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Add a reverse-translation column number array to struct AppendRelInfo.

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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
This commit is contained in:
Tom Lane
2019-12-02 18:05:29 -05:00
parent 4526951d56
commit ce76c0ba53
8 changed files with 61 additions and 39 deletions
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26
src/backend/optimizer/util/appendinfo.c
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@@ -34,7 +34,7 @@ typedef struct
static void make_inh_translation_list(Relation oldrelation,
Relation newrelation,
Index newvarno,
List **translated_vars);
AppendRelInfo *appinfo);
static Node *adjust_appendrel_attrs_mutator(Node *node,
adjust_appendrel_attrs_context *context);
static List *adjust_inherited_tlist(List *tlist,
@@ -55,8 +55,7 @@ make_append_rel_info(Relation parentrel, Relation childrel,
appinfo->child_relid = childRTindex;
appinfo->parent_reltype = parentrel->rd_rel->reltype;
appinfo->child_reltype = childrel->rd_rel->reltype;
make_inh_translation_list(parentrel, childrel, childRTindex,
&appinfo->translated_vars);
make_inh_translation_list(parentrel, childrel, childRTindex, appinfo);
appinfo->parent_reloid = RelationGetRelid(parentrel);
return appinfo;
@@ -65,16 +64,23 @@ make_append_rel_info(Relation parentrel, Relation childrel,
/*
* make_inh_translation_list
* Build the list of translations from parent Vars to child Vars for
* an inheritance child.
* an inheritance child, as well as a reverse-translation array.
*
* The reverse-translation array has an entry for each child relation
* column, which is either the 1-based index of the corresponding parent
* column, or 0 if there's no match (that happens for dropped child columns,
* as well as child columns beyond those of the parent, which are allowed in
* traditional inheritance though not partitioning).
*
* For paranoia's sake, we match type/collation as well as attribute name.
*/
static void
make_inh_translation_list(Relation oldrelation, Relation newrelation,
Index newvarno,
List **translated_vars)
AppendRelInfo *appinfo)
{
List *vars = NIL;
AttrNumber *pcolnos;
TupleDesc old_tupdesc = RelationGetDescr(oldrelation);
TupleDesc new_tupdesc = RelationGetDescr(newrelation);
Oid new_relid = RelationGetRelid(newrelation);
@@ -83,6 +89,11 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
int old_attno;
int new_attno = 0;
/* Initialize reverse-translation array with all entries zero */
appinfo->num_child_cols = newnatts;
appinfo->parent_colnos = pcolnos =
(AttrNumber *) palloc0(newnatts * sizeof(AttrNumber));
for (old_attno = 0; old_attno < oldnatts; old_attno++)
{
Form_pg_attribute att;
@@ -115,6 +126,7 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
atttypmod,
attcollation,
0));
pcolnos[old_attno] = old_attno + 1;
continue;
}
@@ -138,6 +150,7 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
elog(ERROR, "could not find inherited attribute \"%s\" of relation \"%s\"",
attname, RelationGetRelationName(newrelation));
new_attno = ((Form_pg_attribute) GETSTRUCT(newtup))->attnum - 1;
Assert(new_attno >= 0 && new_attno < newnatts);
ReleaseSysCache(newtup);
att = TupleDescAttr(new_tupdesc, new_attno);
@@ -157,10 +170,11 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
atttypmod,
attcollation,
0));
pcolnos[new_attno] = old_attno + 1;
new_attno++;
}
*translated_vars = vars;
appinfo->translated_vars = vars;
}
/*