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Instead of supposing (wrongly, in the general case) that the rowtype

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of an inheritance child table is binary-compatible with the rowtype of
its parent, invent an expression node type that does the conversion
correctly.  Fixes the new bug exhibited by Kris Shannon as well as a
lot of old bugs that would only show up when using multiple inheritance
or after altering the parent table.
This commit is contained in:
Tom Lane
2004-12-11 23:26:51 +00:00
parent fd536dd257
commit 12b1b5d837
15 changed files with 356 additions and 71 deletions
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68
src/backend/optimizer/prep/prepunion.c
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@ -14,7 +14,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.117 2004/10/02 22:39:47 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.118 2004/12/11 23:26:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -40,6 +40,8 @@ typedef struct
{
Index old_rt_index;
Index new_rt_index;
Oid old_rel_type;
Oid new_rel_type;
TupleDesc old_tupdesc;
TupleDesc new_tupdesc;
char *old_rel_name;
@ -826,6 +828,8 @@ adjust_inherited_attrs(Node *node,
context.old_rt_index = old_rt_index;
context.new_rt_index = new_rt_index;
context.old_rel_type = oldrelation->rd_rel->reltype;
context.new_rel_type = newrelation->rd_rel->reltype;
context.old_tupdesc = RelationGetDescr(oldrelation);
context.new_tupdesc = RelationGetDescr(newrelation);
context.old_rel_name = RelationGetRelationName(oldrelation);
@ -910,50 +914,6 @@ translate_inherited_attnum(AttrNumber old_attno,
return 0; /* keep compiler quiet */
}
/*
* Translate a whole-row Var to be correct for a child table.
*
* In general the child will not have a suitable field layout to be used
* directly, so we translate the simple whole-row Var into a ROW() construct.
*/
static Node *
generate_whole_row(Var *var,
adjust_inherited_attrs_context *context)
{
RowExpr *rowexpr;
List *fields = NIL;
int oldnatts = context->old_tupdesc->natts;
int i;
for (i = 0; i < oldnatts; i++)
{
Form_pg_attribute att = context->old_tupdesc->attrs[i];
Var *newvar;
if (att->attisdropped)
{
/*
* can't use atttypid here, but it doesn't really matter what
* type the Const claims to be.
*/
newvar = (Var *) makeNullConst(INT4OID);
}
else
newvar = makeVar(context->new_rt_index,
translate_inherited_attnum(i + 1, context),
att->atttypid,
att->atttypmod,
0);
fields = lappend(fields, newvar);
}
rowexpr = makeNode(RowExpr);
rowexpr->args = fields;
rowexpr->row_typeid = var->vartype; /* report parent's rowtype */
rowexpr->row_format = COERCE_IMPLICIT_CAST;
return (Node *) rowexpr;
}
static Node *
adjust_inherited_attrs_mutator(Node *node,
adjust_inherited_attrs_context *context)
@ -977,8 +937,22 @@ adjust_inherited_attrs_mutator(Node *node,
}
else if (var->varattno == 0)
{
/* expand whole-row reference into a ROW() construct */
return generate_whole_row(var, context);
/*
* Whole-row Var: we need to insert a coercion step to convert
* the tuple layout to the parent's rowtype.
*/
if (context->old_rel_type != context->new_rel_type)
{
ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr);
r->arg = (Expr *) var;
r->resulttype = context->old_rel_type;
r->convertformat = COERCE_IMPLICIT_CAST;
/* Make sure the Var node has the right type ID, too */
Assert(var->vartype == context->old_rel_type);
var->vartype = context->new_rel_type;
return (Node *) r;
}
}
/* system attributes don't need any translation */
}