6.18 Estimating the size of a file output by the adbexport command

This section describes how to determine the size of a data file that is output by the adbexport command.

To determine the total size of data files that are output (EXPORTFILESIZE), use the following formula.

Formula (kilobytes)

EXPORTFILESIZE = ↑(HEADERSIZE × file_num + ROWSIZE × row_num) ÷ 1,024↑

Explanation of variables

HEADERSIZE

Size of the column names to be output to the output data file

Add this value if you specify the --with-column-name option when running the adbexport command. If you do not specify the --with-column-name option, substitute 0.

Use the following formula to determine its value.

Formula (bytes)

HEADERSIZE = 202 × column_num

column_num

Number of columns of the data to be output

file_num

Number of output data files specified in the output data path file

ROWSIZE

Data size of one row

Use the following formula to determine its value.

Formula (bytes)

column_data_size(k)

Column data length of the k-th column

The value to be substituted for the column_data_size variable differs depending on the data type of the column data. See the following table, and substitute the applicable value.

Table 6‒26: Value to be substituted for column_data_size

No.	Classification	Data type	Data length (bytes)
1	Numeric data	INTEGER	20
2		SMALLINT	11
3		DECIMAL(m, n)#	m + 2
4		DOUBLE PRECISION	24
5	Character string data	CHARACTER(n)	2 × n + 2
6		VARCHAR(n)	2 × d + 2
7	Datetime data	DATE	12
8		TIME(p)	11 + p
9		TIMESTAMP(p)	22 + p
10	Binary data	BINARY(n)	2 × n + 2
11		VARBINARY(n)	2 × d + 2

Legend:

m, n: Positive integers

p: 0, 3, 6, 9 or 12

d: Actual data length

#

Indicates a fixed-point number that has a total of m digits, with n digits following the decimal point. If m is omitted, 38 is assumed.

row_num

Number of rows output by the adbexport command

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