Databend Query is a Distributed Query Engine at scale.

• ast contains the SQL parser and related parser tooling.
• catalog defines catalog-facing abstractions such as Catalog, Database, Table, and TableContext.
• codegen contains code generators used by query-side crates, including arithmetic result-type generation.
• config provides query-service configuration types and parsing.
• datavalues is the legacy in-memory value/column representation layer; newer work continues to move toward expression.
• expression is the core scalar expression framework, including expression representation, type checking, and evaluation.
• formats handles data serialization and deserialization for external formats.
• functions implements scalar functions, aggregate functions, and related function infrastructure.
• management contains query-side management utilities such as cluster and quota support.
• pipeline implements the execution pipeline and scheduling framework for physical operators.
• script contains script execution support used by the query service.
• script_udf_support contains optional script UDF integrations that are wired into the query service through the script-udf cargo feature.
• service is the databend-query service crate and runtime integration layer.
• settings defines global and session settings.
• sql contains SQL-side planning, binding, optimization, and related execution support. Read ./sql/README.md for crate structure and shared optimizer test-support entry points.
• storage_stage_support contains optional stage-storage integrations that are wired into the query service through the storage-stage cargo feature.
• task_support contains optional task support integrations that are wired into the query service through the task-support cargo feature.
• storages contains table engines and storage-layer integrations, including Fuse and related indexing components.
• users implements user, role, and access-control support.
• ee contains enterprise query functionality.
• ee_features contains enterprise feature modules used by the query layer.