materialize-poc

Investigate CI failures on a PR using gh and bk CLI tools. Trigger when the user asks about failing checks, Buildkite failures, or CI issues — including casual phrases like "why is CI red", "build broken", "checks failing", "what went wrong in CI", "nightly broke", "tests failing on this PR", or pastes a Buildkite URL. Also trigger when the user mentions a specific PR number and wants to understand why it's failing.

General guide for running tests and choosing the right test framework in Materialize. Trigger when the user wants to "run tests", "run testdrive", "run sqllogictest", "run mzcompose", "run cargo test", "run pgtest", "rewrite test results", "add a test", "reproduce a bug", "write a regression test", or mentions testing, testdrive, sqllogictest, mzcompose, pgtest, cargo test, nextest, flaky tests, or test failures. Use this skill even if the user just says "test this" or "how do I verify this works" without naming a specific framework. For deep guidance on specific frameworks, see the dedicated skills: mz-platform-checks (upgrade/restart survival), mz-parallel-workload (concurrent stress testing), and mz-limits-test (scaling to many objects).

Correctness invariants and architectural guidance for the adapter layer, coordinator, pgwire, peek paths, and timestamp oracle. Trigger when the user works on or asks questions about these subsystems — including "how does the coordinator work", "what are read holds", "explain the peek path", "how does timestamp selection work", "why does this query block". Also trigger when editing files in src/adapter/, src/pgwire/, or src/timestamp-oracle/.

Add, modify, or debug benchmark scenarios for measuring Materialize performance. Covers three frameworks: Feature Benchmark (single-operation micro-benchmarks), Scalability Test (SQL throughput under concurrency), and Parallel Benchmark (sustained latency over time via scenarios.py). Trigger on "benchmark", "feature benchmark", "scalability test", "parallel benchmark", "performance regression", "micro-benchmark", "TPS", "latency test", or when editing files in feature_benchmark/scenarios/, scalability/workload/workloads/, or parallel_benchmark/scenarios.py. Note: this is about benchmark measurement frameworks, not the parallel-workload stress-testing framework (which tests for panics under concurrency, not performance).

This skill should be used when the user wants to "commit", "prepare a commit", "create a PR", "push", "open a pull request", or mentions committing, pre-commit checks, or pull requests in the Materialize repository. Use this skill even if the user just says "ship it" or "ready to merge" without being specific. Note: for reviewing code, use mz-pr-review instead.

This skill should be used when the user wants to add, modify, or debug a limits test. Trigger when the user mentions "limits test", "Generator subclass", "many objects", "scaling test", or wants to stress-test Materialize with large numbers of objects (tables, views, sources, indexes, etc.). Also trigger when the user edits test/limits/mzcompose.py.

Extend the parallel-workload stress-testing framework, which runs random SQL actions concurrently to catch panics and unexpected errors (not performance measurement — see mz-benchmark for that). Trigger when the user mentions "parallel workload", "parallel-workload", "action.py" in the context of parallel workload, or wants to test for panics or unexpected query errors under concurrency. Use this skill even if the user just says "add this to parallel workload" or references a bug that panics under concurrent DDL/DML.

This skill should be used when the user wants to create, modify, or debug a platform check. Trigger when the user mentions "platform check", "platform-checks", "upgrade check", "restart check", or wants to write a Check class that tests feature survival across restarts/upgrades. Also trigger when the user edits files in misc/python/materialize/checks/all_checks/.

Perform a local code review of the current branch's changes against Materialize project standards. Trigger when the user says "review my code", "review my changes", "check my diff", "does this look ok", "what do you think of this PR", "code review", or asks you to look over changes before merging. Also trigger when the user passes a PR number and wants feedback on quality, style, or correctness.

This skill should be used when the user wants to "profile Materialize", "check memory usage", "analyze binary size", "debug performance", or mentions profiling, samply, heaptrack, flame graphs, memory checking, binary size analysis, slow queries, or high CPU/memory usage in the Materialize repository. Use this skill even if the user just says something is "slow" or "using too much memory" without explicitly mentioning profiling.

Debug where time is spent during SQL execution using distributed tracing (OpenTelemetry / Tempo). Trigger when the user asks "why is this query slow", "where is the time going", "this SELECT takes forever", or wants a latency breakdown for any SQL statement. Also trigger on mentions of tracing queries, span analysis, Tempo traces, trace IDs, or opentelemetry_filter.

This skill should be used when the user wants to "run Materialize locally", "start environmentd", "check compilation", "format code", "lint", "cargo check", "cargo fmt", "cargo clippy", "bin/fmt", "bin/lint", or mentions compiling, building, running, formatting, linting, log filters, jemalloc, or CockroachDB setup in the Materialize repository. Use this skill even if the user just says "how do I run this" or "it won't compile" without being specific.