cube-js/cube · error · Error

Can't find dialect for '${dataSource}' data source: ${_dbTyp

Error message

Can't find dialect for '${dataSource}' data source: ${_dbType}

What it means

When the dbType is known but the driver-family lookup (e.g. by driverClass/dialect mapping) still cannot find a dialect implementation for a named data source, this Error is thrown, including both the dataSource name and the underlying _dbType.

Source

Thrown at packages/cubejs-server-core/src/core/CompilerApi.ts:344

    }

    // sqlGenerator.dataSource can return undefined for query without members
    // Queries like this are used by api-gateway to initialize SQL API
    // At the same time, those queries should use concrete dataSource, so we should be good to go with it
    dataSource = compilers.compiler.withQuery(sqlGenerator, () => sqlGenerator.dataSource);
    if (dataSource !== undefined) {
      const _dbType = await this.getDbType(dataSource);
      if (dataSource !== 'default' && dbType !== _dbType) {
        // TODO consider more efficient way than instantiating query
        sqlGenerator = await this.createQueryByDataSource(
          compilers,
          query,
          dataSource,
          _dbType
        );

        if (!sqlGenerator) {
          throw new Error(
            `Can't find dialect for '${dataSource}' data source: ${_dbType}`
          );
        }
      }
    }

    return { sqlGenerator, compilers };
  }

  public async getSql(query: NormalizedQuery, options: GetSqlOptions = {}): Promise<SqlResult> {
    const { includeDebugInfo, exportAnnotatedSql, preAggregationsOnly } = options;
    const { sqlGenerator, compilers } = await this.getSqlGenerator(query);

    const getSqlFn = () => compilers.compiler.withQuery(sqlGenerator, () => ({
      external: sqlGenerator.externalPreAggregationQuery(),
      sql: preAggregationsOnly ? null : sqlGenerator.buildSqlAndParams(exportAnnotatedSql),
      lambdaQueries: preAggregationsOnly ? [] : sqlGenerator.buildLambdaQuery(),
      timeDimensionAlias: sqlGenerator.timeDimensions[0]?.unescapedAliasName(),

View on GitHub (pinned to 7d981676b3)

Solutions

Install the official driver package for that data source's database
Verify the dbType for that dataSource matches a supported dialect family
Use the built-in driver class instead of a wrapper, or ensure the wrapper extends the official driver
Log _dbType and dataSource and check the dialect registry coverage

Example fix

// before
// no clickhouse driver installed, custom wrapper used
// after
yarn add @cubejs-backend/clickhouse-driver
// and driverFactory returns new ClickHouseDriver({...})

Defensive patterns

Strategy: validation

Validate before calling

for (const [ds, driver] of Object.entries(drivers)) {
  const t = await driver.dbType();
  if (!dialectRegistry.has(t)) throw new Error(`Data source '${ds}' has no dialect for dbType '${t}'`);
}

Type guard

const hasDialect = (dbType: string): dbType is KnownDbType => Object.prototype.hasOwnProperty.call(dialectMap, dbType);

Try / catch

try { await compilerApi.getSqlGenerator(query, ds); } catch (e) { if (/Can't find dialect for/.test(e.message)) { /* install/register dialect */ } else throw e; }

Prevention

Install official driver packages for every configured data source
Avoid wrappers that obscure the driver class identity
Test each data source's SQL generation at startup
Keep driver and server versions aligned

When it happens

Trigger: Multi-tenant setups where an additional data source's driver does not map to a supported dialect — e.g. a custom driver class whose family isn't recognized, or dbType set correctly but the dialect module not installed.

Common situations: Adding a second database (e.g. ClickHouse, Databricks) without installing the driver package that registers its dialect; custom driver wrappers that change the prototype/family detection.

Related errors

AI-assisted analysis of cube-js/cube@7d981676b3 (2026-09-02). Data as JSON: /api/errors/337fe121c04572b5. Report an issue: GitHub.