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Imp Buffer

原创 Linux操作系统 作者:BenX22 时间:2012-06-13 20:39:04 0 删除 编辑

BUFFER
Default: operating system-dependent. See your Oracle operating system-specific documentation to determine the default value for this parameter.

Specifies the size, in bytes, of the buffer used to fetch rows. As a result, this parameter determines the maximum number of rows in an array fetched by Export. Use the following formula to calculate the buffer size:

buffer_size = rows_in_array * maximum_row_size

If you specify zero, the Export utility fetches only one row at a time.

Tables with columns of type LOBs, LONG, BFILE, REF, ROWID, LOGICAL ROWID, or DATE are fetched one row at a time.


 Example: Calculating Buffer Size
This section shows an example of how to calculate buffer size.

The following table is created:

CREATE TABLE sample (name varchar(30), weight number);

The maximum size of the name column is 30, plus 2 bytes for the indicator. The maximum size of the weight column is 22 (the size of the internal representation for Oracle numbers), plus 2 bytes for the indicator.

Therefore, the maximum row size is 56 (30+2+22+2).

To perform. array operations for 100 rows, a buffer size of 5600 should be specified.

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