O'Neil did his undergraduate studies at the Massachusetts Institute of Technology, receiving a B.S. in mathematics in 1963. After earning a master's degree at the University of Chicago, he moved to Rockefeller University, where he earned a Ph.D. in combinatorial mathematics in 1969 under the supervision of Gian-Carlo Rota. He was an assistant professor at MIT from 1970 to 1972, but then left academia for industry, returning in 1988 as a member of the UMass/Boston faculty. He became a full professor in 1996.
O'Neil has written highly cited papers on replication in distributed databases, page replacement strategies for databases, SQL isolation, and database indexing strategies. With Elizabeth J. O'Neil, he is the author of the database textbook Database Principles, Programming, and Performance (Morgan Kaufmann, 2nd ed., 2000).
- Curriculum vitae, retrieved 2010-11-26.
- Patrick Eugene O'Neil at the Mathematics Genealogy Project.
- Gray, Jim; Helland, Pat; O'Neil, Patrick; Shasha, Dennis (1996), "The dangers of replication and a solution", Proceedings of the 1996 ACM SIGMOD International Conference on Management of Data (SIGMOD '96), pp. 173–182, doi:10.1145/233269.233330.
- O'Neil, Elizabeth J.; O'Neil, Patrick E.; Weikum, Gerhard (1993), "The LRU-K page replacement algorithm for database disk buffering", Proceedings of the 1993 ACM SIGMOD International Conference on Management of Data (SIGMOD '93), pp. 297–306, doi:10.1145/170035.170081.
- Berenson, Hal; Bernstein, Phil; Gray, Jim; Melton, Jim; O'Neil, Elizabeth; O'Neil, Patrick (1995), "A critique of ANSI SQL isolation levels", Proceedings of the 1995 ACM SIGMOD International Conference on Management of Data (SIGMOD '95), pp. 1–10, arXiv:cs/0701157, doi:10.1145/223784.223785.
- O'Neil, Patrick; Quass, Dallan (1997), "Improved query performance with variant indexes", Proceedings of the 1997 ACM SIGMOD International Conference on Management of Data (SIGMOD '97), pp. 38–49, doi:10.1145/253260.253268.
- O'Neil, Patrick (1987). "Model 204 Architecture and Performance". In Dieter Gawlick; Mark N. Haynie; Andreas Reuter. Proceedings of the 2nd International Workshop on High Performance Transaction Systems. London, UK: Springer-Verlag. pp. 40–59.