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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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49
src/backend/parser/parse_target.c
View File

@ -725,6 +725,8 @@ transformAssignmentIndirection(ParseState *pstate,
else
{
FieldStore *fstore;
Oid baseTypeId;
int32 baseTypeMod;
Oid typrelid;
AttrNumber attnum;
Oid fieldTypeId;
@ -752,7 +754,14 @@ transformAssignmentIndirection(ParseState *pstate,
/* No subscripts, so can process field selection here */
typrelid = typeidTypeRelid(targetTypeId);
/*
* Look up the composite type, accounting for possibility that
* what we are given is a domain over composite.
*/
baseTypeMod = targetTypMod;
baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
typrelid = typeidTypeRelid(baseTypeId);
if (!typrelid)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
@ -796,7 +805,17 @@ transformAssignmentIndirection(ParseState *pstate,
fstore->arg = (Expr *) basenode;
fstore->newvals = list_make1(rhs);
fstore->fieldnums = list_make1_int(attnum);
fstore->resulttype = targetTypeId;
fstore->resulttype = baseTypeId;
/* If target is a domain, apply constraints */
if (baseTypeId != targetTypeId)
return coerce_to_domain((Node *) fstore,
baseTypeId, baseTypeMod,
targetTypeId,
COERCION_IMPLICIT,
COERCE_IMPLICIT_CAST,
location,
false);
return (Node *) fstore;
}
@ -1164,7 +1183,7 @@ ExpandColumnRefStar(ParseState *pstate, ColumnRef *cref,
Node *node;
node = pstate->p_post_columnref_hook(pstate, cref,
(Node *) rte);
(Node *) rte);
if (node != NULL)
{
if (rte != NULL)
@ -1387,22 +1406,18 @@ ExpandRowReference(ParseState *pstate, Node *expr,
* (This can be pretty inefficient if the expression involves nontrivial
* computation :-(.)
*
* Verify it's a composite type, and get the tupdesc. We use
* get_expr_result_type() because that can handle references to functions
* returning anonymous record types. If that fails, use
* lookup_rowtype_tupdesc(), which will almost certainly fail as well, but
* it will give an appropriate error message.
* Verify it's a composite type, and get the tupdesc.
* get_expr_result_tupdesc() handles this conveniently.
*
* If it's a Var of type RECORD, we have to work even harder: we have to
* find what the Var refers to, and pass that to get_expr_result_type.
* find what the Var refers to, and pass that to get_expr_result_tupdesc.
* That task is handled by expandRecordVariable().
*/
if (IsA(expr, Var) &&
((Var *) expr)->vartype == RECORDOID)
tupleDesc = expandRecordVariable(pstate, (Var *) expr, 0);
else if (get_expr_result_type(expr, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
tupleDesc = lookup_rowtype_tupdesc_copy(exprType(expr),
exprTypmod(expr));
else
tupleDesc = get_expr_result_tupdesc(expr, false);
Assert(tupleDesc);
/* Generate a list of references to the individual fields */
@ -1610,15 +1625,9 @@ expandRecordVariable(ParseState *pstate, Var *var, int levelsup)
/*
* We now have an expression we can't expand any more, so see if
* get_expr_result_type() can do anything with it. If not, pass to
* lookup_rowtype_tupdesc() which will probably fail, but will give an
* appropriate error message while failing.
* get_expr_result_tupdesc() can do anything with it.
*/
if (get_expr_result_type(expr, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
tupleDesc = lookup_rowtype_tupdesc_copy(exprType(expr),
exprTypmod(expr));
return tupleDesc;
return get_expr_result_tupdesc(expr, false);
}