/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.service;
/**
* Immutable state for a transaction.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*/
public interface ITxState0 {
/**
* The start time for the transaction as assigned by a centralized
* transaction manager service. Transaction start times are unique and also
* serve as transaction identifiers. Note that this is NOT the time at which
* a transaction begins executing on a specific journal as the same
* transaction may start at different moments on different journals and
* typically will only start on some journals rather than all.
*
* @return The transaction start time.
*
* @see #getReadsOnCommitTime()
*
* TODO Rename since the sign indicates read-only vs read-write and
* hence it can not be directly interpreted as a commitTime? (e.g.,
* getTxId()).
*/
long getStartTimestamp();
/**
* The timestamp of the commit point against which this transaction is
* reading.
* <p>
* Note: This is not currently available on a cluster. In that context, we
* wind up with the same timestamp for {@link #startTime} and
* {@link #readsOnCommitTime} which causes cache pollution for things which
* cache based on {@link #readsOnCommitTime}.
*
* @see <a href="https://sourceforge.net/apps/trac/bigdata/ticket/266">
* Refactor native long tx id to thin object</a>
*
* @see <a href="http://sourceforge.net/apps/trac/bigdata/ticket/546" > Add
* cache for access to historical index views on the Journal by name
* and commitTime. </a>
*/
long getReadsOnCommitTime();
}