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MAPREDUCE-4384. Race conditions in IndexCache (Kihwal Lee via tgraves) 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1357937 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Graves 2012-07-05 21:36:02 +00:00
parent 9a43f05129
commit 3d5a44f919
2 changed files with 23 additions and 15 deletions
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2
hadoop-mapreduce-project/CHANGES.txt
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@ -638,6 +638,8 @@ Release 0.23.3 - UNRELEASED
MAPREDUCE-4392. Counters.makeCompactString() changed behavior from 0.20 MAPREDUCE-4392. Counters.makeCompactString() changed behavior from 0.20
(Jason Lowe via bobby) (Jason Lowe via bobby)
MAPREDUCE-4384. Race conditions in IndexCache (Kihwal Lee via tgraves)
Release 0.23.2 - UNRELEASED Release 0.23.2 - UNRELEASED
INCOMPATIBLE CHANGES INCOMPATIBLE CHANGES

24
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/IndexCache.java
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@ -67,15 +67,15 @@ class IndexCache {
if (info == null) { if (info == null) {
info = readIndexFileToCache(fileName, mapId, expectedIndexOwner); info = readIndexFileToCache(fileName, mapId, expectedIndexOwner);
} else { } else {
synchronized (info) { while (isUnderConstruction(info)) {
while (null == info.mapSpillRecord) {
try { try {
info.wait(); // In case the entry is ready after the above check but
// before the following wait, we do timed wait.
info.wait(200);
} catch (InterruptedException e) { } catch (InterruptedException e) {
throw new IOException("Interrupted waiting for construction", e); throw new IOException("Interrupted waiting for construction", e);
} }
} }
}
LOG.debug("IndexCache HIT: MapId " + mapId + " found"); LOG.debug("IndexCache HIT: MapId " + mapId + " found");
} }
@ -88,6 +88,12 @@ class IndexCache {
return info.mapSpillRecord.getIndex(reduce); return info.mapSpillRecord.getIndex(reduce);
} }
private boolean isUnderConstruction(IndexInformation info) {
synchronized(info) {
return (null == info.mapSpillRecord);
}
}
private IndexInformation readIndexFileToCache(Path indexFileName, private IndexInformation readIndexFileToCache(Path indexFileName,
String mapId, String mapId,
String expectedIndexOwner) String expectedIndexOwner)
@ -95,15 +101,15 @@ class IndexCache {
IndexInformation info; IndexInformation info;
IndexInformation newInd = new IndexInformation(); IndexInformation newInd = new IndexInformation();
if ((info = cache.putIfAbsent(mapId, newInd)) != null) { if ((info = cache.putIfAbsent(mapId, newInd)) != null) {
synchronized (info) { while (isUnderConstruction(info)) {
while (null == info.mapSpillRecord) {
try { try {
info.wait(); // In case the entry is ready after the above check but
// before the following wait, we do timed wait.
info.wait(200);
} catch (InterruptedException e) { } catch (InterruptedException e) {
throw new IOException("Interrupted waiting for construction", e); throw new IOException("Interrupted waiting for construction", e);
} }
} }
}
LOG.debug("IndexCache HIT: MapId " + mapId + " found"); LOG.debug("IndexCache HIT: MapId " + mapId + " found");
return info; return info;
} }
@ -139,7 +145,7 @@ class IndexCache {
*/ */
public void removeMap(String mapId) { public void removeMap(String mapId) {
IndexInformation info = cache.get(mapId); IndexInformation info = cache.get(mapId);
if ((info != null) && (info.getSize() == 0)) { if (info == null || ((info != null) && isUnderConstruction(info))) {
return; return;
} }
info = cache.remove(mapId); info = cache.remove(mapId);