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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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18
src/backend/utils/adt/ruleutils.c
View File

@ -6731,17 +6731,12 @@ get_name_for_var_field(Var *var, int fieldno,
/*
* If it's a Var of type RECORD, we have to find what the Var refers to;
* if not, we can use get_expr_result_type. If that fails, we try
* lookup_rowtype_tupdesc, which will probably fail too, but will ereport
* an acceptable message.
* if not, we can use get_expr_result_tupdesc().
*/
if (!IsA(var, Var) ||
var->vartype != RECORDOID)
{
if (get_expr_result_type((Node *) var, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
tupleDesc = lookup_rowtype_tupdesc_copy(exprType((Node *) var),
exprTypmod((Node *) var));
Assert(tupleDesc);
tupleDesc = get_expr_result_tupdesc((Node *) var, false);
/* Got the tupdesc, so we can extract the field name */
Assert(fieldno >= 1 && fieldno <= tupleDesc->natts);
return NameStr(TupleDescAttr(tupleDesc, fieldno - 1)->attname);
@ -7044,14 +7039,9 @@ get_name_for_var_field(Var *var, int fieldno,
/*
* 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));
Assert(tupleDesc);
tupleDesc = get_expr_result_tupdesc(expr, false);
/* Got the tupdesc, so we can extract the field name */
Assert(fieldno >= 1 && fieldno <= tupleDesc->natts);
return NameStr(TupleDescAttr(tupleDesc, fieldno - 1)->attname);