Thread: pgsql: Fix handling of NULL distances in KNN-GiST
Fix handling of NULL distances in KNN-GiST In order to implement NULL LAST semantic GiST previously assumed distance to the NULL value to be Inf. However, our distance functions can return Inf and NaN for non-null values. In such cases, NULL LAST semantic appears to be broken. This commit fixes that by introducing separate array of null flags for distances. Backpatch to all supported versions. Discussion: https://postgr.es/m/CAPpHfdsNvNdA0DBS%2BwMpFrgwT6C3-q50sFVGLSiuWnV3FqOJuQ%40mail.gmail.com Author: Alexander Korotkov Backpatch-through: 9.4 Branch ------ REL9_6_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/a5431b7d5f6bcccd1fc69c4e4ae6e4d5f39b83f8 Modified Files -------------- src/backend/access/gist/gistget.c | 77 +++++++++++++++++++++++++------------- src/backend/access/gist/gistscan.c | 25 +++++++++++-- src/include/access/gist_private.h | 26 +++++++++++-- 3 files changed, 95 insertions(+), 33 deletions(-)