Jeśli mamy na produkcji problemy z wyciekami pamięci lub innymi problemami w naszych aplikacjach uruchamianych na JVM to mogą nam się przydać następujące parametry:
- -XX:+HeapDumpOnOutOfMemoryError – flaga zrzucająca dump pamięci podczas gdy aplikacja wyłącza się przez OOM
- -XX:OnOutOfMemoryError=… – wykonanie operacji podczas gdy aplikacja wyłącza się przez OOM
- na przykład chcemy zrzucić dump wątków to wpisujemy: “-XX:OnOutOfMemoryError=kill -3 %p”
- -XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput -XX:LogFile=… – zrzut parametrów JVM
- np przykład: -XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput -XX:LogFile=jvm.log
Przykładowy fragment pliku jvm.log bez opcji : -XX:OnOutOfMemoryError=kill -3 %p
<vm_version> <name> OpenJDK 64-Bit Server VM </name> <release> 11.0.4+11-post-Ubuntu-1ubuntu218.04.3 </release> <info> OpenJDK 64-Bit Server VM (11.0.4+11-post-Ubuntu-1ubuntu218.04.3) for linux-amd64 JRE (11.0.4+11-post-Ubuntu-1ubuntu218.04.3), built on Jul 18 2019 18:21:46 by "buildd" with gcc 7.4.0 </info> </vm_version> <vm_arguments> <args> -Xmx128m -XX:+HeapDumpOnOutOfMemoryError -XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput -XX:LogFile=jvm.log </args> <command> eu.craftsoft.tech.CrashMain </command> <launcher> SUN_STANDARD </launcher> <properties> java.vm.specification.name=Java Virtual Machine Specification java.vm.version=11.0.4+11-post-Ubuntu-1ubuntu218.04.3 java.vm.name=OpenJDK 64-Bit Server VM jdk.debug=release sun.boot.library.path=/usr/lib/jvm/java-11-openjdk-amd64/lib java.library.path=/usr/java/packages/lib:/usr/lib/x86_64-linux-gnu/jni:/lib/x86_64-linux-gnu:/usr/lib/x86_64-linux-gnu:/usr/lib/jni:/lib:/usr/lib java.home=/usr/lib/jvm/java-11-openjdk-amd64 java.class.path=target/crash-mem-1.0-SNAPSHOT.jar jdk.boot.class.path.append=:/usr/share/java/java-atk-wrapper.jar java.vm.info=mixed mode, aot, sharing java.vm.specification.vendor=Oracle Corporation java.vm.specification.version=11 java.vm.vendor=Ubuntu sun.java.command=eu.craftsoft.tech.CrashMain sun.java.launcher=SUN_STANDARD </properties> </vm_arguments> <tty> <writer thread='442'/> <blob name='MethodHandlesAdapterBlob' size='32000'> <sect index='1' size='32000' free='31584'/> </blob> java.lang.OutOfMemoryError: Java heap space Dumping heap to java_pid441.hprof ... Heap dump file created [161610591 bytes in 19,238 secs] <writer thread='448'/> <destroy_vm stamp='24,156'/> <tty_done stamp='24,159'/> </tty> <hotspot_log_done stamp='24,159'/> </hotspot_log>
A teraz fragment logu wraz ze zrzuceniem wątków:
<?xml version='1.0' encoding='UTF-8'?> <hotspot_log version='160 1' process='467' time_ms='1573361952698'> <vm_version> <name> OpenJDK 64-Bit Server VM </name> <release> 11.0.4+11-post-Ubuntu-1ubuntu218.04.3 </release> <info> OpenJDK 64-Bit Server VM (11.0.4+11-post-Ubuntu-1ubuntu218.04.3) for linux-amd64 JRE (11.0.4+11-post-Ubuntu-1ubuntu218.04.3), built on Jul 18 2019 18:21:46 by "buildd" with gcc 7.4.0 </info> </vm_version> <vm_arguments> <args> -Xmx128m -XX:+HeapDumpOnOutOfMemoryError -XX:OnOutOfMemoryError=kill -3 %p -XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput -XX:LogFile=jvm.log </args> <command> eu.craftsoft.tech.CrashMain </command> <launcher> SUN_STANDARD </launcher> <properties> java.vm.specification.name=Java Virtual Machine Specification java.vm.version=11.0.4+11-post-Ubuntu-1ubuntu218.04.3 java.vm.name=OpenJDK 64-Bit Server VM jdk.debug=release sun.boot.library.path=/usr/lib/jvm/java-11-openjdk-amd64/lib java.library.path=/usr/java/packages/lib:/usr/lib/x86_64-linux-gnu/jni:/lib/x86_64-linux-gnu:/usr/lib/x86_64-linux-gnu:/usr/lib/jni:/lib:/usr/lib java.home=/usr/lib/jvm/java-11-openjdk-amd64 java.class.path=target/crash-mem-1.0-SNAPSHOT.jar jdk.boot.class.path.append=:/usr/share/java/java-atk-wrapper.jar java.vm.info=mixed mode, aot, sharing java.vm.specification.vendor=Oracle Corporation java.vm.specification.version=11 java.vm.vendor=Ubuntu sun.java.command=eu.craftsoft.tech.CrashMain sun.java.launcher=SUN_STANDARD </properties> </vm_arguments> <tty> <writer thread='468'/> <blob name='MethodHandlesAdapterBlob' size='32000'> <sect index='1' size='32000' free='31584'/> </blob> java.lang.OutOfMemoryError: Java heap space Dumping heap to java_pid467.hprof ... Heap dump file created [161693067 bytes in 19,905 secs] <writer thread='474'/> # # java.lang.OutOfMemoryError: Java heap space # -XX:OnOutOfMemoryError="kill -3 %p" # Executing /bin/sh -c "kill -3 467"... 2019-11-10 05:59:36 Full thread dump OpenJDK 64-Bit Server VM (11.0.4+11-post-Ubuntu-1ubuntu218.04.3 mixed mode, sharing): Threads class SMR info: _java_thread_list=0x00007fc0d8000b20, length=9, elements={ 0x00007fc130013800, 0x00007fc1300e3000, 0x00007fc1300e5000, 0x00007fc1300f3000, 0x00007fc1300f5000, 0x00007fc1300f7800, 0x00007fc1300f9800, 0x00007fc130144000, 0x00007fc13014e000 } "main" #1 prio=5 os_prio=0 cpu=1756,11ms elapsed=23,43s tid=0x00007fc130013800 nid=0x1d4 waiting on condition [0x00007fc139725000] java.lang.Thread.State: RUNNABLE at java.lang.ThreadGroup.uncaughtException(java.base@11.0.4/ThreadGroup.java:1057) at java.lang.ThreadGroup.uncaughtException(java.base@11.0.4/ThreadGroup.java:1050) at java.lang.Thread.dispatchUncaughtException(java.base@11.0.4/Thread.java:2001) "Reference Handler" #2 daemon prio=10 os_prio=0 cpu=1,99ms elapsed=23,39s tid=0x00007fc1300e3000 nid=0x1db waiting on condition [0x00007fc118508000] java.lang.Thread.State: RUNNABLE at java.lang.ref.Reference.waitForReferencePendingList(java.base@11.0.4/Native Method) at java.lang.ref.Reference.processPendingReferences(java.base@11.0.4/Reference.java:241) at java.lang.ref.Reference$ReferenceHandler.run(java.base@11.0.4/Reference.java:213) "Finalizer" #3 daemon prio=8 os_prio=0 cpu=2,61ms elapsed=23,39s tid=0x00007fc1300e5000 nid=0x1dc in Object.wait() [0x00007fc118407000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(java.base@11.0.4/Native Method) - waiting on <0x00000000f8060e10> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(java.base@11.0.4/ReferenceQueue.java:155) - waiting to re-lock in wait() <0x00000000f8060e10> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(java.base@11.0.4/ReferenceQueue.java:176) at java.lang.ref.Finalizer$FinalizerThread.run(java.base@11.0.4/Finalizer.java:170) "Signal Dispatcher" #4 daemon prio=9 os_prio=0 cpu=1,96ms elapsed=23,39s tid=0x00007fc1300f3000 nid=0x1dd runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE "C2 CompilerThread0" #5 daemon prio=9 os_prio=0 cpu=367,00ms elapsed=23,39s tid=0x00007fc1300f5000 nid=0x1de waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE No compile task "C1 CompilerThread0" #8 daemon prio=9 os_prio=0 cpu=96,46ms elapsed=23,39s tid=0x00007fc1300f7800 nid=0x1df waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE No compile task "Sweeper thread" #9 daemon prio=9 os_prio=0 cpu=15,85ms elapsed=23,39s tid=0x00007fc1300f9800 nid=0x1e0 runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE "Service Thread" #10 daemon prio=9 os_prio=0 cpu=0,50ms elapsed=23,33s tid=0x00007fc130144000 nid=0x1e1 runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE "Common-Cleaner" #11 daemon prio=8 os_prio=0 cpu=1,55ms elapsed=23,32s tid=0x00007fc13014e000 nid=0x1e3 in Object.wait() [0x00007fc1091f7000] java.lang.Thread.State: TIMED_WAITING (on object monitor) at java.lang.Object.wait(java.base@11.0.4/Native Method) - waiting on <0x00000000f8061760> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(java.base@11.0.4/ReferenceQueue.java:155) - waiting to re-lock in wait() <0x00000000f8061760> (a java.lang.ref.ReferenceQueue$Lock) at jdk.internal.ref.CleanerImpl.run(java.base@11.0.4/CleanerImpl.java:148) at java.lang.Thread.run(java.base@11.0.4/Thread.java:834) at jdk.internal.misc.InnocuousThread.run(java.base@11.0.4/InnocuousThread.java:134) "VM Thread" os_prio=0 cpu=4312,12ms elapsed=23,44s tid=0x00007fc1300e0000 nid=0x1da runnable "GC Thread#0" os_prio=0 cpu=1540,32ms elapsed=23,49s tid=0x00007fc13002a000 nid=0x1d5 runnable "GC Thread#1" os_prio=0 cpu=1553,31ms elapsed=22,99s tid=0x00007fc100001000 nid=0x1e6 runnable "GC Thread#2" os_prio=0 cpu=1559,13ms elapsed=22,99s tid=0x00007fc100002800 nid=0x1e7 runnable "G1 Main Marker" os_prio=0 cpu=9,80ms elapsed=23,50s tid=0x00007fc130032000 nid=0x1d6 runnable "G1 Conc#0" os_prio=0 cpu=495,58ms elapsed=23,50s tid=0x00007fc130034000 nid=0x1d7 runnable "G1 Conc#1" os_prio=0 cpu=495,51ms elapsed=22,28s tid=0x00007fc10c001000 nid=0x1eb runnable "G1 Refine#0" os_prio=0 cpu=14,58ms elapsed=23,50s tid=0x00007fc1300b8800 nid=0x1d8 runnable "G1 Refine#1" os_prio=0 cpu=7,87ms elapsed=22,75s tid=0x00007fc104002000 nid=0x1e8 runnable "G1 Refine#2" os_prio=0 cpu=6,28ms elapsed=22,75s tid=0x00007fc0c8001000 nid=0x1e9 runnable "G1 Refine#3" os_prio=0 cpu=2,92ms elapsed=22,59s tid=0x00007fc0bc001800 nid=0x1ea runnable "G1 Refine#4" os_prio=0 cpu=0,78ms elapsed=21,87s tid=0x00007fc0c0001000 nid=0x1ec runnable "G1 Young RemSet Sampling" os_prio=0 cpu=1,85ms elapsed=23,51s tid=0x00007fc1300ba800 nid=0x1d9 runnable "VM Periodic Task Thread" os_prio=0 cpu=16,40ms elapsed=23,38s tid=0x00007fc130146800 nid=0x1e2 waiting on condition JNI global refs: 9, weak refs: 0 <writer thread='477'/> Heap garbage-first heap total 10240K, used 694K [0x00000000f8000000, 0x0000000100000000) region size 1024K, 1 young (1024K), 0 survivors (0K) Metaspace used 628K, capacity 4486K, committed 4864K, reserved 1056768K class space used 52K, capacity 386K, committed 512K, reserved 1048576K <writer thread='474'/> <destroy_vm stamp='23,552'/> <tty_done stamp='23,557'/> </tty> <hotspot_log_done stamp='23,557'/> </hotspot_log>
Do analizy wątków, czyli pliku jvm.log możemy wykorzystać stronę:
Do analizy pamięci możemy wykorzystać stronę:
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