q ANY STATEMENT FIRE > USER PROCESS >> DATA DICTIONARY CACHE >>> UGA [USER GLOBAL AREA]
Ü UPDATE EMP SET SALARY=5000 WERE SALARY=4000;
q SYNTAX CHECK
v SQL GRAMMER CHECK
q SEMANTIC CHECK
v USER'S PRIVILEGES [USER AUTHENTICATION] ON THE
TABLE
v IT WILL CHECK DATA DICTIONARY INFORMATION
q HASH VALUE GENERATION
v IF JOINING MULTIPLE TABLES, IT WILL GENERATE VALUE [1237438]
q EXECUTION PLAN
v HOW THE QUERY WILL BE GENERATED
v RULE-BASED
OPTIMIZER
v COST-BASED
OPTIMIZER
·
IT WILL COMPARE ALL PLANS AND
CHOOSE BETTER ONE
q LIBRARY CACHE
v [HASH VALUE GENERATION | EXECUTION PLAN | STATEMENT]
q DATA DICTIONARY CACHE
v SYNTAX CHECK [IT WILL CHECK SQL STATEMENT IS
CORRECT OR NOT]
v SEMANTIC CHECK [IT WILL CHECK DO HAVE PERMISSION TO FIRE THE STATEMENT ON THE TABLE]
q UNDO
v PREVIOUS IMAGE OF THE BLOCK STORE UNTIL COMMIT
FOR ROLLBACK
v WHENEVER YOU MODIFY PREVIOUS IMAGE/VALUE WILL ALSO STORE IN THE DATA BUFFER CACHE BLOCK
q UNCOMMITED DATA WOULD BE WRITTEN FROM REDO LOG BUFFER TO REDO LOG FILE
v AFTER COMMIT
v REDOLOG BUFFER IS 1/3 FILLED UP
v REDO LOG BUFFER IS 1 MB FILLED UP