Jtest fail on ARM

[wangxiyuan]

There is one test failed on my local ARM machine when running make jtest

getOutOfArrayMaxSizeValue(org.rocksdb.RocksDBTest)

java.lang.AssertionError: Expected test to throw (an instance of org.rocksdb.RocksDBException and exception with message a string containing "Requested array size exceeds VM limit")
	at org.junit.Assert.fail(Assert.java:88)
	at org.junit.rules.ExpectedException.failDueToMissingException(ExpectedException.java:263)
	at org.junit.rules.ExpectedException.access$200(ExpectedException.java:106)
	at org.junit.rules.ExpectedException$ExpectedExceptionStatement.evaluate(ExpectedException.java:245)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runners.Suite.runChild(Suite.java:128)
	at org.junit.runners.Suite.runChild(Suite.java:27)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:105)
	at org.junit.runner.JUnitCor

While when I was debugging this test with jdb, and set a breakpoint at L351, I hit a strange behavior. If I print run at once, the test will fail. But if I wait one minute and then print run, this test will pass.

For example, if I type print db.get(key) several times quickly at once when the code stopping at L351. You can see that the value is not updated at once:

main[1] print db.get(key)
 db.get(key) = instance of byte[1073741824] (id=1042)
main[1] print db.get(key)
 db.get(key) = instance of byte[1073741824] (id=1043)
main[1] print db.get(key)
 db.get(key) = instance of byte[1073741824] (id=1044)
main[1] print db.get(key)
 db.get(key) = instance of byte[1073741824] (id=1045)
main[1] print db.get(key)
Exception in expression: org.rocksdb.RocksDBException
 db.get(key) = null

Any suggestion about this case? Is it related to RocksDB cache or anything else.? Need any idea.

Thanks.

[riversand963]

I do not have access to ARM. Look forward to feedback from people who can give this a shot.

[wangxiyuan]

@riversand963 I can provide a ARM VM temporarily. Please let me know if you need one. Thanks.

[Yikun]

Is the db.merge operation an asynchronous operation? I encountered the same problem in my aarch64 env.

The behavior of this operations is like: the merge operations is not completed after the 10 times db.merge. looks like we need wait a moment and then trigger the final RocksDBException.

If it is, I think maybe we should fix the test case.