I came across an ASAP paper today describing substructure searching in Oracle databases. The paper comes from the folks at J & J and is part of their series of papers on the ABCD platform. Performing substructure searches in databases is certainly not a new topic and various products are out there that support this in Oracle (as well as other RDBMSs). The paper describes how the ABCD system does this using a combination of structure-derived hash keys and an inverted bitset based index and discuss their implementation as an Oracle cartridge. They provide an interesting discussion of how their implementation supports Cost Based Optimization of SQL queries involving substructure search. The authors run a number of benchmarks. In terms of comparative benchamrks they compare the performance (i.e., screening efficiency) of their hashed keys versus MACCS keys, CACTVS keys and OpenBabel FP2 fingerprints. Their results indicate that the screening step is a key bottleneck in the query process and that their hash key is generally more selective than the others.
Unfortunately, what would have been interesting but was not provided was a comparison of the performance at the Oracle query level with other products such as JChem Cartridge and OrChem. Furthermore, the test case is just under a million molecules from Golovin & Henrick – the entire dataset (not just the keys) could probably reside in-memory on todays servers. How does the system perform when say faced with PubChem (34 million molecules)? The paper mentions a command line implementation of their search procedure, but as far as I can tell, the Oracle cartridge is not available.
The ABCD system has many useful and interesting features. But as with the other publications on this system, this paper is one more in the line of “Papers About Systems You Can’t Use or Buy“. Unfortunate.