> ## Documentation Index
> Fetch the complete documentation index at: https://doc.lucidworks.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Solr Subquery Stage

export const schema = {
  "type": "object",
  "title": "Solr Subquery",
  "description": "Executes a Solr query against a secondary collection and stores the results in the pipeline context for use by downstream boosting or join stages.",
  "required": ["key", "collection", "handler", "method"],
  "properties": {
    "skip": {
      "type": "boolean",
      "title": "Skip This Stage",
      "description": "Controls whether this stage executes during pipeline processing at runtime. When set to `true`, the stage is completely bypassed and documents pass through unchanged to the next stage. Useful for A/B testing, gradual rollouts, or temporarily disabling a stage without removing it from the pipeline.",
      "default": false,
      "hints": ["advanced"]
    },
    "label": {
      "type": "string",
      "title": "Label",
      "description": "Human-readable identifier displayed in the Fusion Admin UI, monitoring dashboards, and log messages. Use descriptive labels like `Parse Product PDFs` to aid debugging and team collaboration. Labels appear in performance metrics and error reports, making it easier to identify which stage failed.",
      "hints": ["advanced"],
      "maxLength": 255
    },
    "condition": {
      "type": "string",
      "title": "Condition",
      "description": "JavaScript expression evaluated at runtime on each document to conditionally execute this stage. The expression must return `true` to execute or `false` to skip. Access document fields using `doc.getFieldValue('fieldName')` and request parameters via `request.getFirstParam('paramName')`. For example, `doc.getFieldValue('type') === 'premium'` executes this stage only for premium content.",
      "hints": ["code", "code/javascript", "advanced"]
    },
    "legacy": {
      "type": "boolean",
      "title": "Legacy",
      "description": "When `true`, this stage operates in legacy mode only.",
      "hints": ["readonly", "hidden"]
    },
    "asyncConfig": {
      "type": "object",
      "title": "Asynchronous Execution Config",
      "required": ["enabled", "asyncId"],
      "properties": {
        "enabled": {
          "type": "boolean",
          "title": "Enable Async Execution",
          "description": "Run the expensive data loading or processing part of this stage in a separate thread allowing the pipeline to continue executing. The results of this asynchronous execution can be merged into the pipeline request using a downstream Merge Async Results stage.",
          "default": false
        },
        "asyncId": {
          "type": "string",
          "title": "Async ID",
          "description": "A unique value to use as reference in downstream Merge Async Results stages."
        }
      }
    },
    "key": {
      "type": "string",
      "title": "Key",
      "description": "Specifies the context key under which the subquery results are stored.",
      "default": "subquery-results"
    },
    "collection": {
      "type": "string",
      "title": "Collection",
      "description": "Specifies the Solr collection to query. Must exactly match an existing collection name."
    },
    "handler": {
      "type": "string",
      "title": "Request Handler",
      "description": "Specifies the Solr request handler to use for the subquery.",
      "default": "select"
    },
    "method": {
      "type": "string",
      "title": "HTTP Method",
      "description": "Specifies the HTTP method used to query Solr, such as `GET` or `POST`.",
      "enum": ["GET", "POST"],
      "default": "POST"
    },
    "preferredReplicaType": {
      "type": "string",
      "title": "Preferred Replica Type",
      "description": "Specifies the replica type given higher query routing precedence when querying multiple shards.",
      "enum": ["none", "pull", "tlog", "nrt"]
    },
    "parentParams": {
      "type": "array",
      "title": "Query parameters from the parent query",
      "items": {
        "type": "string"
      }
    },
    "rollupKeys": {
      "type": "array",
      "title": "Rollup results to include",
      "items": {
        "type": "string"
      }
    },
    "params": {
      "type": "array",
      "title": "Query Parameters",
      "description": "Specifies additional query parameters to include in the subquery. Supports template expressions such as `<ctx.someContextKey>`.",
      "items": {
        "type": "object",
        "required": ["key"],
        "properties": {
          "key": {
            "type": "string",
            "title": "Parameter Name"
          },
          "value": {
            "type": "string",
            "title": "Parameter Value"
          }
        }
      }
    },
    "headers": {
      "type": "array",
      "title": "Headers",
      "items": {
        "type": "object",
        "required": ["key"],
        "properties": {
          "key": {
            "type": "string",
            "title": "Parameter Name"
          },
          "value": {
            "type": "string",
            "title": "Parameter Value"
          }
        }
      }
    }
  },
  "category": "Fetch Data",
  "categoryPriority": 6,
  "unsafe": false
};

export const SchemaParamFields = ({schema}) => {
  const sanitize = str => {
    if (typeof str !== "string") return str;
    return str.replace(/^"(.*)"$/s, "$1").replace(/\\/g, "").replace(/"/g, "'");
  };
  const renderMd = str => {
    const s = sanitize(str);
    const text = (/[.!?]\)*$/).test(s) ? s : `${s}.`;
    return text.split(/(\*\*[^*]+\*\*|_[^_]+_|`[^`]+`)/g).map((part, i) => {
      if (part.startsWith("**")) return <strong key={i}>{part.slice(2, -2)}</strong>;
      if (part.startsWith("_")) return <em key={i}>{part.slice(1, -1)}</em>;
      if (part.startsWith("`")) return <code key={i}>{part.slice(1, -1)}</code>;
      return part;
    });
  };
  const {description, properties = {}, required: requiredProps = []} = schema;
  const visibleProps = useMemo(() => Object.entries(properties).filter(([, prop]) => !prop.hints?.includes("hidden")), [properties]);
  const renderProp = ([name, prop]) => {
    const isRequired = requiredProps.includes(name);
    const hasDefault = prop.default !== undefined;
    const rawDefault = prop.default;
    const hints = prop.hints || [];
    const isComplexDefault = hasDefault && (typeof rawDefault === "object" || typeof rawDefault === "string" && (rawDefault.length > 20 || rawDefault.includes('"')));
    const postBadges = [];
    if (prop.title) {
      postBadges.push(<><span className="text-stone-400 dark:text-stone-500">API property: </span>{name}</>);
    }
    const constraints = [];
    if (prop.minimum !== undefined && prop.maximum !== undefined) {
      constraints.push(`Range: ${prop.minimum} – ${prop.maximum}`);
    } else if (prop.minimum !== undefined) {
      constraints.push(`Min: ${prop.minimum}`);
    } else if (prop.maximum !== undefined) {
      constraints.push(`Max: ${prop.maximum}`);
    }
    if (prop.minLength !== undefined && prop.maxLength !== undefined) {
      constraints.push(`Length: ${prop.minLength} – ${prop.maxLength}`);
    } else if (prop.minLength !== undefined) {
      constraints.push(`Min length: ${prop.minLength}`);
    } else if (prop.maxLength !== undefined) {
      constraints.push(`Max length: ${prop.maxLength}`);
    }
    const fieldProps = {
      key: name,
      body: prop.title || name,
      type: prop.type,
      ...postBadges.length > 0 && ({
        post: postBadges
      }),
      ...isRequired && ({
        required: true
      }),
      ...!isComplexDefault && hasDefault ? {
        default: sanitize(String(rawDefault))
      } : {}
    };
    const isObject = prop.type === "object" && prop.properties;
    const isArrayOfObjects = prop.type === "array" && prop.items?.type === "object" && prop.items.properties;
    return <ParamField {...fieldProps}>
        {prop.description && <p>{renderMd(prop.description)}</p>}

        {prop.enum && <p>
            Allowed values: 
            {prop.enum.map((v, i) => <>{i > 0 && ", "}<code key={i}>{String(v)}</code></>)}
          </p>}

        {constraints.length > 0 && <p className="text-stone-500 dark:text-stone-400 text-sm">
            {constraints.join(" · ")}
          </p>}

        {isComplexDefault && <div className="flex">
            <p>
              <strong>Default:</strong>
            </p>
            <pre className="!my-0">
              <code>
                {JSON.stringify(rawDefault, null, 2)}
              </code>
            </pre>
          </div>}

        {isArrayOfObjects && <Expandable title="item properties">
            <SchemaParamFields schema={{
      properties: prop.items.properties,
      required: prop.items.required
    }} />
          </Expandable>}

        {isObject && <Expandable title="properties">
            <SchemaParamFields schema={{
      properties: prop.properties,
      required: prop.required
    }} />
          </Expandable>}
      </ParamField>;
  };
  return <div>
      {description && <p>{renderMd(description)}</p>}

      {visibleProps.map(renderProp)}
    </div>;
};

export const LwTemplate = ({title = "Key questions to get you started", icon = "sparkles", cta = "Powered by Agent Studio", linkHref = "https://lucidworks.com/demo/?utm_source=docs&utm_medium=referral&utm_campaign=docs_cta_ai"}) => {
  const [isLoaded, setIsLoaded] = useState(false);
  useEffect(() => {
    const timer = setTimeout(() => {
      setIsLoaded(true);
    }, 500);
    return () => clearTimeout(timer);
  }, []);
  return <div className="lw-template-container">
      <Card title={title} icon={icon}>
        {isLoaded && <span dangerouslySetInnerHTML={{
    __html: `<lw-template id="a029c1a9-28be-427e-b0e1-5d918920246a"></lw-template
            >`
  }} />}
        <Link href={linkHref} className="agent-studio-link text-left text-gray-600 gap-2 dark:text-gray-400 text-sm font-medium flex flex-row items-center hover:text-primary dark:hover:text-primary-light group-hover:text-primary group-hover:dark:text-primary-light">Powered by Lucidworks Agent Studio</Link>
      </Card>
    </div>;
};

[localhost link]: http://localhost:3000/docs/5/fusion/reference/config-ref/pipeline-stages/query-stages/subquery-query-stage

[mintlify link]: https://doc.lucidworks.com/docs/5/fusion/reference/config-ref/pipeline-stages/query-stages/subquery-query-stage

[old doc.lw link]: https://doc.lucidworks.com/fusion/5.9/297

The Solr Subquery query pipeline stage is used to query external collections.
The Solr Subquery stage runs a query and adds the results to the pipeline Request object.
The query must return results in JSON format, so that they can be added to the query pipeline.

This stage supports [asynchronous processing](/docs/5/fusion/getting-data-out/query-basics/query-pipelines/overview).

<LwTemplate />

## Query pipeline stage condition examples

Stages can be triggered conditionally when a script in the **Condition** field evaluates to true.
Some examples are shown below.

Run this stage only for mobile clients:

```js wrap  theme={"dark"}
params.deviceType === "mobile"
```

Run this stage when debugging is enabled:

```js wrap  theme={"dark"}
params.debug === "true"
```

Run this stage when the query includes a specific term:

```js wrap  theme={"dark"}
params.q && params.q.includes("sale")
```

Run this stage when multiple conditions are met:

```js wrap  theme={"dark"}
request.hasParam("fusion-user-name") && request.getFirstParam("fusion-user-name").equals("SuperUser");
!request.hasParam("isFusionPluginQuery")
```

The first condition checks that the request parameter "fusion-user-name" is present and has the value "SuperUser".
The second condition checks that the request parameter "isFusionPluginQuery" is not present.

## Configuration

<Tip>
  When entering configuration values in the UI, use *unescaped* characters, such as `\t` for the tab character. When entering configuration values in the API, use *escaped* characters, such as `\\t` for the tab character.
</Tip>

<SchemaParamFields schema={schema} />