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Add bms_next_member(), and use it where appropriate.

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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
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8
src/backend/rewrite/rewriteHandler.c
View File

@@ -2456,11 +2456,10 @@ static Bitmapset *
adjust_view_column_set(Bitmapset *cols, List *targetlist)
{
Bitmapset *result = NULL;
Bitmapset *tmpcols;
AttrNumber col;
int col;
tmpcols = bms_copy(cols);
while ((col = bms_first_member(tmpcols)) >= 0)
col = -1;
while ((col = bms_next_member(cols, col)) >= 0)
{
/* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber;
@@ -2510,7 +2509,6 @@ adjust_view_column_set(Bitmapset *cols, List *targetlist)
attno);
}
}
bms_free(tmpcols);
return result;
}

6
src/backend/rewrite/rewriteManip.c
View File

@@ -454,13 +454,11 @@ static Relids
offset_relid_set(Relids relids, int offset)
{
Relids result = NULL;
Relids tmprelids;
int rtindex;
tmprelids = bms_copy(relids);
while ((rtindex = bms_first_member(tmprelids)) >= 0)
rtindex = -1;
while ((rtindex = bms_next_member(relids, rtindex)) >= 0)
result = bms_add_member(result, rtindex + offset);
bms_free(tmprelids);
return result;
}