...
GridDhtPartitionSupplyMessage
used) it still processes entries one by one. Such an process has low impact with a pure in-memory Apache Ignite usage but it leads to additional fsyncs and logging WAL records with the native persistence enabled. setRebalanceThreadPoolSize
is set to 1
and setRebalanceBatchSize
to 512K
which means that thousands of key-value pairs will be processed single-thread and individually. Such an approach impacts on: CacheDataStore
will traverse and modify each index tree N-times. It will allocate the space N-times within FreeList
structure and will have to additionally store WAL page delta records with approximate complexity ~ O(N*log(N))
;The rebalancing procedure doesn't utilize the network and storage device throughout to its full extent even with enough meaningful values of setRebalanceThreadPoolSize
. For instance, trying to use a common recommendation of N+1
threads (N
– the number of CPU cores available) to increase rebalance speed will drammatically slowdown computation performance on demander node. This can be easily shown on the graphs below.
CPU utilization (supplier, demaner) | |
---|---|
setRebalanceThreadPoolSize – 9; setRebalanceBatchSize – 512K; | setRebalanceThreadPoolSize – 1; setRebalanceBatchSize – 512K; |
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scp\rsync
commands can be used. The test environment showed us results – 270 MB/s
over the current 40 MB/s
single-threaded rebalance speed;FileChannel.transfertTo()
call is routed to the sendfile()
system call;...
...
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Code Block |
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batches : 146938 rows : 77321844 rows per batch : 526 time (total) : 40 min cache size : 78055 MB rebalacne speed : 31 MB\sec rows per sec : 31470 rows + cache rebalance total : 2456973 ms : 100.00 + + preload on demander : 2415154 ms : 98.30 + + + offheap().invoke(..) : 1640175 ms : 66.76 + + + + dataTree.invoke(..) : 1595260 ms : 64.93 + + + + + BPlusTree.invokeDown(..) : 220390 ms : 8.97 + + + + + FreeList.insertDataRow(..) : 1340636 ms : 54.56 + + + + CacheDataStoreImpl.finishUpdate(..) : 10807 ms : 0.44 + + + ttl().addTrackedEntry(..) : 9678 ms : 0.39 + + + wal().log(..) : 664680 ms : 27.05 + + + continuousQueries().onEntryUpdated(..) : 8521 ms : 0.35 + message serialization : 1618 ms : 0.07 + network delay between nodes : 7788 ms : 0.32 + make batch on supplier handleDemandMessage(..) : 185749 ms : 7.59 |
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