Cursor crashes with java.lang.NullPointerException: null #63
Comments
|
Could you please provide the code to reproduce this error? |
|
I could not reproduce this issue. Please provide your response to reproduce this otherwise I have to close this issue. |
|
seems to happen when multiple threads try to access the cursor. |
|
Based on your input I have constructed the below test cases, but again I am unable to reproduce this. Could you please try to modify the below test case to match your scenario and reproduce this error? @Indices({
@Index(value = "name", type = IndexType.Fulltext)
})
public class PersonEntity {
@Id
private String uuid;
private String name;
private String status;
private PersonEntity friend;
private Date dateCreated;
public PersonEntity() {
this.uuid = UUID.randomUUID().toString();
this.dateCreated = new Date();
}
public PersonEntity(String name) {
this.uuid = UUID.randomUUID().toString();
this.name = name;
this.dateCreated = new Date();
}
// getter and setter...
}
@Test
public void testIssue63() throws InterruptedException {
PersonEntity p1 = new PersonEntity("abcd");
p1.setStatus("Married");
PersonEntity p2 = new PersonEntity("efgh");
p2.setStatus("Married");
PersonEntity p3 = new PersonEntity("ijkl");
p3.setStatus("Un-Married");
ObjectRepository<PersonEntity> repository = db.getRepository(PersonEntity.class);
repository.insert(p1);
repository.insert(p2);
repository.insert(p3);
final CountDownLatch latch = new CountDownLatch(100);
ExecutorService executor = Executors.newFixedThreadPool(10);
final Cursor<PersonEntity> cursor = repository.find();
// now trying to access same cursor from 100 threads
for (int i = 0; i < 100; i++) {
executor.submit(new Runnable() {
@Override
public void run() {
try {
for (PersonEntity entity : cursor) {
assertTrue(entity.getStatus().equals("Married")
|| entity.getStatus().equals("Un-Married"));
}
} catch (Throwable t) {
t.printStackTrace();
} finally {
latch.countDown();
}
}
});
}
latch.await();
}
|
|
I got a similar error on accessing the same cursor from 5 threads: One cursor per threads doesn't work too (error: db already open), What is the trick? |
|
@swissfreedev I have modified your code a bit as follows: @Test
public void testIssue63_2() throws InterruptedException, IOException {
Nitrite db = Nitrite.builder().compressed().filePath("/tmp/nitrite.db").openOrCreate(); //ohne gummi
ObjectRepository<PersonEntity> repRegion = db.getRepository(PersonEntity.class);
PersonEntity p1 = new PersonEntity("abcd");
p1.setStatus("Married");
PersonEntity p2 = new PersonEntity("efgh");
p2.setStatus("Married");
PersonEntity p3 = new PersonEntity("ijkl");
p3.setStatus("Un-Married");
repRegion.insert(p1);
repRegion.insert(p2);
repRegion.insert(p3);
final Cursor<PersonEntity> cursor = repRegion.find();
CountDownLatch latch = new CountDownLatch(5);
TestThreadMultiCursor t1 = new TestThreadMultiCursor(cursor, 1, latch);
TestThreadMultiCursor t2 = new TestThreadMultiCursor(cursor, 2, latch);
TestThreadMultiCursor t3 = new TestThreadMultiCursor(cursor, 3, latch);
TestThreadMultiCursor t4 = new TestThreadMultiCursor(cursor, 4, latch);
TestThreadMultiCursor t5 = new TestThreadMultiCursor(cursor, 5, latch);
t1.start();
t2.start();
t3.start();
t4.start();
t5.start();
latch.await();
Files.delete(Paths.get("/tmp/nitrite.db"));
}
public class TestThreadMultiCursor extends Thread {
Integer threadID;
Cursor<PersonEntity> cursorRegion;
CountDownLatch latch;
public TestThreadMultiCursor(Cursor<PersonEntity> cursorRegion, Integer threadID, CountDownLatch latch) {
this.threadID = threadID;
this.cursorRegion = cursorRegion;
this.latch = latch;
}
public void run() {
System.out.println("Thread " + threadID);
for (PersonEntity t : cursorRegion) {
System.out.println(threadID + ". " + t.getName());
}
latch.countDown();
}
}But still I could not reproduce it.
Can you please provide some additional details like - OS, system arch, java version etc? |
|
Hi Anindya, in my office: win10, netbeans8.2, jdk8, nitrite 2.1.0 I can upload the entire project if it helps? funny, don't tell me it's again a win10 issue ;-) |
|
In my experience lots of funny things happen in Windows. This is the reason why I moved away from it long ago for my development and day to day work :). It would help immensely if you can test your code on suse. Meantime I'll test it on my Win10 also. Let's see what happens! |
|
Oh @swissfreedev one more thing I just noticed. I see @wojsys and you are running old version of nitrite. Is it possible for you to test it against 2.2.0-SNAPSHOT in Win10? |
|
Ok this time win10 is innocent, I got the exception on suse leap 43.2 as well, next step is the update to 2.2.0, news will follow... test startet db=datamulti.db |
|
Really strange. Can you please upload your sample project here? |
|
here it comes: TestMulti() for creating test entries, TestMultiCursor() for producing the error |
|
I ran it using 2.2.0-SNAPSHOT it went smoothly on ubuntu 17.10 (64-bit) with JDK 1.8.0_102
Tried with both nitrite 2.1.0 and 2.1.1, no issues either. I'll try to run it on couple other systems to see if I can reproduce it. |
|
more and more strange, in this case I can omit a random test with snapshot 2.2.0 |
|
by the way, I'm continuously implementing a Nitrite Admin tool based on your Nitrite explorer 2.0.1 and have added some useful custom features, if you are interested I can share it in a couple of week once a stable state is reached... |
|
Superb!!!! I am eager to see the final product. Great job indeed. |
|
for my own usage I basically added: connect /disconnect since nitrite allows just one connection and its weird to get always the "already connected" error while running two programs, remember/load database path in the local preferencies, direct and quick start without intermediate dialogs, and some cosmetical features I would now like to add an edit mode if this isn't a big deal, and a table sql-like view in studio3t... |
|
Another development on this issue. I tried it in my office machine - Ubuntu 14.04 (64-bit) with JDK 1.8.0_102. I can see the NPE while using nitrite 2.1.0, but never encountered this with nitrite 2.1.1 or 2.2.0-SNAPSHOT (tried like 30 times with your uploaded code). Could you please try your code with 2.2.0-SNAPSHOT as well in your machine and share the result? |
|
yes, I'm curious to see what happens, i'll tell you the results soon |
|
Good news: you are right, I switched to 2.1.1 and 2.2.0 the issue is no more reproducible... so just do not use older versions |
|
Great, so I can close this issue. @wojsys please revert back if you are seeing this issue in 2.2.0-SNAPSHOT. On a separate note @swissfreedev I could not thank you enough for being a backer for this project in https://opencollective.com/nitrite-database. It will surely inspire me a lot more to invest my time in this project. Cheers. |
java.lang.NullPointerException: null
at org.h2.mvstore.Page.getRawChildPageCount(Page.java:868) ~[h2-mvstore-1.4.196.jar:1.4.196]
at org.h2.mvstore.MVMap.getChildPageCount(MVMap.java:1179) ~[h2-mvstore-1.4.196.jar:1.4.196]
at org.h2.mvstore.Cursor.fetchNext(Cursor.java:149) ~[h2-mvstore-1.4.196.jar:1.4.196]
at org.h2.mvstore.Cursor.next(Cursor.java:50) ~[h2-mvstore-1.4.196.jar:1.4.196]
at org.dizitart.no2.internals.DocumentCursor$DocumentCursorIterator.next(DocumentCursor.java:106) ~[nitrite-2.1.1.jar:na]
at org.dizitart.no2.internals.DocumentCursor$DocumentCursorIterator.next(DocumentCursor.java:92) ~[nitrite-2.1.1.jar:na]
at org.dizitart.no2.objects.ObjectCursor$ObjectCursorIterator.next(ObjectCursor.java:108) ~[nitrite-2.1.1.jar:na]
The text was updated successfully, but these errors were encountered: