Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Error rate is more than theoretical error rate #28

Open
shreshthagarg21 opened this issue Mar 16, 2021 · 0 comments
Open

Error rate is more than theoretical error rate #28

shreshthagarg21 opened this issue Mar 16, 2021 · 0 comments

Comments

@shreshthagarg21
Copy link

The research paper claims the error rate to be 1.04/sqrt(m)

For log2m = 11 and w = 5 the theoretical error rate should be ~2.3% but in our tests we have seen a variance of upto 3.5% for inserting 100K unique alphanumeric UUIDs. Below is our pseudo code :

HLL hll = new HLL( 11, 5 );
HashFunction hashFunction = Hashing.murmur3_128();

for (String str : UUIDs) {
  Hasher hasher = hashFunction.newHasher();
  hasher.putString(str, StandardCharsets.UTF_8);
  hll.addRaw(hasher.hash().asLong());
}

How can we reduce this additional 1.2% variance and fall in the theoretically claimed error rate ?

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

1 participant