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Search results “Oracle cardinality feedback”
Oracle SQL Tuning Re-Optimizing Execution Plans with Cardinality Feedback
 
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Cardinality feedback, introduced with Oracle Database 11g, has been significantly enhanced with 12c. Cardinality feedback allows the CBO to learn from a cardinality estimate mistake and re-optimize the execution plan. Learn more in this free SQL Tuning tutorial. See all free Oracle Database tutorials at http://www.skillbuilders.com/free-oracle-tutorials.
Views: 3008 SkillBuilders
What is Cardinality and High Cardinality and Low Cardinality in Oracle
 
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What is Cardinality and High Cardinality and Low Cardinality in Oracle SQL Tutorial SQL Tutorial for beginners PLSQL Tutorial PLSQL Tutorial for beginners PL/SQL Tutorial PL SQL Tutorial PL SQL Tutorial for beginners PL/SQL Tutorial for beginners Oracle SQL Tutorial
Views: 676 TechLake
Oracle 12c Dynamic Sampling
 
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Learn how to improve cardinality and performance of SQL statements with Oracle Database 12c Dynamic Sampling. For you Spinal Tap fans, you can now set it to "11".
Views: 912 SkillBuilders
Oracle tutorial : Using execution plan to optimize query in oracle
 
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Oracle tutorial: Explain plan for query optimization in Oracle PLSQL oracle tutorial for beginners using execution plan to optimize query sql query analyzer sql query cost analysis https://techquerypond.wordpress.com This oracle tutorial show you how to use EXPLAIN PLAN in oracle. This video covers how to check cost of the query from DBMS_XPLAN.DISPLAY . You can find the cost of the query using the Using EXPLAIN PLAN FOR and based on the result you can optimize the query for faster performance. Subscribe on youtube: https://www.youtube.com/channel/UCpiyAesWNYOXSz5GPq8lbkA For more tutorial please visit #techquerypond https://twitter.com/techquerypond
Views: 8923 Tech Query Pond
Oracle SQL Tuning - Explain Plan Lies?
 
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Do you use EXPLAIN PLAN to tune Oracle SQL? Does it always "tell the truth", or does it "lie". (Maybe it's not the whole truth!) In this free tutorial from SkillBuilders' Oracle Certified Master John Watson, you will learn why the execution plan generated by EXPLAIN PLAN can be misleading and what to do about it. After a brief lecture, John demonstrates exactly why. You'll hear about dynamic sampling, adaptive cursor sharing (11g), adaptive execution plans (12c) and of course, bind variables. John demonstrates how bind variables cause misleading execution plans using dbms_xplan.display and dbms_xplan.display_cursor. To get the most from this tutorial, you should have some understanding of hard parse, soft parse, cardinality, histograms. See all SkillBuilders FREE Oracle Database tutorials at http://www.skillbuilders.com/free-oracle-tutorials.
Views: 3243 SkillBuilders
Query Tuning 101 What to Look for in Autotrace Output
 
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You're up and running with autotrace, looking at the actual execution plan for a query. Now the real work begins! What is it you're actually looking for in the execution plan? This video shows what you need to investigate and how to use the HotSpot feature of SQL Developer 4.1 to highlight parts of the query you need to pay attention to. ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 7659 The Magic of SQL
Oracle Database 12c: Adaptive Execution Plans with Tom Kyte
 
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Tom Kyte introduces adaptive execution plans followed by a demo. "Adaptive Plans" in SQL Tuning Guide" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=TGSQL221 "Controlling Adaptive Optimization" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=TGSQL257 "Generating and Displaying SQL Execution Plans" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=TGSQL271 "Keeping Your Database Secure" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=DBSEG009
Views: 13315 OracleDBVision
Oracle SQL Tuning - How to Read Execution Plans (Explain Plan)
 
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In this free tutorial you will learn how to generate and read (interpret) an execution plan in Oracle Databases. See more FREE Oracle Tuning tutorials at http://skillbuilders.com/free-oracle-tutorials. Understanding what the Oracle Database does with your SQL is essential to tuning - and the execution plan is the key. Oracle Certified Master DBA John Watson will provide a brief introduction (4 minutes) - which includes John's tuning methodology, then demonstrate EXPLAIN PLAN, SQL*Plus AUTOTRACE and DBMS_XPLAN.DISPLAY_CURSOR. In the tutorial, John will teach you: - How to read an execution plan - Find the 1st step in the plan - Decipher the order of the steps in the plan - That EXPLAIN PLAN can be very misleading Prerequisites: To get the most from this tutorial, you should: 1 Know how to code SQL 2 Be familiar with SQL*Plus 3 Know - in very general terms - what an execution plan is. 4 Have a basic understanding of the Library Cache (this is where Oracle Database stores parsed SQL statements) 5 Have a basic understanding of the Cost Based Optimizer (this is the part of the database that parses your SQL, creates an execution plan. Hopefully the correct - most efficient - plan).
Views: 62514 SkillBuilders
Query Tuning 101: How to Compare Execution Plans
 
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When you're tuning SQL query there's two important questions to keep in mind: * Have my changes made any difference? * If they have, is performance better or worse? In this video we'll look at how you can use SQL Developer to compare execution plans. This will enable you to differences between them and determine which plan performs better. ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 14160 The Magic of SQL
Using DBMS_XPLAN.DISPLAY_CURSOR to examine execution plans
 
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In this video I describe how you can use Oracle's DBMS_XPLAN.DISPLAY_CURSOR to examine the execution plan for a SQL statement that has recently been executed and determine if that plan is optimal or not and where you might be able to optimize it.
Views: 6770 Maria Colgan
Exploring Oracle 12c's Automatic Database Optimization (ADO) Features:
 
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Oracle Database Release 12cR1's new Automatic Database Optimization (ADO) features now make it possible to automatically locate data within the most appropriate storage tier and at the appropriate compression level based on its usage patterns. Join Oracle Ace Director Jim Czuprynski as he discusses how to take advantage of these features to save crucial Tier 0 and Tier 1 storage space ... and perhaps even improve query and DML performance.
Views: 5327 Database Community
12c Adaptive Optimization - Kerry Osborne
 
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One of the most interesting new features of the Oracle Database Optimizer is the ability to recognize its own mistakes and use execution statistics to automatically improve execution plans. Oracle calls this "Adaptive Optimization" and this talk will focus on how it works. More webinars at: http://www.red-gate.com/oracle-webinars
Views: 6803 Redgate Videos
SQL Plan Management SPM
 
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SQL Master Training Class Carlos Sierra - Using DBMS_SPM (SQL Plan Management)
Views: 3829 NoCOUG Channel
Oracle Database SQL Tuning with Constraints - Lesson 1 of 5
 
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Learn how to tune SQL - especially in Data Warehouse environments - with Constraints. Constraints provide critical information to the Cost Based Optimizer in the Oracle Database. Don't drop your constraints for query performance! In these 5 lessons, Oracle Certified Master DBA John Watson will demonstrate how constraints - unique, foreign key, not null - improve the execution plan and thus performance of SQL in an Oracle database. View all 5 lessons, free at http://www.skillbuilders.com/oracle-database-sql-tuning-with-constraints.
Views: 892 SkillBuilders
Oracle Database 11g New Features: Performance Tuning with Feedback Based Optimization
 
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Oracle Database 11g provides a new feature called "feedback based optimization". In this tutorial you will learn what feedback-based optimization is and how it helps Oracle Database 11g performance. One part of nine tutorials dedicated to Oracle 11g Adaptive Cursor Sharing. View all 10 videos for free at SkillBuilders.com/ACS.
Views: 4718 SkillBuilders
Oracle SQL Tuning - How to Read Execution Plan Part 1
 
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Learn how to tune SQL. If you're going to tune Oracle SQL statements, you will need to learn how to read an execution plan! See all Free lessons in this tutorial at http://www.skillbuilders.com/sql-tuning-for-beginners-free-tutorial .
Views: 1913 SkillBuilders
Oracle  AUTOTRACE Fundamentals to Analyze & Tune SQL
 
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This Tutorial will explain fundamentals of Oracle AUTOTRACE. Set up & Use AUTOTRACE. Review PLAN & Statistics generated by AUTOTRACE. Understanding Statistics details.
Views: 22473 Anindya Das
SQL Tuning with Oracle Database 12c Histograms
 
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Learn the new 12c options for creating histograms. See all free video tutorials at http://www.skillbuilders.com/free-oracle-tutorials. In this free tutorial, Oracle Certified Master DBA John Watson demonstrates what histograms do (provide correct cardinality), the difference between histogram types (Frequency and Height Balanced). You will also learn the importance of the auto sample size algorithm in 12c and the new "Hybrid" and "Top Frequency" type histograms.
Views: 3418 SkillBuilders
Oracle 12c SQL Tuning - Adaptive Execution Plans
 
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Learn an Oracle Database 12c new performance feature - Adaptive SQL Plans. During execution, Oracle Database can switch the SQL to a new plan. A very powerful corrective measure! But if you don't know about it , how can you possibly tune SQL in Oracle Database 12c? Time to learn 12c!
Views: 5333 SkillBuilders
Why Oracle DBAs Dislike Auditing and What 12c Unified Audit Does About It - Lesson 1 of 7
 
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See all 7 free modules in this Free Tutorial at http://skillbuilders.com/Oracle-12c-Unified-Audit-Free-Tutorial
Views: 1695 SkillBuilders
Four Steps to Oracle SQL Tuning  - A Methodolgy
 
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Learn a predictable and repeatable methodology for tuning Oracle SQL statements. Just four steps that you should always follow when tuning an SQL statement. (Note this video does not contain examples of how to apply the four steps, just what the steps are.) Oracle Certified Master John Watson presents. John concludes with a brief overview of how SkillBuilders SQL tuning course provides the information you need to apply the four steps. Learn more about SkillBuilders SQL Tuning course http://skillbuilders.com/oracle-sql-tuning-training 1. What is Oracle doing? (explain plan, trace) 2. Why is Oracle doing it that way? (analyze the execution plan) 3. Is there a better way? Test! 4. If there's a better way, push the CBO towards the better way.
Views: 11335 SkillBuilders
Understanding The Execution Plan - Part 1
 
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Topic: Understanding The Execution Plan In this video (part-1) I have explained - The basics of Oracle Execution Plan - How an Execution Plan Looks from SQL Developer, SQL*Plus - How to use Oracle Explain Plan command - Where else one can find Oracle's Execution Plan apart from PLAN_TABLE - Some Examples of Execution Plan - Using DBMS_XPLAN package to format the output while printing the Execution Plan
Views: 5883 Satish Lodam
Why Won't Oracle Use My Index - 12c Attribute Clustering - Lesson 1
 
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Sometimes a poor clustering factor is the cause when Oracle Database cost based optimizer does not choose to use an index. With Oracle 12c (12.1.0.2 EE) offers a new feature that can really help - "Atrribute Clustering". This is implemented with a new keyword on CREATE TABLE - "CLUSTERING BY LINEAR ORDER". In this Free Tutorial from SkillBuilders and Oracle Certified Master DBA John Watson, you'll get a brief refresher on clustering factor and a demonstration of CREATE TABLE - "CLUSTERING BY LINEAR ORDER" - so the CBO will use your index! In this first lesson, John will provide a brief review of clustering factor. See all 6 lessons - FREE - at http://www.skillbuilders.com/12c-attribute-clustering
Views: 357 SkillBuilders
Influencing Oracle SQL Execution Plans
 
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Themis instructor John Mullins discusses Oracle SQL Execution plans and how you can influence them for better SQL performance.
Views: 1724 Themis Education
Oracle 12c PL/SQL Security New Features - Session 5 of 8 - The New Inherit Privileges Privilege
 
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Learn the Oracle Database 12c Inherit Privileges Privilege. Demonstration and Examples. There's a whole new privilege. The inherit privileges privilege. We indeed inherit any privileges privileged. That's just in privileged of course. Any privileges - system privileges, any privileges is an object privilege or new type objects. We can now assign privileges, grant privileges on users. It limits the owner's inheritance of privileges from the invoker. Oracle Corporation is presumably reasonably happy with the way definer's rights code works and definer's rights code as I demonstrated can be highly dangerous. That hasn't really changed in the current release except is will see with the ability to grant roles to code because in invoker's rights we've got huge differences and that's the inheriting of privileges privilege. If you don't have the inheritance enabled, any attempt to execute invoker's rights code will fail because the definer will not be in able to inherit the rights of the invoker. So I'm going to go straight in to do it and then go through the rest of the slides so we can see the sort of issue. Let me lose 11g and go to 12c. What I shall do is create my low privileged user or drop user dev. I don't think he exists. He doesn't. So I'll create my low privileged user. Grant create session, create procedure, select any table to dev identified by dev. It's the same mechanism I use. The same command I use in 11g. I'm creating a developer with a bare minimum that he needs to do his job, which is writing code that lets people query the database. Then log on as him, comm dev/dev and create my procedure. I'll create a version of the code, create or replace procedure list_emp, author ID current user. Invoker's rights code. Remember, this gives my low privilege user dev the ability to insert something horrible in his code which shall then be executed with the invoker's rights. We create the procedure. Now connect / as sysdba - I'll be the highest possible person there is - set server output on and run the code. Execute dev.list_emp looking for the CLARKS. I can't do it. Even as user sys, I can't run that because of the lack of this new privilege. I can correct the situation. I can grant inherit privileges on user sys - which of course one would never normally do - to dev. So I'm now giving my low privilege user the ability to inherit the privileges of user sys when we are running invoker's rights code. And having done that, the code now succeeds. That's the general principle. Without this inherit any privileges code all that doesn't have any privileges privilege, all your invoker's rights code is now blocked. It simply won't run until you grant that privilege to your trusted user. So without inheritance the invoker's rights code will fail. This privilege is in fact granted by default in 12.1 when a user is created. I believe this is purely for backward compatibility. So you don't have to worry about all your codes ceasing to function the moment you have to upgrade but there's no guarantee that this situation will remain as we go through 12.2, 12.3. Also in upgrade I haven't had the time to test comprehensively every possible method of upgrade but certainly this simple test I've done so far, the privilege does appear to be being granted and we can see it. If we look at who's been granted this privilege so far Select grantee, table_name, privilege from dba_tab_privs where privilege like inherit and we see that straight out of the box inherit privileges on a number of users have been granted to public. They have been granted to public. So if I create a brand new user, I grant connect to jw identified by jw, we will see that in the current release - there he is - inherit has beeen granted to public. In the current release by default, your code will continue to function and Oracle often does this with their [05:46 inaudible] with powerful new features. By default, it's configured so there's no change and in the next release it all changes. That's happened to a quite a few releases, quite a few new features, and it wouldn't surprise me if by the time we get to say 12.2 and certainly by the time we get to 13 this behavior changes. So plan for it and look at that privilege and see who it's been granted to and secure your systems. What you need to do is revoke all the inherit privileges grants that's there by default and then grant inherit any privileges very, very sparingly only to a very few trusted users and that should tighten up the danger of definer's inheriting invoker's rights. So a few trusted schemas, create the code in those schemas only and control this very tightly indeed.
Views: 1558 SkillBuilders
Oracle Database 12c New Features Tutorial - Enhanced Online Move Capabilities
 
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Learn the new features in Oracle Database 12c. In this free tutorial, watch Oracle Certified Master demonstrate the enhanced Online Move capabilities in Oracle 12c - Moving Tablespaces and Datafiles Online! (via dbms_redefinition). See all free tutorials in SkillBuilders 12c series at SkillBuilders.com/OracleTutorials.
Views: 3508 SkillBuilders
Oracle SQL Tuning with Unique Constraints
 
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Learn how to tune SQL with Constraints! In this lesson (4 of 5), OCM John Watson from SkillBuilders demonstrates how to improve query performance by adding not null constraints. See all lessons, free at http://www.skillbuilders.com/oracle-database-sql-tuning-with-constraints.
Views: 285 SkillBuilders
Oracle Database SQL Tuning with Direct and Indirect Reads
 
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Oracle Database SQL Tuning tutorial. Learn what direct and indirect reads are and what impact they have on tuning SQL in Oracle Database. In this free tutorial from www.SkillBuilders.com, Oracle Master DBA John Watson will explain and demonstrate what direct / indirect reads are, pros and cons, why they can cause instability in the performance of your SQL (unpredictable response time), why stored outlines, SQL plan baselines and hints usually don't help. Perhaps most importantly, John will tell you what you can do about it. Intended Audience: Experience Oracle DBA's, developers and anyone with Oracle SQL tuning experience.
Views: 1620 SkillBuilders
Oracle SQL Tuning - Equal SQL is not Always Equal
 
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Learn how and why equivalent SQL statements can have a dramatic effect on performance. Certified Master J Watson demonstrates...See all our free Oracle Database tutorials at http://skillbuilders.com/free-oracle-tutorials. The Oracle Database cost-based optimizer (CBO) should recognize equivalent SQL statements and re-write them into the most efficient form. Well, nothing is perfect - not even Oracle Database. Sometimes the way you write your SQL can have a dramatic effect on performance. Presented by John Watson, Oracle Certified Master DBA. Some experience with SQL tuning is expected.
Views: 1870 SkillBuilders
Oracle SQL Performance Tuning for Developers: Understand Explain Plans
 
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Understanding Explain Plans is an excerpt from Oracle SQL Performance Tuning for Developers: http://www.informit.com/store/oracle-sql-performance-tuning-for-developers-livelessons-9780134117027 6+ Hours of Video Instruction The focus of Oracle SQL Performance Tuning for Developers LiveLessons is to illustrate coding techniques that ensure a consistent response time between instances and releases of the Oracle database. This course works closely with performance tuning of actual SQL statements. Description In this video training, Dan Hotka starts out with a complete overview of the Oracle architecture so students can get an understanding how their SQL and applications can take advantage of the computing environment. This course then goes in-depth on understanding and controlling the Explain Plan, which is how and in what order Oracle retrieves data. The discussion includes considerable detail, with SQL examples, on how the optimizers--both rule-based and cost-based, but mostly cost-based--make their decisions. Students will work with a variety of SQL statements, reviewing Explain Plans and making changes to make these SQL statements perform better. Lectures include index design, using hints and coding style to control the Explain Plans, and how to use useful tools such as index monitoring, SQL Trace, and the PL/SQL profiler. This LiveLessons course takes a close look at indexes: how Oracle selects them, why they are sometimes not used, and how to tell if indexes are being used. This course includes Oracle10g, Oracle11g, and Oracle12c SQL tuning topics. Skill Level Intermediate Learn How To Read and understand Explain Plan content Review an Explain Plan and tell quickly if this is a good plan Understand a good index column candidate from a not-so-good candidate Quickly tell the likelihood if your SQL will use an existing index Use coding and a variety of Hints (directives) that can produce better performing SQL Execute and interpret SQL trace output Who Should Take This Course Oracle programmers Oracle database administrators who need additional training on SQL tuning Course Requirements Working knowledge of the SQL query language http://www.informit.com/store/oracle-sql-performance-tuning-for-developers-livelessons-9780134117027
Views: 3176 LiveLessons
Webinar: Ten (Other) Top Tips for Improving PL/SQL Performance
 
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Bulk processing (FORALL and BULK COLLECT), along with the function result cache, are the "big ticket" items when it comes to performance optimization with PL/SQL. But there's still more we can do to tweak our code for even better response times for our users. This third webast in the series starts with the automatic compiler optimization, showcases the extraordinary speediness of PGA data manipulation (a.k.a., package variables), and demonstrates the effect of the simple NOCOPY hint. We finish up with an introduction to pipelined table functions and some thoughts on optimizing your algorithms.
Views: 10195 ODTUG
How to Tune SQL when You Can't Edit the Source Code, Part 1 of 2
 
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Learn Oracle SQL Tuning! How do you add a hint to SQL you can't edit? How do you tune SQL if you don't have access to the source code? Sometimes, Oracle indexes, statistics, stored outlines, profiles or 12c directives will solve a tuning problem. However, as a last resort, you may want to add a hint. In this case DBMS_ADVANCED_REWRITE can be the solution. In this tutorial, Oracle Certified Master DBA John Watson of SkillBuilders demonstrates using DBMS_ADVANCED_REWRITE to change the SQL Oracle executes - without changing the source code!
Views: 1415 SkillBuilders
Oracle SQL Tuning - Equal SQL, Part 1 of 5 by John Watson, SkillBuilders.com
 
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Watch Oracle Master John Watson demonstrate why not all equivalent SQL statements are created equal. John demonstrates how SQL statements that produce equivalent result sets can have radically different response times, why this happens and common solutions. All five new video tutorials are available at SkillBuilders.com/Oracle-Tutorials 1. Introduction including the First Demonstration 2. SubQuery Factoring 3. Star Transformations 4. Aggregations 5. Summary Some experience analyzing Oracle execution plans is required to get the most from this lesson.
Views: 15161 SkillBuilders
Reading Oracle SQL Execution Plans - Practice Makes Perfect
 
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To tune a SQL statement, you need to understand the execution plan. Can you identify the 1st step in an execution plan? The 2nd? The 3rd? In this short tutorial, Oracle Certified Master DBA John Watson of SkillBuilders uses a MERGE JOIN to help you understand how to find the order of execution, essential for SQL tuning.
Views: 1115 SkillBuilders
AIOUG - North India Chapter  Webinar - Adaptive Query Optimization in 12c
 
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About Speaker Anju Garg is an Oracle Ace Associate with over 12 years of experience in IT Industry in various roles. Since 2010, she has been involved in teaching and has trained more than 100 DBAs from across the world in various core DBA technologies like RAC, Data guard, Performance Tuning, SQL statement tuning, Database Administration etc. SSince 2010, she has been involved in teaching and  has  trained more than 100 DBA's from across the world in various core DBA technologies like RAC, Data guard, Performance Tuning, SQL statement tuning, Database Administration etc. She is  certified for - Oracle 12c OCP (DBA) - Oracle 11g R2 RAC OCE - Oracle 11g Performance Tuning OCE - Oracle 11g SQL statement Tuning OCE - Oracle 11g OCP (DBA) - Oracle 9i OCP (DBA) She presented papers on following papers during SANGAM 14 - Histograms Pre-12c and now - Adaptive Query Optimization Her white paper on " Histograms Pre-12c and now" was published in Issue7 of ORACLE CONNECT  (AIOUG publication)  published in Dec 2014. She is passionate about learning and has keen interest in RAC and Performance Tuning. She shares her knowledge via her  technical blog at   http://oracleinaction.com/ .
Oracle 12c PL/SQL Security New Features - Session 6 of 8 - Granting Roles to Procedures
 
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See www.skillbuilders.com/12c-plsql-security for all free modules in this tutorial. It is now in Oracle Database 12c possible to grant roles to the stored program units. Remember this didn't apply to anonymous PL/SQL. Anonymous PL/SQL as always executed with the enabled roles of the invoker. But we can now grant role to a stored procedure. There are a couple of conditions. The role granted must be directly granted to the owner. I'm not sure if this is documented or not or it could've been issues I had during my own testing but certainly the last time I tested this thoroughly I found that if I granted roles to roles to roles to roles as I go down to three, it no longer functions. So that could've been just me or it may be documented. But certainly to be sure, the role granted must be granted directly to the person who's writing the code. Also and it is documented, the owner still needs direct privileges on the object that the code references. That make perfect sense because the role might be disabled at the time that he happens to be creating the object. So you need the role, you need direct privileges on the object referenced by the code. [pause] The invoker however needs absolutely nothing. The invoker now needs nothing, no roles, no privileges. All he needs is execute on the procedure. The invoker will then take on that role during the course of the call. This will tighten up the definer's rights problem and that our user doesn't have much at all. He needs the bare minimum and then only that role will be available, only the role is available to the invoker during the call. Not everything else that the owner happens to have. You can combine this as well with invoker's rights and either way we are controlling privilege inheritance. Invoker's rights plus roles restrict the ability of definer's to inherit privileges from invokers and invokers inherits privileges from definers, both of which raise that ghastly possibility of privilege escalation associated typically to SQL injection. [pause] Grant create session, create procedure to dev, and that will give him select on scott.emp to dev. I've given dev the minimum he needs to write code that hits that table. Then create a role. [pause] Create role r1 and that'll grant select on scott.emp to r1. Finally, grant r1 to dev. It has met the requirements. The role is granted to the owner, the owner does have direct privileges. [pause] So connect as dev/dev and create my favorite procedure. [pause] The same procedure has executed definer's rights and query scott.emp. But now what we can do this new is I can grant r1 to procedure list_emp. [pause] I'll create a very low privileged user now. I need to connect as sysdba and create user low identified by low, and all I shall give him is create session. [pause] And execute on that procedure. [pause] Grant execute on dev.list_emp to low. That's all he's got. He can log on and he can run, run one procedure. What actually is going to happen to him? Let me try to log on. Connect sys low/low set server output on and see if he can run that thing. Just to check, if he tries to select star from scott.emp he is the lowest of the low is my user low. But then execute dev.list_emp, trying to retrieve the CLARKs and it works. And because my user low has virtually no privileges at all, there's no possible danger of the malicious developer being able to inherit dangerous privileges from him. [pause] The final step, that functioned because of the privilege that I mentioned earlier - the privilege that we saw on the previous slide which was inheriting privileges. If I revoke that - and this is what you should be doing in all your systems after upgrade - revoke inherit privileges on user low from public, connect there, and it fails. So the final bit of tightening up the security is to grant the privilege specifically we grant inherit privileges on user low to dev. Now we have a totally secure system and that my low privilege user dev can do that. [pause] And nothing more. My low privileged developer dev can't grab anything in his too as well. That tightens things up totally.
Views: 2817 SkillBuilders
Oracle 12c Grant Role to PL/SQL Procedures - Lesson 1 of 2
 
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A great new security feature that can - among other things - prevent SQL injection and a multitude of other security vulnerabilities. In 12c you can make your PL/SQL code secure using a declarative technique. Simply grant a role to the PL/SQL code and add AUTHID CURRENT_USER so that Oracle runs the code with the privileges of the invoker - not the developer (invoker rights procedures). Presto! Without code reviews and / or debugging you will have hardened your PL/SQL web application! In this free tutorial from SkillBuilders Director of Oracle Database Services, Oracle Certified Master John Watson will demonstrate the development of a simple PL/SQL web application, demonstrate SQL injection and how to prevent it with this new feature.
Views: 659 SkillBuilders
Oracle 10g, 11g, 12c Expert Performance Tuning C & As 3 of 3
 
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In this tutorial you will learn how to do performance tuning on Oracle 10g, 11g, 12c databases.
Views: 3596 DBA Pro
14a  Index Cardinality
 
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Views: 40 B's March
Oracle SQL Tuning with NOT NULL Constraints
 
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Learn how to tune SQL with Constraints! In this lesson (3 of 5), OCM John Watson from SkillBuilders demonstrates how to improve query performance by adding not null constraints. See all lessons, free at http://www.skillbuilders.com/oracle-database-sql-tuning-with-constraints.
Views: 385 SkillBuilders
Histograms Pre-12c and now
 
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Anju Garg is an Oracle Ace Associate with over 12 years of experience in IT Industry in various roles. Since 2010, she has been involved in teaching and has trained more than a hundred DBAs from across the world in various core DBA technologies like RAC, Data guard, Performance Tuning, SQL statement tuning, Database Administration etc. She is a regular speaker at Sangam and OTNYathra.  She also writes articles for All Things Oracle. She is passionate about learning and has keen interest in RAC and Performance Tuning. She shares her knowledge via her technical blog at http://oracleinaction.com/ ABSTRACT--- To improve optimizer estimates in case of skewed data distribution , histograms can be created. Prior to 12c frequency and height balanced histograms could be created.  if no. of buckets >= NDV, frequency histogram is created and the optimizer makes correct estimates. If no. of buckets < NDV, height balanced histogram is created and accuracy of optimizer estimates depends on whether a key value is an endpoint or not. The problem of optimizer misestimates in case of height balanced histograms is resolved to a large extent in Oracle Database 12c by introducing top-frequency and hybrid histograms which are created if no. of buckets < NDV. This webinar explores Pre as well post 12c histograms while highlighting the top-frequency and hybrid histograms introduced in Oracle Database 12c.
Step by Step guide to build dataguard in Oracle 11g
 
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Step by Step guide to build dataguard in Oracle 11g
Views: 11919 sadia appsdba
Oracle Tuning Mistakes and Solutions
 
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Oracle 12c Multi-Threaded Database (parameter threaded_execution=true) provides an fantastic performance improvement by reducing the number of background processes. In this free tutorial, Oracle Certified Master John Watson of SkillBuilders demonstrates how to enable this feature and the resulting performance benefit - in John's demo, a doubling of performance! See all free Oracle 12c tutorials at http://www.skillbuilders.com/free-oracle-tutorials.
Views: 3705 SkillBuilders
SQL Tuning How to Tune Joins - Lesson 2 of 4 - Optimal Join Order
 
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Tune your SQL joins! Learn what "filtered rows percentage" is and how to get the optimal join order. A free tutorial from SkillBuilders and Oracle Certified Master DBA John Watson. See all lessons, Free, at http://skillbuilders.com/tuning-joins-optimal-join-order.
Views: 1499 SkillBuilders
SQL Tuning for Beginners Lesson 1 When and Why to Tune SQL
 
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Lesson 1 in this tuning tutorial Oracle Certified Master DBA John Watson discusses when a SQL should be tuned and why. i.e. Don't waste your time tuning things that will not help.
Views: 726 SkillBuilders
What is Oracle ACFS - Lesson 2 - Functionality and Use Cases
 
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Oracle DBAs, system administrators and anyone charged with supporting Oracle Databases should learn what ACFS can do and how it can be used. In this lesson, Oracle Certified Master John Watson of SkillBuilders discuss ACFS functionality and provides several usage cases. Watch all lessons in this ACFS tutorial, FREE, at http://www.skillbuilders.com/what-is-oracle-acfs.
Views: 1497 SkillBuilders

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