kishore.giri

 Profile Answers by kishore.giri Questions by kishore.giri

• Dec 9th, 2007

 

During the execution of an update statement, the server process prepares its parsing,execution plan in shared pool and then search for that record in the database buffer cache if it finds the record in the buffer then it updates the record else it goes to the datafile to read the record to the database buffer cache and then updates it.

ajaymore

 Profile Answers by ajaymore Questions by ajaymore

• Feb 2nd, 2008

 

During the execution of an update statement, the server process looks into library cache whether same kind of query is recently executed or not i.e. explain plan is ready for execution or not in shared pool and then search for that record block in the database buffer cache if it finds the block in the buffer then it modifies the block else it fetches the same from datafile to database buffer and then modifies it.

premk

 Profile Answers by premk 

• Dec 23rd, 2009

 

When a user issues a update statement the server process checks for weather the same type of command is executed recently or not if that command is executed very recently then it directly proceed to the dictionary cache to fecth the metadata presented in the system.dbf file and required data is going to updated to the system.dbf file and respective database. if the sever process does't find any previously executed similar type of command then parsing is going to be takes place in dictionary cache and ash code is created at the same time execution plan of the command is created.after that the data from database buffer cache is going to be written to the respective data files.

anjum

• May 1st, 2015

 

when update statement fires data will be loaded into buffer from data files and keeps the old image into undo tablespace and modifies the data in buffer once you commit modified data will be written to data files if you rollback data from undotablespace it will read and writes to the data files.