Revision: 7062
http://bigdata.svn.sourceforge.net/bigdata/?rev=7062&view=rev
Author: thompsonbry
Date: 2013-04-19 14:53:33 +0000 (Fri, 19 Apr 2013)
Log Message:
-----------
javadoc and formatting only.
Modified Paths:
--------------
branches/READ_CACHE/bigdata/src/java/com/bigdata/journal/WORMStrategy.java
Modified: branches/READ_CACHE/bigdata/src/java/com/bigdata/journal/WORMStrategy.java
===================================================================
--- branches/READ_CACHE/bigdata/src/java/com/bigdata/journal/WORMStrategy.java 2013-04-19 14:51:49 UTC (rev 7061)
+++ branches/READ_CACHE/bigdata/src/java/com/bigdata/journal/WORMStrategy.java 2013-04-19 14:53:33 UTC (rev 7062)
@@ -1170,6 +1170,19 @@
}
+ /**
+ * The sequence number for the last {@link WriteCache} block written in the
+ * current commit. This is set in {@link #commit()} when we flush the
+ * {@link WriteCacheService}. This is used to prepare the new
+ * {@link IRootBlockView}. The value of this field is NOT incremented as
+ * writes are made, but only after they have been flushed.
+ *
+ * TODO This pattern arose because {@link WriteCacheService#resetSequence()}
+ * is called from {@link #commit()}. It might be more pleasant to call that
+ * from {@link AbstractJournal#commitNow(long)} so we could consolidate this
+ * logic. That requires us to expose the {@link WriteCacheService} to the
+ * {@link AbstractJournal} through the {@link IHABufferStrategy}.
+ */
private long lastBlockSequence = 0;
@Override
@@ -2437,12 +2450,9 @@
private final void releaseWriteCache() {
if (writeCacheService != null) {
-// try {
- // FIXME: just reset to preserve read cache?
- writeCacheService.close();
-// } catch (InterruptedException e) {
-// throw new RuntimeException(e);
-// }
+
+ writeCacheService.close();
+
}
}
@@ -2452,11 +2462,16 @@
* of this method are ignored.
*/
@Override
- public void delete(long addr) {
- if (writeCacheService != null)
- writeCacheService.clearWrite(addr, 0);
- }
+ public void delete(final long addr) {
+ if (writeCacheService != null) {
+
+ writeCacheService.clearWrite(addr, 0);
+
+ }
+
+ }
+
@Override
public void writeRawBuffer(final IHAWriteMessage msg, final IBufferAccess b)
throws IOException, InterruptedException {
@@ -2710,13 +2725,19 @@
// Note: Potentially updated (if root blocks were reinstalled).
storeUUIDRef.set(rootBlock.getUUID());
-
+
}
@Override
public Object snapshotAllocators() {
- // TODO Auto-generated method stub
- throw new UnsupportedOperationException();
+
+ /*
+ * Note: The WORM does not have a concept of allocators. There is
+ * nothing that we need to snapshot since there is no state that is
+ * overwritten.
+ */
+ return null;
+
}
@Override
@@ -2746,6 +2767,17 @@
// The capacity of that buffer (typically 1MB).
final int bufferCapacity = b.capacity();
+ /*
+ * FIXME computeDigest(): This probably should be userExtent +
+ * header, not fileExtent. By choosing userExtent, we are
+ * effectively snapshotting the region on which we will compute the
+ * digest. However, there might be bytes not yet written onto the
+ * backing file (e.g., in the write cache service). Those bytes
+ * would not show up in a read from the file so we would need to do
+ * more work to make this digest computation safe for concurrent
+ * writes. What is safe is to compute the digest from the last
+ * commit point. That "snapshop" is always valid for the WORM.
+ */
// The size of the file at the moment we begin.
final long fileExtent = getExtent();
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