On Nov 28, 2006, at 12:07 PM, Edwin Grubbs wrote:
Under postgres 8.1, the "<<=" comparison yields very slow queries with large tables. I can rewrite the query without the "<<=" operator by generating all 33 possible netmasks (0 through 32) for a given IP. This ugly rewrite runs about 12 times faster (6 seconds versus 0.5 seconds). Be aware that EXPLAIN ANALYZE seems to be run a different query plan since the first query runs even slower with EXPLAIN ANALYZE. Setting enable_seqscan did not improve the query speed.
GiST opclasses for inet to make <<= indexable would be nice, but I don't think anyones done them yet. Depending on exactly what you're doing you might want to look at http://pgfoundry.org/projects/ip4r and see if that'll do what you need. It's not a drop-in replacement, though, so would be a pain to use with existing code. Cheers, Steve
