RSCBC-302: Replica read from specific replica - #503
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🟡 Changes recommended
It introduces new public APIs where at least one is missing rustdoc and one new core options type doesn’t follow established option-type attributes, creating avoidable public-API inconsistency.
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Pull request overview
This PR adds end-to-end support for reading documents from a specific replica, including an SDK-facing strategy API, new result/options types, core KV/memdx plumbing, retry/wrap behavior, and performer/protocol integrations.
Changes:
- Introduces
Collection::get_replicawithGetReplicaStrategy/ReplicaIndexandGetReplicaResult/GetReplicaOptionsin the SDK layer. - Implements replica routing + wrap logic in
couchbase-core, including new memdx opcode/request/response and helper logic to advance across replicas. - Extends error modeling and performer mappings to represent replica-specific error cases and capabilities.
File summaries
| File | Description |
|---|---|
| sdk/couchbase/src/results/kv_results.rs | Adds GetReplicaResult SDK result type with decoding helpers and core-result conversion. |
| sdk/couchbase/src/options/kv_options.rs | Adds GetReplicaOptions for SDK-level configuration (retry strategy). |
| sdk/couchbase/src/lib.rs | Exposes get_replica_strategy module publicly. |
| sdk/couchbase/src/get_replica_strategy.rs | Adds public strategy API for selecting a replica by index (with optional wrapping). |
| sdk/couchbase/src/error.rs | Adds replica-specific error kinds and maps core errors into SDK errors (including replica-not-found). |
| sdk/couchbase/src/collection_crud.rs | Adds Collection::get_replica operation wired through tracing + core client. |
| sdk/couchbase/src/clients/couchbase_core_kv_client.rs | Translates SDK strategy/options into core agent call and converts the result type. |
| sdk/couchbase/src/clients/core_kv_client.rs | Exposes get_replica across backend variants (core + couchbase2 stub). |
| sdk/couchbase-core/src/vbucketrouter.rs | Propagates replica index/topology info into NoServerAssigned and adds wrap test coverage. |
| sdk/couchbase-core/src/vbucketmap.rs | Fixes replica index bounds check and adds tests for valid/invalid positions. |
| sdk/couchbase-core/src/retry.rs | Refactors retry decision logic into reusable retry_after_error helper. |
| sdk/couchbase-core/src/results/kv.rs | Adds GetReplicaResult at core results level. |
| sdk/couchbase-core/src/replica_helpers.rs | Adds wrap/advance logic for replica selection and comprehensive unit tests. |
| sdk/couchbase-core/src/options/crud.rs | Adds core GetReplicaOptions and GetReplicaStrategy used by the agent/crudcomponent. |
| sdk/couchbase-core/src/memdx/response.rs | Adds GetReplicaResponse decoding and tracing attributes. |
| sdk/couchbase-core/src/memdx/request.rs | Adds GetReplicaRequest request model. |
| sdk/couchbase-core/src/memdx/ops_crud.rs | Implements memdx CRUD operation for GetReplica. |
| sdk/couchbase-core/src/memdx/opcode.rs | Adds memdx opcode mapping for GetReplica (0x83). |
| sdk/couchbase-core/src/lib.rs | Registers internal replica_helpers module. |
| sdk/couchbase-core/src/kvclient_ops.rs | Adds get_replica to KV client ops trait and implementation. |
| sdk/couchbase-core/src/error.rs | Extends NoServerAssigned context and tracks is_replica on memdx errors. |
| sdk/couchbase-core/src/crudcomponent.rs | Implements core get_replica orchestration, routing, wrapping, and retry integration. |
| sdk/couchbase-core/src/agent_ops.rs | Exposes Agent::get_replica operation with optional top-level spans. |
| performer/src/translations/kv_options.rs | Adds proto→SDK translations for GetReplicaOptions and GetReplicaStrategy. |
| performer/src/translations/common.rs | Maps new SDK error kinds to corresponding proto exception types. |
| performer/src/performer.rs | Advertises SdkGetReplica capability. |
| performer/src/common/content.rs | Enables content decoding for GetReplicaResult via existing decoder abstraction. |
| performer/src/commands/sdk.rs | Adds command building/plumbing for the new GetReplica operation + transcoder support. |
| performer/src/commands/kv.rs | Adds GetReplicaCommand execution and result-to-proto mapping. |
Review details
- Files reviewed: 29/29 changed files
- Comments generated: 2
- Review effort level: Lite
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| pub struct GetReplicaOptions<'a> { | ||
| pub key: &'a [u8], | ||
| pub scope_name: &'a str, | ||
| pub collection_name: &'a str, | ||
| pub strategy: GetReplicaStrategy, | ||
| pub retry_strategy: Arc<dyn RetryStrategy>, | ||
| } |
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| pub async fn get_replica( | ||
| &self, | ||
| id: impl AsRef<str>, | ||
| strategy: impl Into<GetReplicaStrategy>, | ||
| options: impl Into<Option<GetReplicaOptions>>, | ||
| ) -> crate::error::Result<GetReplicaResult> { |
|
Bencher Report| Project | couchbase-rs |
| Branch | get_replica-33888600930-202-1 |
| Testbed | ubuntu-latest |
🚨 1 Alert
| Benchmark | Measure Units | View | Benchmark Result (Result Δ%) | Upper Boundary (Limit %) |
|---|---|---|---|---|
| upsert_and_get | Latency microseconds (µs) | 📈 plot 🚷 threshold 🚨 alert (🔔) | 454.22 µs(+16.39%)Baseline: 390.25 µs | 448.79 µs (101.21%) |
Click to view all benchmark results
| Benchmark | Latency | Benchmark Result microseconds (µs) (Result Δ%) | Upper Boundary microseconds (µs) (Limit %) |
|---|---|---|---|
| query | 📈 view plot 🚷 view threshold | 441.17 µs(+5.16%)Baseline: 419.54 µs | 482.47 µs (91.44%) |
| upsert_and_get | 📈 view plot 🚷 view threshold 🚨 view alert (🔔) | 454.22 µs(+16.39%)Baseline: 390.25 µs | 448.79 µs (101.21%) |
|
| Project | couchbase-rs |
| Branch | get_replica-33888600930-202-2 |
| Testbed | ubuntu-latest |
Click to view all benchmark results
| Benchmark | Latency | Benchmark Result microseconds (µs) (Result Δ%) | Upper Boundary microseconds (µs) (Limit %) |
|---|---|---|---|
| query | 📈 view plot 🚷 view threshold | 443.97 µs(+5.82%)Baseline: 419.54 µs | 482.47 µs (92.02%) |
| upsert_and_get | 📈 view plot 🚷 view threshold | 430.01 µs(+10.19%)Baseline: 390.25 µs | 448.79 µs (95.82%) |
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