Oracle Performance: SDU, SEND_BUF_SIZE and RECV_BUF_SIZE

最新推荐文章于 2024-01-22 12:27:42 发布

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最新推荐文章于 2024-01-22 12:27:42 发布 · 1.5k 阅读

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本文讨论了Oracle数据库中SDU（Session Data Unit）、SEND_BUF_SIZE和RECV_BUF_SIZE参数如何影响网络性能。默认情况下，SDU大小为2048字节，但可以根据需求配置。SEND_BUF_SIZE和RECV_BUF_SIZE是网络发送和接收缓冲区的大小，它们对流量控制决策有直接影响。通过调整这些参数，例如改变RECV_BUF_SIZE的值，可以观察到查询性能的显著变化，尤其是在执行`SELECT`操作时。

Refer from: http://docs.oracle.com/cd/B19306_01/network.102/b14212/performance.htm

Problem Statement:

The select operation is too slow compared with expected value.

Session Data Unit(SDU):

Under typical database configuration, Oracle Net encapsulates data into buffers the size of the session data unit (SDU) before sending the data across the network. Oracle Net sends each buffer when it is filled, flushed, or when an application tries to read data.

The SDU size you choose should be 70 bytes larger than the predominant message size, as long as the maximum SDU size is not exceeded. The SDU size can range from 512 bytes to 32767 bytes. If the DEFAULT_SDU_SIZE parameter is not configured in the