Apparatus, methods and computer code for estimating a synopsis error are disclosed herein. In some embodiments, one or more queries of a query workload are analyzed without running the analyzed queries. In some embodiments, the synopsis error is first estimated for a first memory allocation vector, and then, using intermediate or final results of the first estimated, estimated for a second memory allocation vector. In some embodiments, teachings related to estimating synopsis error are applied to the memory reconciliation problem.