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-rw-r--r--src/backend/access/nbtree/nbtcompare.c77
-rw-r--r--src/backend/access/nbtree/nbtsearch.c2
-rw-r--r--src/backend/access/nbtree/nbtutils.c4
3 files changed, 50 insertions, 33 deletions
diff --git a/src/backend/access/nbtree/nbtcompare.c b/src/backend/access/nbtree/nbtcompare.c
index 4b131efb87d..90b0c933c49 100644
--- a/src/backend/access/nbtree/nbtcompare.c
+++ b/src/backend/access/nbtree/nbtcompare.c
@@ -22,11 +22,10 @@
*
* The result is always an int32 regardless of the input datatype.
*
- * Although any negative int32 (except INT_MIN) is acceptable for reporting
- * "<", and any positive int32 is acceptable for reporting ">", routines
+ * Although any negative int32 is acceptable for reporting "<",
+ * and any positive int32 is acceptable for reporting ">", routines
* that work on 32-bit or wider datatypes can't just return "a - b".
- * That could overflow and give the wrong answer. Also, one must not
- * return INT_MIN to report "<", since some callers will negate the result.
+ * That could overflow and give the wrong answer.
*
* NOTE: it is critical that the comparison function impose a total order
* on all non-NULL values of the data type, and that the datatype's
@@ -44,13 +43,31 @@
* during an index access won't be recovered till end of query. This
* primarily affects comparison routines for toastable datatypes;
* they have to be careful to free any detoasted copy of an input datum.
+ *
+ * NOTE: we used to forbid comparison functions from returning INT_MIN,
+ * but that proves to be too error-prone because some platforms' versions
+ * of memcmp() etc can return INT_MIN. As a means of stress-testing
+ * callers, this file can be compiled with STRESS_SORT_INT_MIN defined
+ * to cause many of these functions to return INT_MIN or INT_MAX instead of
+ * their customary -1/+1. For production, though, that's not a good idea
+ * since users or third-party code might expect the traditional results.
*-------------------------------------------------------------------------
*/
#include "postgres.h"
+#include <limits.h>
+
#include "utils/builtins.h"
#include "utils/sortsupport.h"
+#ifdef STRESS_SORT_INT_MIN
+#define A_LESS_THAN_B INT_MIN
+#define A_GREATER_THAN_B INT_MAX
+#else
+#define A_LESS_THAN_B (-1)
+#define A_GREATER_THAN_B 1
+#endif
+
Datum
btboolcmp(PG_FUNCTION_ARGS)
@@ -95,11 +112,11 @@ btint4cmp(PG_FUNCTION_ARGS)
int32 b = PG_GETARG_INT32(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
static int
@@ -109,11 +126,11 @@ btint4fastcmp(Datum x, Datum y, SortSupport ssup)
int32 b = DatumGetInt32(y);
if (a > b)
- return 1;
+ return A_GREATER_THAN_B;
else if (a == b)
return 0;
else
- return -1;
+ return A_LESS_THAN_B;
}
Datum
@@ -132,11 +149,11 @@ btint8cmp(PG_FUNCTION_ARGS)
int64 b = PG_GETARG_INT64(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
static int
@@ -146,11 +163,11 @@ btint8fastcmp(Datum x, Datum y, SortSupport ssup)
int64 b = DatumGetInt64(y);
if (a > b)
- return 1;
+ return A_GREATER_THAN_B;
else if (a == b)
return 0;
else
- return -1;
+ return A_LESS_THAN_B;
}
Datum
@@ -169,11 +186,11 @@ btint48cmp(PG_FUNCTION_ARGS)
int64 b = PG_GETARG_INT64(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
Datum
@@ -183,11 +200,11 @@ btint84cmp(PG_FUNCTION_ARGS)
int32 b = PG_GETARG_INT32(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
Datum
@@ -197,11 +214,11 @@ btint24cmp(PG_FUNCTION_ARGS)
int32 b = PG_GETARG_INT32(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
Datum
@@ -211,11 +228,11 @@ btint42cmp(PG_FUNCTION_ARGS)
int16 b = PG_GETARG_INT16(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
Datum
@@ -225,11 +242,11 @@ btint28cmp(PG_FUNCTION_ARGS)
int64 b = PG_GETARG_INT64(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
Datum
@@ -239,11 +256,11 @@ btint82cmp(PG_FUNCTION_ARGS)
int16 b = PG_GETARG_INT16(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
Datum
@@ -253,11 +270,11 @@ btoidcmp(PG_FUNCTION_ARGS)
Oid b = PG_GETARG_OID(1);
if (a > b)
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else if (a == b)
PG_RETURN_INT32(0);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
static int
@@ -267,11 +284,11 @@ btoidfastcmp(Datum x, Datum y, SortSupport ssup)
Oid b = DatumGetObjectId(y);
if (a > b)
- return 1;
+ return A_GREATER_THAN_B;
else if (a == b)
return 0;
else
- return -1;
+ return A_LESS_THAN_B;
}
Datum
@@ -299,9 +316,9 @@ btoidvectorcmp(PG_FUNCTION_ARGS)
if (a->values[i] != b->values[i])
{
if (a->values[i] > b->values[i])
- PG_RETURN_INT32(1);
+ PG_RETURN_INT32(A_GREATER_THAN_B);
else
- PG_RETURN_INT32(-1);
+ PG_RETURN_INT32(A_LESS_THAN_B);
}
}
PG_RETURN_INT32(0);
diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c
index 798ebbfceae..ce33b3d73da 100644
--- a/src/backend/access/nbtree/nbtsearch.c
+++ b/src/backend/access/nbtree/nbtsearch.c
@@ -498,7 +498,7 @@ _bt_compare(Relation rel,
scankey->sk_argument));
if (!(scankey->sk_flags & SK_BT_DESC))
- result = -result;
+ INVERT_COMPARE_RESULT(result);
}
/* if the keys are unequal, return the difference */
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index 4360661789e..c724b38e3a9 100644
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -507,7 +507,7 @@ _bt_compare_array_elements(const void *a, const void *b, void *arg)
cxt->collation,
da, db));
if (cxt->reverse)
- compare = -compare;
+ INVERT_COMPARE_RESULT(compare);
return compare;
}
@@ -1640,7 +1640,7 @@ _bt_check_rowcompare(ScanKey skey, IndexTuple tuple, TupleDesc tupdesc,
subkey->sk_argument));
if (subkey->sk_flags & SK_BT_DESC)
- cmpresult = -cmpresult;
+ INVERT_COMPARE_RESULT(cmpresult);
/* Done comparing if unequal, else advance to next column */
if (cmpresult != 0)
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-05 17:49:10 +0000