jhat fails reading very large (>2GB) heap dumps:

jhat -debug 1 ...

Read record type 2, length 16 at position 0x337c13
Read record type 2, length 16 at position 0x337c2c
Read record type 12, length -1452344221 at position 0x337c45
java.io.IOException: Bad record length of -1452344221 at byte 0x337c4a of file.
       at com.sun.tools.hat.internal.parser.HprofReader.read(HprofReader.java:192)
       at com.sun.tools.hat.internal.parser.Reader.readFile(Reader.java:79)
       at com.sun.tools.hat.Main.main(Main.java:143) 

This is an overflow: the  customer  (i.e. heap dump) size in the dump file is 2.7GB, which has been read as a signed int.


It is understood that the heap size requirements will be very large for jhat to read such a dump.  A 64-bit JVM will usually be needed.  e.g.  jhat -J-d64 -J-Xmx6g etc...
Posted Date : 2007-10-08 10:54:53.0

It turns out that this bug has been seen in nightly testing:

New vm.heapdump failures (from 2008.03.29)
    heapdump/JMapHeap
    heapdump/JMapPerm
    heapdump/OnOOMToFile
    heapdump/OnOOMToPath
        These tests failed due to "IOException: Bad record length of
        -174853360 at byte 0x45c9b06c of file." on Solaris AMD64 Server
        VM (machine intelsdv01).

        Update: JMapHeap and JMapPerm were executed in the 2008.03.30
            nightly on machine vm-v20z-5 and did not reproduce this
            failure mode.

        Update: JMapHeap and OnOOMToPath failed in the 2008.07.03
            nightly with this failure mode. In the same run, JMapPerm
            and OnOOMToFile failed due to 6650690.

        Last failure on 2008.07.03 with Solaris AMD64 Server VM (machine intelsdv01)
        Previous failure on 2008.03.29 with Solaris AMD64 Server VM (machine intelsdv01)


http://sqeweb.sfbay.sun.com/nfs/results/vm/gtee/JDK7/NIGHTLY/VM/2008-03-29/Serv_Baseline/vm/solaris-amd64/server/comp/vm-solaris-amd64_server_comp_vm.heapdump.testlist2008-03-29-22-27-49/analysis.html
http://sqeweb.sfbay.sun.com/nfs/results/vm/gtee/JDK7/NIGHTLY/VM/2008-07-03/Serv_Baseline/vm/solaris-amd64/server/comp/vm-solaris-amd64_server_comp_vm.heapdump.testlist2008-07-03-19-44-52/analysis.html
Posted Date : 2008-09-09 20:04:53.0

N/A

Overflow, 32-bit unsigned value treated as signed.
Posted Date : 2007-11-28 15:07:55.0

http://hg.openjdk.java.net/jdk6/jdk6/jdk/rev/dd7969318d7a
Posted Date : 2009-12-08 22:14:29.0

This doesn't seem to work for us at all:

 >java -version
java version "1.6.0_03"
Java(TM) SE Runtime Environment (build 1.6.0_03-b05)
Java HotSpot(TM) 64-Bit Server VM (build 1.6.0_03-b05, mixed mode)
 >jhat -version                     
jhat version 2.0 (java version 1.6.0_03)
 >jhat -J-d64 -J-Xmx6g snapshot.jmap
Reading from snapshot.jmap...
Dump file created Wed Jan 16 11:22:00 UTC 2008
java.io.IOException: Bad record length of -1627816209 at byte 0x3b62eb of file.
        at com.sun.tools.hat.internal.parser.HprofReader.read(HprofReader.java:192)
        at com.sun.tools.hat.internal.parser.Reader.readFile(Reader.java:79)
        at com.sun.tools.hat.Main.main(Main.java:143)

snapshot.jmap size is 2.48GB.

Upgraded to 1.6.0_04 and it still will not open a file
larger than 2G.  Opens a file with size of 1.4G just fine.

I don't think this is an issue with jvm 32/64 bit size.  This is
an issue with HprofReader.java using normal 32bit java
io functions.

I can't  open a 1g heap:
ls -l /tmp/*.hprof
-rw-r--r--    1 gcolpitt g680     10780873 Feb  4 12:00 /tmp/snapshot.hprof
jhat /tmp/*.hprof
Reading from /tmp/snapshot.hprof...
Dump file created Mon Feb 04 11:59:45 PST 2008
Snapshot read, resolving...
Resolving 249228 objects...
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
	at com.sun.tools.hat.internal.model.JavaLazyReadObject.intAt(JavaLazyReadObject.java:136)
	at com.sun.tools.hat.internal.model.JavaLazyReadObject.objectIdAt(JavaLazyReadObject.java:108)
	at com.sun.tools.hat.internal.model.JavaObject.parseFields(JavaObject.java:257)
	at com.sun.tools.hat.internal.model.JavaObject.resolve(JavaObject.java:76)
	at com.sun.tools.hat.internal.model.Snapshot.resolve(Snapshot.java:257)
	at com.sun.tools.hat.Main.main(Main.java:152)
ap615ses% java -version
java version "1.6.0_03"
Java(TM) SE Runtime Environment (build 1.6.0_03-b05)
Java HotSpot(TM) Server VM (build 1.6.0_03-b05, mixed mode)
ap615ses% 

If it is fixed where can i how can i get the latest patch of Jhat