public TransactionService GetTransaction(bool create, bool queryOnly, out bool isNew)
{
var transaction = _slot.Value;
if (create && transaction == null)
{
isNew = true;
bool alreadyLock;
// must lock _transaction before work with _transactions (GetInitialSize use _transactions)
lock (_transactions)
{
if (_transactions.Count >= MAX_OPEN_TRANSACTIONS)
{
throw new LiteException(0, "Maximum number of transactions reached");
}
var initialSize = this.GetInitialSize();
// check if current thread contains any transaction
alreadyLock = _transactions.Values.Any(x => x.ThreadID == Environment.CurrentManagedThreadId);
transaction = new TransactionService(_header, _locker, _disk, _walIndex, initialSize, this, queryOnly);
// add transaction to execution transaction dict
_transactions[transaction.TransactionID] = transaction;
}
// enter in lock transaction after release _transaction lock
if (alreadyLock == false)
{
_locker.EnterTransaction();
}
// do not store in thread query-only transaction
if (queryOnly == false)
{
_slot.Value = transaction;
}
}
else
{
isNew = false;
}
return(transaction);
}
public TransactionService(HeaderPage header, LockService locker, DiskService disk, WalIndexService walIndex, int maxTransactionSize, Action <uint> done)
{
// retain instances
_header = header;
_locker = locker;
_disk = disk;
_walIndex = walIndex;
_maxTransactionSize = maxTransactionSize;
_done = done;
// create new transactionID
_transactionID = walIndex.NextTransactionID();
_startTime = DateTime.UtcNow;
_reader = _disk.GetReader();
// enter transaction locker to avoid 2 transactions in same thread
_locker.EnterTransaction();
}