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Error Logs

Error Log: “failed to parse query” parsing_exception – The syntax error

By November 19, 2025No Comments

Error Log: This error is usually found inside the root_cause of a SearchPhaseExecutionException.

JSON

{
  "error": {
    "root_cause": [
      {
        "type": "parsing_exception",
        "reason": "[match] query malformed, no start_object after query name",
        "line": 1, // <-- Your clue!
        "col": 23  // <-- Your other clue!
      }
    ],
    "type": "search_phase_execution_exception",
    // ...
  },
  "status": 400
}

Why… is this happening? This is a pure syntax error. The JSON for your Query DSL is malformed, and the OpenSearch parser cannot understand it.

The error message gives you everything you need to fix it:

  • reason: Tells you what is wrong. In the example, no start_object after query name means you probably wrote "match": "my_field": "my_value" instead of the correct "match": { "my_field": "my_value" }.
  • line and col: Tell you exactly where in your JSON the parser gave up.

Common causes include:

  • A typo in a query type: e.g., "macth" instead of "match".
  • Missing { } or [ ].
  • A trailing comma after the last item in a list or object.
  • Forgetting to wrap a field name in quotes.

Best Practice:

  1. Use OpenSearch Dashboards Dev Tools: This is the #1 way to prevent this error. Write, test, and format your queries in the Dev Tools console. It has auto-complete for query clauses and built-in JSON validation that catches these errors before you even send the request.
  2. Read the Error Message: The reason, line, and col fields are your roadmap to the bug. Trust them.
  3. Use a JSON Linter: If you are building queries in your application code, copy-paste the final JSON into a “JSON validator” or “linter” online to quickly find syntax errors like mismatched brackets or bad commas.
  4. Check API Version: Ensure the query syntax you’re using (e.g., knn search) is supported by the version of OpenSearch you are running.

What else can I do? Can’t spot the syntax error even after looking at the line and column? We’ve all been there. Post your query and the error message on the OpenSearch community forums—a fresh set of eyes can often find it in seconds. For direct support, contact us in The OpenSearch Slack Channel in #General.

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