Oracle Hints Tutorial for improving performance APPEND PARALLEL JOIN INDEX NO_INDEX SELECT /*+ FIRST_ROWS(10) */ * FROM emp WHERE deptno = 10; SELECT /*+ ALL_ROWS */ * FROM emp WHERE deptno = 10; SELECT /*+ NO_INDEX(emp emp_dept_idx) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; SELECT /*+ INDEX(e,emp_dept_idx) */ * FROM emp e WHERE e.deptno = 10; -- SELECT /*+ INDEX(scott.emp,emp_dept_idx) */ * FROM scott.emp; SELECT /*+ AND_EQUAL(e,emp_dept_idx) */ * FROM emp e; SELECT /*+ INDEX_JOIN(e,emp_dept_idx) */ * FROM emp e; SELECT /*+ PARALLEL_INDEX(e,emp_dept_idx , 8) */ * FROM emp e; SELECT /*+ LEADING (dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; SELECT /*+ PARALLEL(8) CACHE (e) FULL (e) */ * FROM emp e ; SELECT /*+ PARALLEL FULL (e) */ * FROM emp e ; SELECT /*+ PARALLEL USE_MERGE (emp dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; -- SORT Merge Join SELECT /*+ PARALLEL USE_HASH (emp dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; -- Hash Join SELECT /*+ PARALLEL */ * FROM emp e ; INSERT /*+ APPEND */ INTO mytmp select /*+ CACHE (e) */ *from emp e; commit;
Views: 8534 TechLake
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: 3443 SkillBuilders
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 (220.127.116.11). Audience: Operating System Administrators, Storage Administrators, Oracle Administrators and Management responsible for Storage and / or Oracle Databases.
Views: 2961 SkillBuilders
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 (18.104.22.168). Audience: Operating System Administrators, Storage Administrators, Oracle Administrators and Management responsible for Storage and / or Oracle Databases.
Views: 4583 SkillBuilders
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: 713 Tanel Poder
This is the 2nd video from " Partitioning in Oracle " series, It explains how oracle stores and manages data. What is single Block IO and Multi Block IO ? Why full table scan is better than index access in few cases. The video is very elaborate, I have tried my level best to keep it as simple as possible
Views: 11335 Tech Coach
Unusable indexes in Oracle, DML statements are not use the index to its maintenance, at the same time the optimizer will not use the index. Unusable indexes no segment exists. Unavailable index index becomes available methods are: 1. Place the index can not be truncate operation corresponding table; 2.rebuild index; In addition, the query optimizer can use conversion method expand table so that the SQL statement has encountered unusable index partition table to generate better execution plans.
Views: 65 崔旭
The video explains Reference partitioning and its advantages in Oracle with real project example. It builds on the limitations of reference partitioning in oracle 11g (Interval partitioning) and scenarios where you should implement reference partitioning
Views: 2105 Tech Coach
Explain plan is a wonderful utility in Oracle PL SQL. It helps you to understand how much cost a query takes to perform based on indexed table or table without index. In this oracle tutorial a full description is given on a table containing huge number of rows first based on index on a column and then without index.
Views: 3790 Subhroneel Ganguly
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: 1615 SkillBuilders
Oracle Ace Liron Amitzi presents an entertaining session about appreciating the Oracle Optimizer; exploring the stability of plans and examining new features that ruin your system performance, just when you get it tuned just right.
Views: 597 Database Community
“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: 294 Oracle Developers
blog: connor-mcdonald.com Highlights from the April DBA Office Hours session. Office Hours is 100% free Q&A sessions held every month by Oracle experts to help you succeed with the Oracle suite of technologies. Music: Smells Like Summer - Del (Vlog Music No Copyrighted) Video Link: https://youtu.be/IrkMsqcOjGU
Views: 1326 Connor McDonald
Learn what's different about cost-based optimization in 11g Release 2. In this training Dave Anderson will guide you through some critical performance and SQL tuning enhancements and other surprises in the Oracle 11g cost-based optimizer. Through live demonstrations and lecture, you will learn about features such as adaptive cursor sharing, feedback-based optimization, new join techniques, DBMS_STATS enhancements, direct (PGA) reads for "large" full table scans, new hints and more. Presented at NYOUG by SkillBuilders' Founder and Oracle DBA, Dave Anderson.
Views: 6901 SkillBuilders
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: 1665 SkillBuilders
In this tutorial, you'll learn how to compare queries to know the better performance query..
Views: 99518 radhikaravikumar
China Sun Yat-sen University and Dell co-established course IT System Management Introduction Lecture 5 Oracle Database Performance Tuning - Guy Harrison The Oracle database is highly tuneable with many options for optimizing performance. However, the sheer quantity of tuning options can be overwhelming, and you can waste precious time unless you know which tuning activities are most likely to provide a return on your time investment. In this lecture we'll review some of the fundamental Oracle performance tuning practices and see how to use these in a systematic way to improve Oracle performance. Topics will include workload and SQL optimization, identification and elimination of key contention points, configuring memory to avoid physical IO, and disk IO optimization. We will also see how to use commercial tools to assist in Oracle database tuning. This lecture will be based on materials from the lecturer's book on Oracle performance: http://product.china-pub.com/60833).
Views: 13276 Quest University
In this video, I will describe the 3 Join Operators SQL Server uses and the reason why it comes to the individual selections by the Optimizer. Please check my blog azizsharif.blogspot.com for more videos!
Views: 8088 azizsharif.blogspot.com
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: 1695 SkillBuilders
In this tutorial, you'll learn...what are optimizer hints and how to use it.. SQL (pronounced "ess-que-el") stands for Structured Query Language. SQL is used to communicate with a database. According to ANSI (American National Standards Institute), it is the standard language for relational database management systems.
Views: 11808 radhikaravikumar
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: 66301 SkillBuilders
This video explains how to improve performance of materialized view while doing complete refresh in oracle. Here i have created table and materialized view and described the refresh options. Also demonstrated with small script to compare the performance impact Oracle version used: Oracle 11gR2 Oracle client tool: Oracle SQL Developer Try to create our own table with more no of rows and observe the performance impact.
Views: 731 ShareTechTip
blog: https://connor-mcdonald.com Brand new to Oracle ... and want to get a basic installation up and running on your Windows laptop, with SQL Developer to access the database ?.... .... Here you go :-)
Views: 1188 Connor McDonald
for remaining interview you can contact at WhatsApp No. +1.732.524.8134 or [email protected]
Views: 66 cino mann
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: 2706 DWS Ltd
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: 16325 SkillBuilders
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/
Views: 58179 AllCertifications Tutorials
In this video, you will learn why you should not blindly follow the SSMS Missing Index Hints. Video resources including presentation, demo files, code snippets and more learning material is available on http://www.dataplatformgeeks.com/ (Join for free and access all the resources) Connect With The Speaker (Amit Bansal) -Follow on Twitter: https://twitter.com/A_Bansal -Follow on FaceBook at http://www.facebook.com/amit.r.bansal -Follow on LinkedIN: http://www.linkedin.com/in/amitbansal2010 -Facebook Page: https://www.facebook.com/AmitRSBansal/ Connect with SQLMaestros: http://sqlmaestros.com/ -http://www.twitter.com/SQLMaestros -https://www.facebook.com/SQLMaestros -Email us: [email protected] Have technical questions? Join the largest SQL group on FB www.facebook.com/groups/theSQLGeeks Our LinkedIn group https://www.linkedin.com/groups/6753546 DataPlatformGeeks (DPG) Community Join the fastest growing community of data & analytics professionals Why Join DPG? http://www.dataplatformgeeks.com/ -Attend all events hosted by DPG, including SQLMaestros Special Events -Get access to free videos, labs, magazines and host of learning resources -Download all events & conference material -Learn new skills. Sharpen existing skills -Be part of Asia’s Largest Data/Analytics Community -Opportunity to be a regional mentor & speaker at our events -Immense technical & professional development Do you know about Data Platform Summit? http://www.DPS10.com
Views: 1276 SQLMaestros
A video to help you understand the "thought process" behind answering AskTom questions. In this episode, we look at direct path reads and how they interact with objects that may already have changed buffers in the buffer cache blog: https://connor-mcdonald.com
Views: 568 Connor McDonald
Storing dates as numbers can cause unexpected problems. In this video Chris looks at one possible issue: inconsistent query performance. He then shows methods you can use to improve performance, including function-based indexes and histograms. ============================ 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: 7420 The Magic of SQL
Temporary Table in Oracle | Global Temporary Table in Sql| Advantages of Global Temporary Table in Sql --------------------------------------------------------------------------------------------------------- use of global temporary table in oracle,advantages of global temporary table in oracle,local temporary table in oracle,how to use global temporary table in oracle procedure,create global temporary table in oracle,temporary, table, tables, global, oracle, sql, delete, create global temporary table, temporary tables, oracle sql, global temporary table in oracle, preserve, on commit, drop global temporary table, oracle pl/sql, global temporary table, sql insert data into temp table, difference between temporary table and global temporary table in oracle,limitations of global temporary table in oracle,oracle create temp table on the fly, sql tutorials for beginners, sql expert, sql expert tutorials, database, oracle, table, online training,insert into oracle,oracle insert into multiple rows,create table oracle,oracle 12c alter table add identity column,oracle create table default value sysdate,collections in oracle pl sql with examples,Oracle 12c, database, oracle database (software), sql, sql developer, sql tutorials, how to create database using dbca, how to create database in oracle,oracle cloud, database 12c, dba genesis,database services, database, create, 11g, dba, db, beginner, Please Subscribe My Channel
Views: 93 Learning With Mahamud
This Tutorial will explain fundamentals of Oracle AUTOTRACE. Set up & Use AUTOTRACE. Review PLAN & Statistics generated by AUTOTRACE. Understanding Statistics details.
Views: 23298 Anindya Das
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: 3434 LiveLessons
Hints for Join Orders(USE_NL) - USE_NL 힌트는 테이블을 조인 하는 경우 중첩 루프 조인(Nested Loop Join)이 일어나도록 하는 힌트 문장이다. 중첩 루프 조인은 중첩반복 이라고도 하는데 하나의 테이블(outer/driving table)에서 추출된 ROW를 가지고 일일이 다른 테이블(inner/probed table)을 반복해서 조회하여 찾아지는 레코드를 최종 데이터로 간주하는 방법 이다. - EMP 테이블과 DEPT 테이블을 조인하는 경우 DEPT 테이블이 건수가 작다면 우선 이 테이블을 외부 루프로 해서 하나씩 읽으면서 이에 대응하는 EMP 테이블의 데이터를 추출 하는 경우가 중첩 루프 조인에 해당 한다. 이때 EMP 테이블의 경우 대부분 조인 칼럼에 인덱스를 이용하는 것이 성능상 좋다. 즉 중첩 루프 조인은 테이블 중 적어도 하나의 조인 컬럼에 대해 인덱스(or Hash Index)가 존재할 때 연관되는 방식으로 이 중첩 루프 조인에서 테이블 중 하나의 테이블 또는 중간 결과 셋을 대상으로 FULL SCAN이 일어나게 된다. 보통 USE_NL 힌트 구문은 ORDERED 힌트 구문과 같이 사용되는데 USE_NL이 취하는 인자는 FROM절에서 두 번째 나오는 테이블(비드라이빙 테이블, inner/probed table)을 명시해 주어야 한다. 인수로 사용되지 않은 첫 번째 테이블이 드라이빙 테이블(outer table)이 된다. Hints for Join Orders(ORDERED) 힌트는 FROM 뒤에 기술되는 테이블의 순서대로 조인이 일어나도록 해주는 구문이며 대부분 단독으로는 사용되지 않고 USE_NL(중첩 루프 조인을 유도), USE_MERGE(머지 소트 조인을 유도), USE_HASH(HASH 조인을 유도)등과 같이 사용된다. USE_NL/USE_MERGE/USE_HASH등의 인자로 사용되는 테이블은 FROM절에서 두 번째로 나타나는 테이블 이어야 하는데 FROM절에서 처음 나타나는 테이블이 드라이빙 테이블(OUTER/DRIVING TABLE)이 되고 나중에 나타나는 테이블이 PROBED TABLE(INNER TABLE)이 된다. 보통 드라이빙 테이블의 경우 데이터 건수가 적거나 조인 칼럼에 대해 인덱스가 없는 테이블이 주로 사용된다. 중첩 루프 조인(Nested Loop Join)이나 해시조인(Hash Join)의 경우 성능이 FROM절 뒤에 나타나는 테이블의 순서에 영향을 받지만 MERGE 조인은 영향을 받지 않는다. 머지 조인은 메모리에 올려서 정렬 시킨 후 병합하니까 실행 계획은 다르게 나올지 모르지만 성능에는 관계 없다.
Views: 209 이종철
China Sun Yat-sen University and Dell co-established course IT System Management Introduction Lecture 5 Oracle Database Performance Tuning - Guy Harrison The Oracle database is highly tuneable with many options for optimizing performance. However, the sheer quantity of tuning options can be overwhelming, and you can waste precious time unless you know which tuning activities are most likely to provide a return on your time investment. In this lecture we'll review some of the fundamental Oracle performance tuning practices and see how to use these in a ystematic way to improve Oracle performance. Topics will include workload and SQL optimization, identification and elimination of key contention points, configuring memory to avoid physical IO, and disk IO optimization. We will also see how to use commercial tools to assist in Oracle database tuning. This lecture will be based on materials from the lecturer's book on Oracle performance: http://product.china-pub.com/60833).
Views: 30423 Quest University
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: 1967 SkillBuilders
sub partitioning in oracle or composite partitioning 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: 715 TechLake
Joining large tables in a Data Warehouse will often generate star transformations in the execution plan. So, what is a star transformation? And, what if you don't have Enterprise Edition - so you can't build Bitmap Indexes? In this free tutorial, Oracle Master John Watson will demonstrate star transformations in EE and how to make them work even without bitmap indexes - Standard Edition can save you thousands in licensing fees! This is Part 3 of a 5 Part series. View all video tutorials at SkillBuilders.com/EqualSQL.
Views: 4590 SkillBuilders
Feel free to contact Call : +91-8870903864 Or E-mail contactex[email protected] ORACLE PERFORMANCE TUNNING 1 – 1: Introduction to Oracle tuning - The top-down approach to tuning - The history of Oracle tuning - A review of the Oracle architecture - The goals of Oracle tuning - Overview of SQL tuning - Oracle network bottlenecks - Oracle RAM usage and bottlenecks - Oracle CPU usage and bottlenecks - Oracle disk I/O overview - Monitoring server (sat, vmstat, top, glance) - Movement toward server consolidation 1 – 2: Oracle disk I/O tuning - History of DASD - Understanding disk I/O - Monitoring disk I/O (AWR, dba_hist_filestatxs) - Sorted hash cluster tables - Disk I/O waits - Oracle data buffer internals (db_cache_size) - Caching data blocks in the PGA (parallel full-table scans) - Blocksize and I/O performance 1 – 3: Oracle CPU Tuning - Finding your cpu_count - Measuring CPU usage with vmstat - Oracle CPU usage - Using processor affinity - _optimizer_cost_model=cpu - Parallel query and CPU 1 – 4: Oracle RAM tuning - all_rows and first_rows optimization and RAM - Multiple data buffers - Multiple blocksizes - Measuring RAM paging - Oracle SGA RAM - Oracle PGA RAM - Using the KEEP pool - Automatic Memory Management (AMM) 1 – 5: Oracle Instance Tuning - Global tuning techniques - Display possible unnecessary large-table full-table scans - Library cache tuning - Finding missing indexes - Tuning the database writer - instance parameter tuning 1 – 6: Oracle SQL Tuning Introduction - SQL tuning hierarchy - SQL tuning goals - optimizer modes - query re-write - cursor_sharing - viewing execution plans (autotrace) - verifying optimal join techniques - parallelizing SQL execution - dynamic statistics - Exercise – count times when a table is invoked - 12c new SQL features - function-based virtual column - adaptive execution plans - 12c new optimizer metadata collection features 2 – 1: AWR and ASH - AWR vs STATSPACK - Reading an AWR report - AWR report analyzer - Basics of predictive modeling for performance - Finding repeating signatures of data 2 - 2: Oracle RAC Tuning - RAC architecture tuning - Tuning disk I/O on RAC - Tuning the cache fusion layer on RAC 2 – 3: Oracle Tuning Pack - creating SQL Profiles - Recommending new indexes - “automatic” SQL Tuning - SQL Performance Advisor (SPA) - recommending object reorganization 2 – 5: Oracle Diagnostic pack - AWR and ASH - real time SQL monitoring - comparing performance periods - Oracle monitoring & alert notifications (setting thresholds) 2 – 6: Oracle Tracing - 10046 tracing - TKPROF tracing - Trace analyzer - Autotrace 3 – 1: Introduction to SQL tuning - Pre-SQL database communications - The evolution of SQL - Declarative languages 3 –2: Optimizing Oracle SQL - Parsing a SQL statement - Semantic parsing - Hard parse vs. soft parse - Decision tree generation - Making SQL reentrant 3 –3: Optimizer statistics - Types of metadata - Index metadata - Segment metadata - Server metadata - System stats 3 – 4: Exposing & Reading Execution Plans - autotrace - SQL*Trace - Determine the steps of an execution plan 3 – 5: altering execution plans - Changing CBO statistics - Changing init.ora SGA parameters - Changing optimizer parameters - Using hints - Using the opt_param hint 3 – 6: Oracle indexing - Overview of Oracle indexing - bitmap indexes - bitmap join indexes - guidelines for creating indexes - function-based indexes (FBI) - index usage monitoring - fishing in the library cache - optimizing indexes - The transient nature of indexing - database modality of workloads - SQL Workload analysis - Identifying EOW, EOM and EOY SQL. - Creating on-demand indexing - oracle text indexes Oracle Performance Tuning training online, Oracle Performance Tuning training material, IBM Websphere Application Server training cost, Oracle Performance Tuning training pdf, Websphere Application Server training in USA uae India, Oracle Performance Tuning training, online Corporate training malaysia Singapore, Oracle Performance Tuning software, Oracle Performance Tuning training in bangalore, Oracle Performance Tuning training institutes in hyderabad, Oracle Performance Tuning training in chennai, Oracle Performance Tuning training in hyderabad, Delhi, Mumbai, Pune, Oracle Performance Tuning, IBM Websphere ApplicationServer webinar, online training singapore, Oracle Performance Tuning eam, Oracle Performance Tuning as a service,Oracle Performance Tuning online Training Oracle Performance Tuning online Training Oracle Performance Tuning online Training Oracle Performance Tuning online Training maximo scheduler, Oracle Performance Tuning (consumer product) Oracle Performance Tuning online Training Oracle Performance Tuning online Training Oracle Performance Tuning online Training Oracle Performance Tuning online Training Oracle Performance Tuning online Training , Post Training Support