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.
We all know that CHAR and VARCHAR2 are two different datatypes used for storing strings in Oracle. When I asked many people about what’s the difference exactly, all were saying VARCHAR2 can be used for variable sized character strings. As I’m not satesfied with the answer, as always, I’ve decided to do my own experiments on these two.
When I was doing a research on Oracle Database creation, through DBCA, last week, I came across a very interesting scenario which I couldn’t stop sharing with you :)
I have a cluster of machines (don’t confuse it with a RAC cluster but just a group of machines required for my application deployment) with 220.127.116.11 installed and a Database instance running.
I got a requirement to remove everything accumulated in the machine as a result of the Oracle installation and the Database creation: The installation directories, the datafiles, oratab entries etc…
After removing all th
Hi Oracle geeks,
Last Friday, I’ve noticed a strange thing happening in my 18.104.22.168 Database: I’m able to create objects in a tablespace which is marked READ ONLY !!!
Don’t believe this??