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Support domains over composite types.

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This is the last major omission in our domains feature: you can now
make a domain over anything that's not a pseudotype.

The major complication from an implementation standpoint is that places
that might be creating tuples of a domain type now need to be prepared
to apply domain_check().  It seems better that unprepared code fail
with an error like "<type> is not composite" than that it silently fail
to apply domain constraints.  Therefore, relevant infrastructure like
get_func_result_type() and lookup_rowtype_tupdesc() has been adjusted
to treat domain-over-composite as a distinct case that unprepared code
won't recognize, rather than just transparently treating it the same
as plain composite.  This isn't a 100% solution to the possibility of
overlooked domain checks, but it catches most places.

In passing, improve typcache.c's support for domains (it can now cache
the identity of a domain's base type), and rewrite the argument handling
logic in jsonfuncs.c's populate_record[set]_worker to reduce duplicative
per-call lookups.

I believe this is code-complete so far as the core and contrib code go.
The PLs need varying amounts of work, which will be tackled in followup
patches.

Discussion: https://postgr.es/m/4206.1499798337@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2017-10-26 13:47:45 -04:00
parent 08f1e1f0a4
commit 37a795a60b
37 changed files with 1085 additions and 293 deletions
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48
src/backend/parser/parse_coerce.c
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@ -499,9 +499,26 @@ coerce_type(ParseState *pstate, Node *node,
* Input class type is a subclass of target, so generate an
* appropriate runtime conversion (removing unneeded columns and
* possibly rearranging the ones that are wanted).
*
* We will also get here when the input is a domain over a subclass of
* the target type. To keep life simple for the executor, we define
* ConvertRowtypeExpr as only working between regular composite types;
* therefore, in such cases insert a RelabelType to smash the input
* expression down to its base type.
*/
Oid baseTypeId = getBaseType(inputTypeId);
ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr);
if (baseTypeId != inputTypeId)
{
RelabelType *rt = makeRelabelType((Expr *) node,
baseTypeId, -1,
InvalidOid,
COERCE_IMPLICIT_CAST);
rt->location = location;
node = (Node *) rt;
}
r->arg = (Expr *) node;
r->resulttype = targetTypeId;
r->convertformat = cformat;
@ -966,6 +983,8 @@ coerce_record_to_complex(ParseState *pstate, Node *node,
int location)
{
RowExpr *rowexpr;
Oid baseTypeId;
int32 baseTypeMod = -1;
TupleDesc tupdesc;
List *args = NIL;
List *newargs;
@ -1001,7 +1020,14 @@ coerce_record_to_complex(ParseState *pstate, Node *node,
format_type_be(targetTypeId)),
parser_coercion_errposition(pstate, location, node)));
tupdesc = lookup_rowtype_tupdesc(targetTypeId, -1);
/*
* Look up the composite type, accounting for possibility that what we are
* given is a domain over composite.
*/
baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
tupdesc = lookup_rowtype_tupdesc(baseTypeId, baseTypeMod);
/* Process the fields */
newargs = NIL;
ucolno = 1;
arg = list_head(args);
@ -1070,10 +1096,22 @@ coerce_record_to_complex(ParseState *pstate, Node *node,
rowexpr = makeNode(RowExpr);
rowexpr->args = newargs;
rowexpr->row_typeid = targetTypeId;
rowexpr->row_typeid = baseTypeId;
rowexpr->row_format = cformat;
rowexpr->colnames = NIL; /* not needed for named target type */
rowexpr->location = location;
/* If target is a domain, apply constraints */
if (baseTypeId != targetTypeId)
{
rowexpr->row_format = COERCE_IMPLICIT_CAST;
return coerce_to_domain((Node *) rowexpr,
baseTypeId, baseTypeMod,
targetTypeId,
ccontext, cformat, location,
false);
}
return (Node *) rowexpr;
}
@ -2401,13 +2439,13 @@ is_complex_array(Oid typid)
/*
* Check whether reltypeId is the row type of a typed table of type
* reloftypeId. (This is conceptually similar to the subtype
* relationship checked by typeInheritsFrom().)
* reloftypeId, or is a domain over such a row type. (This is conceptually
* similar to the subtype relationship checked by typeInheritsFrom().)
*/
static bool
typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId)
{
Oid relid = typeidTypeRelid(reltypeId);
Oid relid = typeOrDomainTypeRelid(reltypeId);
bool result = false;
if (relid)