Re: sys_guid()

From: angelo <angelolistas_at_gmail.com>
Date: Fri, 1 Oct 2021 08:46:20 -0300
Message-ID: <CAEX1xDXsojrj3UWqrAdJAsDPmhHAh4wVXUKszD9yXa=L4037yQ_at_mail.gmail.com>

Hello, Jonathan,

I ran again just for certifying

Connected to:
Oracle Database 19c Standard Edition 2 Release 19.0.0.0.0 - Production Version 19.12.0.0.0

SQL> select sys_guid() from all_tables where rownum <= 5;

SYS_GUID()

---

CD49EAB78EB01638E053283210ACAC6E
CD49EAB78EB11638E053283210ACAC6E
CD49EAB78EB21638E053283210ACAC6E
CD49EAB78EB31638E053283210ACAC6E
CD49EAB78EB41638E053283210ACAC6E SQL> select sys_guid() from all_tables where rownum <= 5;

SYS_GUID()

---

CD49EAB78*EB5*1638E053283210ACAC6E
CD49EAB78EB61638E053283210ACAC6E
CD49EAB78EB71638E053283210ACAC6E
CD49EAB78EB81638E053283210ACAC6E
CD49EAB78EB91638E053283210ACAC6E SQL> yep, has changed on the same session

Disconnect and connect again

Connected to:
Oracle Database 19c Standard Edition 2 Release 19.0.0.0.0 - Production Version 19.12.0.0.0

SQL> select sys_guid() from all_tables where rownum <= 5;

SYS_GUID()

---

CD49*FB65A*51B281AE053283210AC31C2
CD49FB65A51C281AE053283210AC31C2
CD49FB65A51D281AE053283210AC31C2
CD49FB65A51E281AE053283210AC31C2
CD49FB65A51F281AE053283210AC31C2

SQL> Yes, they had changed on 12th character I didn't see before

regards

Angelo

On Fri, 1 Oct 2021 at 08:21, Jonathan Lewis <jlewisoracle_at_gmail.com> wrote:

> Angelo.
>
> Thanks for the response.
> "... got these same guids above" - that's a little worrying since GUID are
> supposed to be "Globally Unique"!
> Are you sure they didn't change on the 12th and 13th characters ?
>
> Regards
> Jonathan Lewis
>
>
>
> On Fri, 1 Oct 2021 at 11:59, angelo <angelolistas_at_gmail.com> wrote:
>
>> Hello Jonathan,
>>
>> I did.. 19.12 running on OCI (Oracle Cloud)
>>
>> First execution
>>
>> SQL> select sys_guid() from all_tables where rownum <= 5;
>>
>> SYS_GUID()
>> --------------------------------
>> CD491BB3C35586D4E053283210AC3600
>> CD491BB3C35686D4E053283210AC3600
>> CD491BB3C35786D4E053283210AC3600
>> CD491BB3C35886D4E053283210AC3600
>> CD491BB3C35986D4E053283210AC3600
>>
>> obs: running the query again with / I got these same guids above
>>
>> then disconnect and reconnect another session
>>
>> Second execution (new session):
>>
>> SQL> select sys_guid() from all_tables where rownum <= 5;
>>
>> SYS_GUID()
>> --------------------------------
>> CD4924E586A095C0E053283210ACDD33
>> CD4924E586A195C0E053283210ACDD33
>> CD4924E586A295C0E053283210ACDD33
>> CD4924E586A395C0E053283210ACDD33
>> CD4924E586A495C0E053283210ACDD33
>>
>> SQL>
>>
>> guid has changed, similar yours
>>
>> I´ve never observed them before
>>
>> regards ,
>>
>> Angelo
>>
>>
>> On Fri, 1 Oct 2021 at 06:28, Jonathan Lewis <jlewisoracle_at_gmail.com>
>> wrote:
>>
>>>
>>> I put out a tweet yesterday (
>>> https://twitter.com/JLOracle/status/1443302780266029061 ) about
>>> sys_guid() and the different pattern of results you could get depending on
>>> the platform you were running on. The most recent check I had done was
>>> 12.1.0.2, and I don't have access to anything other than OEL 7.9 at the
>>> moment to check more recent versions.
>>>
>>> It would be nice if a few people could run the following query on their
>>> systems and report the results, along with O/S, for 19c to see if there are
>>> stll differences.
>>>
>>>
>>> Here's my result from 19.11
>>>
>>> SQL> select sys_guid() from all_tables where rownum <= 5;
>>>
>>> SYS_GUID()
>>> --------------------------------
>>> CD47CA7FBE987B90E0530100007FE7D5
>>> CD47CA7FBE997B90E0530100007FE7D5
>>> CD47CA7FBE9A7B90E0530100007FE7D5
>>> CD47CA7FBE9B7B90E0530100007FE7D5
>>> CD47CA7FBE9C7B90E0530100007FE7D5
>>>
>>> 5 rows selected.
>>>
>>> Almost simultaneously from another session
>>> SYS_GUID()
>>> --------------------------------
>>> CD47CB493173114BE0530100007FA8A8
>>> CD47CB493174114BE0530100007FA8A8
>>> CD47CB493175114BE0530100007FA8A8
>>> CD47CB493176114BE0530100007FA8A8
>>> CD47CB493177114BE0530100007FA8A8
>>>
>>> This seems to have a sequential component tied to the session (possibly
>>> to the moment the session connected** rather than the session id). If you
>>> follow the links in the tweet you'll find that Oracle on Windows used to
>>> produce very random-looking leading values
>>> you reconnect once per session and run t
>>>
>>> ** If I reconnect once per session then the 7th digit of the guid
>>> increments by 1.
>>>
>>>
>>> Regards
>>> Jonathan Lewis
>>>
>>>
>>>

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Received on Fri Oct 01 2021 - 13:46:20 CEST