/*
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
*/
/*
* Created on Jul 3, 2008
*/
package com.bigdata.sparse;
import java.util.UUID;
import org.apache.log4j.Logger;
import com.bigdata.btree.IIndex;
import com.bigdata.btree.IndexMetadata;
import com.bigdata.journal.IIndexManager;
import com.bigdata.journal.ITx;
import com.bigdata.journal.TimestampUtility;
import com.bigdata.relation.AbstractRelation;
/**
* Helper class.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*
*/
public class GlobalRowStoreHelper {
static final public transient String GLOBAL_ROW_STORE_INDEX = "__globalRowStore";
/**
* Note: It is important that this reference is not exposed since that can
* break isolation when using group commit by allowing the GRS index to be
* registered from within a task .
*
* @see <a href="http://trac.blazegraph.com/ticket/1132"> GlobalRowStoreHelper
* can hold hard reference to GSR index (GROUP COMMIT) </a>
*/
private final IIndexManager indexManager;
protected static final transient Logger log = Logger.getLogger(GlobalRowStoreHelper.class);
// protected static final boolean INFO = log.isInfoEnabled();
public GlobalRowStoreHelper(final IIndexManager indexManager) {
if (indexManager == null)
throw new IllegalArgumentException();
this.indexManager = indexManager;
}
/**
* @return The unisolated view of the GRS index
*
* @see <a href="http://trac.blazegraph.com/ticket/867"> NSS concurrency problem
* with list namespaces and create namespace </a>
* @see <a href="http://trac.blazegraph.com/ticket/1132"> GlobalRowStoreHelper
* can hold hard reference to GSR index (GROUP COMMIT) </a>
*/
synchronized public SparseRowStore getGlobalRowStore() {
if (log.isInfoEnabled())
log.info("");
final SparseRowStore globalRowStore;
// if (globalRowStore == null)
{
/**
* The GRS view needs to be protected by an
* UnisolatedReadWriteIndex.
*
* @see <a href="http://trac.blazegraph.com/ticket/867"> NSS
* concurrency problem with list namespaces and create
* namespace </a>
*/
IIndex ndx = AbstractRelation.getIndex(indexManager,
GLOBAL_ROW_STORE_INDEX, ITx.UNISOLATED);
if (ndx == null) {
if (log.isInfoEnabled())
log.info("Global row store does not exist - will try to register now");
try {
/*
* Note: This specifies an split handler that keeps the
* logical row together. This is a hard requirement. The
* atomic read/update guarantee depends on this.
*
* @todo The global row store does not get properties so
* only system defaults are used when it is registered.
*/
final IndexMetadata indexMetadata = new IndexMetadata(
GLOBAL_ROW_STORE_INDEX, UUID.randomUUID());
// Ensure that splits do not break logical rows.
indexMetadata
.setSplitHandler(LogicalRowSplitHandler.INSTANCE);
/*
* This is now handled by using the UTF8 encoding of the primary key regardless
* of the collator mode chosen (this fixes the problem with embedded nuls).
*/
// if (CollatorEnum.JDK.toString().equals(
// System.getProperty(KeyBuilder.Options.COLLATOR))) {
// /*
// * The JDK RulesBasedCollator embeds nul bytes in the
// * Unicode sort keys. This makes them unsuitable for the
// * SparseRowStore, which can not locate the start of the
// * column name if there are embedded nuls in a Unicode
// * primary key. As a work around, this forces an ASCII
// * collation sequence if the JDK collator is the
// * default. This is not ideal since non-ascii
// * distinctions will be lost, but it is better than
// * being unable to decode the column names.
// */
// log.warn("Forcing ASCII collator.");
// indexMetadata
// .setTupleSerializer(new DefaultTupleSerializer(
// new ASCIIKeyBuilderFactory()));
// }
// Register the index.
indexManager.registerIndex(indexMetadata);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
/**
* The live view of the global row store must be wrapped by an
* UnisolatedReadWriteIndex on a Journal.
*
* @see http://sourceforge.net/apps/trac/bigdata/ticket/616 (Row
* store read/update not isolated on Journal)
*/
ndx = AbstractRelation.getIndex(indexManager,
GLOBAL_ROW_STORE_INDEX, ITx.UNISOLATED);
// ndx = indexManager.getIndex(GLOBAL_ROW_STORE_INDEX, ITx.UNISOLATED);
if (ndx == null) {
throw new RuntimeException("Could not find index?");
}
}
// row store is flyweight wrapper around index.
globalRowStore = new SparseRowStore(ndx);
}
return globalRowStore;
}
/**
* Note: The hard reference to the unisolated view of the GSR is no longer
* cached.
*
* @see <a href="http://trac.blazegraph.com/ticket/1132"> GlobalRowStoreHelper
* can hold hard reference to GSR index (GROUP COMMIT) </a>
*/
// private transient SparseRowStore globalRowStore;
/**
* Return a view of the global row store as of the specified timestamp IFF
* the backing index exists as of that timestamp.
*/
public SparseRowStore get(final long timestamp) {
if (log.isInfoEnabled())
log.info(TimestampUtility.toString(timestamp));
if (timestamp == ITx.UNISOLATED) {
/* This version does an implicit create if the GRS does not exist. */
return getGlobalRowStore();
}
final IIndex ndx;
/**
* The live view of the global row store must be wrapped by an
* UnisolatedReadWriteIndex on a Journal.
*
* @see http://sourceforge.net/apps/trac/bigdata/ticket/616 (Row store
* read/update not isolated on Journal)
*/
ndx = AbstractRelation.getIndex(indexManager, GLOBAL_ROW_STORE_INDEX,
TimestampUtility.asHistoricalRead(timestamp));
// ndx = indexManager.getIndex(GLOBAL_ROW_STORE_INDEX,
// TimestampUtility.asHistoricalRead(timestamp));
if (ndx == null) {
return null;
}
return new SparseRowStore(ndx);
}
}