Staff Engineer - DAX (BI Engine)

Responsibilities:

• Build the next-generation DAX-like formula engine that turns complex evaluation contexts into efficient SQL on modern warehouses.
• Own the core compiler and runtime for our standalone BI (parser, metadata, planning, translation, and SQL backends) and deliver a BI experience that mirrors native models while integrating tightly with Arrow- and DuckDB-based storage.
• Own the Spotonix BI engine end to end: BI catalogue and metadata, formula-language grammar and parser, query planner and optimiser, SQL generation/execution layers, client connectivity/session management, and multi-dialect SQL support.
• Design and optimise the query compiler that lowers expressions into an internal multidimensional algebra, applies rule- and cost-based transformations, orchestrates algebraic plans, manages evaluation contexts, and enforces lineage propagation before emitting SQL.
• Evolve the execution runtime: translate complex algebra into SQL with maximum warehouse pushdown and expose the instrumentation hooks needed by clients and regression suites.
• Own the BI algebra itself: define and implement the suite of DAX/MDX-style operators (hierarchy navigation, cube operators, table manipulations, and iterators) and ensure each algebraic primitive ships with tests and SQL strategies.
• Partner with integrations teams to support additional warehouses, metadata loaders, and client APIs (evaluate and discover metadata) and drive observability for plan generation, SQL issuance, and cache effectiveness.
• Mentor engineers on query-compilation fundamentals, context transition debugging, and deterministic developer workflows (diagram generation, regression fixtures, CLI ergonomics).

Requirements:

• 10-14 years building database engines, query compilers, or analytical runtimes with deep experience in SQL planning and execution internals (costing, rewrites, vectorised operators, and columnar caches).
• Expert-level Python and ease working in large metaprogrammed codebases; C++/Rust/Scala for runtime paths are a plus.
• Demonstrated ownership of multidimensional or BI algebra design, defining operators, invariants, and execution strategies across catalogues, hierarchies, and cube semantics.
• Hands-on knowledge of DAX-like BI languages (MDX, LookML metrics, dbt semantic models, etc. ) and their filter/context semantics, especially CALCULATE, context transitions, and time intelligence functions.
• Proven track record translating high-level DSLs into relational algebra or SQL, including dependency tracking, lineage-aware filter propagation, and multi-stage compilation pipelines.
• Familiarity with Arrow, DuckDB, or similar columnar storage engines plus the ability to reason about concurrency, caching, and resource management in a long-running service.
• Experience building client/session infrastructure (CLI, APIs) and managing multi-dialect SQL connectors is a plus.
• Comfortable operating in product-orientated environments: writing dev notes, codifying manual plans into tests, and collaborating with UI and data modelling teams.

Nice to Have:

• Experience ingesting PBIX or tabular models, XML/A-style protocols, or enterprise BI ecosystem tooling.
• Background in time-intelligence modelling, date-relationship functions, or working-day calendars.
• Contributions to open-source database engines, query planners, or columnar execution projects.
• Passion for developer tooling: GraphViz visualisations, SQL trace explorers, CLI experiences, and regression harnesses for semantic languages.

Skills

dax, dbt, lookml, mdx, python, sql