Re: ALL_SYNONYMS versus USER_SYNONYMS
- From: "David Fitzjarrell" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "oratune@xxxxxxxxx" for DMARC)
- To: "dedba@xxxxxxxxxx" <dedba@xxxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 15 Sep 2014 08:02:39 -0700
It will but not with the query posted as the WHERE clause restricts the output
to only those synonyms owned by user.
David Fitzjarrell
Principal author, "Oracle Exadata Survival Guide"
On Monday, September 15, 2014 2:56 AM, De DBA <dedba@xxxxxxxxxx> wrote:
I think that user_synonyms won't list public synonyms, whereas all_synonyms
should...
Cheers,
Tony
On 15/09/14 18:39, Chitale, Hemant K wrote:
>I have developers who prefer to use the ALL_% views (e.g. ALL_TABLES) even
>when I tell them to use the USER_% views (USER_TABLES).
>Must be something in their prior experiences that “taught” them to use the
>ALL_% views !
>
>Hemant K Chitale
>
>
>From:oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
>Behalf Of David Fitzjarrell
>Sent: Friday, September 12, 2014 11:07 PM
>To: lyallbarbour@xxxxxxxxxxxxxxx; mohamed.houri@xxxxxxxxx; ORACLE-L
>Subject: Re: ALL_SYNONYMS versus USER_SYNONYMS
>
>In the absence of the qualifier "where owner=user" ALL_SYNONYMS can contain
>more synonyms than USER_SYNONYMS however the queries you post are equivalent.
>I second Lyall's question of why does the app 'need' to know about synonyms?
>This should be a configuration step prior to releasing the application to
>production; there should be no need for such a query to be run.
>
>It sounds like either the developers are misinformed or, well, arrogant. I
>would hope it is due to misinformation.
>
>David Fitzjarrell
>
>Principal author, "Oracle Exadata Survival Guide"
>
>On Friday, September 12, 2014 4:02 AM, Lyall personal
><lyallbarbour@xxxxxxxxxxxxxxx> wrote:
>
>You could give your developers the code for those two views. user_synonyms
>text does what they are doing in the where clause. At least looks like that to
>me.
>Strange query for an "application" to run. Why does the app need to know if
>synonyms exist?
>
>Sent from my BlackBerry 10 smartphone.
>From: Mohamed Houri
>Sent: Friday, September 12, 2014 5:47 AM
>To: ORACLE-L
>Reply To: mohamed.houri@xxxxxxxxx
>Subject: ALL_SYNONYMS versus USER_SYNONYMS
>
>Dear list,
>
>I was tuning an application wide performance issue via an AWR report when I
>found a SQL consuming a huge number of logical I/O and executed several times.
>This SQL looks like:
>SELECT COUNT(1)
>FROM DUAL
>WHERE EXISTS
>(SELECT 1 FROM ALL_SYNONYMS WHERE SYNONYM_NAME = :B1 AND OWNER = USER
>);
>
>After a couple of minutes of discussion with developers, they refused to get
>rid of this part of the code which seems to me useless. Then, in a second
>tentative, I suggested them to replace the above code with the following one:
>SELECT COUNT(1)
>FROM DUAL
>WHERE EXISTS
>(SELECT 1 FROM USER_SYNONYMS WHERE SYNONYM_NAME = :B1
>);
>
>They refused again saying that it will not give the same results.
>
>Can someone let me know a situation where this result difference is possible?
>
>SQL> SELECT count(1) FROM ALL_SYNONYMS where OWNER = USER;
>
> COUNT(1)
>----------
> 405
>
>SQL> SELECT count(1) FROM USER_SYNONYMS;
>
> COUNT(1)
>----------
> 405
>
>Thanks in advance
>
>--
>Houri Mohamed
>Oracle DBA-Developer-Performance & Tuning
>Member of Oraworld-team
>Visit My - Blog
>Let's Connect - Linkedin Profile
>My Twitter - MohamedHouri
>
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