Oracle : Steps for Select Statement Process in SGA

Steps for Select Statement Process in SGA :

 

>SELECT * FROM EMP;

step 1

when user fires update statement first it will start user processes

step 2

user processes to server processes with the help of user processe interface

step 3

server processes to sga with the help of server processes interface

step 4

it will check wheter this statement already executed or not

step 5

parsing will be done in library cache

> hard parsing or soft parsing

hard parsing first time execution

soft parsing second time execution

step 6

after parsing symantical checking will be done in ddc

step 7

after symantical checking here comes the oracle optimizer

oracle optimizer will choose the best execution plan to fetch the data from the server

step 8

with the help of best execution plan server processes will fetch the data from datafiles and it will store in the database buffer cache

Step 9

From database buffer cache to server processes  and server processes to user