8000 Add a reverse-translation column number array to struct AppendRelInfo. · postgrespro/postgres_cluster@ce76c0b · GitHub
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Add a reverse-translation column number array to struct AppendRelInfo.
This provides for cheaper mapping of child columns back to parent columns. The one existing use-case in examine_simple_variable() would hardly justify this by itself; but an upcoming bug fix will make use of this array in a mainstream code path, and it seems likely that we'll find other uses for it as we continue to build out the partitioning infrastructure. Discussion: https://postgr.es/m/12424.1575168015@sss.pgh.pa.us
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8 files changed

+62
-40
lines changed

8 files changed

+62
-40
lines changed

‎src/backend/nodes/copyfuncs.c‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2327,6 +2327,8 @@ _copyAppendRelInfo(const AppendRelInfo *from)
23272327
COPY_SCALAR_FIELD(parent_reltype);
23282328
COPY_SCALAR_FIELD(child_reltype);
23292329
COPY_NODE_FIELD(translated_vars);
2330+
COPY_SCALAR_FIELD(num_child_cols);
2331+
COPY_POINTER_FIELD(parent_colnos, from->num_child_cols * sizeof(AttrNumber));
23302332
COPY_SCALAR_FIELD(parent_reloid);
23312333

23322334
return newnode;

‎src/backend/nodes/equalfuncs.c‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -900,6 +900,8 @@ _equalAppendRelInfo(const AppendRelInfo *a, const AppendRelInfo *b)
900900
COMPARE_SCALAR_FIELD(parent_reltype);
901901
COMPARE_SCALAR_FIELD(child_reltype);
902902
COMPARE_NODE_FIELD(translated_vars);
903+
COMPARE_SCALAR_FIELD(num_child_cols);
904+
COMPARE_POINTER_FIELD(parent_colnos, a->num_child_cols * sizeof(AttrNumber));
903905
COMPARE_SCALAR_FIELD(parent_reloid);
904906

905907
return true;

‎src/backend/nodes/nodeFuncs.c‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3103,6 +3103,7 @@ expression_tree_mutator(Node *node,
31033103

31043104
FLATCOPY(newnode, appinfo, AppendRelInfo);
31053105
MUTATE(newnode->translated_vars, appinfo->translated_vars, List *);
3106+
/* Assume nothing need be done with parent_colnos[] */
31063107
return (Node *) newnode;
31073108
}
31083109
break;

‎src/backend/nodes/outfuncs.c‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2509,6 +2509,8 @@ _outAppendRelInfo(StringInfo str, const AppendRelInfo *node)
25092509
WRITE_OID_FIELD(parent_reltype);
25102510
WRITE_OID_FIELD(child_reltype);
25112511
WRITE_NODE_FIELD(translated_vars);
2512+
WRITE_INT_FIELD(num_child_cols);
2513+
WRITE_ATTRNUMBER_ARRAY(parent_colnos, node->num_child_cols);
25122514
WRITE_OID_FIELD(parent_reloid);
25132515
}
25142516

‎src/backend/optimizer/prep/prepjointree.c‎

Lines changed: 13 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -81,7 +81,7 @@ static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
8181
int parentRTindex, Query *setOpQuery,
8282
int childRToffset);
8383
static void make_setop_translation_list(Query *query, Index newvarno,
84-
List **translated_vars);
84+
AppendRelInfo *appinfo);
8585
static bool is_simple_subquery(Query *subquery, RangeTblEntry *rte,
8686
JoinExpr *lowest_outer_join);
8787
static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
@@ -1313,8 +1313,7 @@ pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
13131313
appinfo->child_relid = childRTindex;
13141314
appinfo->parent_reltype = InvalidOid;
13151315
appinfo->child_reltype = InvalidOid;
1316-
make_setop_translation_list(setOpQuery, childRTindex,
1317-
&appinfo->translated_vars);
1316+
make_setop_translation_list(setOpQuery, childRTindex, appinfo);
13181317
appinfo->parent_reloid = InvalidOid;
13191318
root->append_rel_list = lappend(root->append_rel_list, appinfo);
13201319

@@ -1356,14 +1355,22 @@ pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
13561355
* a UNION ALL member. (At this point it's just a simple list of
13571356
* referencing Vars, but if we succeed in pulling up the member
13581357
* subquery, the Vars will get replaced by pulled-up expressions.)
1358+
* Also create the rather trivial reverse-translation array.
13591359
*/
13601360
static void
13611361
make_setop_translation_list(Query *query, Index newvarno,
1362-
List **translated_vars)
1362+
AppendRelInfo *appinfo)
13631363
{
13641364
List *vars = NIL;
1365+
AttrNumber *pcolnos;
13651366
ListCell *l;
13661367

1368+
/* Initialize reverse-translation array with all entries zero */
1369+
/* (entries for resjunk columns will stay that way) */
1370+
appinfo->num_child_cols = list_length(query->targetList);
1371+
appinfo->parent_colnos = pcolnos =
1372+
(AttrNumber *) palloc0(appinfo->num_child_cols * sizeof(AttrNumber));
1373+
13671374
foreach(l, query->targetList)
13681375
{
13691376
TargetEntry *tle = (TargetEntry *) lfirst(l);
@@ -1372,9 +1379,10 @@ make_setop_translation_list(Query *query, Index newvarno,
13721379
continue;
13731380

13741381
vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
1382+
pcolnos[tle->resno - 1] = tle->resno;
13751383
}
13761384

1377-
*translated_vars = vars;
1385+
appinfo->translated_vars = vars;
13781386
}
13791387

13801388
/*

‎src/backend/optimizer/util/appendinfo.c‎

Lines changed: 20 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -34,7 +34,7 @@ typedef struct
3434
static void make_inh_translation_list(Relation oldrelation,
3535
Relation newrelation,
3636
Index newvarno,
37-
List **translated_vars);
37+
AppendRelInfo *appinfo);
3838
static Node *adjust_appendrel_attrs_mutator(Node *node,
3939
adjust_appendrel_attrs_context *context);
4040
static List *adjust_inherited_tlist(List *tlist,
@@ -55,8 +55,7 @@ make_append_rel_info(Relation parentrel, Relation childrel,
5555
appinfo->child_relid = childRTindex;
5656
appinfo->parent_reltype = parentrel->rd_rel->reltype;
5757
appinfo->child_reltype = childrel->rd_rel->reltype;
58-
make_inh_translation_list(parentrel, childrel, childRTindex,
59-
&appinfo->translated_vars);
58+
make_inh_translation_list(parentrel, childrel, childRTindex, appinfo);
6059
appinfo->parent_reloid = RelationGetRelid(parentrel);
6160

6261
return appinfo;
@@ -65,16 +64,23 @@ make_append_rel_info(Relation parentrel, Relation childrel,
6564
/*
6665
* make_inh_translation_list
6766
* Build the list of translations from parent Vars to child Vars for
68-
* an inheritance child.
67+
* an inheritance child, as well as a reverse-translation array.
68+
*
69+
* The reverse-translation array has an entry for each child relation
70+
* column, which is either the 1-based index of the corresponding parent
71+
* column, or 0 if there's no match (that happens for dropped child columns,
72+
* as well as child columns beyond those of the parent, which are allowed in
73+
* traditional inheritance though not partitioning).
6974
*
7075
* For paranoia's sake, we match type/collation as well as attribute name.
7176
*/
7277
static void
7378
make_inh_translation_list(Relation oldrelation, Relation newrelation,
7479
Index newvarno,
75-
List **translated_vars)
80+
AppendRelInfo *appinfo)
7681
{
7782
List *vars = NIL;
83+
AttrNumber *pcolnos;
7884
TupleDesc old_tupdesc = RelationGetDescr(oldrelation);
7985
TupleDesc new_tupdesc = RelationGetDescr(newrelation);
8086
Oid new_relid = RelationGetRelid(newrelation);
@@ -83,6 +89,11 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
8389
int old_attno;
8490
int new_attno = 0;
8591

92+
/* Initialize reverse-translation array with all entries zero */
93+
appinfo->num_child_cols = newnatts;
94+
appinfo->parent_colnos = pcolnos =
95+
(AttrNumber *) palloc0(newnatts * sizeof(AttrNumber));
96+
8697
for (old_attno = 0; old_attno < oldnatts; old_attno++)
8798
{
8899
Form_pg_attribute att;
@@ -115,6 +126,7 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
115126
atttypmod,
116127
attcollation,
117128
0));
129+
pcolnos[old_attno] = old_attno + 1;
118130
continue;
119131
}
120132

@@ -138,6 +150,7 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
138150
elog(ERROR, "could not find inherited attribute \"%s\" of relation \"%s\"",
139151
attname, RelationGetRelationName(newrelation));
140152
new_attno = ((Form_pg_attribute) GETSTRUCT(newtup))->attnum - 1;
153+
Assert(new_attno >= 0 && new_attno < newnatts);
141154
ReleaseSysCache(newtup);
142155

143156
att = TupleDescAttr(new_tupdesc, new_attno);
@@ -157,10 +170,11 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
157170
atttypmod,
158171
attcollation,
159172
0));
173+
pcolnos[new_attno] = old_attno + 1;
160174
new_attno++;
161175
}
162176

163-
*translated_vars = vars;
177+
appinfo->translated_vars = vars;
164178
}
165179

166180
/*

‎src/backend/utils/adt/selfuncs.c‎

Lines changed: 6 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -4769,29 +4769,17 @@ examine_simple_variable(PlannerInfo *root, Var *var,
47694769
root)->rtekind == RTE_RELATION)
47704770
{
47714771
int parent_varattno;
4772-
ListCell *l;
47734772

4774-
parent_varattno = 1;
47754773
found = false;
4776-
foreach(l, appinfo->translated_vars)
4777-
{
4778-
Var *childvar = lfirst_node(Var, l);
4779-
4780-
/* Ignore dropped attributes of the parent. */
4781-
if (childvar != NULL &&
4782-
varattno == childvar->varattno)
4783-
{
4784-
found = true;
4785-
break;
4786-
}
4787-
parent_varattno++;
4788-
}
4789-
4790-
if (!found)
4791-
break;
4774+
if (varattno <= 0 || varattno > appinfo->num_child_cols)
4775+
break; /* safety check */
4776+
parent_varattno = appinfo->parent_colnos[varattno - 1];
4777+
if (parent_varattno == 0)
4778+
break; /* Var is local to child */
47924779

47934780
varno = appinfo->parent_relid;
47944781
varattno = parent_varattno;
4782+
found = true;
47954783

47964784
/* If the parent is itself a child, continue up. */
47974785
appinfo = root->append_rel_array[varno];

‎src/include/nodes/pathnodes.h‎

Lines changed: 16 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -2151,17 +2151,13 @@ struct SpecialJoinInfo
21512151
* "append relation" (essentially, a list of child RTEs), we build an
21522152
* AppendRelInfo for each child RTE. The list of AppendRelInfos indicates
21532153
* which child RTEs must be included when expanding the parent, and each node
2154-
* carries information needed to translate Vars referencing the parent into
2155-
* Vars referencing that child.
2156-
*
2157-
* These structs are kept in the PlannerInfo node's append_rel_list.
2158-
* Note that we just throw all the structs into one list, and scan the
2159-
* whole list when desiring to expand any one parent. We could have used
2160-
* a more complex data structure (eg, one list per parent), but this would
2161-
* be harder to update during operations such as pulling up subqueries,
2162-
* and not really any easier to scan. Considering that typical queries
2163-
* will not have many different append parents, it doesn't seem worthwhile
2164-
* to complicate things.
2154+
* carries information needed to translate between columns of the parent and
2155+
* columns of the child.
2156+
*
2157+
* These structs are kept in the PlannerInfo node's append_rel_list, with
2158+
* append_rel_array[] providing a convenient lookup method for the struct
2159+
* associated with a particular child relid (there can be only one, though
2160+
* parent rels may have many entries in append_rel_list).
21652161
*
21662162
* Note: after completion of the planner prep phase, any given RTE is an
21672163
* append parent having entries in append_rel_list if and only if its
@@ -2218,6 +2214,15 @@ typedef struct AppendRelInfo
22182214
*/
22192215
List *translated_vars; /* Expressions in the child's Vars */
22202216

2217+
/*
2218+
* This array simplifies translations in the reverse direction, from
2219+
* child's column numbers to parent's. The entry at [ccolno - 1] is the
2220+
* 1-based parent column number for child column ccolno, or zero if that
2221+
* child column is dropped or doesn't exist in the parent.
2222+
*/
2223+
int num_child_cols; /* length of array */
2224+
AttrNumber *parent_colnos; /* array of parent attnos, or zeroes */
2225+
22212226
/*
22222227
* We store the parent table's OID here for inheritance, or InvalidOid for
22232228
* UNION ALL. This is only needed to help in generating error messages if

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