prestodb/presto · error · SemanticException

NOT_SUPPORTED

NOT_SUPPORTED

Error message

'%s' is a materialized view, and alter column is not supported

What it means

Changing a column's type is only supported on real tables. When the resolved name refers to a materialized view and IF EXISTS was not specified, Presto rejects the ALTER with NOT_SUPPORTED because altering materialized view columns is not implemented.

Source

Thrown at presto-main-base/src/main/java/com/facebook/presto/execution/SetColumnTypeTask.java:77

    {
        return "SET COLUMN TYPE";
    }

    public ListenableFuture<Void> execute(SetColumnType 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> tableHandle = metadata.getMetadataResolver(session).getTableHandle(tableName);
        if (!tableHandle.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()) {
            if (!statement.isTableExists()) {
                throw new SemanticException(SemanticErrorCode.NOT_SUPPORTED, statement, "'%s' is a materialized view, and alter column is not supported", tableName);
            }
            return immediateFuture(null);
        }

        accessControl.checkCanAlterColumn(session.getRequiredTransactionId(), session.getIdentity(), session.getAccessControlContext(), tableName);

        TableHandle tableHandleOptional = tableHandle.get();
        Map<String, ColumnHandle> columnHandles = metadata.getColumnHandles(session, tableHandleOptional);
        ColumnHandle column = columnHandles.get(statement.getColumnName().getValue());
        if (column == null) {
            throw new SemanticException(MISSING_COLUMN, statement, "Column '%s' does not exist", statement.getColumnName());
        }
        metadata.setColumnType(session, tableHandleOptional, column, getColumnType(statement));

        return immediateFuture(null);
    }

    private Type getColumnType(SetColumnType statement)

View on GitHub (pinned to 55bb57d202)

Solutions

1. Alter the column type on the underlying base table and let the materialized view refresh/recreate accordingly
2. Drop and recreate the materialized view with the corrected column type
3. Use IF EXISTS if the statement should skip non-table targets silently

Example fix

// before
ALTER TABLE hive.default.mv_sales ALTER COLUMN amount SET DATA TYPE DOUBLE;
// after
ALTER TABLE hive.default.base_sales ALTER COLUMN amount SET DATA TYPE DOUBLE;

QualifiedObjectName name = createQualifiedObjectName(session, stmt, table, metadata);
if (metadata.getMetadataResolver(session).getMaterializedView(name).isPresent()) {
    throw new IllegalArgumentException("Cannot ALTER COLUMN on materialized view: " + name);
}

try {
    return task.execute(stmt, ...);
} catch (SemanticException e) {
    if (e.getCode() == SemanticErrorCode.NOT_SUPPORTED) {
        // target the base table instead
    } else {
        throw e;
    }
}

When it happens

Trigger: ALTER TABLE <mv name> ALTER COLUMN ... SET DATA TYPE ... where getMaterializedView(tableName) returns a definition and statement.isTableExists() is false.

Common situations: Treating materialized views like tables in migration scripts; the object was replaced by a materialized view since the script was authored; schema drift between environments.

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

• INVALID_TABLE_PROPERTY
• NOT_SUPPORTED
• NOT_SUPPORTED
• NOT_SUPPORTED
• NOT_SUPPORTED

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/4cfe90512fd1e1ba. Report an issue: GitHub.