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Subject: Re: updates for handling optional argument in system functions
From: Chao Li <li.evan.chao@gmail.com>
In-Reply-To: <adWWxf5YrHATATw3@ltdrgnflg2>
Date: Wed, 8 Apr 2026 09:33:56 +0800
Cc: Andreas Karlsson <andreas@proxel.se>,
 pgsql-hackers@lists.postgresql.org
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Message-Id: <576EE368-AFB1-4375-BB77-A04CE92CC2A4@gmail.com>
References: <aTiwu9o8vBkLreAL@ltdrgnflg2> <ac63G6p1LAdbsca0@ltdrgnflg2>
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 <9e3ad0f4-c4ef-436b-a5a1-28f600d76a61@proxel.se>
 <adWWxf5YrHATATw3@ltdrgnflg2>
To: Mark Wong <markwkm@gmail.com>
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 <https://www.postgresql.org/message-id/576EE368-AFB1-4375-BB77-A04CE92CC2A4%40gmail.com>
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> On Apr 8, 2026, at 07:44, Mark Wong <markwkm@gmail.com> wrote:
>=20
> On Wed, Apr 08, 2026 at 01:28:29AM +0200, Andreas Karlsson wrote:
>> On 4/8/26 12:26 AM, Andreas Karlsson wrote:
>>> On 4/2/26 8:36 PM, Mark Wong wrote:
>>>> I've attached v5, simply a needed rebase due to some other churn in
>>>> pg_proc.dat.
>>>=20
>>> Nice, I like the patch. The code changes looks good and I like the=20=

>>> removal of these duplicate functions and use of default arguments. =
But I=20
>>> think the names of the arguments should be aligned with the names we=20=

>>> have in the documentation. And that may mean that we should change =
the=20
>>> documentation.
>> Forgot to attach rebased patches.
>=20
> Another rebase needed so quickly? :)  Thanks for the assist!
>=20
> Regards,
> Mark

I still have the question as I raised previously. Let=E2=80=99s use 0001 =
as an example. 0001 removes function 1573.

Say, an existing view depends on 1573:
```
evantest=3D# CREATE VIEW v_ruledef AS
evantest-# SELECT pg_get_ruledef(oid) AS ruledef
evantest-# FROM pg_rewrite
evantest-# WHERE rulename =3D '_RETURN';
CREATE VIEW
```

The view is stored as:
```
 _RETURN  | v_ruledef | ({QUERY :commandType 1 :querySource 0 :canSetTag =
true :utilityStmt <> :resultRelation 0 :forPortionOf <> :hasAggs false =
:hasWindowFuncs false :hasTargetSRFs false :hasSubLinks false =
:hasDistinctOn false :hasRecursive false :hasModifyingCTE false =
:hasForUpdate false :hasRowSecurity false :hasGroupRTE false :isReturn =
false :cteList <> :rtable ({RANGETBLENTRY :alias <> :eref {ALIAS =
:aliasname pg_rewrite :colnames ("oid" "rulename" "ev_class" "ev_type" =
"ev_enabled" "is_instead" "ev_qual" "ev_action")} :rtekind 0 :relid 2618 =
:inh true :relkind r :rellockmode 1 :perminfoindex 1 :tablesample <> =
:lateral false :inFromCl true :securityQuals <>}) :rteperminfos =
({RTEPERMISSIONINFO :relid 2618 :inh true :requiredPerms 2 :checkAsUser =
0 :selectedCols (b 8 9) :insertedCols (b) :updatedCols (b)}) :jointree =
{FROMEXPR :fromlist ({RANGETBLREF :rtindex 1}) :quals {OPEXPR :opno 93 =
:opfuncid 62 :opresulttype 16 :opretset false :opcollid 0 :inputcollid =
950 :args ({VAR :varno 1 :varattno 2 :vartype 19 :vartypmod -1 =
:varcollid 950 :varnullingrels (b) :varlevelsup 0 :varreturningtype 0 =
:varnosyn 1 :varattnosyn 2 :location -1} {CONST :consttype 19 =
:consttypmod -1 :constcollid 950 :constlen 64 :constbyval false =
:constisnull false :location -1 :constvalue 64 [ 95 82 69 84 85 82 78 0 =
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 =
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ]}) :location -1}} =
:mergeActionList <> :mergeTargetRelation 0 :mergeJoinCondition <> =
:targetList ({TARGETENTRY :expr {FUNCEXPR :funcid 1573 :funcresulttype =
25 :funcretset false :funcvariadic false :funcformat 0 :funccollid 100 =
:inputcollid 0 :args ({VAR :varno 1 :varattno 1 :vartype 26 :vartypmod =
-1 :varcollid 0 :varnullingrels (b) :varlevelsup 0 :varreturningtype 0 =
:varnosyn 1 :varattnosyn 1 :location -1}) :location -1} :resno 1 =
:resname ruledef :ressortgroupref 0 :resorigtbl 0 :resorigcol 0 :resjunk =
false}) :override 0 :onConflict <> :returningOldAlias <> =
:returningNewAlias <> :returningList <> :groupClause <> :groupDistinct =
false :groupByAll false :groupingSets <> :havingQual <> :windowClause <> =
:distinctClause <> :sortClause <> :limitOffset <> :limitCount <> =
:limitOption 0 :rowMarks <> :setOperations <> :constraintDeps <> =
:withCheckOptions <> :stmt_location -1 :stmt_len -1})
```

We can clearly see ":expr {FUNCEXPR :funcid 1573 =E2=80=9C.

With this patch, will that view break? How would users find all such =
broken views? Maybe PostgreSQL already has some recommended way to =
handle this kind of situation that I am not aware of?

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/