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Commit1661a40

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Cosmetic improvements in setup of planner's per-RTE arrays.
Merge setup_append_rel_array into setup_simple_rel_arrays. There's noparticularly good reason to keep them separate, and it's inconsistentwith the lack of separation in expand_planner_arrays. The only apparentbenefit was that the fast path for trivial queries in query_planner()doesn't need to set up the append_rel_array; but all we're saving thereis an if-test and NULL assignment, which surely ought to be negligible.Also improve some obsolete comments.Discussion:https://postgr.es/m/17220.1565301350@sss.pgh.pa.us
1 parentb8f2da0 commit1661a40

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5 files changed

+34
-47
lines changed

5 files changed

+34
-47
lines changed

‎src/backend/optimizer/plan/planmain.c‎

Lines changed: 1 addition & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -79,9 +79,7 @@ query_planner(PlannerInfo *root,
7979
root->initial_rels=NIL;
8080

8181
/*
82-
* Make a flattened version of the rangetable for faster access (this is
83-
* OK because the rangetable won't change any more), and set up an empty
84-
* array for indexing base relations.
82+
* Set up arrays for accessing base relations and AppendRelInfos.
8583
*/
8684
setup_simple_rel_arrays(root);
8785

@@ -156,12 +154,6 @@ query_planner(PlannerInfo *root,
156154
}
157155
}
158156

159-
/*
160-
* Populate append_rel_array with each AppendRelInfo to allow direct
161-
* lookups by child relid.
162-
*/
163-
setup_append_rel_array(root);
164-
165157
/*
166158
* Construct RelOptInfo nodes for all base relations used in the query.
167159
* Appendrel member relations ("other rels") will be added later.

‎src/backend/optimizer/prep/prepunion.c‎

Lines changed: 1 addition & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -132,16 +132,10 @@ plan_set_operations(PlannerInfo *root)
132132
/*
133133
* We'll need to build RelOptInfos for each of the leaf subqueries, which
134134
* are RTE_SUBQUERY rangetable entries in this Query. Prepare the index
135-
* arrays forthat.
135+
* arrays forthose, and for AppendRelInfos in case they're needed.
136136
*/
137137
setup_simple_rel_arrays(root);
138138

139-
/*
140-
* Populate append_rel_array with each AppendRelInfo to allow direct
141-
* lookups by child relid.
142-
*/
143-
setup_append_rel_array(root);
144-
145139
/*
146140
* Find the leftmost component Query. We need to use its column names for
147141
* all generated tlists (else SELECT INTO won't work right).

‎src/backend/optimizer/util/relnode.c‎

Lines changed: 28 additions & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -67,46 +67,39 @@ static void build_child_join_reltarget(PlannerInfo *root,
6767

6868
/*
6969
* setup_simple_rel_arrays
70-
* Prepare the arrays we use for quickly accessing base relations.
70+
* Prepare the arrays we use for quickly accessing base relations
71+
* and AppendRelInfos.
7172
*/
7273
void
7374
setup_simple_rel_arrays(PlannerInfo*root)
7475
{
76+
intsize;
7577
Indexrti;
7678
ListCell*lc;
7779

7880
/* Arrays are accessed using RT indexes (1..N) */
79-
root->simple_rel_array_size=list_length(root->parse->rtable)+1;
81+
size=list_length(root->parse->rtable)+1;
82+
root->simple_rel_array_size=size;
8083

81-
/* simple_rel_array is initialized to all NULLs */
84+
/*
85+
* simple_rel_array is initialized to all NULLs, since no RelOptInfos
86+
* exist yet. It'll be filled by later calls to build_simple_rel().
87+
*/
8288
root->simple_rel_array= (RelOptInfo**)
83-
palloc0(root->simple_rel_array_size*sizeof(RelOptInfo*));
89+
palloc0(size*sizeof(RelOptInfo*));
8490

8591
/* simple_rte_array is an array equivalent of the rtable list */
8692
root->simple_rte_array= (RangeTblEntry**)
87-
palloc0(root->simple_rel_array_size*sizeof(RangeTblEntry*));
93+
palloc0(size*sizeof(RangeTblEntry*));
8894
rti=1;
8995
foreach(lc,root->parse->rtable)
9096
{
9197
RangeTblEntry*rte= (RangeTblEntry*)lfirst(lc);
9298

9399
root->simple_rte_array[rti++]=rte;
94100
}
95-
}
96-
97-
/*
98-
* setup_append_rel_array
99-
*Populate the append_rel_array to allow direct lookups of
100-
*AppendRelInfos by child relid.
101-
*
102-
* The array remains unallocated if there are no AppendRelInfos.
103-
*/
104-
void
105-
setup_append_rel_array(PlannerInfo*root)
106-
{
107-
ListCell*lc;
108-
intsize=list_length(root->parse->rtable)+1;
109101

102+
/* append_rel_array is not needed if there are no AppendRelInfos */
110103
if (root->append_rel_list==NIL)
111104
{
112105
root->append_rel_array=NULL;
@@ -116,6 +109,12 @@ setup_append_rel_array(PlannerInfo *root)
116109
root->append_rel_array= (AppendRelInfo**)
117110
palloc0(size*sizeof(AppendRelInfo*));
118111

112+
/*
113+
* append_rel_array is filled with any already-existing AppendRelInfos,
114+
* which currently could only come from UNION ALL flattening. We might
115+
* add more later during inheritance expansion, but it's the
116+
* responsibility of the expansion code to update the array properly.
117+
*/
119118
foreach(lc,root->append_rel_list)
120119
{
121120
AppendRelInfo*appinfo=lfirst_node(AppendRelInfo,lc);
@@ -135,6 +134,10 @@ setup_append_rel_array(PlannerInfo *root)
135134
* expand_planner_arrays
136135
*Expand the PlannerInfo's per-RTE arrays by add_size members
137136
*and initialize the newly added entries to NULLs
137+
*
138+
* Note: this causes the append_rel_array to become allocated even if
139+
* it was not before. This is okay for current uses, because we only call
140+
* this when adding child relations, which always have AppendRelInfos.
138141
*/
139142
void
140143
expand_planner_arrays(PlannerInfo*root,intadd_size)
@@ -145,18 +148,18 @@ expand_planner_arrays(PlannerInfo *root, int add_size)
145148

146149
new_size=root->simple_rel_array_size+add_size;
147150

148-
root->simple_rte_array= (RangeTblEntry**)
149-
repalloc(root->simple_rte_array,
150-
sizeof(RangeTblEntry*)*new_size);
151-
MemSet(root->simple_rte_array+root->simple_rel_array_size,
152-
0,sizeof(RangeTblEntry*)*add_size);
153-
154151
root->simple_rel_array= (RelOptInfo**)
155152
repalloc(root->simple_rel_array,
156153
sizeof(RelOptInfo*)*new_size);
157154
MemSet(root->simple_rel_array+root->simple_rel_array_size,
158155
0,sizeof(RelOptInfo*)*add_size);
159156

157+
root->simple_rte_array= (RangeTblEntry**)
158+
repalloc(root->simple_rte_array,
159+
sizeof(RangeTblEntry*)*new_size);
160+
MemSet(root->simple_rte_array+root->simple_rel_array_size,
161+
0,sizeof(RangeTblEntry*)*add_size);
162+
160163
if (root->append_rel_array)
161164
{
162165
root->append_rel_array= (AppendRelInfo**)

‎src/include/nodes/pathnodes.h‎

Lines changed: 4 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -204,17 +204,16 @@ struct PlannerInfo
204204

205205
/*
206206
* simple_rte_array is the same length as simple_rel_array and holds
207-
* pointers to the associated rangetable entries. This lets us avoid
208-
* rt_fetch(), which can be a bit slow once large inheritance sets have
209-
* been expanded.
207+
* pointers to the associated rangetable entries. Using this is a shade
208+
* faster than using rt_fetch(), mostly due to fewer indirections.
210209
*/
211210
RangeTblEntry**simple_rte_array;/* rangetable as an array */
212211

213212
/*
214213
* append_rel_array is the same length as the above arrays, and holds
215214
* pointers to the corresponding AppendRelInfo entry indexed by
216-
* child_relid, or NULL ifnone. The array itself is not allocated if
217-
* append_rel_list is empty.
215+
* child_relid, or NULL ifthe rel is not an appendrel child. The array
216+
*itself is not allocated ifappend_rel_list is empty.
218217
*/
219218
structAppendRelInfo**append_rel_array;
220219

‎src/include/optimizer/pathnode.h‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -277,7 +277,6 @@ extern Path *reparameterize_path_by_child(PlannerInfo *root, Path *path,
277277
* prototypes for relnode.c
278278
*/
279279
externvoidsetup_simple_rel_arrays(PlannerInfo*root);
280-
externvoidsetup_append_rel_array(PlannerInfo*root);
281280
externvoidexpand_planner_arrays(PlannerInfo*root,intadd_size);
282281
externRelOptInfo*build_simple_rel(PlannerInfo*root,intrelid,
283282
RelOptInfo*parent);

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