bytebase/bytebase · error

failed to parse target schema

Error message

failed to parse target schema

What it means

After resolving the parser engine, DiffSchema parses the user-supplied target DDL with schema.GetDatabaseMetadata. This wrap means the schema text failed to parse for the detected engine dialect, so no target metadata could be built.

Source

Thrown at backend/api/v1/database_service.go:1174

		if dbMetadata == nil {
			return nil, errors.Errorf("database schema not found for %s/%s", instanceID, databaseID)
		}
		return dbMetadata, nil
	}

	// If schema is provided, we need to parse it using GetDatabaseMetadata
	schemaStr := request.GetSchema()
	if schemaStr != "" {
		// Get the engine from the source database
		engine, err := s.getParserEngine(ctx, request)
		if err != nil {
			return nil, errors.Wrapf(err, "failed to get parser engine")
		}

		// Parse the schema string into metadata
		metadata, err := schema.GetDatabaseMetadata(engine, schemaStr)
		if err != nil {
			return nil, errors.Wrapf(err, "failed to parse target schema")
		}

		// Get instance to determine case sensitivity
		projectID, instanceID, _, err := common.GetDatabaseResourceName(request.Name)
		if err != nil {
			return nil, err
		}
		instance, err := s.getInstanceForDatabaseResource(ctx, projectID, instanceID)
		if err != nil {
			return nil, err
		}
		if instance == nil {
			return nil, errors.Errorf("instance %s not found", instanceID)
		}

		// Create DatabaseSchema from the parsed metadata
		return model.NewDatabaseMetadata(
			metadata,

View on GitHub (pinned to 1870550677)

Solutions

1. Read the wrapped cause to find the exact parse error line and fix the DDL syntax.
2. Ensure the schema dialect matches the source instance's engine (convert DDL if you diffed across engines).
3. Validate the DDL by applying it to a scratch database or a parser before calling DiffSchema.
4. Check the schema string is complete and non-empty (no truncation from the client).

Example fix

// before (Postgres DDL on a MySQL instance)
request.Schema = "CREATE TABLE t (id SERIAL PRIMARY KEY);"
// after (dialect-correct)
request.Schema = "CREATE TABLE t (id INT AUTO_INCREMENT PRIMARY KEY);"

// lint the DDL against the right dialect before sending it
import { Parser } from 'sql-parser';
try {
  Parser.parse(mysqlDialect, request.schema); // use the dialect matching the instance engine
} catch (e) {
  throw new Error(`target schema DDL invalid: ${e.message}`);
}

function isNonEmptySchema(s) { return typeof s === 'string' && s.trim().length > 0; }

try {
  const diff = await api.DiffSchema(req);
} catch (e) {
  if (String(e.message).includes('failed to parse target schema')) {
    // inspect e.cause for the exact line/column of the DDL parse failure
  }
  throw e;
}

When it happens

Trigger: DiffSchema with request.schema set; schema.GetDatabaseMetadata(engine, schemaStr) returns a parse error, wrapped at backend/api/v1/database_service.go:1174.

Common situations: DDL written for a different dialect than the source database's engine (e.g. Postgres DDL against a MySQL instance), syntax errors or unsupported statements in the pasted schema, engine aliasing surprises (MariaDB/OceanBase parsed as MySQL), or an empty/truncated schema string.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• empty DDL result
• keywords 'STORED AS' and 'STORED BY' cannot appear at the sa
• keywords 'CLUSTERED ON' and 'DISTRIBUTED ON' cannot appear a
• unsupported PostgreSQL metadata diff: event
• index key part expression is empty

AI-assisted analysis of bytebase/bytebase@1870550677 (2026-09-06). Data as JSON: /api/errors/abf1580cd513d2e1. Report an issue: GitHub.