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[Bigdata-commit] SF.net SVN: bigdata:[3967] branches/JOURNAL_HA_BRANCH/bigdata/src
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From: <tho...@us...> - 2010-11-18 19:14:12
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Revision: 3967
http://bigdata.svn.sourceforge.net/bigdata/?rev=3967&view=rev
Author: thompsonbry
Date: 2010-11-18 19:14:05 +0000 (Thu, 18 Nov 2010)
Log Message:
-----------
Added exception to help identify problems where the caller reading against a historical commit point is not using a read-only transaction and hence is not protected by a read-lock.
Modified Paths:
--------------
branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/RWStore.java
branches/JOURNAL_HA_BRANCH/bigdata/src/samples/com/bigdata/samples/btree/JournalReadOnlyTxExample.java
Added Paths:
-----------
branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/PhysicalAddressResolutionException.java
Added: branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/PhysicalAddressResolutionException.java
===================================================================
--- branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/PhysicalAddressResolutionException.java (rev 0)
+++ branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/PhysicalAddressResolutionException.java 2010-11-18 19:14:05 UTC (rev 3967)
@@ -0,0 +1,54 @@
+/**
+
+Copyright (C) SYSTAP, LLC 2006-2010. All rights reserved.
+
+Contact:
+ SYSTAP, LLC
+ 4501 Tower Road
+ Greensboro, NC 27410
+ lic...@bi...
+
+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 Nov 18, 2010
+ */
+
+package com.bigdata.rwstore;
+
+/**
+ * Exception thrown when a logical address maps onto a physical address which is
+ * not currently allocated. The most common cause of this exception is a read on
+ * the database using a historical commit point which is not protected by a read
+ * lock. You should be using a read-only transaction rather than a bare
+ * historical read in order to be protected by a read lock.
+ *
+ * @author <a href="mailto:tho...@us...">Bryan Thompson</a>
+ * @version $Id$
+ */
+public class PhysicalAddressResolutionException extends
+ IllegalArgumentException {
+
+ /**
+ *
+ */
+ private static final long serialVersionUID = 1L;
+
+ public PhysicalAddressResolutionException(final long addr) {
+
+ super("Address did not resolve to physical address: " + addr);
+
+ }
+
+}
Property changes on: branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/PhysicalAddressResolutionException.java
___________________________________________________________________
Added: svn:keywords
+ Id Date Revision Author HeadURL
Modified: branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/RWStore.java
===================================================================
--- branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/RWStore.java 2010-11-18 18:33:30 UTC (rev 3966)
+++ branches/JOURNAL_HA_BRANCH/bigdata/src/java/com/bigdata/rwstore/RWStore.java 2010-11-18 19:14:05 UTC (rev 3967)
@@ -1258,12 +1258,7 @@
assertAllocators();
- final String msg = "Address did not resolve to physical address: "
- + addr;
-
- log.warn(msg);
-
- throw new IllegalArgumentException(msg);
+ throw new PhysicalAddressResolutionException(addr);
}
Modified: branches/JOURNAL_HA_BRANCH/bigdata/src/samples/com/bigdata/samples/btree/JournalReadOnlyTxExample.java
===================================================================
--- branches/JOURNAL_HA_BRANCH/bigdata/src/samples/com/bigdata/samples/btree/JournalReadOnlyTxExample.java 2010-11-18 18:33:30 UTC (rev 3966)
+++ branches/JOURNAL_HA_BRANCH/bigdata/src/samples/com/bigdata/samples/btree/JournalReadOnlyTxExample.java 2010-11-18 19:14:05 UTC (rev 3967)
@@ -171,10 +171,20 @@
}
- /*
- * Open a read-only transaction on the last commit time.
- */
- final long tx2 = store.newTx(ITx.READ_COMMITTED);
+ /*
+ * Open a read-only transaction on the last commit time.
+ *
+ * Note: If you use store.getLastCommitTime() here instead you will
+ * have a read-historical view of the same data, but that view is
+ * NOT protected by a read lock. Running the example with this
+ * change will cause the RWStore to throw out an exception since the
+ * writes will have overwritten the historical data by the time you
+ * try to read it.
+ */
+ // Obtaining a tx here protects against recycling.
+// final long tx2 = store.newTx(ITx.READ_COMMITTED);
+ // Using a historical read w/o a tx does NOT protect against recycling.
+ final long tx2 = store.getLastCommitTime();
try {
// lookup the UNISOLATED B+Tree.
@@ -186,30 +196,20 @@
store.commit();
/*
- * Verify that the read-only view has not seen those changes.
- */
- if(false) {
- final BTree readOnlyBTree = (BTree) store.getIndex(name, tx2);
-
- verifyWriteSet1(readOnlyBTree);
-
- }
-
- /*
* Write some new records on the unisolated index.
*/
writeSet2(unisolatedBTree);
store.commit();
-
- /*
- * Verify that the read-only view has not seen those changes.
- *
- * Note: This probably hits the index cache and everything in
- * the read-only B+Tree was already materialized when we
- * verified it just before writing writeSet2 onto the unisolated
- * index, so this is not really testing anything.
- */
+
+ /*
+ * Verify that the read-only view has not seen those changes.
+ *
+ * Note: If you used a historical read rather than a read-only
+ * tx then this is where the RWStore will throw out an exception
+ * because the recycled has reused some of the records
+ * associated with the historical revision of the BTree.
+ */
{
final BTree readOnlyBTree = (BTree) store.getIndex(name, tx2);
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