prestodb/presto · error · SemanticException

NOT_SUPPORTED

NOT_SUPPORTED

Error message

'%s' is a materialized view, and drop tag is not supported

What it means

Thrown by DropTagTask when the target table exists but is a materialized view. Tags are not supported on materialized views, so the task raises NOT_SUPPORTED unconditionally (no IF EXISTS escape) after detecting optionalMaterializedView.isPresent().

Source

Thrown at presto-main-base/src/main/java/com/facebook/presto/execution/DropTagTask.java:62

        return "DROP TAG";
    }

    @Override
    public ListenableFuture<?> execute(DropTag statement, TransactionManager transactionManager, Metadata metadata, AccessControl accessControl, Session session, List<Expression> parameters, WarningCollector warningCollector, String query)
    {
        QualifiedObjectName tableName = createQualifiedObjectName(session, statement, statement.getTableName(), metadata);
        Optional<TableHandle> tableHandleOptional = metadata.getMetadataResolver(session).getTableHandle(tableName);

        if (!tableHandleOptional.isPresent()) {
            if (!statement.isTableExists()) {
                throw new SemanticException(MISSING_TABLE, statement, "Table '%s' does not exist", tableName);
            }
            return immediateFuture(null);
        }

        Optional<MaterializedViewDefinition> optionalMaterializedView = metadata.getMetadataResolver(session).getMaterializedView(tableName);
        if (optionalMaterializedView.isPresent()) {
            throw new SemanticException(NOT_SUPPORTED, statement, "'%s' is a materialized view, and drop tag is not supported", tableName);
        }

        getConnectorIdOrThrow(session, metadata, tableName.getCatalogName());
        accessControl.checkCanDropTag(session.getRequiredTransactionId(), session.getIdentity(), session.getAccessControlContext(), tableName);

        metadata.dropTag(session, tableHandleOptional.get(), statement.getTagName(), statement.isTagExists());
        return immediateFuture(null);
    }
}

View on GitHub (pinned to 55bb57d202)

Solutions

  1. Skip materialized views in the tag cleanup script by checking the object type first
  2. If the tag is no longer meaningful, drop and recreate the object as a table or manage the view's tags via the connector's supported mechanism
  3. File/use connector support for materialized-view tags if your use case requires it
Defensive patterns

Strategy: validation

Validate before calling

-- skip materialized views before DROP TAG
SELECT table_type FROM system.metadata.tables
WHERE schema_name = 'my_schema' AND table_name = ?;

Try / catch

try { dropTag(...); } catch (SemanticException e) { if (e.getCode() == SemanticErrorCode.NOT_SUPPORTED && e.getErrorMessage().contains("materialized view")) { /* skip MV */ } else { throw e; } }

Prevention

When it happens

Trigger: Executing `DROP TAG ON <name> ...` where the name resolves to a materialized view (metadataResolver.getMaterializedView returns present), regardless of IF EXISTS.

Common situations: Table was converted to a materialized view after tags were applied via scripts; bulk tag-removal tooling iterating over all tables including materialized views.

Understand the failure class

Background: Presto NOT_SUPPORTED error: what "not supported" means and how to fix it — this error's family across 3 libraries.

Related errors

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/238152baead66c6f. Report an issue: GitHub.