scylladb / scylladb/cpp-rs-driver
Describe how load balancing differs from the legacy CPP Driver's
Nobody has claimed this yet.
- Dominant language
- C++
- Stars
- 26
- Forks
- 19
- Avg merge
- 1d 21h
- Merged PRs (30d)
- 7
Description
Load balancing in CPP-RS Driver is implemented on top of Rust Driver's DefaultPolicy. This results in a few differences in behaviour that are worth mentions in cassandra.h and in the documentation.
Differences
-
There's no round-robin in DefaultPolicy - instead, replicas are randomly chosen.
This is deliberate, as it prevents imbalance inherent to round-robin. If some node were down, then round-robin would make the next node in the ring/tablet list receive both its own load and all load of the down node. Random selection of replica from the set of alive replicas solves the imbalance issue.
Symptoms:
cass_cluster_set_load_balance_round_robindoes not set round-robin load balancing.
-
more difference TODO
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by comparing the CPP-RS Driver's DefaultPolicy behavior with the legacy CPP Driver, then review the load-balancing API documentation and cassandra.h. Document the known differences, including the round-robin setter behavior and random replica selection, and replace the remaining TODO with the other confirmed differences.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp, rust
- Domain
- api, documentation
- Issue type
- Documentation
- Difficulty
- 3/5
- Estimated time
- Half a day
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100