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LUCENE-5958: fix IW deadlock 

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1627003 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Michael McCandless 2014-09-23 13:14:45 +00:00
parent 1dd2ecb282
commit da87077edd
2 changed files with 76 additions and 61 deletions
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130
lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
View File

@ -2068,15 +2068,15 @@ public class IndexWriter implements Closeable, TwoPhaseCommit, Accountable {
* get in our way and do unnecessary work. -- if we don't lock this here we might
* get in trouble if */
synchronized (fullFlushLock) {
/*
* We first abort and trash everything we have in-memory
* and keep the thread-states locked, the lockAndAbortAll operation
* also guarantees "point in time semantics" ie. the checkpoint that we need in terms
* of logical happens-before relationship in the DW. So we do
* abort all in memory structures
* We also drop global field numbering before during abort to make
* sure it's just like a fresh index.
*/
/*
* We first abort and trash everything we have in-memory
* and keep the thread-states locked, the lockAndAbortAll operation
* also guarantees "point in time semantics" ie. the checkpoint that we need in terms
* of logical happens-before relationship in the DW. So we do
* abort all in memory structures
* We also drop global field numbering before during abort to make
* sure it's just like a fresh index.
*/
try {
docWriter.lockAndAbortAll(this);
processEvents(false, true);
@ -2101,8 +2101,6 @@ public class IndexWriter implements Closeable, TwoPhaseCommit, Accountable {
segmentInfos.changed();
globalFieldNumberMap.clear();
success = true;
} catch (OutOfMemoryError oom) {
tragicEvent(oom, "deleteAll");
} finally {
if (!success) {
if (infoStream.isEnabled("IW")) {
@ -2111,6 +2109,8 @@ public class IndexWriter implements Closeable, TwoPhaseCommit, Accountable {
}
}
}
} catch (OutOfMemoryError oom) {
tragicEvent(oom, "deleteAll");
} finally {
docWriter.unlockAllAfterAbortAll(this);
}
@ -2889,63 +2889,70 @@ public class IndexWriter implements Closeable, TwoPhaseCommit, Accountable {
}
}
private synchronized final void finishCommit() throws IOException {
private final void finishCommit() throws IOException {
boolean success = false;
if (pendingCommit != null) {
try {
if (infoStream.isEnabled("IW")) {
infoStream.message("IW", "commit: pendingCommit != null");
}
pendingCommit.finishCommit(directory);
success = true;
// we committed, if anything goes wrong after this: we are screwed
try {
if (infoStream.isEnabled("IW")) {
infoStream.message("IW", "commit: wrote segments file \"" + pendingCommit.getSegmentsFileName() + "\"");
}
segmentInfos.updateGeneration(pendingCommit);
lastCommitChangeCount = pendingCommitChangeCount;
rollbackSegments = pendingCommit.createBackupSegmentInfos();
// NOTE: don't use this.checkpoint() here, because
// we do not want to increment changeCount:
deleter.checkpoint(pendingCommit, true);
} catch (Throwable tragedy) {
tragicEvent(tragedy, "finishCommit");
}
} finally {
// Matches the incRef done in prepareCommit:
try {
if (success == false || tragedy == null) {
boolean commitCompleted = false;
boolean finished = false;
String committedSegmentsFileName = null;
try {
synchronized(this) {
if (pendingCommit != null) {
try {
if (infoStream.isEnabled("IW")) {
infoStream.message("IW", "commit: pendingCommit != null");
}
committedSegmentsFileName = pendingCommit.finishCommit(directory);
// we committed, if anything goes wrong after this, we are screwed and it's a tragedy:
commitCompleted = true;
// NOTE: don't use this.checkpoint() here, because
// we do not want to increment changeCount:
deleter.checkpoint(pendingCommit, true);
lastCommitChangeCount = pendingCommitChangeCount;
rollbackSegments = pendingCommit.createBackupSegmentInfos();
finished = true;
} finally {
notifyAll();
try {
deleter.decRef(filesToCommit);
} catch (Throwable t) {
// if the commit succeeded, we are in screwed state
// otherwise, throw our original exception
if (success) {
tragicEvent(tragedy, "finishCommit");
if (finished) {
// all is good
deleter.decRef(filesToCommit);
} else if (commitCompleted == false) {
// exc happened in finishCommit: not a tragedy
deleter.decRefWhileHandlingException(filesToCommit);
}
}
} finally {
pendingCommit = null;
filesToCommit = null;
}
}
} else {
assert filesToCommit == null;
if (infoStream.isEnabled("IW")) {
infoStream.message("IW", "commit: pendingCommit == null; skip");
}
} finally {
filesToCommit = null;
pendingCommit = null;
notifyAll();
}
}
} catch (Throwable t) {
if (infoStream.isEnabled("IW")) {
infoStream.message("IW", String.format(Locale.ROOT, "commit: took %.1f msec", (System.nanoTime()-startCommitTime)/1000000.0));
infoStream.message("IW", "hit exception during finishCommit: " + t.getMessage());
}
} else {
if (infoStream.isEnabled("IW")) {
infoStream.message("IW", "commit: pendingCommit == null; skip");
if (commitCompleted) {
tragicEvent(t, "finishCommit");
} else {
IOUtils.reThrow(t);
}
}
if (infoStream.isEnabled("IW")) {
infoStream.message("IW", "commit: wrote segments file \"" + committedSegmentsFileName + "\"");
infoStream.message("IW", String.format(Locale.ROOT, "commit: took %.1f msec", (System.nanoTime()-startCommitTime)/1000000.0));
infoStream.message("IW", "commit: done");
}
}
@ -4375,12 +4382,17 @@ public class IndexWriter implements Closeable, TwoPhaseCommit, Accountable {
}
private void tragicEvent(Throwable tragedy, String location) {
// We cannot hold IW's lock here else it can lead to deadlock:
assert Thread.holdsLock(this) == false;
if (infoStream.isEnabled("IW")) {
infoStream.message("IW", "hit " + tragedy.getClass().getSimpleName() + " inside " + location);
}
// its possible you could have a really bad day
if (this.tragedy == null) {
this.tragedy = tragedy;
synchronized (this) {
// its possible you could have a really bad day
if (this.tragedy == null) {
this.tragedy = tragedy;
}
}
// if we are already closed (e.g. called by rollback), this will be a no-op.
synchronized(commitLock) {

7
lucene/core/src/java/org/apache/lucene/index/SegmentInfos.java
View File

@ -704,14 +704,16 @@ public final class SegmentInfos implements Cloneable, Iterable<SegmentCommitInfo
return files;
}
final void finishCommit(Directory dir) throws IOException {
/** Returns the committed segments_N filename. */
final String finishCommit(Directory dir) throws IOException {
if (pendingCommit == false) {
throw new IllegalStateException("prepareCommit was not called");
}
boolean success = false;
final String dest;
try {
final String src = IndexFileNames.fileNameFromGeneration(IndexFileNames.PENDING_SEGMENTS, "", generation);
final String dest = IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, "", generation);
dest = IndexFileNames.fileNameFromGeneration(IndexFileNames.SEGMENTS, "", generation);
dir.renameFile(src, dest);
success = true;
} finally {
@ -723,6 +725,7 @@ public final class SegmentInfos implements Cloneable, Iterable<SegmentCommitInfo
pendingCommit = false;
lastGeneration = generation;
return dest;
}
/** Writes & syncs to the Directory dir, taking care to