRACE("Erase txd id %d not found in recovery txn table", (int)txn_id);
}
}
/**
* @brief Recovery system based on log file
*/
void WriteBehindFrontendLogger::DoRecovery() {
// Set log file size
log_file_size = GetLogFileSize(log_file_fd);
// Go over the log size if needed
if (log_file_size > 0) {
bool reached_end_of_file = false;
// check whether first item is LOGRECORD_TYPE_TRANSACTION_COMMIT
// if not, no need to do recovery.
// if yes, need to replay all log records before we hit
// LOGRECORD_TYPE_TRANSACTION_DONE
bool need_recovery = NeedRecovery();
if (need_recovery == true) {
TransactionRecord dummy_transaction_record(LOGRECORD_TYPE_INVALID);
cid_t current_commit_id = INVALID_CID;
// Go over each log record in the log file
while (reached_end_of_file == false) {
// Read the first byte to identify log record type
// If that is not possible, then wrap up recovery
LogRecordType log_type = GetNextLogRecordType(log_file, log_file_size);
switch (log_type) {
case LOGRECORD_TYPE_TRANSACTION_DONE:
case LOGRECORD_TYPE_TRANSACTION_COMMIT: {
// read but do nothing
ReadTransactionRecordHeader(dummy_transaction_record, log_file,
log_file_size);
} break;
case LOGRECORD_TYPE_WBL_TUPLE_INSERT: {
TupleRecord insert_record(LOGRECORD_TYPE_WBL_TUPLE_INSERT);
ReadTupleRecordHeader(insert_record, log_file, log_file_size);
auto insert_location = insert_record.GetInsertLocation();
auto info = SetInsertCommitMark(insert_location);
current_commit_id = info.first;
} break;
case LOGRECORD_TYPE_WBL_TUPLE_DELETE: {
TupleRecord delete_record(LOGRECORD_TYPE_WBL_TUPLE_DELETE);
ReadTupleRecordHeader(delete_record, log_file, log_file_size);
auto delete_location = delete_record.GetDeleteLocation();
auto info = SetDeleteCommitMark(delete_location);
current_commit_id = info.first;
} break;
case LOGRECORD_TYPE_WBL_TUPLE_UPDATE: {
TupleRecord update_record(LOGRECORD_TYPE_WBL_TUPLE_UPDATE);
ReadTupleRecordHeader(update_record, log_file, log_file_size);
auto delete_location = update_record.GetDeleteLocation();
SetDeleteCommitMark(delete_location);
auto insert_location = update_record.GetInsertLocation();
auto info = SetInsertCommitMark(insert_location);
current_commit_id = info.first;
} break;
default:
reached_end_of_file = true;
break;
}
}
// Update latest commit id
if (latest_commit_id < current_commit_id) {
latest_commit_id = current_commit_id;
}
// write out a trasaction done log record to file
// to avoid redo next time during recovery
WriteTransactionLogRecord(
TransactionRecord(LOGRECORD_TYPE_TRANSACTION_DONE));
}
// After finishing recovery, set the next oid with maximum oid
// observed during the recovery
auto &manager = catalog::Manager::GetInstance();
manager.SetNextOid(max_oid);
}
}
