RE: "JPPD bypassed: DISTINCT clause" in 19c

From: Noveljic Nenad <nenad.noveljic_at_vontobel.com>
Date: Mon, 7 Sep 2020 08:53:39 +0000
Message-ID: <23317_1599468840_5F55F528_23317_7555_1_836f5ce0493d4408a985548de90fba43_at_vontobel.com>



Hi Sayan,

Indeed, there aren’t any indications that this change in behavior between 12c and 18c is deliberate. Optimizer possibly sets a flag during parsing when JSON functions are referenced, and it doesn’t differentiate between “select” and “from”.

Fortunately, it doesn’t check for dependencies, so your workaround with the inline functions works perfectly. I have already integrated it in a more complex query.

Thank you very much for providing this smart solution!

Best regards,

Nenad

https://nenadnoveljic.com/blog

From: Sayan Malakshinov <xt.and.r_at_gmail.com> Sent: Sonntag, 6. September 2020 00:00
To: Noveljic Nenad <nenad.noveljic_at_vontobel.com> Cc: Andy Sayer <andysayer_at_gmail.com>; ORACLE-L (oracle-l_at_freelists.org) <oracle-l_at_freelists.org> Subject: Re: "JPPD bypassed: DISTINCT clause" in 19c

Hi Nenad,

I'm sorry, I hadn't time to investigate it earlier. Just checked it and can confirm that Cost-based JPPD doesn't work with JSON_OBJECT, though Old-style OJPPD still works fine with it and pushes predicates without problems. Do you need it exactly in new cost-based jppd?

>Do you have any workaround when JSON_OBJECT is in the select clause of the main query block?
I've checked v$system_fix_control and haven't found anything related to this limitation. I've tried many different variants: to pull it into parent views, wrap it into (select/*+ no_unnest */ ... from dual), but unfortunately the only workaround I found is to wrap it in your own user-defined function instead of JSON_OBJECT, for example: with
  function json_x(xval int) return varchar2 as

     res varchar2(4000);
  begin

     select
     JSON_OBJECT (
           'id' VALUE xval
           RETURNING VARCHAR2 (10)
           STRICT) as x
        into res
     from dual;
     return res;

  end;
select /*+ qb_name(QB_MAIN) */
 json_x(1) as x
  from t1 left outer join
    ( select /*+ qb_name(QB_MIDDLE) */ t2.n2
        from
          t2  ,
         ( select  /*+ qb_name(QB_INNER ) */  t3.n2
            from t3, t4
            where   t4.n1 = t3.n1
         ) v2
        where  v2.n2(+) = t2.n1

    ) v1 on v1.n2 = t1.n1;
/

On Fri, Sep 4, 2020 at 4:08 PM Noveljic Nenad <nenad.noveljic_at_vontobel.com<mailto:nenad.noveljic_at_vontobel.com>> wrote: Thank you, Sayan.

As opposed to your case, where you referenced json & co in the from clause, I used it only in the select clause.

In this particular case, I don’t see any reason for bypassing JPPD – JSON_OBJECT is applied at the end.

In fact, this used to work in 12c (tested on 12.2.0.1.190716), but it doesn’t as of 18c (tested on 18.7.0.0.190716 and 19.7.0.0.200414)

Do you have any workaround when JSON_OBJECT is in the select clause of the main query block?

Best regards,

Nenad

From: Sayan Malakshinov <xt.and.r_at_gmail.com<mailto:xt.and.r_at_gmail.com>> Sent: Freitag, 4. September 2020 14:55
To: Noveljic Nenad <nenad.noveljic_at_vontobel.com<mailto:nenad.noveljic_at_vontobel.com>> Cc: Andy Sayer <andysayer_at_gmail.com<mailto:andysayer_at_gmail.com>>; ORACLE-L (oracle-l_at_freelists.org<mailto:oracle-l_at_freelists.org>) <oracle-l_at_freelists.org<mailto:oracle-l_at_freelists.org>> Subject: Re: "JPPD bypassed: DISTINCT clause" in 19c

Hi Nenad,

Yes, JPPD doesn't work in case of table(), XMLTABLE and JSON_TABLE: http://orasql.org/2019/05/30/workarounds-for-jppd-with-view-and-tablekokbf-xmltable-or-json_table-functions/



Please consider the environment before printing this e-mail. Bitte denken Sie an die Umwelt, bevor Sie dieses E-Mail drucken.

Important Notice
This message is intended only for the individual named. It may contain confidential or privileged information. If you are not the named addressee you should in particular not disseminate, distribute, modify or copy this e-mail. Please notify the sender immediately by e-mail, if you have received this message by mistake and delete it from your system. Without prejudice to any contractual agreements between you and us which shall prevail in any case, we take it as your authorization to correspond with you by e-mail if you send us messages by e-mail. However, we reserve the right not to execute orders and instructions transmitted by e-mail at any time and without further explanation. E-mail transmission may not be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete. Also processing of incoming e-mails cannot be guaranteed. All liability of Vontobel Holding Ltd. and any of its affiliates (hereinafter collectively referred to as "Vontobel Group") for any damages resulting from e-mail use is excluded. You are advised that urgent and time sensitive messages should not be sent by e-mail and if verification is required please request a printed version. Please note that all e-mail communications to and from the Vontobel Group are subject to electronic storage and review by Vontobel Group. Unless stated to the contrary and without prejudice to any contractual agreements between you and Vontobel Group which shall prevail in any case, e-mail-communication is for informational purposes only and is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. The legal basis for the processing of your personal data is the legitimate interest to develop a commercial relationship with you, as well as your consent to forward you commercial communications. You can exercise, at any time and under the terms established under current regulation, your rights. If you prefer not to receive any further communications, please contact your client relationship manager if you are a client of Vontobel Group or notify the sender. Please note for an exact reference to the affected group entity the corporate e-mail signature. For further information about data privacy at Vontobel Group please consult www.vontobel.com<https://www.vontobel.com>.

--
Best regards,
Sayan Malakshinov
Oracle performance tuning engineer
Oracle ACE Associate
http://orasql.org

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css">p { font-family: Arial;font-size:9pt }</style>
</head>
<body>
<p>
<br>Important Notice</br>
<br />

This message is intended only for the individual named. It may contain confidential or privileged information. If you are not the named addressee you should in particular not disseminate, distribute, modify or copy this e-mail. Please notify the sender immediately by e-mail, if you have received this message by mistake and delete it from your system.<br /> Without prejudice to any contractual agreements between you and us which shall prevail in any case, we take it as your authorization to correspond with you by e-mail if you send us messages by e-mail. However, we reserve the right not to execute orders and instructions transmitted by e-mail at any time and without further explanation.<br /> E-mail transmission may not be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete. Also processing of incoming e-mails cannot be guaranteed. All liability of Vontobel Holding Ltd. and any of its affiliates (hereinafter collectively referred to as "Vontobel Group") for any damages resulting from e-mail use is excluded. You are advised that urgent and time sensitive messages should not be sent by e-mail and if verification is required please request a printed version.</br> Please note that all e-mail communications to and from the Vontobel Group are subject to electronic storage and review by Vontobel Group. Unless stated to the contrary and without prejudice to any contractual agreements between you and Vontobel Group which shall prevail in any case, e-mail-communication is for informational purposes only and is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction.<br /> The legal basis for the processing of your personal data is the legitimate interest to develop a commercial relationship with you, as well as your consent to forward you commercial communications. You can exercise, at any time and under the terms established under current regulation, your rights. If you prefer not to receive any further communications, please contact your client relationship manager if you are a client of Vontobel Group or notify the sender. Please note for an exact reference to the affected group entity the corporate e-mail signature. For further information about data privacy at Vontobel Group please consult <a href="https://www.vontobel.com">www.vontobel.com</a>.<br />
</p>
</body>
</html>


--
http://www.freelists.org/webpage/oracle-l
Received on Mon Sep 07 2020 - 10:53:39 CEST

Original text of this message