ab596105b5
Adds BRIN opclasses similar to the existing minmax, except that instead of summarizing the page range into a single [min,max] range, the summary consists of multiple ranges and/or points, allowing gaps. This allows more efficient handling of data with poor correlation to physical location within the table and/or outlier values, for which the regular minmax opclassed tend to work poorly. It's possible to specify the number of values kept for each page range, either as a single point or an interval boundary. CREATE TABLE t (a int); CREATE INDEX ON t USING brin (a int4_minmax_multi_ops(values_per_range=16)); When building the summary, the values are combined into intervals with the goal to minimize the "covering" (sum of interval lengths), using a support procedure computing distance between two values. Bump catversion, due to various catalog changes. Author: Tomas Vondra <tomas.vondra@postgresql.org> Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Reviewed-by: Sokolov Yura <y.sokolov@postgrespro.ru> Reviewed-by: John Naylor <john.naylor@enterprisedb.com> Discussion: https://postgr.es/m/c1138ead-7668-f0e1-0638-c3be3237e812@2ndquadrant.com Discussion: https://postgr.es/m/5d78b774-7e9c-c94e-12cf-fef51cc89b1a%402ndquadrant.com
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