Context Switches and Performance
Almost every program PL/SQL developers write includes both PL/SQL and SQL statements. PL/SQL statements are run by the PL/SQL statement executor; SQL statements are run by the SQL statement executor. When the PL/SQL runtime engine encounters a SQL statement, it stops and passes the SQL statement over to the SQL engine. The SQL engine executes the SQL statement and returns information back to the PL/SQL engine This transfer of control is called a context switch, and each one of these switches incurs overhead that slows down the overall performance of programs
Bulk Processing in PL/SQL
The bulk processing features of PL/SQL are designed specifically to reduce the number of context switches required to communicate from the PL/SQL engine to the SQL engine
