On Sun, Feb 18, 2024 at 7:29 AM Tomas Vondra
<tomas.von...@enterprisedb.com> wrote:
>
>
> Also, now that I looked at the v2 patch again, I see it only really
> tweaked the pg_proc.dat entry, but the code still does PG_GETARG_OID (so
> the "any" bit is not really correct).
>
PG_GETARG_OID part indeed is wrong. so I change to following:
+Datum
+pg_basetype(PG_FUNCTION_ARGS)
+{
+ Oid oid;
+
+ oid = get_fn_expr_argtype(fcinfo->flinfo, 0);
+ if (!SearchSysCacheExists1(TYPEOID, ObjectIdGetDatum(oid)))
+ PG_RETURN_NULL();
+
+ PG_RETURN_OID(getBaseType(oid));
+}
I still name the function as pg_basetype, feel free to change it.
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_basetype</primary>
+ </indexterm>
+ <function>pg_basetype</function> ( <type>"any"</type> )
+ <returnvalue>regtype</returnvalue>
+ </para>
+ <para>
+ Returns the OID of the base type of a domain or if the
argument is a basetype it returns the same type.
+ If there's a chain of domain dependencies, it will recurse
until finding the base type.
+ </para>
compared with pg_typeof's explanation, I feel like pg_basetype's
explanation doesn't seem accurate.
However, I don't know how to rephrase it.
From a06f2de575da6e5fa45919c792f3dab2470f4927 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Mon, 19 Feb 2024 15:01:19 +0800
Subject: [PATCH v3 1/1] Add pg_basetype("any") function
Currently obtaining the base type of a domain involves a complex SQL query,
this specially in the case of recursive domain types.
To solve this, use the already available getBaseType() function,
and expose it as the pg_basetype SQL function.
if the argument is not a doamin type, return the type of the argument as is.
if the argument is a type of doamin, pg_basetype will recurse the domain dependencies chain
and return the real inner base type of the domain.
discussion: https://postgr.es/m/CAGRrpzZSX8j=MQcbCSEisFA=ic=K3bknVfnFjAv1diVJxFHJvg@mail.gmail.com
---
doc/src/sgml/func.sgml | 25 +++++++++++++++++++
src/backend/utils/adt/misc.c | 16 +++++++++++++
src/include/catalog/pg_proc.dat | 3 +++
src/test/regress/expected/domain.out | 36 ++++++++++++++++++++++++++++
src/test/regress/sql/domain.sql | 16 +++++++++++++
5 files changed, 96 insertions(+)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index cf3de803..5af0f4c6 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -24778,6 +24778,31 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_basetype</primary>
+ </indexterm>
+ <function>pg_basetype</function> ( <type>"any"</type> )
+ <returnvalue>regtype</returnvalue>
+ </para>
+ <para>
+ Returns the OID of the base type of a domain or if the argument is a basetype it returns the same type.
+ If there's a chain of domain dependencies, it will recurse until finding the base type.
+ </para>
+ <para>
+ For example:
+<programlisting>
+CREATE DOMAIN mytext as text;
+
+SELECT pg_basetype('mytext'::mytext);
+ pg_basetype
+-----------
+ text
+</programlisting>
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-char-to-encoding" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 2d7d7806..30f6a2e5 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -45,6 +45,7 @@
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/ruleutils.h"
+#include "utils/syscache.h"
#include "utils/timestamp.h"
@@ -566,6 +567,21 @@ pg_typeof(PG_FUNCTION_ARGS)
PG_RETURN_OID(get_fn_expr_argtype(fcinfo->flinfo, 0));
}
+/*
+ * Return the base type of the argument.
+ * iff the argument is not a type of domain, return the argument's type as is.
+ */
+Datum
+pg_basetype(PG_FUNCTION_ARGS)
+{
+ Oid oid;
+
+ oid = get_fn_expr_argtype(fcinfo->flinfo, 0);
+ if (!SearchSysCacheExists1(TYPEOID, ObjectIdGetDatum(oid)))
+ PG_RETURN_NULL();
+
+ PG_RETURN_OID(getBaseType(oid));
+}
/*
* Implementation of the COLLATE FOR expression; returns the collation
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 9c120fc2..bbd6b411 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -3877,6 +3877,9 @@
{ oid => '1619', descr => 'type of the argument',
proname => 'pg_typeof', proisstrict => 'f', provolatile => 's',
prorettype => 'regtype', proargtypes => 'any', prosrc => 'pg_typeof' },
+{ oid => '6312', descr => 'get the base type of a domain',
+ proname => 'pg_basetype', proisstrict => 'f', provolatile => 's',
+ prorettype => 'regtype', proargtypes => 'any', prosrc => 'pg_basetype' },
{ oid => '3162',
descr => 'collation of the argument; implementation of the COLLATION FOR expression',
proname => 'pg_collation_for', proisstrict => 'f', provolatile => 's',
diff --git a/src/test/regress/expected/domain.out b/src/test/regress/expected/domain.out
index 6d94e844..13bf7877 100644
--- a/src/test/regress/expected/domain.out
+++ b/src/test/regress/expected/domain.out
@@ -1207,3 +1207,39 @@ create domain testdomain1 as int constraint unsigned check (value > 0);
alter domain testdomain1 rename constraint unsigned to unsigned_foo;
alter domain testdomain1 drop constraint unsigned_foo;
drop domain testdomain1;
+--
+-- Get the base type of a domain
+--
+create domain mytext as text;
+create domain mytext_child_1 as mytext;
+create domain mytext_child_2 as mytext_child_1;
+select pg_basetype('mytext'::mytext);
+ pg_basetype
+-------------
+ text
+(1 row)
+
+-- gets base types recursively
+select pg_basetype('mytext_child_1'::mytext_child_1);
+ pg_basetype
+-------------
+ text
+(1 row)
+
+select pg_basetype('mytext_child_2'::mytext_child_2);
+ pg_basetype
+-------------
+ text
+(1 row)
+
+-- if already a base type, get the same
+select pg_basetype('text'::text);
+ pg_basetype
+-------------
+ text
+(1 row)
+
+drop domain mytext cascade;
+NOTICE: drop cascades to 2 other objects
+DETAIL: drop cascades to type mytext_child_1
+drop cascades to type mytext_child_2
diff --git a/src/test/regress/sql/domain.sql b/src/test/regress/sql/domain.sql
index 745f5d5f..58540519 100644
--- a/src/test/regress/sql/domain.sql
+++ b/src/test/regress/sql/domain.sql
@@ -809,3 +809,19 @@ create domain testdomain1 as int constraint unsigned check (value > 0);
alter domain testdomain1 rename constraint unsigned to unsigned_foo;
alter domain testdomain1 drop constraint unsigned_foo;
drop domain testdomain1;
+
+--
+-- Get the base type of a domain
+--
+create domain mytext as text;
+create domain mytext_child_1 as mytext;
+create domain mytext_child_2 as mytext_child_1;
+
+select pg_basetype('mytext'::mytext);
+-- gets base types recursively
+select pg_basetype('mytext_child_1'::mytext_child_1);
+select pg_basetype('mytext_child_2'::mytext_child_2);
+-- if already a base type, get the same
+select pg_basetype('text'::text);
+
+drop domain mytext cascade;
\ No newline at end of file
--
2.34.1
