com.bigdata.service.ndx.ISplitter Maven / Gradle / Ivy
/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
[email protected]
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
*/
/*
* Created on May 7, 2009
*/
package com.bigdata.service.ndx;
import java.util.LinkedList;
import com.bigdata.btree.keys.KVO;
import com.bigdata.mdi.IMetadataIndex;
import com.bigdata.resources.StaleLocatorException;
import com.bigdata.service.Split;
/**
* Interface for finding the {@link Split}s for an ordered set of unsigned
* byte[] keys. Each key MUST be fully specified, e.g., point lookup. This
* algorithm does NOT handle cases where multiple partitions must be scanned
* because they share the same prefix as the key.
*
* The splitter processes the keys in order. It queries the
* {@link IMetadataIndex} for the partition spanning the first key. It then
* places all keys spanned by that partition into that split. When it reaches
* the first key which is GTE the rightSeparator, it queries the MDI for that
* key. Index partition Split, Move and Joins should not be able to cause a
* problem for this algorithm. At the worst, some tuples will be directed to a
* stale locator and the stale locator exception is handled.
*
* The split operation is not atomic, however it is consistent in the following
* sense. Any identified {@link Split}s will either be for a valid index
* partition, for a partition of an index which has been deleted, or for an
* index partition which has since been split, joined or moved. In the latter
* case a {@link StaleLocatorException} will be thrown if the client attempts an
* operation on the unisolated view of that index partition. All clients know
* how to handle that exception and redirect the request as appropriate.
*
* @author Bryan Thompson
* @version $Id$
*/
public interface ISplitter {
/**
* Identify the {@link Split}s for an ordered array of keys such that there
* is one {@link Split} per index partition spanned by the data.
*
* @param ts
* The timestamp for the {@link IMetadataIndex} view that will be
* applied to choose the {@link Split}s.
* @param fromIndex
* The index of the first key in keys to be processed
* (inclusive).
* @param toIndex
* The index of the last key in keys to be processed.
* @param keys
* An array of keys. Each key is an interpreted as an unsigned
* byte[] which fully specifies the desired tuple (no prefix
* scans). All keys must be non-null. The keys must be in sorted
* order.
*
* @return The {@link Split}s that you can use to form requests based on the
* identified first/last key and partition identified by this
* process.
*/
LinkedList splitKeys(final long ts, final int fromIndex,
final int toIndex, final byte[][] keys);
/**
* Identify the {@link Split}s for an ordered {@link KVO}[] such that there
* is one {@link Split} per index partition spanned by the data.
*
* @param ts
* The timestamp for the {@link IMetadataIndex} view that will be
* applied to choose the {@link Split}s.
* @param fromIndex
* The index of the first key in keys to be processed
* (inclusive).
* @param toIndex
* The index of the last key in keys to be processed.
* @param keys
* An array of keys. Each key is an interpreted as an unsigned
* byte[] which fully specifies the desired tuple (no prefix
* scans). All keys must be non-null. The keys must be in sorted
* order.
*
* @return The {@link Split}s that you can use to form requests based on the
* identified first/last key and partition identified by this
* process.
*/
LinkedList splitKeys(final long ts, final int fromIndex,
final int toIndex, final KVO[] a);
}