Description
The constructor of the class o.a.n.protocol.Content instantiates a new MimeUtil object. That's not cheap as it always creates a new Tika object and there is a lock on the job/jar file when config files are read:
"FetcherThread" #146 daemon prio=5 os_prio=0 tid=0x00007f70523c3800 nid=0x1de2 waiting for monitor entry [0x00007f70193a8000]
java.lang.Thread.State: BLOCKED (on object monitor)
at java.util.zip.ZipFile.getEntry(ZipFile.java:314)
- waiting to lock <0x00000005e0285758> (a java.util.jar.JarFile)
at java.util.jar.JarFile.getEntry(JarFile.java:240)
at java.util.jar.JarFile.getJarEntry(JarFile.java:223)
at sun.misc.URLClassPath$JarLoader.getResource(URLClassPath.java:1042)
at sun.misc.URLClassPath$JarLoader.findResource(URLClassPath.java:1020)
at sun.misc.URLClassPath$1.next(URLClassPath.java:267)
at sun.misc.URLClassPath$1.hasMoreElements(URLClassPath.java:277)
at java.net.URLClassLoader$3$1.run(URLClassLoader.java:601)
at java.net.URLClassLoader$3$1.run(URLClassLoader.java:599)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader$3.next(URLClassLoader.java:598)
at java.net.URLClassLoader$3.hasMoreElements(URLClassLoader.java:623)
at sun.misc.CompoundEnumeration.next(CompoundEnumeration.java:45)
at sun.misc.CompoundEnumeration.hasMoreElements(CompoundEnumeration.java:54)
at java.util.Collections.list(Collections.java:5239)
at org.apache.tika.config.ServiceLoader.identifyStaticServiceProviders(ServiceLoader.java:325)
at org.apache.tika.config.ServiceLoader.loadStaticServiceProviders(ServiceLoader.java:352)
at org.apache.tika.config.ServiceLoader.loadServiceProviders(ServiceLoader.java:274)
at org.apache.tika.detect.DefaultEncodingDetector.<init>(DefaultEncodingDetector.java:45)
at org.apache.tika.config.TikaConfig.getDefaultEncodingDetector(TikaConfig.java:92)
at org.apache.tika.config.TikaConfig.<init>(TikaConfig.java:248)
at org.apache.tika.config.TikaConfig.getDefaultConfig(TikaConfig.java:386)
at org.apache.tika.Tika.<init>(Tika.java:116)
at org.apache.nutch.util.MimeUtil.<init>(MimeUtil.java:69)
at org.apache.nutch.protocol.Content.<init>(Content.java:83)
at org.apache.nutch.protocol.http.api.HttpBase.getProtocolOutput(HttpBase.java:316)
at org.apache.nutch.fetcher.FetcherThread.run(FetcherThread.java:341)
If there are many Fetcher threads this may cause a significant bottleneck, running a Fetcher with 120 threads I've found up to 50 threads waiting for this lock:
# pid 7195 is a Fetcher map task
% sudo -u yarn jstack 7195 \
| grep -A25 'waiting to lock' \
| grep -F 'org.apache.tika.Tika.<init>' \
| wc -l
49
As MimeUtil is thread-safe including the called Tika detector, the best solution seems to cache the MimeUtil object in the actual protocol implementation as it is done in Nutch 2.x (lib-http HttpBase, line #151).
Attachments
Issue Links
- relates to
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TIKA-2645 Reuse SAXParsers where possible
-
- Resolved
-
- links to