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Oracle Locks
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Tuning Oracle Instance
Instance Tuning
Main Components SGA
Shared Pool Tuning
Oracle Library Cache
Query Dictionary Cache
Global Area Session
Data Buffer Cache
Redo Log Buffer
Instance Tuning Conclusion
Shared Pool Tuning
Shared Pool Optimal Tuning
Pin Packages Shared Pool
Reserved Size
Identifying High Use Packages
IIdentify Swapped out Items
Statistics gathered from Startup
Detecting Library Cache Contention
Library Cache Statistics
Reuse SQL Library Cache
Tuning Shared Pool
Data Buffer Cache
Tuning Data Buffer
Calculate buffer Hit Ratio
Non- Full table Scan
Full table Scan
Impact Adding Data Buffers
Predict Amount Spare Memory
Create multiple Buffer Pools
Configure Multiple Buffer Pools
Size Buffer Pools
Monitor Buffer Cache
Use Table Caching
Databuffer Cache Conclusion
Redo Log Tuning
Oracle Redo Logs
Tuning Techniques
View RedoLog Activity
Redo Log Parameters
RedoLog Wait Statistics
RedoLogs Online Size Determination
size Archived RedoLog FileSystem
Tune redo Log Operations
log_checkpoint_interval
RedoLog Tuning Conclusion
Sorting Operations
Oracle Sorting Basics
Sorting Parameters
SQL Join Operations
Monitor for Disk Sorts
Sorting Direct Writes
Temporary Sorting Space
Monitoring Temp Tablespace
Remove SQL Sorts
Sorting Operations Conclusion
Intro Tuning Oracle Locks
Oracle Locking Scheme
Shared Exclusive Locks
Oracle Lock Modes
Database Deadlocks
Preventing Database Deadlocks
Dictionary Lock Views
Lock Utility Scripts
DBMS Lock Package
Tuning Oracle Locks Conclusion
Oracle Lock Modes - Exericse
Overview of Oracle lock modes
Objective:
Describe the Oracle lock modes.
Exercise scoring
For this exercise, you will need to respond to the scenario presented below using what you now know about Oracle locks. Once you have completed your answer, you will submit your answer.
Background
Your programming community has been having a problem when attempting to acquire a whole table with an exclusive lock (using the LOCK TABLE command). Their task is updating 3,000 rows in a table, and the task has been waiting too long for all shared locks to clear.
The programmers are upset because they cannot understand why the task must wait for shared locks. You have been asked to describe to your programmer community why Oracle will not allow a task to acquire an exclusive lock until all other tasks are done reading a row (with shared locks), and outline another method for achieving the goal.
Instructions
Prepare a short paragraph explaining why it is necessary for Oracle to wait until all shared locks have cleared for a row before allowing an exclusive lock to be set. It should also explain another alternative to a full table lock.
Hint
Remember the discussion about Oracle's locking scheme from the beginning of this module.
Submitting your Exercise
Enter your answer into the text box below. Click the
Submit
button to submit your answer
.