Re: purge of AWR historical tables

I've just found the note I wrote about this "pending = future date" trick; https://jonathanlewis.wordpress.com/2018/07/09/historic-stats/

Regards
Jonathan Lewis

On Fri, 23 Apr 2021 at 12:48, Jonathan Lewis <jlewisoracle_at_gmail.com> wrote:

> I've just commented on something similar on Dominic's blog note.
> It's possible that this has something to do with pending or priviate
> statistics.
> The last time I looked (possibly in a recent version only) pending stats
> had a future date.
> Maybe at some time in the past they were implemented with a date in the
> far past constructed from the SID and Serial# of the session creatring them
> - which would explain the SQL reported by Dominic in his blognote.
>
>
> Regards
> Jonathan Lewis
>
>
>
> On Fri, 23 Apr 2021 at 12:23, Noveljic Nenad <nenad.noveljic_at_vontobel.com>
> wrote:
>
>> I remembered a similar problem on a 12.1 database from long time ago.
>>
>>
>>
>> sys.wri$_optstat_tab_history was growing.
>>
>>
>>
>> I figured out the statistics purging job was executing the following
>> delete:
>>
>>
>>
>> DELETE /*+ dynamic_sampling(4) */
>>
>> FROM sys.wri$_optstat_tab_history
>>
>> WHERE savtime < :1
>>
>> AND savtime > TIMESTAMP '1900-01-01 00:00:00 -0:0'
>>
>> AND ROWNUM <= NVL ( :2, ROWNUM);
>>
>>
>>
>> I assume that :1 was systimestamp-retention.
>>
>>
>>
>> The key point was that the statistics from the 19th century weren’t
>> considered for deleting.
>>
>>
>>
>> Statistics for two tables were from long ago:
>>
>>
>>
>> select table_name,last_analyzed from dba_tables where table_name in
>>
>> (select object_name from dba_objects where object_id in
>>
>> ( select obj# from sys.tab$ where analyzetime in (select
>> max(analyzetime) from sys.tab$ where analyzetime is not null ) ));
>>
>> TABLE_NAME LAST_ANALYZED
>>
>> TAB1 01.01.0001
>>
>> TAB2 01.01.0001
>>
>>
>>
>> These weren’t considered by the delete.
>>
>>
>>
>> To rule this out, check for strange last_analyzed entries.
>>
>>
>>
>> I don’t know the origin of these entries. There were already there when I
>> started the job. I couldn’t find v$database.created in my notes, but people
>> who have been here longer swear that the database was created in this
>> century.
>>
>>
>>
>> I reset the last_analyzed by setting manually setting statistics, which
>> fixed the problem:
>>
>>
>>
>> exec dbms_stats.set_table_stats(
>> OWNNAME=>'K',TABNAME=>'TAB1',NUMROWS=>10000);
>>
>> exec dbms_stats.set_table_stats(
>> OWNNAME=>'K',TABNAME=>'TAB2',NUMROWS=>10000);
>>
>>
>>
>>
>>
>> Best regards,
>>
>>
>>
>> Nenad
>>
>>
>>
>> ____________________________________________________
>>
>> 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.
>>
>

--
http://www.freelists.org/webpage/oracle-l