DB2 read-only clause and performance

Question: Why do some sql queries use a read-only clause? Is there any performance gain by using the read only clause? Answer:Sometimes you will see a sql statement such as : Select name from mytable for read only The purpose of using the read only clause is to make the cursor unambiguous. When the read only clause is used , positional updates cannot occur By unambiguous I mean : Normally the SELECT is turned into a cursor. If the cursor is explicitly defined as a READ ONLY – “blocking” is used. “Blocking” means the DB2 server sends groups of rows... Read more →