I don't believe integers or even 1kb buffers are the right case for
directmemory. Small keys, large payloads (+4kb) are. In any case: how were
the heap and xxmaxdirectmemory settings? And did you try the Unsafe storage
as well? It would be helpful if you could share the benchmark code.
Thanks,
R
Il giorno 08/nov/2012 02:49, "Jan Kotek" <[email protected]> ha scritto:
> Hi,
>
> MapDB now has DirectMemory storage.
> I made little test to compare our two libraries + java.util.TreeMap
>
> All tests are on 64bit Linux, 16GB RAM, JDK6. Default JVM settings.
> Source code is here: https://github.com/jankotek/**
> mapdb-junk/tree/master/src/**main/java/**directMemoryBenchmark<https://github.com/jankotek/mapdb-junk/tree/master/src/main/java/directMemoryBenchmark>
>
>
> First is performance test. How long does it take to insert and fetch 1
> million records, each 1KB large.
> - DM - 6901 ms
> - MapDB - 2045 ms
> - java.util.TreeMap - 940 ms
>
> Second is overhead test. It inserts pair of integers in cycle, until JVM
> runs out of memory.
> It should measure how much memory library each consumes for its own
> structures.
> - DM - inserts 9 000 000 records and then it becomes very slow. Profiler
> shows high GC activity.
> - MapDB - works about 10 minutes and than it runs out of memory with 217
> 000 000 records.
> - java.util.TreeMap - crashes after 99 000 000 records , it consumed
> about 12GB heap.
>
>
> I am not sure I configured DM correctly, JVM kept crashing when I
> increased size too much.
> I ended with this setting:
>
> CacheService<Object, Object> m = new DirectMemory<Object, Object>()
> .setNumberOfBuffers( 30 )
> .setSize((int) 1e8)
> .setInitialCapacity( 10000 )
> .setConcurrencyLevel( 4 )
> .setDisposalTime(1000000)
> .newCacheService();
>
>
> Hope this helps.
>
> Jan
>
>
