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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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12
src/backend/optimizer/util/joininfo.c
View File

@@ -96,17 +96,15 @@ add_join_clause_to_rels(PlannerInfo *root,
RestrictInfo *restrictinfo,
Relids join_relids)
{
Relids tmprelids;
int cur_relid;
tmprelids = bms_copy(join_relids);
while ((cur_relid = bms_first_member(tmprelids)) >= 0)
cur_relid = -1;
while ((cur_relid = bms_next_member(join_relids, cur_relid)) >= 0)
{
RelOptInfo *rel = find_base_rel(root, cur_relid);
rel->joininfo = lappend(rel->joininfo, restrictinfo);
}
bms_free(tmprelids);
}
/*
@@ -125,11 +123,10 @@ remove_join_clause_from_rels(PlannerInfo *root,
RestrictInfo *restrictinfo,
Relids join_relids)
{
Relids tmprelids;
int cur_relid;
tmprelids = bms_copy(join_relids);
while ((cur_relid = bms_first_member(tmprelids)) >= 0)
cur_relid = -1;
while ((cur_relid = bms_next_member(join_relids, cur_relid)) >= 0)
{
RelOptInfo *rel = find_base_rel(root, cur_relid);
@@ -140,5 +137,4 @@ remove_join_clause_from_rels(PlannerInfo *root,
Assert(list_member_ptr(rel->joininfo, restrictinfo));
rel->joininfo = list_delete_ptr(rel->joininfo, restrictinfo);
}
bms_free(tmprelids);
}

6
src/backend/optimizer/util/var.c
View File

@@ -773,11 +773,10 @@ static Relids
alias_relid_set(PlannerInfo *root, Relids relids)
{
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)
{
RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
@@ -786,6 +785,5 @@ alias_relid_set(PlannerInfo *root, Relids relids)
else
result = bms_add_member(result, rtindex);
}
bms_free(tmprelids);
return result;
}