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Specialize intarray sorting

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There is at least one report in the field of storing millions of
integers in arrays, so it seems like a good time to specialize
intarray's qsort function. In doing so, streamline the comparators:
Previously there were three, two for each direction for sorting
and one passed to qunique_arg. To preserve the early exit in the
case of descending input, pass the direction as an argument to
the comparator. This requires giving up duplicate detection, which
previously allowed skipping the qunique_arg() call. Testing showed
no regressions this way.

In passing, get rid of nearby checks that the input has at least
two elements, since preserving them would make some macros less
readable. These are not necessary for correctness, and seem like
premature optimizations.

Author: Andrey M. Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/098A3E67-E4A6-4086-9C66-B1EAEB1DFE1C@yandex-team.ru
This commit is contained in:
John Naylor
2025-02-18 11:04:55 +07:00
parent 164bac92f0
commit 53d3daa491
2 changed files with 34 additions and 48 deletions
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20
contrib/intarray/_int.h
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@ -41,17 +41,17 @@ typedef struct
#define SORT(x) \
do { \
int _nelems_ = ARRNELEMS(x); \
if (_nelems_ > 1) \
isort(ARRPTR(x), _nelems_); \
bool _ascending = true; \
isort(ARRPTR(x), _nelems_, &_ascending); \
} while(0)
/* sort the elements of the array and remove duplicates */
#define PREPAREARR(x) \
do { \
int _nelems_ = ARRNELEMS(x); \
if (_nelems_ > 1) \
if (isort(ARRPTR(x), _nelems_)) \
(x) = _int_unique(x); \
bool _ascending = true; \
isort(ARRPTR(x), _nelems_, &_ascending); \
(x) = _int_unique(x); \
} while(0)
/* "wish" function */
@ -109,7 +109,7 @@ typedef struct
/*
* useful functions
*/
bool isort(int32 *a, int len);
void isort(int32 *a, size_t len, void *arg);
ArrayType *new_intArrayType(int num);
ArrayType *copy_intArrayType(ArrayType *a);
ArrayType *resize_intArrayType(ArrayType *a, int num);
@ -176,16 +176,12 @@ bool execconsistent(QUERYTYPE *query, ArrayType *array, bool calcnot);
bool gin_bool_consistent(QUERYTYPE *query, bool *check);
bool query_has_required_values(QUERYTYPE *query);
int compASC(const void *a, const void *b);
int compDESC(const void *a, const void *b);
/* sort, either ascending or descending */
#define QSORT(a, direction) \
do { \
int _nelems_ = ARRNELEMS(a); \
if (_nelems_ > 1) \
qsort((void*) ARRPTR(a), _nelems_, sizeof(int32), \
(direction) ? compASC : compDESC ); \
bool _ascending = (direction) ? true : false; \
isort(ARRPTR(a), _nelems_, &_ascending); \
} while(0)
#endif /* ___INT_H__ */