EXPLAIN

EXPLAIN describes a proposed finite SELECT plan and its output columns. The console, query workspace inspect operation and shared query client use the same Fuze compiler as query execution.

EXPLAIN SELECT value FROM items WHERE id > 0 LIMIT 2;
EXPLAIN SELECT count(*) FROM items;
EXPLAIN SELECT value AS amount, value AS copy FROM items;

The result lists logical operators in evaluation order, the predicate column and operator or cell state, input projection and limit, output columns and configured execution budgets. Literal values are omitted. Checked SUM outputs int64 and COUNT outputs uint64. The supported SELECT syntax and type limits apply; EXPLAIN ANALYZE, cost estimates and alternative physical plans are unsupported.

Input projections retain source column names; output columns contain any AS names. Repeated input columns remain separate output positions with distinct names, using the same schema validation as execution.

The ordinary query inspection scope contains one configured source. Current source/requester read access and query policy must authorize the declaration before name resolution and before the response is returned. The response's metadata revision is an observation of current authorization and schema, not a captured source basis. The plan acquires no data snapshot and creates no query request or execution. See the inspection contract for the neutral result and exact limits.

The opt-in relational Table profile uses the same metadata-only principle through RelationalCompilation: explicit catalog routes, exact schemas, prepared plan identity and no captured execution basis. It reports join kind, grouping and proposed disk storage. Each metadata route checks current inspection access; execution independently requires current read access. The console's ordinary single-Table profile captures and releases a schema-bound snapshot for inspection, executes no rows, and gives a later SELECT its own basis.

Source: explainStatement.