Tom Kyte

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Updated: 2 hours 25 min ago

Index Rebuild and analyze

2 hours 25 min ago
Hello Tom , I have a query regarding Index rebuild . what according to you should be time lag between index rebuilds. We are rebuilding indexes every week .but we found it is causing lot of fragmentation. is there any way we could find out whet...
Categories: DBA Blogs

Views of Views

2 hours 25 min ago
I remember hearing some time ago that creating views based upon other existing views should be avoided as it can often confuse the optimiser and result in full table scans. I expect that this is just another urban myth however I would be intereste...
Categories: DBA Blogs

Inserts with APPEND Hint.

2 hours 25 min ago
<code>insert /*+ append */ into t select rownum,mod(rownum,5) from all_objects where rownum <=1000 call count cpu elapsed disk query current rows ------- ------ -------- ---------- ---------- ---------- -----...
Categories: DBA Blogs

Kill a session from database procedure

2 hours 25 min ago
How i can kill a session from a stored database procedure. There is some way to do this?
Categories: DBA Blogs

Why cost for TABLE ACCESS BY INDEX ROWID to high for only one row

Sat, 2019-10-19 15:45
Dear Tom, I have problem with query on table have function base index. create index : <code> create index customer_idx_idno on Customer (lower(id_no)) ; --- id_no varchar2(40) </code> <b>Query 1:</b> execute time 0.031s but cost 5,149, 1 row ...
Categories: DBA Blogs

How to get unique values/blanks across all columns

Sat, 2019-10-19 15:45
Hi, I have a wide table with 200 odd columns. Requirement is to pivot the columns and display the unique values and count of blanks within each column <code>CREATE TABLE example( c1 VARCHAR(10), c2 VARCHAR(10), c3 VARCHAR(10) ); / INSERT ...
Categories: DBA Blogs

Elastic search using Oracle 19c

Sat, 2019-10-19 15:45
Team, Very recently we got a question from our customer that "can I replace Elastic search using Oracle 19c or any version of Oracle database prior to that"? Any inputs/directions to that please - kindly advice.
Categories: DBA Blogs

Add NULLABLE column with DEFAULT values to a large table

Sat, 2019-10-19 15:45
I'm adding a number of columns with DEFAULT values that are NULLABLE to a large table e.g <code> alter table big_table add (col1 varchar2(1) default 0, col2 varchar2(1) default 0); </code> It's taking a long time to do because Oracle is e...
Categories: DBA Blogs

Create table from select with changes in the column values

Sat, 2019-10-19 15:45
Hello, In the work we have an update script that takes around 20 hours, and some of the most demanding queries are updates where we change some values, something like: <code> UPDATE table1 SET column1 = DECODE(table1.column1,null,null,'no...
Categories: DBA Blogs

Data archival and purging for OLTP database.

Sat, 2019-10-19 15:45
Hi Tom, Need your suggestion regarding data archival and purging solution for OLTP db. Currently we are planning to have below approach. database is size is 150 Gb and planning to run the jobs monthly. 1) Generate flat files from table based on...
Categories: DBA Blogs

Job to end in case connection not establishing with utl_http.begin_request

Sat, 2019-10-19 15:45
i am tracking around 17000 orders through a web service through pl/sql to a destination server. i am running multiple jobs in batches(for 500 orders each job) for invoking webservice to get the order status. so around 34 jobs are running (17000/500) ...
Categories: DBA Blogs

Inserting values into a table with '&'

Sat, 2019-10-19 15:45
Hi, I want to insert a values into a table as follows: create table test (name varchar2(35)); insert into test values ('&Vivek'); I tried the escape character '\' but the system asks for a value of the substitution variable. I also did a...
Categories: DBA Blogs

Pivot with list of rows

Thu, 2019-09-26 06:46
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 USER4 USER2 USER5 USER3 Database version:...
Categories: DBA Blogs

confuse at the order of execution plan table

Thu, 2019-09-26 06:46
As we were told that "The execution order in EXPLAIN PLAN output begins with the line that is the furthest indented to the right. The next step is the parent of that line. If two lines are indented equally, then the top line is executed first." howe...
Categories: DBA Blogs

Converting data types in where clause

Thu, 2019-09-26 06:46
Hi Tom, My question is regarding when a query is not having the right datatype in the where clause Example: -- Create table <code>CREATE TABLE mytable ( mynumber varchar2(20), primary key(mynumber));</code> -- Insert some rows <...
Categories: DBA Blogs

Resetting a live sequence

Thu, 2019-09-26 06:46
A sequence was about to finish, so I had make it bigger. I work on database 11.2 so I had to use a workaround described here (https://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1119633817597). The procedure shown in LiveSQL was ru...
Categories: DBA Blogs

Strange behavior in analytic functions with partitions

Thu, 2019-09-26 06:46
Hello, I have met strange behavior that I can't understand. I have this table <code>CREATE TABLE test_table (id NUMBER(10,0) NOT NULL, register_date DATE DEFAULT sysdate NOT NULL, row...
Categories: DBA Blogs

Issue in generating Custom Reference ID and Mapping with Form's field

Thu, 2019-09-26 06:46
Building an app for blocking a demo calendar for particular product setup. I wanted to create a custom reference ID ( CURRENT_MONTH-CURRENT_YEAR-SEQUENCE like SEPT-2019-003) which will be the Primary Key (Column BOOKING_REF) for the table (table ...
Categories: DBA Blogs

Inserting without a full list for field names

Thu, 2019-09-26 06:46
We have an issue when we perform an insert like this <code> INSERT INTO STS_RESP_LOG(STS_REQ_LOG_SYSTEM_ID,HSTRY_FLG, SNGL_STS, FRQNCY, CRT_DATE ) VALUES ( ?, ?, ?, ?, sysdate); </code> ?...
Categories: DBA Blogs

RMAN MAXPIECESIZE VS SECTION SIZE

Thu, 2019-09-26 06:46
HELLO , i've made some test to try to parallelizethe best the backup of bigdatabase and i wanted to know if it's possible to parallelize the backup of a backuppiece (multiple backupset) on mulitple channel with maxpiecesize because our SBT media is ...
Categories: DBA Blogs

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