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Add bms_next_member(), and use it where appropriate.

This patch adds a way of iterating through the members of a bitmapset
nondestructively, unlike the old way with bms_first_member().  While
bms_next_member() is very slightly slower than bms_first_member()
(at least for typical-size bitmapsets), eliminating the need to palloc
and pfree a temporary copy of the target bitmapset is a significant win.
So this method should be preferred in all cases where a temporary copy
would be necessary.

Tom Lane, with suggestions from Dean Rasheed and David Rowley
This commit is contained in:
Tom Lane
2014-11-28 13:37:25 -05:00
parent 96d66bcfc6
commit f4e031c662
13 changed files with 114 additions and 76 deletions

View File

@ -93,10 +93,7 @@ fixup_whole_row_references(Oid relOid, Bitmapset *columns)
static Bitmapset *
fixup_inherited_columns(Oid parentId, Oid childId, Bitmapset *columns)
{
AttrNumber attno;
Bitmapset *tmpset;
Bitmapset *result = NULL;
char *attname;
int index;
/*
@ -105,10 +102,12 @@ fixup_inherited_columns(Oid parentId, Oid childId, Bitmapset *columns)
if (parentId == childId)
return columns;
tmpset = bms_copy(columns);
while ((index = bms_first_member(tmpset)) > 0)
index = -1;
while ((index = bms_next_member(columns, index)) >= 0)
{
attno = index + FirstLowInvalidHeapAttributeNumber;
/* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
AttrNumber attno = index + FirstLowInvalidHeapAttributeNumber;
char *attname;
/*
* whole-row-reference shall be fixed-up later
@ -128,12 +127,11 @@ fixup_inherited_columns(Oid parentId, Oid childId, Bitmapset *columns)
elog(ERROR, "cache lookup failed for attribute %s of relation %u",
attname, childId);
index = attno - FirstLowInvalidHeapAttributeNumber;
result = bms_add_member(result, index);
result = bms_add_member(result,
attno - FirstLowInvalidHeapAttributeNumber);
pfree(attname);
}
bms_free(tmpset);
return result;
}