KallaxDB

KallaxDB is a table-less hash-based key-value store developed for storage hardware with built-in transparent compression. It saves each key-value pair to a specific location/page of a storage device according to the hashed key and keeps those overflow key-value pairs in a temporary store. Also, it performs background rehashing when the space allocated for database is not large enough. The source code of KallaxDB uses KVell as a reference (https://github.com/BLepers/KVell).

Environment set up

• Use -o discard option when mounting a storage device.
• Put RocksDB library 'librocksdb.so' or 'librocksdb.a' into the system path like '/usr/lib64'. Compile the RocksDB library using the source code which can be unzipped from rocksdb-master.zip in the directory. Refer to the compile instructions of RocksDB itself.
• make to compile KallaxDB source code.

KallaxDB test

• KallaxDB integrates several YCSB tests including ycsba, ycsbb, ycsbc, ycsbd, ycsbe, ycsbf. There is also a write-only test which is called ycsbg. Use ycsba as an example, one test command is like
  ./bench --create_db=1 --nb_workers=16 --nb_rehash=4 --load_kv_num=1000000 --slab_size=81920 --nb_slabs=16 --request_kv_num=200000 --loader_num=4 --client_num=8 --db_bench=ycsba --value_size=400 --nb_paths=1 --db_path=/kallaxdb.

• Description of key parameters in the command:

Parameter | Default value | Description --------- | ------------- | ----------- create_db | 1 | Whether to create a new database for test nb_workers | 1 | Number of background threads for read and write nb_rehash | 1 | Number of rehash threads nb_slabs | 1 | Number of slabs slab_size | 1 | Total size of all slabs (MB) load_kv_num| 40000000 | Number of KVs for loading loader_num | 1 | Number of threads when loading client_num | 1 | Number of test threads value_size | 200 | Byte length of value key_size | 16 | Byte length of key (minimum 8) page_size | 4096 | Byte length of page size queue_depth| 64 | IO queue depth of each background thread nb_paths | 0 | Number of paths for database files db_path | null | Absolute file paths for database; number of paths equal to nb_paths and paths are separated by comma like --db_path=/dir0,/dir1 db_bench | ycsba | Benchmark for test