The only point here that would make a difference in practice is leveldb using a worse hash function. For us it's not worth making partitioning worse to make compaction better.
On Mon, Feb 11, 2013 at 12:53 PM, Radim Kolar <h...@filez.com> wrote: > 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 > hole) > 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. -- Jonathan Ellis Project Chair, Apache Cassandra co-founder, http://www.datastax.com @spyced
