# Performance of Numeric Data Types in PL/SQL

Oracle provide a variety of numeric data types that have differing performance characteristics. This article demonstrates the performance differences between the basic integer and real number datatypes.

## NUMBER Data Type

The `NUMBER`

data type is the supertype of all numeric datatypes. It is an internal type, meaning the Oracle program performs the mathematical operations, making it slower, but extremely portable. All the tests in this article will compare the performance of other types with the `NUMBER`

data type.

## Integer Data Types

The following code compares the performance of some integer data types with that of the `NUMBER`

data type.

SET SERVEROUTPUT ON DECLARE l_number1 NUMBER := 1; l_number2 NUMBER := 1; l_integer1 INTEGER := 1; l_integer2 INTEGER := 1; l_pls_integer1 PLS_INTEGER := 1; l_pls_integer2 PLS_INTEGER := 1; l_binary_integer1 BINARY_INTEGER := 1; l_binary_integer2 BINARY_INTEGER := 1; l_simple_integer1 SIMPLE_INTEGER := 1; l_simple_integer2 SIMPLE_INTEGER := 1; l_loops NUMBER := 10000000; l_start NUMBER; BEGIN -- Time NUMBER. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_number1 := l_number1 + l_number2; END LOOP; DBMS_OUTPUT.put_line('NUMBER : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); -- Time INTEGER. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_integer1 := l_integer1 + l_integer2; END LOOP; DBMS_OUTPUT.put_line('INTEGER : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); -- Time PLS_INTEGER. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_pls_integer1 := l_pls_integer1 + l_pls_integer2; END LOOP; DBMS_OUTPUT.put_line('PLS_INTEGER : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); -- Time BINARY_INTEGER. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_binary_integer1 := l_binary_integer1 + l_binary_integer2; END LOOP; DBMS_OUTPUT.put_line('BINARY_INTEGER : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); -- Time SIMPLE_INTEGER. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_simple_integer1 := l_simple_integer1 + l_simple_integer2; END LOOP; DBMS_OUTPUT.put_line('SIMPLE_INTEGER : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); END; / NUMBER : 24 hsecs INTEGER : 44 hsecs PLS_INTEGER : 9 hsecs BINARY_INTEGER : 9 hsecs SIMPLE_INTEGER : 8 hsecs PL/SQL procedure successfully completed. SQL>

From this we can make a number of conclusions:

`NUMBER`

: As mentioned previously, since`NUMBER`

is an internal datatype, it is not the fastest of the numeric types.`INTEGER`

: Like`NUMBER`

, the`INTEGER`

type is an internal type, but the extra constraints on this datatype make it substantially slower than`NUMBER`

. If possible, you should avoid constrained internal datatypes.`PLS_INTEGER`

: This type uses machine arithmetic, making it much faster than the internal datatypes. If in doubt, you should use`PLS_INTEGER`

for integer variables.`BINARY_INTEGER`

: Prior to Oracle 10g,`BINARY_INTEGER`

was an internal type with performance characteristics worse than the`INTEGER`

datatype. From Oracle 10g upward`BINARY_INTEGER`

is identical to`PLS_INTEGER`

.`SIMPLE_INTEGER`

: This subtype of`PLS_INTEGER`

was introduced in Oracle 11g. In interpreted mode it has similar performance to`BINARY_INTEGER`

and`PLS_INTEGER`

, but in natively compiled code it is typically about twice as fast as those types. You can read more about the`SIMPLE_INTEGER`

data type here.

There are additional predefined subtypes of `PLS_INTEGER`

, listed here.

If you are dealing with an integer value, using `PLS_INTEGER`

is a safe option. It has good performance, whilst still having all the boundary checking. Only use other data types if you have a specific need they meet.

## Real Number Data Types

Oracle 10g introduced the `BINARY_FLOAT`

and `BINARY_DOUBLE`

data types to handle real numbers. Both new types use machine arithmetic, making them faster than the `NUMBER`

data type, as shown in the following example.

SET SERVEROUTPUT ON DECLARE l_number1 NUMBER := 1.1; l_number2 NUMBER := 1.1; l_binary_float1 BINARY_FLOAT := 1.1; l_binary_float2 BINARY_FLOAT := 1.1; l_simple_float1 SIMPLE_FLOAT := 1.1; l_simple_float2 SIMPLE_FLOAT := 1.1; l_binary_double1 BINARY_DOUBLE := 1.1; l_binary_double2 BINARY_DOUBLE := 1.1; l_simple_double1 SIMPLE_DOUBLE := 1.1; l_simple_double2 SIMPLE_DOUBLE := 1.1; l_loops NUMBER := 10000000; l_start NUMBER; BEGIN -- Time NUMBER. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_number1 := l_number1 + l_number2; END LOOP; DBMS_OUTPUT.put_line('NUMBER : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); -- Time BINARY_FLOAT. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_binary_float1 := l_binary_float1 + l_binary_float2; END LOOP; DBMS_OUTPUT.put_line('BINARY_FLOAT : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); -- Time SIMPLE_FLOAT. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_simple_float1 := l_simple_float1 + l_simple_float2; END LOOP; DBMS_OUTPUT.put_line('SIMPLE_FLOAT : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); -- Time BINARY_DOUBLE. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_binary_double1 := l_binary_double1 + l_binary_double2; END LOOP; DBMS_OUTPUT.put_line('BINARY_DOUBLE : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); -- Time SIMPLE_DOUBLE. l_start := DBMS_UTILITY.get_time; FOR i IN 1 .. l_loops LOOP l_simple_double1 := l_simple_double1 + l_simple_double2; END LOOP; DBMS_OUTPUT.put_line('SIMPLE_DOUBLE : ' || (DBMS_UTILITY.get_time - l_start) || ' hsecs'); END; / NUMBER : 26 hsecs BINARY_FLOAT : 14 hsecs SIMPLE_FLOAT : 14 hsecs BINARY_DOUBLE : 15 hsecs SIMPLE_DOUBLE : 14 hsecs PL/SQL procedure successfully completed. SQL>

Both `BINARY_FLOAT`

and `BINARY_DOUBLE`

out-perform the `NUMBER`

data type, but the fact they use machine arithmetic can potentially make them less portable. The same mathematical operations performed on two different underlying architectures may result in minor rounding errors. If portability is your primary concern, then you should use the `NUMBER`

type, otherwise you can take advantage of these types for increased performance.

Similar to `SIMPLE_INTEGER`

, `SIMPLE_FLOAT`

and `SIMPLE_DOUBLE`

provide improved performance in natively compiled code because of the removal of NULL checking.

If you are dealing with anything to do with finance, I would stick to using `NUMBER`

. For anything else the BINARY_* data types probably make more sense. If in doubt use `NUMBER`

.

For more information see:

Hope this helps. Regards Tim...