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Indexes in Oracle :Index Scan Methods :Part 2
 
30:18
The Video Explains when should you create indexes. The difference between Simple and composite Index, Relevance of order in composite indexes and Index Scan Methods in detail. 1.Index Unique scan 2.Index Range Scan 3. Index Skip Scan 4. Fast full Index Scan 5. Full Index Scan If you have any questions just drop in a comment
Views: 9808 Tech Coach
A Story of Indexes and Full Table Scans: Finding All the Red Sweets Part 1
 
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"Why isn't Oracle using my index?!" is a common question people have when tuning SQL queries. In this episode Chris compares two methods for finding all the red candies from party bags he's prepared. He shows how these are like a full table scan and an index range scan. He goes on to compare the performance of these two approaches. He shows when a full table scan becomes more efficient than an index range scan and vice versa. ============================ 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: 8827 The Magic of SQL
06 06 Index Full Scan Operations
 
03:27
ORACLE
Views: 952 oracle ocm
What is Index Scan ,Index Seek and Table Scan?
 
06:34
An index scan or table scan is when SQL Server has to scan the data or index pages to find the appropriate records. index seek happens when data is searched among the index.Please watch full video for detail.
Views: 22080 SqlIsEasy
FTS vs Index Scan   Part 1
 
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what is "full table scan in oracle" and "oracle index scan" Small Excerpt from "Oracle performance Tuning Session". http://www.dbvidya.com/oracle-performance-tuning-videos/ [email protected] +91 991 2323 000 Oracle Performance Tuning Online Training : http://www.dbvidya.com/course/performance-tuning-for-dba/ Oracle SQL Performance Tuning Training Online : http://www.dbvidya.com/course/sql-tuning-advanced/ Oracle Performance Tuning Videos Tutorial for DBA and Developers : http://www.dbvidya.com/oracle-performance-tuning-videos/ Oracle AWR Tutorial: http://www.dbvidya.com/course/oracle-awr/ Erwin Tool Online Training : http://www.dbvidya.com/course/erwin-tool/ ER Data Modeling Course : http://www.dbvidya.com/course/er-modeling/ Dimensional Modeling Training Online : http://www.dbvidya.com/course/dimensional-modeling/ Oracle Database Blogs : http://www.dbvidya.com/blog/
Views: 333 DbVidya
Index Range Scan
 
03:18
Index Range Scan
Views: 92 TUTOR SC
07 06 Index Skip Scan Operations
 
03:14
ORACLE
Views: 955 oracle ocm
07 07 Index Selectivity
 
07:56
ORACLE
Views: 467 oracle ocm
Why Isn't My Query Using an Index?
 
47:01
“Why isn’t my query using an index?” is a common question people have when tuning SQL. This session explores the factors that influence the optimizer’s decision to answer this question. It does so by comparing fetching rows from a database table to finding all the red M&Ms a packet, and contrasts using an index range scan and a full table scan. It also introduces the concepts of blocks and the clustering factor. The session offers a discussion of how these affect the optimizer's calculations, and includes a demo of how these concepts work in practice using real SQL queries. This session is intended for developers who want to learn the basics of how the optimizer chooses between an index range or full table scan. Speaker: Chris Saxon
Views: 313 Oracle Developers
FTS vs Index Scan  Part 2
 
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Discusses "When Full table scan is recommended and when index scan is suggested" -small excerpt from "Oracle Performance tuning" http://www.dbvidya.com/blended-training/ [email protected] +91 991 2323 000 Oracle Performance Tuning Online Training : http://www.dbvidya.com/course/performance-tuning-for-dba/ Oracle SQL Performance Tuning Training Online : http://www.dbvidya.com/course/sql-tuning-advanced/ Oracle Performance Tuning Videos Tutorial for DBA and Developers : http://www.dbvidya.com/oracle-performance-tuning-videos/ Oracle AWR Tutorial: http://www.dbvidya.com/course/oracle-awr/ Erwin Tool Online Training : http://www.dbvidya.com/course/erwin-tool/ ER Data Modeling Course : http://www.dbvidya.com/course/er-modeling/ Dimensional Modeling Training Online : http://www.dbvidya.com/course/dimensional-modeling/ Oracle Database Blogs : http://www.dbvidya.com/blog/
Views: 220 DbVidya
Oracle full table scans, direct path reads, object level checkpoints, ORA 8103s (old videos)
 
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As the name says, in this hacking session I'll demo how full table scans (and full segment scans) work and related stuff too, like direct path read checkpoints and ORA-8103 errors.  It's an old video from 2011 so not with the best recording resolution, but should still be fun. As direct path reads go, some things have changed and should be clarified, perhaps the best explanation is here: https://blogs.oracle.com/smartscan-deep-dive/when-bloggers-get-it-wrong-part-1 https://blogs.oracle.com/smartscan-deep-dive/when-bloggers-get-it-wrong-part-2
Views: 844 Tanel Poder
Which Order Should Columns Go in an Index?: Finding All the Red Sweets Part 4
 
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When you create an index on multiple columns there's an important question you need to answer: In which order should you list the columns? This video looks at some of the factors you should consider to help answer this question. ============================ 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: 4619 The Magic of SQL
Improving performance of full table scans in Oracle - Hebrew - שיפור ביצועים של סריקת טבלה באורקל
 
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בסשן הזה אני מציג כיצד ניתן לשפר ביצועים של סריקת טבלה (Full Table Scan) באורקל ומדגים כיצד זה בפועל מתבטא ומתבצע בסביבת ייצור אמיתית. נתוודע למושג ה-High Water Mark, החשיבות שלו בעת Full Table Scan והעובדה ש-DELETE לא משפיע עליו. נראה כיצד נוכל לזהות אם יש בלוקים ריקים ומיותרים שאנו קוראים בעת סריקת הטבלה וכיצד ניתן לפתור את הבעיה.
Views: 330 Eran Koren
14.300 Motivation for Index Structures, Selectivities, Scan vs. Index Access on Disk and Main Memory
 
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Video for my inverted classroom "Database Systems". The complete list of videos and additional material is (will be) available at http://datenbankenlernen.de Computer Science, Saarland University: Bachelor (in German): http://www.cs.uni-saarland.de/index.php?id=52&L=1 Master (in English): http://www.cs.uni-saarland.de/index.php?id=132&L=1 Ph.D./Grad School: http://gradschool.cs.uni-saarland.de/
Chris Saxon - Finding All the Red M&Ms: A Story of Indexes and Full Table Scans
 
46:01
'Why isn’t my query using an index?' is a common question people have when tuning SQL. This talk explores the factors that influence the optimizer’s decision behind this question. It does so by comparing fetching rows from a database table to finding all the red M&Ms from their bags. It contrasts using an index range scan and a full table scan to do this. It introduces the concepts of blocks and the clustering factor. It discusses how these affect the optimizer's calculations. It goes on to demonstrate how these concepts work in practice using real SQL queries. This session is intended for developers and DBAs who want to learn the basics of how the optimizer chooses between an index range or full table scan.
Views: 113 Riga Dev Days
Oracle Indexes - Live Demonstration
 
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When is a Full Table Scan faster than an Index Scan? Watch Ross and Jordan act out an Oracle database reading and caching data via both methods, explaining the costs and benefits in simple and easy to understand terms. The demonstration is part of a talk by Ross Leishman of DWS Ltd on the principles of Understanding Indexes for SQL Tuning. The full lecture is at this link: https://www.youtube.com/watch?v=Z4hKomnGHFA DWS Ltd is a leading publicly listed Australian IT Services company, providing services to blue chip organisations since 1991. With a business philosophy based upon integrity, reliability and professional service delivery, DWS provides end to end IT solutions. www.dws.com.au
Views: 2724 DWS Ltd
How Does the Phyiscal Location of Rows Affect Indexes?: Finding All the Red Sweets Part 2
 
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In part one of the red candy series, Chris compared the efficiency of using a index range scan and full table scan to access data. He found that a full table scan was more efficient when fetching more rows than there are table blocks. This analysis made a big assumption however. It worked on the presumption that there was no correlation between the order of candies in the document and which the bags they were in. In this episode tests this assumption. Chris looks at how the physical order of rows in a table can affect the efficiency of indexes on it. He discusses how Oracle tracks this via the clustering factor. ============================ 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: 3484 The Magic of SQL
Types of Indexes (A B-tree index,A bitmap index )
 
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Hi guys today is very most important topic in oracle is INDEXES help to increase performance at the time of search and modification into table records. #TypesofIndexes #B-treeindex#bitmapindex
Views: 30403 Oracle World
What Impact Do Indexes Have on Inserts?: Finding All the Red Sweets Part 0
 
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Creating indexes can improve query performance. Oracle must maintain the indexes however. This increases the work it must do whenever you modify data in indexed columns. In this video Chris looks at this overhead using a real world analogy - recording the color of all the candies stored in party bags! ============================ 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: 2873 The Magic of SQL
B*Tree Index Fundamentals(Indexes in Oracle-1)
 
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Part -1 : Introduction to Indexes, B*Tree Indexes, Index scan methods. Part -2 : B*Tree Index Types(different types of B*Tree indexes) Part -3: Using B*Tree Indexes(When use B*Tree indexes, factors related to B*Tree Access) Part -4 : Index Organized Table Part -5 : Bitmap Indexes Part -6: Partitioned Indexes Part- 7: Other type of Indexes based on characteristics & use. Part -8: Managing Indexes
Views: 49983 Anindya Das
What is High Water Mark(HVM) in oracle and how it effects the performance of queries?
 
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This video tutorial is to understand the concept of a High Water Mark or HVM of a oracle table, also it states the various changes in the HVM when we perform a insert, delete and Truncate operation on the table, and the video also informs why is the truncate operation more advisable and optimized then the delete operation.
Views: 4080 Kishan Mashru
07 03 Bitmap Indexes
 
06:43
ORACLE
Views: 10473 oracle ocm
Reverse Key Index :Types of Btree Index in Oracle
 
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Please subscribe to my new channel. https://www.youtube.com/c/AnIndianAbroadd The Videos explains how Reverse Btree Index works and in what condition they shall be used. Reverse Btree index are used to solve index block contention. You can't perform range scans in reverse btree Index.
Views: 2930 Tech Coach
Table Scan Vs Index Scan Vs Index Seek in sql server | by SQL Training Sessions
 
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This session will help you understand following : 1. Table Scan vs Index Scan vs Index Seek 2. How these concepts affects the sql query performance. 3. Explain Actual Execution Plan 4. How to include actual execution plan in sql query 5. How to analyse sql query Thanks for watching! By sql Training Sessions By SQL Enjoy learning :)
07 02 B Tree Indexes
 
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ORACLE
Views: 2340 oracle ocm
A Story of Index Only Scans: Finding all the Red Sweets Part 3
 
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So far in the red candy series, Chris has compared using an index to a full table scan to access sweets from his table. In this video he asks a different question: What if you just want to count how many sweets are red? In this case the index holds all the information Oracle needs to answer the query. He shows how the optimizer is able to process this via an index only scan. Chris goes on to investigate index only scans further. He discusses how theses can provide better performance than queries accessing the table itself. He finishes by looking at the conditions necessary to enable these. ============================ 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: 1848 The Magic of SQL
Oracle Tuning Tutorial - Long Full Table Scans Part 2 of 5
 
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See all 5 tutorials, free, at SkillBuilders.com/OracleTuningFullTableScans Number Eight in the "Performance tuning Guide, Top Ten Mistakes Found in Oracle Systems" Long Full Table Scans is described as follows: "Long full table scans for high-volume or interactive online operations could indicate poor transaction design, missing indexes, or poor SQL optimization. Long table scans, by nature, are I/O intensive and unscalable." Actually, there are many cases where the full table scan is your friend. But whether they are good or bad for the performance of the SQL that invokes them, there may be implications (for better or for worse) for performance of other statements. This is particularly true in 11.2.x, where direct reads are possible for serial scans, and indirect reads are possible for parallel scans. Do you trust the optimizer? The change in behaviour in recent releases may need some investigation, and revisiting older code. As always with a SkillBuilders Tutorial, we shall illustrate the issues and solutions with live demonstrations using release 11g (11.2.0.3). Audience: Operating System Administrators, Storage Administrators, Oracle Administrators and Management responsible for Storage and / or Oracle Databases.
Views: 4609 SkillBuilders
Oracle Tuning Tutorial - Long Full Table Scans Part 1 of  5
 
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Learn SQL Tuning! Tune full table scans! Part 1 of 5 videos in this series. See all 5 tutorials, free, at http://www.skillbuilders.com/tuning-long-full-table-scans Number Eight in the "Performance tuning Guide, Top Ten Mistakes Found in Oracle Systems" Long Full Table Scans is described as follows: "Long full table scans for high-volume or interactive online operations could indicate poor transaction design, missing indexes, or poor SQL optimization. Long table scans, by nature, are I/O intensive and unscalable." Actually, there are many cases where the full table scan is your friend. But whether they are good or bad for the performance of the SQL that invokes them, there may be implications (for better or for worse) for performance of other statements. This is particularly true in 11.2.x, where direct reads are possible for serial scans, and indirect reads are possible for parallel scans. Do you trust the optimizer? The change in behaviour in recent releases may need some investigation, and revisiting older code. As always with a SkillBuilders Tutorial, we shall illustrate the issues and solutions with live demonstrations using release 11g (11.2.0.3). Audience: Operating System Administrators, Storage Administrators, Oracle Administrators and Management responsible for Storage and / or Oracle Databases.
Views: 2988 SkillBuilders
Oracle Database Indexes: Myths, Tips and Tricks
 
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In this tutorial, OCM John Watson will - via demonstrations - debunk these myths: Myth #1: Oracle Database does not index NULL Myth #2: A search that includes wildcards can't use an index if the wildcard precedes the string. Myth #3: Oracle will not use a function-based index unless the FBI is coded in the predicate. Myth #4: Indexes always help. The more indexes the better. See http://skillbuilders.com/free-oracle-tutorials for gigabytes of free Oracle video tutorials.
Views: 16457 SkillBuilders
Choosing between FULL and INDEX scan
 
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Choosing between FULL and INDEX scan
Views: 4 TUTOR SC
Oracle Performance - Indexes
 
28:28
Oracle Performance - Indexes
Views: 286 The Silent DBA
Heap Tables and Index Organized Tables in Oracle | Chris Saxon
 
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Chris Saxon, a database evangelist, developer advocate, and SQL specialist with Oracle, uses up his two minutes with a tip on using heap tables and index organized tables in Oracle Database.
Views: 2872 ArchBeat Archive
What do you mean the Oracle Optimizer won't use my Index
 
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Learn some details about how the Oracle optimizer works with Themis instructor John Mullins.
Views: 786 Themis Education
Oracle views, functions, indexes
 
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Create views in Oracle training/discussion with Andy.
Views: 24 Adam Lodge
Making Smart Scan for Exadata Work (Demonstration)
 
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Making Smart Scan Work - Demo I'll go through a simple example of the kind of thing we need to think about when trying to achieve Smart Scan. Let me just enable tracing, run a simple query, select and * from *. Now, there's my query. The result set comes back, and how is it executed? An index full scan with the PK* index. The optimizer is intelligent enough to know that my query can be satisfied purely by reading the index and therefore it didn't have to go to the table at all. It looks very good. Well, it wasn't. Index full scans are an operation that cannot be offloaded. So, to execute that statement, every block of that index was delivered into the buffer cache of my own database instance, and the compute node then has to do the work of extracting those values. What can we do about it? One solution would be to hint the code. I select and demand an index fast full scan, and now we see the magic word "storage." An index fast full scan is offloadable, because an index fast full scan can do direct reads. An alternative approach? Well, you might not want to hint many, many thousands of lines of code. An alternative approach would be to do it through DDL. For example, take that index, make it invisible. Now run my statements without any hint at all, table access storage full, and that was offloaded. Having made the index invisible, Oracle has no option but a full-table scan, and a full-table scan is offloadable. Now, this means I have three options of this very simple example. I can let the optimizer get on with what it wants to do, and then I use an index that I'm doing block serving into the buffer cache. I can hint the code, index fast full scan. That's probably the best option for performance, but it's also the most work. In this intervening case, I make the index invisible so that it will still be used of course for enforcing the primary key constraints, but it will not be visible to the optimizer and therefore influence the optimizer towards using plans that can be offloaded the Smart Scan. Making the choice between this and influencing the optimizer in the correct direction is an extremely difficult job, and it is not always easy to determine what is going to be the best solution.
Views: 3702 SkillBuilders
SQL Server Scans Vs Seeks
 
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Why syntax is so important to queries
Views: 622 Tips For IT Pros
Global Index rebuild scenario in Oracle Database 11g
 
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Why and How we need to rebuild global Index in Oracle 11g
Views: 3668 Athar Fahad
Oracle Exadata SmartScan
 
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Are you a believer? You will be. This three minute video explains how Oracle Exadata Smart Scan offloads query processing to the storage layer to deliver extreme performance for data warehousing applications.
Views: 15192 Oracle Video
Oracle Exadata Smart Scan - Limitations and Best Practices
 
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Smart Scan is a wonderful capability, but you don't always get it. It's impossible for many execution plans, and this is a major restriction. If you think about what a Smart Scan actually does, it delivers individual columns, individual rows back to the instance. Now, a buffer cache can accept only blocks. Therefore, Smart Scan cannot possibly put those columns of rows into the buffer cache. It's simply not formatted appropriately. So, a Smart Scan has to return values directly into the session's PGA or, to put it another way, the only access method that can use Smart Scan is direct read. Well, what access methods can use direct read? There are only two, which are table full scan and index fast full scan. Any other access method, typically index range scan, table access by row ID, cannot use a Smart Scan. The second major issue, there are strict limitations of the type of objects that can be accessed through Smart Scan. It really is only heap tables. You can't use indexes. You can't use clusters. You can't use IOTs. Heap tables only. Perhaps hardest to track down and giving sometimes very erratic results is that Smart Scan can be interrupted by various conditions. You've met all the requirements for Smart Scan, directory and so on, got the right execution plan. The Smart Scan starts and then hits something that causes a problem. Issues that we know cause problems are, for instance, read consistency, also delayed block cleanout, change rows. Any of those issues and a few others mean that the storage tier will have to interrupt its Smart Scan, deliver complete blocks into that buffer cache, let your session then do what is necessary to the block, and only then can the Smart Scan proceed. Now, in order to maximize the use of Smart Scan, there may be quite a lot of work. Very often, you'll have to adjust your index structures. Making them invisible is a nice technique there. There are many, many, many parameters that can influence the likelihood of achieving a Smart Scan, and almost inevitably you're going to be rewriting a lot of hint SQL and putting hints in it to get the correct execution plans that can enable a Smart Scan to occur. This is all because of one fundamental problem; the optimizer is not in any way aware of the Exadata. The optimizer develops an execution plan in exactly the way it would without the Exadata storage. The use of Smart Scan, the awareness of Exadata comes at the next level down. The optimizer develops the plan through a normal pass and then passes it through to the SQL execution engine, and it's the SQL execution engine that determines, on a case-by-case basis, whether to use the Smart Scan. This means that you might develop a plan and execute the statement 50 times. Forty-nine times, you get a Smart Scan. The 50th time, for whatever reason, the SQL execution engine decides not to. This can result in somewhat erratic performance.
Views: 1715 SkillBuilders
ORACLE SQL Functional Based Indexes
 
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FUNCTION BASED INDEX IN ORACLE SQL
Views: 16 Gees info
Oracle Tuning Tutorial - Long Full Table Scans Part 5 of 5
 
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See all 5 tutorials, free, at SkillBuilders.com/OracleTuningFullTableScans. In summary, serial full table scans were always indirect before 11.2, parallel scans always direct before 11.2. These are the two critical parameters. That hidden parameter _serial_direct_read, remember, defaults to auto so your application may start behaving very differently as you upgrade from 11.2.01 or 11.2.02. Parallel_degree_policy, that defaults to manual. But again, it becomes an option when you go to 11.2 to enable the automatic facility which allows not only automatic tuning to the degree of parallelism but also enables the ability to make indirect reads when doing a full table scan.
Views: 1634 SkillBuilders
Oracle Tutorial || Online Training || Adv Sql | Index Organized Table Part - 1 by basha
 
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DURGASOFT is INDIA's No.1 Software Training Center offers online training on various technologies like JAVA, .NET , ANDROID,HADOOP,TESTING TOOLS ,ADF,INFORMATICA,TABLEAU,IPHONE,OBIEE,ANJULAR JS, SAP... courses from Hyderabad & Bangalore -India with Real Time Experts. Mail us your requirements to [email protected] so that our Supporting Team will arrange Demo Sessions. Ph:Call +91-8885252627,+91-7207212428,+91-7207212427,+91-8096969696. http://durgasoft.com http://durgasoftonlinetraining.com https://www.facebook.com/durgasoftware http://durgajobs.com https://www.facebook.com/durgajobsinfo......
Real-World Performance - 15 - Index Contention
 
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Check out the entire series on the Oracle Learning Library at http://www.oracle.com/goto/oll/rwp In this video, listen and watch Andrew Holdsworth, Vice President of Oracle Database Real-World Performance at Oracle Corporation, as he explains how index contention affects performance. Copyright © 2014 Oracle and/or its affiliates. Oracle® is a registered trademark of Oracle and/or its affiliates. All rights reserved. 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 of merchantability, fitness for a particular purpose, and non-infringement.
01 Overview of table Partition in oracle
 
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Partitioning enhances the performance, manageability, and availability of a wide variety of applications and helps reduce the total cost of ownership for storing large amounts of data. Partitioning allows tables, indexes, and index-organized tables to be subdivided into smaller pieces, enabling these database objects to be managed and accessed at a finer level of granularity. Oracle provides a rich variety of partitioning strategies and extensions to address every business requirement. Moreover, since it is entirely transparent, partitioning can be applied to almost any application without the need for potentially expensive and time consuming application changes. Partitioning allows a table, index, or index-organized table to be subdivided into smaller pieces, where each piece of such a database object is called a partition. Each partition has its own name, and may optionally have its own storage characteristics. From the perspective of a database administrator, a partitioned object has multiple pieces that can be managed either collectively or individually. This gives the administrator considerable flexibility in managing partitioned objects. However, from the perspective of the application, a partitioned table is identical to a non-partitioned table; no modifications are necessary when accessing a partitioned table using SQL queries and DML statements. Partitioning Key ======================== Each row in a partitioned table is unambiguously assigned to a single partition. The partitioning key is comprised of one or more columns that determine the partition where each row will be stored. Oracle automatically directs insert, update, and delete operations to the appropriate partition through the use of the partitioning key. When to Partition a Table ========================== Here are some suggestions for when to partition a table: Tables greater than 2 GB should always be considered as candidates for partitioning. Tables containing historical data, in which new data is added into the newest partition. A typical example is a historical table where only the current month's data is updatable and the other 11 months are read only. When the contents of a table need to be distributed across different types of storage devices. When to Partition an Index ============================= Here are some suggestions for when to consider partitioning an index: Avoid rebuilding the entire index when data is removed. Perform maintenance on parts of the data without invalidating the entire index. Reduce the impact of index skew caused by an index on a column with a monotonically increasing value. Partitioned Index-Organized Tables =================================== Partitioned index-organized tables are very useful for providing improved performance, manageability, and availability for index-organized tables. For partitioning an index-organized table: ============================================ Partition columns must be a subset of the primary key columns Secondary indexes can be partitioned (both locally and globally) OVERFLOW data segments are always equi-partitioned with the table partitions See Also: Oracle Database Concepts for more information about index-organized tables System Partitioning System partitioning enables application-controlled partitioning without having the database controlling the data placement. The database simply provides the ability to break down a table into partitions without knowing what the individual partitions are going to be used for. All aspects of partitioning have to be controlled by the application. For example, an insertion into a system partitioned table without the explicit specification of a partition will fail. System partitioning provides the well-known benefits of partitioning (scalability, availability, and manageability), but the partitioning and actual data placement are controlled by the application. See Also: Oracle Database Data Cartridge Developer's Guide for more information about system partitioning Partitioning for Information Lifecycle Management Information Lifecycle Management (ILM) is concerned with managing data during its lifetime. Partitioning plays a key role in ILM because it enables groups of data (that is, partitions) to be distributed across different types of storage devices and managed individually.
Views: 7495 Md Arshad
Indexing Scans in Healthquest
 
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Key Points: - A clinic team should have a standard practice on terms used to index scans - Physicians need to provide input to the terms used - Panel management is assisted by consistent use of terms - Both the scan type and description words are searchable in Healthquest (these can inform a CDS Notification) - When free typing in the description area be aware of typos because this will impact the ability to search
Views: 171 TOP AB Doctors
Oracle SQL Tuning - Oracle Execution Plans for Beginners
 
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For More Tutorials Related To Cisco,CCNA,Microsoft,Oracle,HP,Adobe,IBM,Java And Much More Please Visit This Site http://www.geteveryvideos.com/category/certification-tutorials/