//
// Summary:
// Enlists in the specified transaction. TODO
//
// Parameters:
// transaction:
// A reference to an existing System.Transactions.Transaction in which to enlist.
//public override void EnlistTransaction(PqsqlTransaction transaction)
//{
// throw new NotImplementedException();
//}
//
// Summary:
// Opens a database connection with the settings specified by the System.Data.Common.DbConnection.ConnectionString.
public override void Open()
{
if (mConnection != IntPtr.Zero && !mNewConnectionString)
{
// close and open with current connection setting
PqsqlWrapper.PQreset(mConnection);
// update connection and transaction status
if (Status == ConnStatusType.CONNECTION_BAD || TransactionStatus != PGTransactionStatusType.PQTRANS_IDLE)
{
string err = GetErrorMessage();
PqsqlWrapper.PQfinish(mConnection); // force release of mConnection memory
Init();
var connStr = mConnectionStringBuilder.GetConnectionStringWithObfuscatedPassword();
throw new PqsqlException("Could not reset connection with connection string «" + connStr + "»: " + err, (int)PqsqlState.CONNECTION_FAILURE);
}
OnStateChange(new StateChangeEventArgs(ConnectionState.Closed, ConnectionState.Open));
// always set application_name, after a DISCARD ALL (usually issued by PqsqlConnectionPool / pgbouncer)
// the session information is gone forever, and the shared connection will drop application_name
SetApplicationName();
// successfully reestablished connection
return;
}
if (mStatus != ConnStatusType.CONNECTION_BAD)
{
Close(); // force release of mConnection memory
}
// check connection pool for a connection
mConnection = PqsqlConnectionPool.GetPGConn(mConnectionStringBuilder, out mStatus, out mTransStatus);
if (mConnection == IntPtr.Zero)
{
throw new PqsqlException("libpq: unable to allocate struct PGconn");
}
// check connection and transaction status
if (mStatus == ConnStatusType.CONNECTION_BAD || mTransStatus != PGTransactionStatusType.PQTRANS_IDLE)
{
string err = GetErrorMessage();
PqsqlWrapper.PQfinish(mConnection); // force release of mConnection memory
Init();
var connStr = mConnectionStringBuilder.GetConnectionStringWithObfuscatedPassword();
throw new PqsqlException("Could not create connection with connection string «" + connStr + "»: " + err);
}
mNewConnectionString = false;
OnStateChange(new StateChangeEventArgs(ConnectionState.Closed, ConnectionState.Open));
// always set application_name, after a DISCARD ALL (usually issued by PqsqlConnectionPool / pgbouncer)
// the session information is gone forever, and the shared connection will drop application_name
SetApplicationName();
}
private static bool CheckOrRelease(IntPtr pgConn, out ConnStatusType connStatus, out PGTransactionStatusType tranStatus)
{
if (pgConn == IntPtr.Zero)
{
connStatus = ConnStatusType.CONNECTION_BAD;
tranStatus = PGTransactionStatusType.PQTRANS_UNKNOWN;
return(false);
}
// is connection reusable?
connStatus = PqsqlWrapper.PQstatus(pgConn);
if (connStatus != ConnStatusType.CONNECTION_OK)
{
goto broken;
}
tranStatus = PqsqlWrapper.PQtransactionStatus(pgConn);
if (tranStatus != PGTransactionStatusType.PQTRANS_IDLE)
{
goto broken;
}
//
// now check the connection: first try to fix the client encoding if it is not utf8 for some reason.
// if client_encoding is utf8, we send the empty query to check whether the socket is still usable
// for the backend communiction. here, we could make use of tcp_keepalive settings.
//
int client_encoding = PqsqlWrapper.PQclientEncoding(pgConn);
if (client_encoding == -1)
{
goto broken;
}
if (client_encoding == (int)PgEnc.PG_UTF8) // client_encoding == utf8
{
// send empty query to test whether we are really connected (tcp_keepalive might have closed socket)
unsafe
{
byte[] empty = { 0 }; // empty query string
fixed(byte *eq = empty)
{
if (PqsqlWrapper.PQsendQuery(pgConn, eq) == 0) // could not send query
{
goto broken;
}
}
}
// Reading result: consume and clear remaining results until we reach the NULL result.
// PQgetResult will block here
IntPtr res;
ExecStatusType st = ExecStatusType.PGRES_EMPTY_QUERY;
while ((res = PqsqlWrapper.PQgetResult(pgConn)) != IntPtr.Zero)
{
ExecStatusType st0 = PqsqlWrapper.PQresultStatus(res);
if (st0 != ExecStatusType.PGRES_EMPTY_QUERY)
{
st = st0;
}
// always free res
PqsqlWrapper.PQclear(res);
}
if (st != ExecStatusType.PGRES_EMPTY_QUERY) // received wrong exec status
{
goto broken;
}
}
else // set client_encoding to utf8
{
// set client_encoding to test whether we are really connected (tcp_keepalive might have closed socket)
if (PqsqlWrapper.PQsetClientEncoding(pgConn, PgEncName.PG_UTF8) != 0)
{
goto broken;
}
}
return(true); // successfully reused connection
broken:
// reconnect with current connection setting
PqsqlWrapper.PQreset(pgConn);
connStatus = PqsqlWrapper.PQstatus(pgConn);
if (connStatus == ConnStatusType.CONNECTION_OK)
{
tranStatus = PqsqlWrapper.PQtransactionStatus(pgConn);
if (tranStatus == PGTransactionStatusType.PQTRANS_IDLE)
{
return(true); // successfully reconnected
}
}
else
{
tranStatus = PGTransactionStatusType.PQTRANS_UNKNOWN;
}
// could not reconnect: finally give up and clean up memory
PqsqlWrapper.PQfinish(pgConn);
return(false);
}
