Yu Li created HBASE-16032:
-----------------------------
Summary: Possible memory leak in StoreScanner
Key: HBASE-16032
URL: https://issues.apache.org/jira/browse/HBASE-16032
Project: HBase
Issue Type: Bug
Reporter: Yu Li
Assignee: Yu Li
We observed frequent fullGC of RS in our production environment, and after
analyzing the heapdump, we found large memory occupancy by
HStore#changedReaderObservers, the map is surprisingly containing 7500w
objects...
After some debugging, I located some possible memory leak in StoreScanner
constructor:
{code}
public StoreScanner(Store store, ScanInfo scanInfo, Scan scan, final
NavigableSet<byte[]> columns,
long readPt)
throws IOException {
this(store, scan, scanInfo, columns, readPt, scan.getCacheBlocks());
if (columns != null && scan.isRaw()) {
throw new DoNotRetryIOException("Cannot specify any column for a raw
scan");
}
matcher = new ScanQueryMatcher(scan, scanInfo, columns,
ScanType.USER_SCAN, Long.MAX_VALUE, HConstants.LATEST_TIMESTAMP,
oldestUnexpiredTS, now, store.getCoprocessorHost());
this.store.addChangedReaderObserver(this);
// Pass columns to try to filter out unnecessary StoreFiles.
List<KeyValueScanner> scanners = getScannersNoCompaction();
...
seekScanners(scanners, matcher.getStartKey(), explicitColumnQuery
&& lazySeekEnabledGlobally, parallelSeekEnabled);
...
resetKVHeap(scanners, store.getComparator());
}
{code}
If there's any Exception thrown after
{{this.store.addChangedReaderObserver(this)}}, the returned scanner might be
null and there's no chance to remove the scanner from changedReaderObservers,
like in HRegion#get
{code}
RegionScanner scanner = null;
try {
scanner = getScanner(scan);
scanner.next(results);
} finally {
if (scanner != null)
scanner.close();
}
{code}
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