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 ------ REL_12_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/e6af7b367cf46fc385307efcef5a1fece0e5fef3 Modified Files -------------- src/backend/access/gist/gistget.c | 70 ++++++++++++++++++++---------- src/backend/access/gist/gistscan.c | 25 +++++++++-- src/backend/access/index/indexam.c | 14 ++++-- src/backend/access/spgist/spgscan.c | 1 + src/include/access/genam.h | 4 +- src/include/access/gist_private.h | 26 +++++++++-- src/test/regress/expected/create_index.out | 2 +- 7 files changed, 106 insertions(+), 36 deletions(-)