Submitted by dave on Fri, 10/28/2011 - 00:11
I'm starting work on some DB tuning utilities written in Java. I am running the utilities on my local machine against remote servers and I needed a way to hold some data locally. The volume of data I plan on storing is more than I would feel comfortable keeping in local properties or XML files and I didn't want to deal with setting up an Oracle XE instance just to service my lightweight utilities so I checked into a bunch of embedded databases. Embedded databases are databases that I can wrap into my application.
Submitted by dave on Fri, 10/14/2011 - 17:18
I started a new project for a utility I started writing. It has some basic functionality now but will probably increase in utility int he future.
It is a Perl script that extracts the SQL statements from an Oracle 10046 trace file. This is useful if you need to re-run SQL that was captured during a trace. It also helps reduce the amount of junk you have to slog through if you are interested in
trc2sql.pl - Extract SQL Statements From Oracle 10046 Trace File
-Dave
Submitted by dave on Thu, 10/13/2011 - 13:35
When working on a SQL Tuning issue I often kick off a SQL Tuning Advisor job on the SQL while I gather info about statistics and other things I like to check when tuning. After I get an idea of where performance might be suffering I use the SQL Tuning Advisor results for a second opion.
Unfortunately more often than not the SQL Tuning Advisor reports it can dramatically improve the performance of a SQL Statement by using a SQL Profile to force a different plan.
Submitted by dave on Tue, 10/11/2011 - 23:33
I have been trying to chase down the same SQL being submitted against the same 10.2.0.4 Solaris database from different query tools used in our organization. I have been striking out when trying to match up with SQL IDs.
I connected with 5 different tools (including SQLPLUS on 2 platforms) and submitted the following 4 lines of SQL:
SELECT *
FROM EMP,
DEPT
WHERE EMP.DEPTNO=DEPT.DEPTNO
Submitted by dave on Fri, 10/07/2011 - 11:45
Question:
I want to get the information about when a table is queried in oracle. Is there any log in oracle which shows the queries. I was looking around v$sqlarea and v$sqltext but, the system admin does not allow me to reach those tables. - Dursan @ Stack Overflow
My answer:
Submitted by dave on Mon, 10/03/2011 - 14:53
Ever had a customer asking about the growth of a table? Or suspect an execution plan change might be because of an influx of data into a table?
Well you are in luck (maybe!).
Oracle 10g and 11g have a months worth of historical statistics stored by default. Before stats are gathered for a table their current values are written off into SYS.WRI$OPTSTAT_TAB_HISTORY table.
Submitted by dave on Tue, 09/27/2011 - 12:54
"The TPC-DS benchmark models the decision support system of a retail product supplier, including queries and data maintenance. Although the underlying business model of TPC-DS is a retail product supplier, the database schema, data population, queries, data maintenance model and implementation rules have been designed to be broadly representative of modern decision support systems."
http://www.tpc.org/tpcds/
Submitted by dave on Wed, 09/14/2011 - 15:12
Was cruising StackOverflow today looking for interesting Oracle questions and noticed a DBA specific Stack has been started - it lives at http://dba.stackexchange.com/.
It is database agnostic but I love the Stack setup and the helpful people it attracts. You can filter by Oracle and create an RSS feed on that filter if you aren't interested in going back to the site periodically to find topics you might be interested in.
-Dave
Submitted by dave on Tue, 09/13/2011 - 15:04
When trying to debug for another user sometimes it is helpful to be able to log in as that user. In the past magic was done by admins by storing the encrypted passwords, setting to a new temporary password, logging in, and then resetting the old encrypted password back.
Luckily modern Oracle versions we have the concept of a Proxy user. This allows connecting as one user but masquerading as another user (once proper permissions have been granted of course).
So far I have done this with SQL Developer and SQLPLUS, instructions are below for a test case.
Submitted by dave on Tue, 08/30/2011 - 10:57
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