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| author | Alexander Korotkov <akorotkov@postgresql.org> | 2019-09-19 21:30:19 +0300 |
|---|---|---|
| committer | Alexander Korotkov <akorotkov@postgresql.org> | 2019-09-19 21:48:39 +0300 |
| commit | 6cae9d2c10e151f741e7bc64a8b70bb2615c367c (patch) | |
| tree | 1d2530905cfabaef098a1e1378097a0bb9c4ed2c /src/backend/access/gist/gistscan.c | |
| parent | 0a97edb12ec44f8d2d8828cbca6dd7639408ac88 (diff) | |
| download | postgresql-6cae9d2c10e151f741e7bc64a8b70bb2615c367c.tar.gz postgresql-6cae9d2c10e151f741e7bc64a8b70bb2615c367c.zip | |
Improve handling of NULLs in KNN-GiST and KNN-SP-GiST
This commit improves subject in two ways:
* It removes ugliness of 02f90879e7, which stores distance values and null
flags in two separate arrays after GISTSearchItem struct. Instead we pack
both distance value and null flag in IndexOrderByDistance struct. Alignment
overhead should be negligible, because we typically deal with at most few
"col op const" expressions in ORDER BY clause.
* It fixes handling of "col op NULL" expression in KNN-SP-GiST. Now, these
expression are not passed to support functions, which can't deal with them.
Instead, NULL result is implicitly assumed. It future we may decide to
teach support functions to deal with NULL arguments, but current solution is
bugfix suitable for backpatch.
Reported-by: Nikita Glukhov
Discussion: https://postgr.es/m/826f57ee-afc7-8977-c44c-6111d18b02ec%40postgrespro.ru
Author: Nikita Glukhov
Reviewed-by: Alexander Korotkov
Backpatch-through: 9.4
Diffstat (limited to 'src/backend/access/gist/gistscan.c')
| -rw-r--r-- | src/backend/access/gist/gistscan.c | 16 |
1 files changed, 6 insertions, 10 deletions
diff --git a/src/backend/access/gist/gistscan.c b/src/backend/access/gist/gistscan.c index e72bf08f952..7d0d3524bb6 100644 --- a/src/backend/access/gist/gistscan.c +++ b/src/backend/access/gist/gistscan.c @@ -33,26 +33,23 @@ pairingheap_GISTSearchItem_cmp(const pairingheap_node *a, const pairingheap_node const GISTSearchItem *sb = (const GISTSearchItem *) b; IndexScanDesc scan = (IndexScanDesc) arg; int i; - double *da = GISTSearchItemDistanceValues(sa, scan->numberOfOrderBys), - *db = GISTSearchItemDistanceValues(sb, scan->numberOfOrderBys); - bool *na = GISTSearchItemDistanceNulls(sa, scan->numberOfOrderBys), - *nb = GISTSearchItemDistanceNulls(sb, scan->numberOfOrderBys); /* Order according to distance comparison */ for (i = 0; i < scan->numberOfOrderBys; i++) { - if (na[i]) + if (sa->distances[i].isnull) { - if (!nb[i]) + if (!sb->distances[i].isnull) return -1; } - else if (nb[i]) + else if (sb->distances[i].isnull) { return 1; } else { - int cmp = -float8_cmp_internal(da[i], db[i]); + int cmp = -float8_cmp_internal(sa->distances[i].value, + sb->distances[i].value); if (cmp != 0) return cmp; @@ -100,8 +97,7 @@ gistbeginscan(Relation r, int nkeys, int norderbys) so->queueCxt = giststate->scanCxt; /* see gistrescan */ /* workspaces with size dependent on numberOfOrderBys: */ - so->distanceValues = palloc(sizeof(double) * scan->numberOfOrderBys); - so->distanceNulls = palloc(sizeof(bool) * scan->numberOfOrderBys); + so->distances = palloc(sizeof(so->distances[0]) * scan->numberOfOrderBys); so->qual_ok = true; /* in case there are zero keys */ if (scan->numberOfOrderBys > 0) { |