presto-main/src/main/java/io/prestosql/security/AccessControlManager.java/AccessControlManager/filterSchemas
class AccessControlManager:    @Override
    public Set<String> filterSchemas(SecurityContext context, String catalogName, Set<String> schemaNames)
    {
        requireNonNull(context, "context is null");
        requireNonNull(catalogName, "catalogName is null");
        requireNonNull(schemaNames, "schemaNames is null");

        if (filterCatalogs(context.getIdentity(), ImmutableSet.of(catalogName)).isEmpty()) {
            return ImmutableSet.of();
        }

        schemaNames = systemAccessControl.get().filterSchemas(context.toSystemSecurityContext(), catalogName, schemaNames);

        CatalogAccessControlEntry entry = getConnectorAccessControl(context.getTransactionId(), catalogName);
        if (entry != null) {
            schemaNames = entry.getAccessControl().filterSchemas(entry.toConnectorSecurityContext(context), schemaNames);
        }
        return schemaNames;
    }