Explain

Applies to: Embedded ❌, Enterprise ✅

EXPLAIN SELECT * FROM documents WHERE identifier < 1000
EXPLAIN ANALYZE SELECT * FROM documents WHERE identifier < 1000

Statement	What it returns
`EXPLAIN <query>`	Logical and physical plan, without executing the query.
`EXPLAIN ANALYZE <query>`	Executes the query and annotates each operator with runtime metrics (rows, timing).
`EXPLAIN VERBOSE <query>`	Adds intermediate optimizer plans on top of `EXPLAIN`.

The result is a small relation with plan_type and plan columns, read through the same client you use for regular queries. See Connecting. SQL plans and the SDK’s explain_plan and analyze_plan output share scan and index operators. Use the same approach to inspect index coverage and filter pushdown; SQL can also add joins, aggregates and other operators:

What it shows

Reading a plan: operators, pushdown, index usage.

What it measures

Reading the metrics, and a worked before/after.

What to look for

Sign	Means
`ScalarIndexQuery`	the predicate used a scalar index
`LanceScan` with high `bytes_read`	inspect the selected columns, filter pushdown and index use
`FilterExec` above a search	the filter ran after search rather than pushing into it
`ANNSubIndex` / `ANNIvfPartition`	the vector index was used

A LanceScan feeding a join is the common one worth acting on. See Joins. For a table’s columns and types without a plan, see DESCRIBE.

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What it shows

What it measures

What to look for

What it shows

What it measures

​What to look for

What to look for