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Remove bms_first_member().

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This function has been semi-deprecated ever since we invented
bms_next_member().  Its habit of scribbling on the input bitmapset
isn't great, plus for sufficiently large bitmapsets it would take
O(N^2) time to complete a loop.  Now we have the additional problem
that reducing the input to empty while leaving it still accessible
would violate a planned invariant.  So let's just get rid of it,
after updating the few extant callers to use bms_next_member().

Patch by me; thanks to Nathan Bossart and Richard Guo for review.

Discussion: https://postgr.es/m/1159933.1677621588@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2023-03-02 11:34:29 -05:00
parent 2f80c95740
commit 462bb7f128
9 changed files with 23 additions and 70 deletions
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27
src/backend/access/heap/heapam.c
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@@ -3859,9 +3859,6 @@ heap_attr_equals(TupleDesc tupdesc, int attrnum, Datum value1, Datum value2,
* has_external indicates if any of the unmodified attributes (from those
* listed as interesting) of the old tuple is a member of external_cols and is
* stored externally.
*
* The input interesting_cols bitmapset is destructively modified; that is OK
* since this is invoked at most once in heap_update.
*/
static Bitmapset *
HeapDetermineColumnsInfo(Relation relation,
@@ -3870,19 +3867,20 @@ HeapDetermineColumnsInfo(Relation relation,
HeapTuple oldtup, HeapTuple newtup,
bool *has_external)
{
int attrnum;
int attidx;
Bitmapset *modified = NULL;
TupleDesc tupdesc = RelationGetDescr(relation);
while ((attrnum = bms_first_member(interesting_cols)) >= 0)
attidx = -1;
while ((attidx = bms_next_member(interesting_cols, attidx)) >= 0)
{
/* attidx is zero-based, attrnum is the normal attribute number */
AttrNumber attrnum = attidx + FirstLowInvalidHeapAttributeNumber;
Datum value1,
value2;
bool isnull1,
isnull2;
attrnum += FirstLowInvalidHeapAttributeNumber;
/*
* If it's a whole-tuple reference, say "not equal". It's not really
* worth supporting this case, since it could only succeed after a
@@ -3890,9 +3888,7 @@ HeapDetermineColumnsInfo(Relation relation,
*/
if (attrnum == 0)
{
modified = bms_add_member(modified,
attrnum -
FirstLowInvalidHeapAttributeNumber);
modified = bms_add_member(modified, attidx);
continue;
}
@@ -3905,9 +3901,7 @@ HeapDetermineColumnsInfo(Relation relation,
{
if (attrnum != TableOidAttributeNumber)
{
modified = bms_add_member(modified,
attrnum -
FirstLowInvalidHeapAttributeNumber);
modified = bms_add_member(modified, attidx);
continue;
}
}
@@ -3924,9 +3918,7 @@ HeapDetermineColumnsInfo(Relation relation,
if (!heap_attr_equals(tupdesc, attrnum, value1,
value2, isnull1, isnull2))
{
modified = bms_add_member(modified,
attrnum -
FirstLowInvalidHeapAttributeNumber);
modified = bms_add_member(modified, attidx);
continue;
}
@@ -3943,8 +3935,7 @@ HeapDetermineColumnsInfo(Relation relation,
* member of external_cols.
*/
if (VARATT_IS_EXTERNAL((struct varlena *) DatumGetPointer(value1)) &&
bms_is_member(attrnum - FirstLowInvalidHeapAttributeNumber,
external_cols))
bms_is_member(attidx, external_cols))
*has_external = true;
}