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From Radim Kolar <>
Subject real leveldb vs cassandra leveldb
Date Mon, 11 Feb 2013 18:53:17 GMT
real leveldb is better in lot of areas:

L0 are 1/10 of L1 sstable size
tables can be promoted to upper levels if no merging is needed (there is 
variable number of sstables per level, but it tries to keep 1:10:100 
sstable ratios. Not hard requirement
very important - better hash function. murmur and md5 hashes are 
unsuitable for ldb because it turns key sequence into more or less 
random noise. Changing hash function to leveldb one gives about 8 times 
speed increase during seq. writes because far less table merges is needed
better merge policy: merge 1 table + up to 10 tables from next level 
into next + 2 level.

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