Numeric data type overflow

Vertica does not check for overflow (positive or negative) except in the aggregate function SUM(). If you encounter overflow when using SUM, use SUM_FLOAT() which converts to floating point.

For a detailed discussion of how Vertica handles overflow when you use the functions SUM, SUM_FLOAT, and AVG with numeric data types, see Numeric data type overflow with SUM, SUM_FLOAT, and AVG. The discussion includes directives for turning off silent numeric overflow and setting precision for numeric data types. Dividing by zero returns an error:

=> SELECT 0/0;
ERROR 3117:  Division by zero

=> SELECT 0.0/0;
ERROR 3117:  Division by zero

=> SELECT 0 // 0;
ERROR 3117:  Division by zero

=> SELECT 200.0/0;
ERROR 3117:  Division by zero

=> SELECT 116.43 // 0;
ERROR 3117:  Division by zero

Dividing zero as a FLOAT by zero returns NaN:

=> SELECT 0.0::float/0;
 ?column?
----------
      NaN
=> SELECT 0.0::float//0;
 ?column?
----------
      NaN

Dividing a non-zero FLOAT by zero returns Infinity:

=> SELECT 2.0::float/0;
 ?column?
----------
Infinity
=> SELECT 200.0::float//0;
?column?
----------
Infinity

Add, subtract, and multiply operations ignore overflow. Sum and average operations use 128-bit arithmetic internally. SUM() reports an error if the final result overflows, suggesting the use of SUM_FLOAT(INT), which converts the 128-bit sum to a FLOAT. For example:

=> CREATE TEMP TABLE t (i INT);
=> INSERT INTO t VALUES (1<<62);
=> INSERT INTO t VALUES (1<<62);
=> INSERT INTO t VALUES (1<<62);
=> INSERT INTO t VALUES (1<<62);
=> INSERT INTO t VALUES (1<<62);
=> SELECT SUM(i) FROM t;
   ERROR: sum() overflowed
   HINT: try sum_float() instead
=> SELECT SUM_FLOAT(i) FROM t;
     SUM_FLOAT
---------------------
 2.30584300921369e+19