I'm trying to use datanucleus.TenantReadIds at the EntityManager level, setting this property entityManager.setProperty(PropertyNames.PROPERTY_MAPPING_TENANT_READ_IDS, tenant);

As it doesn't seems applied, I look at PersistenceNucleusContextImpl:getMultiTenancyReadIds

public String[] getMultiTenancyReadIds(ExecutionContext ec)
{
    if (multiTenancyProvider != null)
    {
        String[] tenantReadIds = multiTenancyProvider.getTenantReadIds(ec);
        return (tenantReadIds != null) ? tenantReadIds : new String[] {multiTenancyProvider.getTenantId(ec)};
    }

    String readIds = config.getStringProperty(PropertyNames.PROPERTY_MAPPING_TENANT_READ_IDS);
    if (readIds != null)
    {
        // Return the tenant read ids if defined (for context)
        return readIds.split(",");
    }

    // Fallback to just the current tenant id for this execution context
    return new String[] {ec.getStringProperty(PropertyNames.PROPERTY_MAPPING_TENANT_ID)};
}

Is it possible to read the PROPERTY_MAPPING_TENANT_READ_IDS from the EntityManger settings before doing the fallback ? 

thanks,
--
Stephane