Exception in thread "H2-lob-cleaner"

[wburzyns]

This just happened while using the current master:

Exception in thread "H2-lob-cleaner": org.h2.mvstore.MVStoreException: java.lang.ArrayIndexOutOfBoundsException: 11910 [2.2.219/3] at org.h2.mvstore.DataUtils.newMVStoreException(DataUtils.java:996) at org.h2.mvstore.MVStore.tryExecuteUnderStoreLock(MVStore.java:942) at org.h2.mvstore.RandomAccessStore.doHousekeeping(RandomAccessStore.java:721) at org.h2.mvstore.FileStore.writeInBackground(FileStore.java:1834) at org.h2.mvstore.FileStore$BackgroundWriterThread.run(FileStore.java:2245) Caused by: java.lang.ArrayIndexOutOfBoundsException: 11910 at org.h2.mvstore.FileStore.rewriteChunks(FileStore.java:1906) at org.h2.mvstore.FileStore.compactRewrite(FileStore.java:1893) at org.h2.mvstore.FileStore.rewriteChunks(FileStore.java:1854) at org.h2.mvstore.RandomAccessStore.lambda$doHousekeeping$4(RandomAccessStore.java:726) at org.h2.mvstore.MVStore.tryExecuteUnderStoreLock(MVStore.java:938) ... 3 more

The crash occured while running "SELECT DATA, DESC FROM MATDB_DATA WHERE GLOBAL_STAMP = ?" . Both DATA and DESC are blobs. Till the moment of the error this query executed 16M times. I've done this massive data dump many times before and never seen seen any problems (till now). The DB reopened without problems, it does not seem to be damaged. Unfortunately I don't think I'll be able to provide you with a testcase.

[grandinj]

So based on that stacktrace, the chunksToC cache is getting out of sync with the chunk.occupancy BitSet field.

@andreitokar any ideas? I can't see what serialisation mechanism is keeping these two things in sync?

Also noting that "occupancy" seems to be a misnomer now, it is no longer (or perhaps never was?) a bitset of "occupied" pages, it is a bitset of "deleted" pages :-)

[andreitokar]

@grandinj There is nothing to keep in-sync, really. Table of Content {toc) is immutable and contains element per page in chunk, and number of pages stored in chunk.pageCount. Somehow toc comes out of the cache shorter than it should.

[JohnNiang]

I had a similar problem when I saved too much data (100) at the same time:

• JVM Options: -Xmx192m

Exception in thread "H2-lob-cleaner" org.h2.mvstore.MVStoreException: Map lobRef(8) is closed. org.h2.mvstore.MVStoreException: java.lang.OutOfMemoryError: Capacity: 35831808 [2.1.214/3] [2.1.214/4]
    at org.h2.mvstore.DataUtils.newMVStoreException(DataUtils.java:1004)
    at org.h2.mvstore.MVMap.beforeWrite(MVMap.java:962)
    at org.h2.mvstore.MVMap.operate(MVMap.java:1757)
    at org.h2.mvstore.MVMap.remove(MVMap.java:518)
    at org.h2.mvstore.db.LobStorageMap.doRemoveLob(LobStorageMap.java:474)
    at org.h2.mvstore.db.LobStorageMap.cleanup(LobStorageMap.java:443)
    at org.h2.mvstore.db.LobStorageMap.lambda$null$0(LobStorageMap.java:122)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: org.h2.mvstore.MVStoreException: java.lang.OutOfMemoryError: Capacity: 35831808 [2.1.214/3]
    at org.h2.mvstore.DataUtils.newMVStoreException(DataUtils.java:1004)
    at org.h2.mvstore.MVStore.serializeAndStore(MVStore.java:1605)
    at org.h2.mvstore.MVStore.lambda$storeNow$4(MVStore.java:1518)
    at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
    at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java)
    ... 3 more
Caused by: java.lang.OutOfMemoryError: Capacity: 35831808
    at org.h2.mvstore.WriteBuffer.grow(WriteBuffer.java:322)
    at org.h2.mvstore.WriteBuffer.ensureCapacity(WriteBuffer.java:302)
    at org.h2.mvstore.WriteBuffer.put(WriteBuffer.java:164)
    at org.h2.mvstore.type.ByteArrayDataType.write(ByteArrayDataType.java:31)
    at org.h2.mvstore.type.ByteArrayDataType.write(ByteArrayDataType.java:17)
    at org.h2.mvstore.type.BasicDataType.write(BasicDataType.java:67)
    at org.h2.mvstore.Page$Leaf.writeValues(Page.java:1609)
    at org.h2.mvstore.Page.write(Page.java:721)
    at org.h2.mvstore.Page$Leaf.writeUnsavedRecursive(Page.java:1618)
    at org.h2.mvstore.Page$NonLeaf.writeChildrenRecursive(Page.java:1344)
    at org.h2.mvstore.Page$NonLeaf.writeUnsavedRecursive(Page.java:1330)
    at org.h2.mvstore.Page$NonLeaf.writeChildrenRecursive(Page.java:1344)
    at org.h2.mvstore.Page$NonLeaf.writeUnsavedRecursive(Page.java:1330)
    at org.h2.mvstore.MVStore.serializeToBuffer(MVStore.java:1669)
    at org.h2.mvstore.MVStore.serializeAndStore(MVStore.java:1598)
    ... 7 more