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Good Morning,Is there some underlying rule or DBA agreement that every table should have a primary key? To me it doesn't make logical sense that every table we define needs a primary key. Just recently I came across a primary key made up of two columns with ...
0122 years ago5 days ago

Hi Tom,can u tell me that how can i scheduled my procedures execution. for example there is a procedure namely 'abc' i want to execute it at 4'o clock every day. it would by highly appreciated if u provide my any code, or reffer documents etc. in this regard.p...
0122 years ago20.8 years ago

hello tomi wanted to know what is the perfect scenario to implement a IOT(index organized table) on a database design from what i know so far we need to create an IOT when the table is small(both row and column) and almost all of the column in the table are in...
0122 years ago8 days ago

Tom,I have been trying to understand the concept of redo log threads in a RAC environment. I understand how the redo logs work in a single instance database. But I cannot find proper documentation anywhere that clearly explains what a redo log thread is and ho...
0122 years ago15 years ago

I'm playing around with Oracle 12c and trying out the new features. One of the new features is that the WITH clause in a SQL query now allows for a PL/SQL function.I created the following sample query:<code>WITH FUNCTION get_number RETURN NUMBER IS BEGI...
0122 years ago4.1 years ago

In the Production Application we randomly notice a hiccup (slowness) in the database. The AWR shows as ‘Waiting for event "library cache lock" in wait class "Concurrency"’. The respective SQL statement is one of the frequently running statement (15,000 times p...
0122 years ago5 days ago

Hi Tom,We are supporting a Siebel application having Oracle 11g as backed. Last month we upgraded database to 19C and after that we are facing performance issues on daily basis. When we checked DB reports like AWR and ASH, I have below observations:a) In AWR r...
0122 years ago5 days ago

In the company where I work, we have the services of JD Edwards and Orchestrator Studio, but we are using APEX for fast applications. The problem is that we have not managed to use the JD Edwards SMTP in APEX or an external one to test that the apex_mail.send(...
0122 years ago5 days ago

Hi, In a 19.0, I've found a daily update that lasts for more than 30 mins in a 3rd party software.I would like to execute it in parallel.PDML is disabled, and when I try to create a profile for that update, I cannot get the desired plan.I made a small case to ...
0122 years ago5 days ago

Hello,I've configured RMAN backup with the following schedulation:- FULL Level 0 , every Sunday at 01:05 AM- INCREMENTAL Level 1, from Monday to Saturday at 01:05 AM- Archive Log Backup every day, every 30 minutesThe retention policy is set to Redundancy 2:<co...
0122 years ago8 days ago

I encountered ORA-24263 when migrating from Oracle Database 11g to 12.2.0.1. This error is thrown when using UTL_HTTP to access a site via HTTPS, and that site is a multi-server domain (as is common in today's cloud based world).I no longer have a question, r...
0122 years ago4.4 years ago

Hi,Access by ROWID is supposed to fastest of all and when same is used in below DELETE statement. It is taking time.There are also "db file sequential read" and "free buffer waits" wait events.1)Why statement is taking time ?2)Does reorganizing table help this...
0122 years ago5 weeks ago

hi tom i have a simple question about result cache.1.how exactly does the oracle access the result cache? and how does it knew that it is the same sql statement executed last time?2.when we cache result of the SQL statement into the result cache and re run the...
0122 years ago8 days ago

hi tom i just finished studying about TKPROF and SQLtrace. when we use TKPROF we can analyze which part of the query is having performance problem.my question is why is cpu time is so important? what does cpu time affect? and what is the best method to reduce ...
0122 years ago8 days ago

We have a table which contains db_name and usernames. In the output we need list of users per DB i.e. number of columns will be equal to distinct db_name.sample output format:<b>DB1 DB2</b>USER1 USER4USER2 USER5USER3 Database version: <b>11g</b>Below is sample...
0122 years ago2.3 years ago

I have a SQL query as:<code>With jtable as (:inp)Select * from table t,jtable where t.DATE = jtable.DATE</code>Here <code>inp </code>is a dataframe which I take care of by converting to json and eveything and it works perfectly fine except when it has to deal ...
0122 years ago2.5 years ago

Hi guys.I have a problem with the estimation of the cardinality of a skewed columnThe distribution of the data is as follows:<code>select m.m_pricelist_id, count(*)from m_pricelist_version mgroup by m.m_pricelist_id 2 3 ;</code>M_PRICELIST_ID COUNT(*)-...
0122 years ago5.2 years ago

I have a bit of an unexplainable situation.We have a procedure which executes a query and it consistently chooses the worst index. When I execute it in SQL*Plus or SQL Developer it chooses the correct index. The only way I can get it to work fast in the proced...
0122 years ago8 days ago

Hello Tom,I have a table with a CLOB column:<code>create table plch_clob(i int primary key, x clob);begin for indx in 1 .. 1000 loop insert into plch_clob( i, x) values (indx, 'CLOB Row: ' || indx); end loop; commit;end;</code>By calling the func...
0122 years ago5.9 years ago

Does MySql Btree index store NULL value?I execute a sql like "explain select * from t1 where id is null",most id of table t1 is NULL, I think it should use full table scan instead of index scan. But MySql use index. why? ...
0122 years ago8 days ago