Feature request: support for jump_fnv1a_ch hashing algorithm

[piotr1212]

The consistent hashring sharding is very unbalanced as discussed here: https://github.com/graphite-project/carbon/issues/485 @grobian implemented jump_fnv1a_ch in https://github.com/grobian/carbon-c-relay which is better balanced.

It would be nice if graphite-web would support jump_fnv1a_ch.

[obfuscurity]

Please re-open this issue under the https://github.com/graphite-project/carbon project.

[piotr1212]

My request is for graphite-web to support jump_fnv1a so I can use graphite-web in combination with carbon-c-relay in jump_fnv1a_ch mode. Now graphite-web's carbonlink queries fail because they query the wrong cache.

From what I can tell the hashring (used for carbonlink queries) is implemented here: https://github.com/graphite-project/graphite-web/blob/master/webapp/graphite/render/hashing.py

I could open a second issue on carbon to request it implemented in carbon-relay, but I personally don't need it as I don't use carbon-relay. I'm not sure if I understand why this issue is closed.

[obfuscurity]

My apologies, I misunderstood your request.

[piotr1212]

Thinking more about it, it would make sense to have the ConsistentHashRing class not duplicated in the two projects. ConsistentHashRing could be defined in carbon and imported in graphite-web (unless you want to prevent dependencies between the projects).

A quick check between https://github.com/graphite-project/graphite-web/blob/master/webapp/graphite/render/hashing.py#L45-L100 and https://github.com/graphite-project/carbon/blob/master/lib/carbon/hashing.py#L8-L62 shows that there are slight differences. I haven't looked into details so don't know if there are issues, but I would expect it to be identical.

[deniszh]

Both carbon and graphite-web has support of user keyfunc for hashing, not sure if that enough for proper fnv1a support, suspecting that's not...

[bemeyert]

We really could use this feature. We use the fnv1a_ch from Carbon-C-Relay to make our cluster easy to scale out, since we are not dependent on hostnames and ports.

[deniszh]

I added FNV1a support in PR https://github.com/graphite-project/graphite-web/pull/1723

[piotr1212]

Amazing!! thanks

[obfuscurity]

Fixed by #1723.

[Civil]

Just a note - FNV1a != Jump FNV1a, so the issue is not fixed.

[cjagus]

Do we have any plans to support jump_fnv1a_ch hashing algorithm in graphite-web?. @deniszh

[deniszh]

Well, I can try. I do not remember what stopped me, probably complete different implementation of hash ring for jump hash.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.