Agreed that this is an issue! I opened https://github.com/elasticsearch/elasticsearch/issues/6962
On Tue, Jul 22, 2014 at 1:33 PM, [email protected] < [email protected]> wrote: > This is really an issue. > > I could work on a pull request for better control of Unsafe usage together > with a new setting "jvm.use.unsafe" (or something) which should be true by > default and auto-detectable, so ES could run OOTB also on other JVMs or big > endian platforms. > > Jörg > > > > > On Tue, Jul 22, 2014 at 11:43 AM, David Roberts < > [email protected]> wrote: > >> Hello, >> >> After upgrading from Elasticsearch 1.0.1 to 1.2.2 I'm getting JVM core >> dumps on Solaris 10 on SPARC. >> >> # A fatal error has been detected by the Java Runtime Environment: >> # >> # SIGBUS (0xa) at pc=0xffffffff7e452d78, pid=15483, tid=263 >> # >> # JRE version: Java(TM) SE Runtime Environment (7.0_55-b13) (build >> 1.7.0_55-b13) >> # Java VM: Java HotSpot(TM) 64-Bit Server VM (24.55-b03 mixed mode >> solaris-sparc compressed oops) >> # Problematic frame: >> # V [libjvm.so+0xc52d78] Unsafe_GetLong+0x158 >> >> I'm pretty sure the problem here is that Elasticsearch is making >> increasing use of "unsafe" functions in Java, presumably to speed things >> up, and some CPUs are more picky than others about memory alignment. In >> particular, x86 will tolerate misaligned memory access whereas SPARC won't. >> >> Somebody has tried to report this to Oracle in the past and >> (understandably) Oracle has said that if you're going to use unsafe >> functions you need to understand what you're doing: >> http://bugs.java.com/bugdatabase/view_bug.do?bug_id=8021574 >> >> A quick grep through the code of the two versions of Elasticsearch shows >> that the new use of "unsafe" memory access functions is in the >> BytesReference, MurmurHash3 and HyperLogLogPlusPlus classes: >> >> bash-3.2$ git checkout v1.0.1 >> Checking out files: 100% (2904/2904), done. >> >> bash-3.2$ find . -name '*.java' | xargs grep UnsafeUtils >> ./src/main/java/org/elasticsearch/common/util/UnsafeUtils.java:public >> enum UnsafeUtils { >> ./src/main/java/org/elasticsearch/search/aggregations/bucket/BytesRefHash.java: >> if (id == -1L || UnsafeUtils.equals(key, get(id, spare))) { >> ./src/main/java/org/elasticsearch/search/aggregations/bucket/BytesRefHash.java: >> } else if (UnsafeUtils.equals(key, get(curId, spare))) { >> ./src/test/java/org/elasticsearch/benchmark/common/util/BytesRefComparisonsBenchmark.java:import >> org.elasticsearch.common.util.UnsafeUtils; >> ./src/test/java/org/elasticsearch/benchmark/common/util/BytesRefComparisonsBenchmark.java: >> return UnsafeUtils.equals(b1, b2); >> >> bash-3.2$ git checkout v1.2.2 >> Checking out files: 100% (2220/2220), done. >> >> bash-3.2$ find . -name '*.java' | xargs grep UnsafeUtils >> ./src/main/java/org/elasticsearch/common/bytes/BytesReference.java:import >> org.elasticsearch.common.util.UnsafeUtils; >> ./src/main/java/org/elasticsearch/common/bytes/BytesReference.java: >> return UnsafeUtils.equals(a.array(), a.arrayOffset(), b.array(), >> b.arrayOffset(), a.length()); >> ./src/main/java/org/elasticsearch/common/hash/MurmurHash3.java:import >> org.elasticsearch.common.util.UnsafeUtils; >> ./src/main/java/org/elasticsearch/common/hash/MurmurHash3.java: >> return UnsafeUtils.readLongLE(key, blockOffset); >> ./src/main/java/org/elasticsearch/common/hash/MurmurHash3.java: >> long k1 = UnsafeUtils.readLongLE(key, i); >> ./src/main/java/org/elasticsearch/common/hash/MurmurHash3.java: >> long k2 = UnsafeUtils.readLongLE(key, i + 8); >> ./src/main/java/org/elasticsearch/common/util/BytesRefHash.java: >> if (id == -1L || UnsafeUtils.equals(key, get(id, spare))) { >> ./src/main/java/org/elasticsearch/common/util/BytesRefHash.java: >> } else if (UnsafeUtils.equals(key, get(curId, spare))) { >> ./src/main/java/org/elasticsearch/common/util/UnsafeUtils.java:public >> enum UnsafeUtils { >> ./src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/HyperLogLogPlusPlus.java:import >> org.elasticsearch.common.util.UnsafeUtils; >> ./src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/HyperLogLogPlusPlus.java: >> return UnsafeUtils.readIntLE(readSpare.bytes, readSpare.offset); >> ./src/test/java/org/elasticsearch/benchmark/common/util/BytesRefComparisonsBenchmark.java:import >> org.elasticsearch.common.util.UnsafeUtils; >> ./src/test/java/org/elasticsearch/benchmark/common/util/BytesRefComparisonsBenchmark.java: >> return UnsafeUtils.equals(b1, b2); >> >> Presumably one of these three new uses is what is causing the JVM SIGBUS >> error I'm seeing. >> >> A quick look at the MurmurHash3 class shows that the hash128 method >> accepts an arbitrary offset and passes it to an unsafe function with no >> check that it's a multiple of 8: >> >> public static Hash128 hash128(byte[] key, int offset, int length, >> long seed, Hash128 hash) { >> long h1 = seed; >> long h2 = seed; >> >> if (length >= 16) { >> >> final int len16 = length & 0xFFFFFFF0; // higher multiple of >> 16 that is lower than or equal to length >> final int end = offset + len16; >> for (int i = offset; i < end; i += 16) { >> long k1 = UnsafeUtils.readLongLE(key, i); >> long k2 = UnsafeUtils.readLongLE(key, i + 8); >> >> This is a recipe for generating JVM core dumps on architectures such as >> SPARC, Itanium and PowerPC that don't support unaligned 64 bit memory >> access. >> >> Does Elasticsearch have any policy for support of hardware other than >> x86? If not, I don't think many people would care but you really ought to >> clearly say so on your platform support page. If you do intend to support >> non-x86 architectures then you need to be much more careful about the use >> of unsafe memory accesses. >> >> Regards, >> >> David >> >> -- >> You received this message because you are subscribed to the Google Groups >> "elasticsearch" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/elasticsearch/e57c7412-4878-4cd5-b21f-72b4d39e98f1%40googlegroups.com >> <https://groups.google.com/d/msgid/elasticsearch/e57c7412-4878-4cd5-b21f-72b4d39e98f1%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > > -- > You received this message because you are subscribed to the Google Groups > "elasticsearch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elasticsearch/CAKdsXoFF%3DSG-epttqi%2B%3DwzJC%3DKdN%3DbM1Z3MD7U_vkUgb%3DvZ1Fw%40mail.gmail.com > <https://groups.google.com/d/msgid/elasticsearch/CAKdsXoFF%3DSG-epttqi%2B%3DwzJC%3DKdN%3DbM1Z3MD7U_vkUgb%3DvZ1Fw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- Adrien Grand -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/elasticsearch/CAL6Z4j7e9JVEogE1E3VOHbexZVFiec9TYLHy70Sg_Ehs-HmR6w%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
