why we use nocopy?
Answers were Sorted based on User's Feedback
Answer / shivaindu
When you use a Collection (Records, VARRAY etc having
records of data) as a Return type (OUT or IN OUT parameter)
as we know, it will be passed by value only. That means the
entire data will be copied to the formal parameter location,
which leads to lot of CPU and memory consumption.
Here comes the usage of NOCOPY parameter. Provide NOCOPY
after the OUT/IN OUT parameter, which instructs the PL/SQL
Engine to avoid using the pass by value method. So, the
Engine uses pass by reference instead. This helps reducing a
lot of CPU usage as well as memory consumption.
Eg: Just an example how to put the NOCOPY parameter.
PROCEDURE PRC_NOCOPY_EXAMPLE
(
P_EMPNO IN
NUMBER,
P_ENAME IN
VARCHAR2(50),
P_SAL OUT NOCOPY
RECORD_SAL --PL/SQL Record
);
REC_SAL RECORD_SAL;
Now if you call the Procedure PRC_NOCOPY_EXAMPLE, the
parameter P_SAL would only use Pass by reference method.
Disadvantage:
However, you need to be extremely careful while
using this method in coding for high priority data
transactions. When you pass parameters to a procedure by
reference, any change that happens on the passed Parameters
gets updated in the same memory location as the Actual
parameter. So when an exception occurs in a
procedure/function, these changes are not Rolled back . To
be precise, the PL/SQL engine cannot rollback these
parameter changes. So, if the actual values get changed,
then it may result in incorrect results.
Thus, to conclude, it is up to a Developer to take a
trade-off between using or not using the NOCOPY parameter.
NOCOPY could provide better performance by reducing Memory
and CPU cost, but at the same time, could result in
incorrect results too.
| Is This Answer Correct ? | 4 Yes | 0 No |
OUT and IN OUT Parameters which will avoid copy overhead.so we will use NOCOPY.
| Is This Answer Correct ? | 0 Yes | 0 No |
What are sql commands?
Does it possible to pass object (or) table as an argument to a remote procedure?
how will you find out the last three records in a table with n no of records and delete them
Can you inner join the same table?
Let us suppose we have a table with structure in order empno empname empdesig empcountry and now i want to re-organize the columns of this table to empno empdesig empname empcountry how can i do this with queries ? assume that table contains the data.
what is explain plan?
what is the difference between truncate and delete statement? : Transact sql
How many types of index are there?
What operating systems are supported by oracle sql developer?
What is ROWID?
What can be a size of a pl/sql block? Is there any limit?
Which function is used to return remainder in a division operator in sql?
Oracle (3253)
SQL Server (4518)
MS Access (429)
MySQL (1402)
Postgre (483)
Sybase (267)
DB Architecture (141)
DB Administration (291)
DB Development (113)
SQL PLSQL (3330)
MongoDB (502)
IBM Informix (50)
Neo4j (82)
InfluxDB (0)
Apache CouchDB (44)
Firebird (5)
Database Management (1411)
Databases AllOther (288)