Notes.txt

### fix sbt notes:

bloop

Among these efforts we find organizations like Stripe or Wix working on better Scala support for Bazel or 
Twitter getting excellent Scala support in Pants, and individuals like Jan Christopher Vogt or Li Haoyi working on cbt and mill respectively.

vovapolu/sbt-big-project -- faster sbt by extra caching

lihaoyi/mill -- sbt alternative
lihaoyi/acyclic -- may be this can be base for modules, not sbt subprojects

coursier/coursier


### hash to compare objects -- exploration state:

vovapolu/scala-data-classes -- replace case class-es by @data

http://greenrobot.org/essentials/features/performant-hash-functions-for-java/comparison-of-hash-functions/

Perfect_hash_function -- after data become constant, with no collisions.

https://en.wikipedia.org/wiki/List_of_hash_functions#Non-cryptographic_hash_functions
?SpookyHash, cityhash, farmhash
?collisions rare: FNV-1, FNV-1a, DJB2, DJB2a, SDBM & MurmurHash
MurmurHash is very fast and version 3 supports 128bit length, Implemented in Java and Scala.
128: fnv, murmur, spooky, city, highway

mvn:
  net.jpountz.lz4 -- fast, used by kafka, but 64bit
  com.twitter : util-hashing -- bound to scala version
  OpenHFT/Zero-Allocation-Hashing -- 64bit only?
google/guava -- slow?

to try more:
    greenrobot/essentials -- aka java-common
    sangupta/murmur
    https://github.com/google/guava/wiki/HashingExplained

aappleby/smhasher -- utility to test hashes