---
title: "Get query execution plan explanation"
method: POST
path: "/v1/table/{id}/explain_plan"
tags: ["Table", "Data"]
---

# Get query execution plan explanation

`POST /v1/table/{id}/explain_plan`

Get the query execution plan for a query against table `id`.
Returns a human-readable explanation of how the query will be executed.

REST NAMESPACE ONLY
REST namespace returns the response as a plain string
instead of the `ExplainTableQueryPlanResponse` JSON object.

## Path parameters

- `id` string, required

## Query parameters

- `delimiter` string

## Request body

- ExplainTableQueryPlanRequest
  - `identity` Identity — Identity information of a request.
    - `api_key` string — API key for authentication. REST NAMESPACE ONLY This is passed via the `x-api-key` header.
    - `auth_token` string — Bearer token for authentication. REST NAMESPACE ONLY This is passed via the `Authorization` header with the Bearer scheme (e.g., `Bearer <token>`).
  - `context` unknown
  - `id` string[]
  - `branch` string — Branch to target. When not specified, the main branch is used.
  - `query` QueryTableRequest, required
    - `identity` Identity — Identity information of a request.
      - `api_key` string — API key for authentication. REST NAMESPACE ONLY This is passed via the `x-api-key` header.
      - `auth_token` string — Bearer token for authentication. REST NAMESPACE ONLY This is passed via the `Authorization` header with the Bearer scheme (e.g., `Bearer <token>`).
    - `context` unknown
    - `id` string[]
    - `branch` string — Branch to target. When not specified, the main branch is used.
    - `bypass_vector_index` boolean — Whether to bypass vector index
    - `columns` QueryTableRequestColumns, nullable — Optional field paths to return. Provide either column_names or column_aliases, not both.
      - `column_names` string[] — List of Lance field paths to return. Nested fields use dot-separated segments; use backtick-quoted segments for literal dots and double backticks inside quoted segments.
      - `column_aliases` unknown
    - `distance_type` string — Distance metric to use
    - `ef` integer — Search effort parameter for HNSW index
    - `fast_search` boolean — Whether to use fast search
    - `filter` string — Optional SQL filter expression. Field references in the expression must use Lance field path syntax: nested fields use dot-separated segments, literal dots require backtick-quoted segments, and backticks inside quoted segments are doubled.
    - `full_text_query` QueryTableRequestFullTextQuery, nullable — Optional full-text search query. Provide either string_query or structured_query, not both.
      - `string_query` StringFtsQuery
        - `columns` string[] — Lance field paths to search. Nested fields use dot-separated segments; use backtick-quoted segments for literal dots and double backticks inside quoted segments. Omit to search all indexed FTS fields.
        - `query` string, required
      - `structured_query` StructuredFtsQuery
        - `query` FtsQuery, required — Full-text search query. Exactly one query type field must be provided. This structure follows the same pattern as AlterTransactionAction to minimize differences and compatibility issues across codegen in different languages.
          - `match` MatchQuery
            - `boost` number, float
            - `column` string — Lance field path to match. Nested fields use dot-separated segments; use backtick-quoted segments for literal dots and double backticks inside quoted segments. Omit to use the query default fields.
            - `fuzziness` integer
            - `max_expansions` integer — The maximum number of terms to expand for fuzzy matching. Default to 50.
            - `operator` string — The operator to use for combining terms. Case insensitive, supports both PascalCase and snake_case. Valid values are: - And: All terms must match. - Or: At least one term must match.
            - `prefix_length` integer — The number of beginning characters being unchanged for fuzzy matching. Default to 0.
            - `terms` string, required
          - `phrase` PhraseQuery
            - `column` string — Lance field path to match. Nested fields use dot-separated segments; use backtick-quoted segments for literal dots and double backticks inside quoted segments. Omit to use the query default fields.
            - `slop` integer
            - `terms` string, required
          - `boost` BoostQuery — Boost query that scores documents matching positive query higher and negative query lower
            - `positive` FtsQuery, required — recursive
            - `negative` FtsQuery, required — recursive
            - `negative_boost` number, float — Boost factor for negative query (default: 0.5)
          - `multi_match` MultiMatchQuery
            - `match_queries` MatchQuery[], required
              - …
          - `boolean` BooleanQuery — Boolean query with must, should, and must_not clauses
            - `must` FtsQuery[], required — Queries that must match (AND)
            - `must_not` FtsQuery[], required — Queries that must not match (NOT)
            - `should` FtsQuery[], required — Queries that should match (OR)
    - `k` integer, required — Number of results to return
    - `lower_bound` number, float — Lower bound for search
    - `nprobes` integer — Number of probes for IVF index
    - `offset` integer — Number of results to skip
    - `prefilter` boolean — Whether to apply filtering before vector search
    - `refine_factor` integer — Refine factor for search
    - `upper_bound` number, float — Upper bound for search
    - `vector` QueryTableRequestVector, nullable, required — Query vector(s) for similarity search. Provide either single_vector or multi_vector, not both.
      - `single_vector` number[] — Single query vector
      - `multi_vector` array[] — Multiple query vectors for batch search
        - number[]
    - `vector_column` string — Lance field path of the vector field to search. Nested fields use dot-separated segments; use backtick-quoted segments for literal dots and double backticks inside quoted segments. Use canonical full paths for display and errors; leaf names alone only identify top-level fields; invalid or unresolved paths should return InvalidInput or TableColumnNotFound.
    - `version` integer — Table version to query
    - `with_row_id` boolean — If true, return the row id as a column called `_rowid`
  - `verbose` boolean — Whether to return verbose explanation

## Response `200`

Query execution plan explanation

- string — Human-readable query execution plan

## Other responses

- `400` — Indicates a bad request error. It could be caused by an unexpected request body format or other forms of request validation failure, such as invalid json. Usually serves application/json content, although in some cases simple text/plain content might be returned by the server's middleware.
- `401` — Unauthorized. The request lacks valid authentication credentials for the operation.
- `403` — Forbidden. Authenticated user does not have the necessary permissions.
- `404` — A server-side problem that means can not find the specified resource.
- `503` — The service is not ready to handle the request. The client should wait and retry. The service may additionally send a Retry-After header to indicate when to retry.
- `5XX` — A server-side problem that might not be addressable from the client side. Used for server 5xx errors without more specific documentation in individual routes.

---

[API](https://skmtc.net/lance-format/apis/lance-namespace-specification.md) · [All operations](https://skmtc.net/lance-format/apis/lance-namespace-specification/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/lance-format/lance-namespace-specification/versions/f09656f7f568/schema)