PostGIS
2.5.7dev-r@@SVN_REVISION@@
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PG_FUNCTION_INFO_V1 | ( | gserialized_gist_joinsel | ) |
Join selectivity of the && operator.
The selectivity is the ratio of the number of rows we think will be returned divided the maximum number of rows the join could possibly return (the full combinatoric join).
joinsel = estimated_nrows / (totalrows1 * totalrows2)