Thread safety issues with Compression.Algorithm.GZ and CompressionTest
----------------------------------------------------------------------
Key: HBASE-5458
URL: https://issues.apache.org/jira/browse/HBASE-5458
Project: HBase
Issue Type: Bug
Components: io
Affects Versions: 0.90.5
Reporter: David McIntosh
Priority: Minor
I've seen some occasional NullPointerExceptions in
ZlibFactory.isNativeZlibLoaded(conf) during region server startups and the
completebulkload process. This is being caused by a null configuration getting
passed to the isNativeZlibLoaded method. I think this happens when 2 or more
threads call the CompressionTest.testCompression method at once. If the GZ
algorithm has not been tested yet both threads could continue on and attempt to
load the compressor. For GZ the getCodec method is not thread safe which could
lead to one thread getting a reference to a GzipCodec that has a null
configuration.
current:
DefaultCodec getCodec(Configuration conf) {
if (codec == null) {
codec = new GzipCodec();
codec.setConf(new Configuration(conf));
}
return codec;
}
one possible fix would be something like this:
DefaultCodec getCodec(Configuration conf) {
if (codec == null) {
GzipCodec gzip = new GzipCodec();
gzip.setConf(new Configuration(conf));
codec = gzip;
}
return codec;
}
But that may not be totally safe without some synchronization. An upstream fix
in CompressionTest could also prevent multi thread access to GZ.getCodec(conf)
exceptions:
12/02/21 16:11:56 ERROR handler.OpenRegionHandler: Failed open of
region=all-monthly,,1326263896983.bf574519a95263ec23a2bad9f5b8cbf4.
java.io.IOException: java.lang.NullPointerException
at
org.apache.hadoop.hbase.util.CompressionTest.testCompression(CompressionTest.java:89)
at
org.apache.hadoop.hbase.regionserver.HRegion.checkCompressionCodecs(HRegion.java:2670)
at
org.apache.hadoop.hbase.regionserver.HRegion.openHRegion(HRegion.java:2659)
at
org.apache.hadoop.hbase.regionserver.HRegion.openHRegion(HRegion.java:2647)
at
org.apache.hadoop.hbase.regionserver.handler.OpenRegionHandler.openRegion(OpenRegionHandler.java:312)
at
org.apache.hadoop.hbase.regionserver.handler.OpenRegionHandler.process(OpenRegionHandler.java:99)
at
org.apache.hadoop.hbase.executor.EventHandler.run(EventHandler.java:158)
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at
org.apache.hadoop.io.compress.zlib.ZlibFactory.isNativeZlibLoaded(ZlibFactory.java:63)
at
org.apache.hadoop.io.compress.GzipCodec.getCompressorType(GzipCodec.java:166)
at
org.apache.hadoop.io.compress.CodecPool.getCompressor(CodecPool.java:100)
at
org.apache.hadoop.io.compress.CodecPool.getCompressor(CodecPool.java:112)
at
org.apache.hadoop.hbase.io.hfile.Compression$Algorithm.getCompressor(Compression.java:236)
at
org.apache.hadoop.hbase.util.CompressionTest.testCompression(CompressionTest.java:84)
... 9 more
Caused by: java.io.IOException: java.lang.NullPointerException
at
org.apache.hadoop.hbase.util.CompressionTest.testCompression(CompressionTest.java:89)
at
org.apache.hadoop.hbase.io.hfile.HFile$Reader.readTrailer(HFile.java:890)
at
org.apache.hadoop.hbase.io.hfile.HFile$Reader.loadFileInfo(HFile.java:819)
at
org.apache.hadoop.hbase.mapreduce.LoadIncrementalHFiles.groupOrSplit(LoadIncrementalHFiles.java:405)
at
org.apache.hadoop.hbase.mapreduce.LoadIncrementalHFiles$2.call(LoadIncrementalHFiles.java:323)
at
org.apache.hadoop.hbase.mapreduce.LoadIncrementalHFiles$2.call(LoadIncrementalHFiles.java:321)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at
org.apache.hadoop.io.compress.zlib.ZlibFactory.isNativeZlibLoaded(ZlibFactory.java:63)
at
org.apache.hadoop.io.compress.GzipCodec.getCompressorType(GzipCodec.java:166)
at
org.apache.hadoop.io.compress.CodecPool.getCompressor(CodecPool.java:100)
at
org.apache.hadoop.io.compress.CodecPool.getCompressor(CodecPool.java:112)
at
org.apache.hadoop.hbase.io.hfile.Compression$Algorithm.getCompressor(Compression.java:236)
at
org.apache.hadoop.hbase.util.CompressionTest.testCompression(CompressionTest.java:84)
... 10 more
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