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https://issues.apache.org/jira/browse/CASSANDRA-9120?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14396291#comment-14396291
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Vladimir commented on CASSANDRA-9120:
-------------------------------------

What about saving checksums in a separate file? In thi case old versions will 
use saved caved cache as is, new will check whole cache or separate records. Is 
there reason to not have it? Otherwise it's still possible to read some 
inconsistent data that wont cause a crash.

> OutOfMemoryError when read auto-saved cache (probably broken)
> -------------------------------------------------------------
>
>                 Key: CASSANDRA-9120
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9120
>             Project: Cassandra
>          Issue Type: Bug
>         Environment: Linux
>            Reporter: Vladimir
>            Assignee: Jeff Jirsa
>             Fix For: 3.0, 2.0.15, 2.1.5
>
>
> Found during tests on a 100 nodes cluster. After restart I found that one 
> node constantly crashes with OutOfMemory Exception. I guess that auto-saved 
> cache was corrupted and Cassandra can't recognize it. I see that similar 
> issues was already fixed (when negative size of some structure was read). 
> Does auto-saved cache have checksum? it'd help to reject corrupted cache at 
> the very beginning.
> As far as I can see current code still have that problem. Stack trace is:
> {code}
> INFO [main] 2015-03-28 01:04:13,503 AutoSavingCache.java (line 114) reading 
> saved cache 
> /storage/core/loginsight/cidata/cassandra/saved_caches/system-sstable_activity-KeyCache-b.db
> ERROR [main] 2015-03-28 01:04:14,718 CassandraDaemon.java (line 513) 
> Exception encountered during startup
> java.lang.OutOfMemoryError: Java heap space
>         at java.util.ArrayList.<init>(Unknown Source)
>         at 
> org.apache.cassandra.db.RowIndexEntry$Serializer.deserialize(RowIndexEntry.java:120)
>         at 
> org.apache.cassandra.service.CacheService$KeyCacheSerializer.deserialize(CacheService.java:365)
>         at 
> org.apache.cassandra.cache.AutoSavingCache.loadSaved(AutoSavingCache.java:119)
>         at 
> org.apache.cassandra.db.ColumnFamilyStore.<init>(ColumnFamilyStore.java:262)
>         at 
> org.apache.cassandra.db.ColumnFamilyStore.createColumnFamilyStore(ColumnFamilyStore.java:421)
>         at 
> org.apache.cassandra.db.ColumnFamilyStore.createColumnFamilyStore(ColumnFamilyStore.java:392)
>         at org.apache.cassandra.db.Keyspace.initCf(Keyspace.java:315)
>         at org.apache.cassandra.db.Keyspace.<init>(Keyspace.java:272)
>         at org.apache.cassandra.db.Keyspace.open(Keyspace.java:114)
>         at org.apache.cassandra.db.Keyspace.open(Keyspace.java:92)
>         at 
> org.apache.cassandra.db.SystemKeyspace.checkHealth(SystemKeyspace.java:536)
>         at 
> org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:261)
>         at 
> org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:496)
>         at 
> org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:585)
> {code}
> I looked at source code of Cassandra and see:
> http://grepcode.com/file/repo1.maven.org/maven2/org.apache.cassandra/cassandra-all/2.0.10/org/apache/cassandra/db/RowIndexEntry.java
> 119 int entries = in.readInt();
> 120 List<IndexHelper.IndexInfo> columnsIndex = new 
> ArrayList<IndexHelper.IndexInfo>(entries);
> It seems that value entries is invalid (negative) and it tries too allocate 
> an array with huge initial capacity and hits OOM. I have deleted saved_cache 
> directory and was able to start node correctly. We should expect that it may 
> happen in real world. Cassandra should be able to skip incorrect cached data 
> and run.



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