This is Part 3 of The Bitmap Conspiracy, a four part epic on Bitmap Indexes.
In Part 1 we touched briefly on how Oracle can use Bitmap Indexes to resolve queries by translating equality and range predicates into bitmap retrievals. Now that we know more about how they are stored (see Part 2), let’s look closer at some of the operations that Oracle uses to access Bitmap Indexes and manipulate bitmaps.
This is one of those myths that is probably best demonstrated by example. First, let’s create some test data: 10 million rows with the following columns:
- COL1 – Alternating values of 1 and 0 – not indexed
- COL2 – Identical to COL1 – bitmap indexed
- PAYLOAD – 100 bytes of X’s to make the rows a realistic width – not indexed
COL1 and COL2 are identical low cardinality columns: there are only two valid values.
Apps clone is like cloning a human being. Please read the detail below.
1) Run adpreclone on DB/CM/AP tiers
This is pre-requisite step of cloning 11i prod and will not change anything in any system. This script will only create on $COMMON_TOP, a directory called "clone", with a basic structure of executable, scripts, templates and java files.
I recently did a comparison caching mechanisms of scalar subquery caching(SSC) and deterministic functions in 11.2. Unfortunately, I do not have enough time to do a full analysis, so I will post it in parts.
1. Both mechanisms are based on hash functions.(About hash tables and hash collisions for scalar subquery caching excelent wrote Tom Kyte and Jonathan Lewis(“Cost-Based Oracle fundamentals” chapter 9))
2. Deterministic caching depends on fetch size(arraysize) – results cached only within one fetch call, ssc has no this limitation.
I want to share my modifications of Tom Kyte's runstats package, which include:
- Any number of runs sets for analyzing
- Standalone: No need to create other objects
- Ability to specify session SID for statistics gathering
- Ability to specify what to gather: latches, stats or both
- Separate mask filters for output by statname and latchname
- Ability to specify difference percentage for output separately for latches and statistics
- More accurate with some statistics because of avoiding global temporary table usage, but less in
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1.DML data can be recovered by rollback before commit
2.Remove any subset of data
3.Delete is slower when table have numerous indexes and triggers
4.DML triggers fire for delete mthod
5.data can be recovered after commit by flashback method
6.high water mark will remain the same
7.data deleted info capture with returning clause
8. you can not delete data if function based index is invalid
9. can not delete data from complex views.
Oracle Database 12c: New Features – Pluggable Databases by Michael Rajendran
Oracle has leap forwarded the middleware technologies especially the database technology into the cloud. So far Oracle has been the traditional RDBMS database suitable for the private enterprise data centers within corporate walls.
The COST column cannot be used to compare execution plans. Punkt.
R12 - XLA / FAH - Create Accounting errs out with "95357 - There are no values for the system source XXXXX used by SLA"Submitted by vamsi kasina on Fri, 2012-09-14 12:42
In case of unitended usage of system source in conditions may lead to the following error in Create Accounting:
There is a missing system source value. Please inform your system administrator or support representative that: There are no values for the system source XXXXXXXXXXXXXXXXX used by Oracle Subledger Accounting.