Post-processing steps like checking the compound inventory are abstracted away from the querying knowledge graph step. The resolution of the inventory status of substances can be therefore considered to happen in a "lazy execution" manner. This, however, can lead to situations where only some or none of the synthesis routes based on the SP query would start from substances available from inventory. Moreover, it is possible, that the SP query omits paths that would start from substances available from inventory. This is a limitation of the SP query for the interest of performance. All Neo4j queries were executed using transaction timeouts of 5 minutes were used for all queries. Neo4j "dbms memory transaction size" was 4GB, heap initial size used was 2GB, heap max size used was 4GB and page cache size used was 2GB.