Small Datum

I previously shared Linkbench results for MongoDB 3.2.0 with a cached database. Here I provide results for a database larger than cache using SSD and a disk array to compare RocksDB with the WiredTiger B-Tree. The performance summary is: the peak load rate is 2X better with WiredTiger in 3.2 vs 3.0 the load rate for WiredTiger is much better than for RocksDB the load rate for WiredTiger and RocksDB does not get slower with disk vs SSD or with a cached database vs an uncached database. For RocksDB this occurs because secondary index maintenance doesn't require page reads. This might be true for WiredTiger only because the secondary index pages fit in cache. the peak query rates were between 2X and 3X better for RocksDB vs WiredTiger Configuration The previous post explains the benchmark and test hardware. The test was repeated for 1, 4, 8, 16 and 24 concurrent clients for the disk array test and 1, 4, 8, 12, 16, 20 and 24 concurrent clients for the SSD test. Load pe