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Change array comparison rules to consider dimensionality information,

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not only the array contents, before claiming two arrays are equal.
Per recent discussion.
This commit is contained in:
Tom Lane
2005-11-19 19:44:55 +00:00
parent daea4d8eae
commit 659f681638
2 changed files with 47 additions and 10 deletions
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42
src/backend/utils/adt/arrayfuncs.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.124 2005/11/17 22:14:52 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.125 2005/11/19 19:44:55 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2965,10 +2965,9 @@ array_eq(PG_FUNCTION_ARGS)
int ndims2 = ARR_NDIM(array2);
int *dims1 = ARR_DIMS(array1);
int *dims2 = ARR_DIMS(array2);
int nitems1 = ArrayGetNItems(ndims1, dims1);
int nitems2 = ArrayGetNItems(ndims2, dims2);
Oid element_type = ARR_ELEMTYPE(array1);
bool result = true;
int nitems;
TypeCacheEntry *typentry;
int typlen;
bool typbyval;
@ -2986,8 +2985,9 @@ array_eq(PG_FUNCTION_ARGS)
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("cannot compare arrays of different element types")));
/* fast path if the arrays do not have the same number of elements */
if (nitems1 != nitems2)
/* fast path if the arrays do not have the same dimensionality */
if (ndims1 != ndims2 ||
memcmp(dims1, dims2, 2 * ndims1 * sizeof(int)) != 0)
result = false;
else
{
@ -3021,13 +3021,14 @@ array_eq(PG_FUNCTION_ARGS)
NULL, NULL);
/* Loop over source data */
nitems = ArrayGetNItems(ndims1, dims1);
ptr1 = ARR_DATA_PTR(array1);
ptr2 = ARR_DATA_PTR(array2);
bitmap1 = ARR_NULLBITMAP(array1);
bitmap2 = ARR_NULLBITMAP(array2);
bitmask = 1; /* use same bitmask for both arrays */
for (i = 0; i < nitems1; i++)
for (i = 0; i < nitems; i++)
{
Datum elt1;
Datum elt2;
@ -3221,13 +3222,13 @@ array_cmp(FunctionCallInfo fcinfo)
NULL, NULL);
/* Loop over source data */
min_nitems = Min(nitems1, nitems2);
ptr1 = ARR_DATA_PTR(array1);
ptr2 = ARR_DATA_PTR(array2);
bitmap1 = ARR_NULLBITMAP(array1);
bitmap2 = ARR_NULLBITMAP(array2);
bitmask = 1; /* use same bitmask for both arrays */
min_nitems = Min(nitems1, nitems2);
for (i = 0; i < min_nitems; i++)
{
Datum elt1;
@ -3317,8 +3318,31 @@ array_cmp(FunctionCallInfo fcinfo)
}
}
if ((result == 0) && (nitems1 != nitems2))
result = (nitems1 < nitems2) ? -1 : 1;
/*
* If arrays contain same data (up to end of shorter one), apply additional
* rules to sort by dimensionality. The relative significance of the
* different bits of information is historical; mainly we just care that
* we don't say "equal" for arrays of different dimensionality.
*/
if (result == 0)
{
if (nitems1 != nitems2)
result = (nitems1 < nitems2) ? -1 : 1;
else if (ndims1 != ndims2)
result = (ndims1 < ndims2) ? -1 : 1;
else
{
/* this relies on LB array immediately following DIMS array */
for (i = 0; i < ndims1 * 2; i++)
{
if (dims1[i] != dims2[i])
{
result = (dims1[i] < dims2[i]) ? -1 : 1;
break;
}
}
}
}
/* Avoid leaking memory when handed toasted input. */
PG_FREE_IF_COPY(array1, 0);