RE: [External] Slow query accessing remote database tables

You could try taking your select and converting it into a view on the remote database. Then select from that view. That has worked for us in the past when doing joins on remote tables.

From: oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org> On Behalf Of Amit Saroha Sent: Tuesday, December 22, 2020 3:02 PM To: Laurentiu Oprea <laurentiu.oprea06_at_gmail.com> Cc: ORACLE-L (oracle-l_at_freelists.org) <oracle-l_at_freelists.org> Subject: Re: [External] Slow query accessing remote database tables

Thank you, Laurentiu. I'll try with the hint you have suggested. However, because there are multiple remote tables used in the query, will it take care of the whole join itself with other remote tables by adding a hint in only one table in this case PO_HEADERS_ALL?

Best Regards,
AMIT SAROHA On Tue, Dec 22, 2020 at 2:43 PM Laurentiu Oprea <laurentiu.oprea06_at_gmail.com<mailto:laurentiu.oprea06_at_gmail.com>> wrote: You can try using DRIVING_SITE hint:

................

        SELECT  /*+ DRIVING_SITE(poh)*/
            trunc(to_date(sysdate))                                                     issue_date,
            mp.organization_code                                                        ship_to_location,
......................


         ) > xss.max_update_date )


        UNION
        SELECT /*+ DRIVING_SITE(poh)*/
            trunc(to_date(sysdate))                                                     issue_date,
            mp.organization_code                                                        ship_to_location,
...........................................

În mar., 22 dec. 2020 la 20:29, Amit Saroha <eramitsaroha_at_gmail.com<mailto:eramitsaroha_at_gmail.com>> a scris: Hi All,

I apologize but I couldn't find a way to send the execution plan details in an email because every time I send my post didn't show up in the forum. I have posted the detail at PASTEBIN at the below location. It seems there is some character limit for posting in the forum.

https://pastebin.com/QsiDZFXC

I am looking for your expert advice to improve the performance of the below query which is running nearly 3 hours every day. This query is accessing data from multiple tables from the remote database over the DB link and with my minimum understanding of the execution plan, I surmise PO_HEADERS_ALL table data is coming into the local database and is the main issue. I have also studied that the REMOTE hint can be used in such scenarios but I couldn't figure out how and where to place the hint in the below query. Do let me know if it can be re-written any other way to run time and the below information is enough for you to comment on the issue?

Database details -

Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production PL/SQL Release 12.1.0.2.0 - Production
"CORE 12.1.0.2.0 Production"
TNS for Linux: Version 12.1.0.2.0 - Production NLSRTL Version 12.1.0.2.0 - Production

Thank you in advance for all your inputs in this regard.

Regards,
Amit

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