Export Parameter : Buffer

最新推荐文章于 2025-12-17 14:20:19 发布

转载最新推荐文章于 2025-12-17 14:20:19 发布 · 113 阅读

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#数据库

本文介绍了如何计算用于导出操作的缓冲区大小。通过指定缓冲区大小，可以确定每次导出操作中处理的行数。文章提供了一个计算公式，并通过一个具体的例子展示了计算过程。

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 typeLONG,LOB,BFILE,REF,ROWID,LOGICALROWID, 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 thename column is 30, plus 2 bytes for the indicator. The
maximum size of theweight 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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