Tom Kyte

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These are the most recently asked questions on Ask Tom
Updated: 2 weeks 3 days ago

Best practices for keeping passwords hidden

Wed, 2019-02-13 03:26
Can you recommend best practices for keeping passwords hidden in command lines for impdp/expdp, shell scripts etc.?
Categories: DBA Blogs

Object View To Manipulate Data In Tables

Wed, 2019-02-13 03:26
Hi, I have been using Object View, User Defined Types in Oracle for sometime. I tried to follow the approach here. <code>https://docs.oracle.com/cd/A64702_01/doc/server.805/a58241/ch_ov.htm</code> I am wondering if we put all the data manipul...
Categories: DBA Blogs

Lob: Basic - Secure

Wed, 2019-02-13 03:26
We observed frequent wait event 'enq HW - contention' in performance reports with SQL includes LOB Objects. Lob object Details ? Object - WF_WORKFLOW Owner - IBMUCD What changes we can face if we convert LOB from basic to secure?...
Categories: DBA Blogs

Distinct count across multiple tables

Wed, 2019-02-13 03:26
I have three possible places where accounts data can be requested. On the MONTHLY USAGE, HISTORY USAGE or ENROLLMENT tables. The same account(s) could be on all three tables, or on the table(S) multiple times, but some accounts could be on one or ...
Categories: DBA Blogs

lost update

Wed, 2019-02-13 03:26
Tom, I was reading your book expert one-on-one and in Chapter 3: Locking and Concurrency, you have mentioned a scenario of lost update. I was trying to simulate that and I did not succeed in doing the test. I tried to update emp table in session...
Categories: DBA Blogs

Update a column after multiple criteria

Wed, 2019-02-13 03:26
Hello, I have the following data: Id AMAOUNT NO_PRATITION ID_STRATEGY 1 100 99 XXX 2 200 99 XXX 3 0 99 YYY 4 100 99 YYY 5 200 99 YYY 6 0 99 ZZZ 7 100 99 ZZZ 8 200 99 ...
Categories: DBA Blogs

How Oracle Database gets the data from multiple left joins

Wed, 2019-02-13 03:26
Hi Tom, I came across a scenario today. table1 id integer name varchar table2 id integer name varchar designation varchar table3 id integer name varchar relation_status varchar I have the query as below which is working fine ...
Categories: DBA Blogs

Please help understand expiration_secs in sys.dbms_lock.allocate_unique

Tue, 2019-02-12 09:06
Please help understand the meaning of the param <b>expiration_secs</b> in <code>sys.dbms_lock.allocate_unique</code> Does it represent the time till which the named DB lock stays on, if not unlocked/commit/rollback by the same session? https:/...
Categories: DBA Blogs

Cautions using GMT/UTC in AWS RDS instance when located in EST region

Tue, 2019-02-12 09:06
Background: 1. I have just created a Database out on an AWS RDS instance on the East Coast. 2. I noted that the TimeZone was set to GMT/UTC (Greenwich Mean Time) when I setup DB in AWS. 3. I note that when I query <select sysdate from dual;> from ...
Categories: DBA Blogs

Log Stored Procedure calls

Tue, 2019-02-12 09:06
Our solution exposes a Stored Procedure to a DB user having the right grants to execute it. We need to know the date and time for each execution for that stored procedure. We are in production, so we can not instrument the running code of the store...
Categories: DBA Blogs

Unable to read trace file generated by EXPDP

Tue, 2019-02-12 09:06
HI THERE, We are running EXPDP on a daily basis and size for the schema is only 14GB but the job is taking around 6 hours to complete. so yesterday i executed the expdp with TRACE=480300 and i got One trace file for the master processes testd...
Categories: DBA Blogs

How to create a cursor of select * from dual with input arguments?

Tue, 2019-02-12 09:06
Hi Tom, Recently I am using the rqEval function which is part of Oracle Advanced Analytics. The input of this function includes a cursor such as SELECT * FROM table(rqEval(cursor(SELECT 50 "divisor", 500 "numDots" FROM dual), 'SELECT 1 ...
Categories: DBA Blogs

APEX Licensing

Mon, 2019-02-11 14:46
Why are you talking about the license, there is a license to have the software?
Categories: DBA Blogs

Getting Started with APEX

Mon, 2019-02-11 14:46
From where I start my career in Apex Mean how to start apex
Categories: DBA Blogs

JSON Simple Dot-Notation Access Returning Null

Mon, 2019-02-11 14:46
Hi All, I am having an issue to retrieve data from JSON column based on key. Find below the json. I already validate the JSON. I didn't find any issue with the JSON. <code>"{ "Test": "123.40.4", "allowedtables": [{ "name": "t", "attri...
Categories: DBA Blogs

SQL to find indexed and unindexed queries

Mon, 2019-02-11 14:46
Hi Guys, Is there a way to determine the indexed and unindexed queries running on the database? Thanks.
Categories: DBA Blogs

Getting results based on dates

Mon, 2019-02-11 14:46
Hello, Ask tom Team. I want to make a procedure (if it's the best way) to be execute every day based on two possible dates. I thing I have to fill two variables first. --<b>Gettings dates</b> If today's date is <= 15th day of the current mont...
Categories: DBA Blogs

Database administration of log buffer

Mon, 2019-02-11 14:46
2. The airline database is an active database. The admin of the database has configured the redo log buffer to 16M. Assume that, in every 1/2 second 1M of redo log entries are created. LGWR copies those entries from buffer to file when 1M full in 1 s...
Categories: DBA Blogs

Unlock user shell script for Oracle

Fri, 2019-02-08 13:26
Hello, We have so many user ID locks from the front-end users. We need to provide a shell script to the user which they can run on OS level and unlock the ID themselves when the DBA is not present. The sys password needs to be decrypted during ...
Categories: DBA Blogs

Join all_tables to a normal table

Fri, 2019-02-08 13:26
Hi Is it possible to join ALL_TABLES and normal table? I like make dynamic SQL and select columns that shown after selected from list. Something like this: <b>select * from table1 a where a.columns in (SELECT DISTINCT A...
Categories: DBA Blogs

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