请问各位专家：oracle批量导入数据，阵列端来看，属于顺序写IO还是随机？

iamhuman77

找到一点资料，大家可以看一下
This is fairly well documented in various books and white papers, but can be tricky to find out on the Internet so I am summarising it here in this blog.
The key questions is “what are SQL Server’s I/O Characteristics”. This helps answer questions like why is a 1MB block size bad; why don’t we often care about random I/O for log files; what extra benefit for I/O does enterprise edition have; and why do we mainly test random I/O for data files in OLTP systems
The table below shows general I/O characteristics for the storage engine that will be important to most OLTP workloads. If you “really” know your workload you can optimise your storage. For example:
•        if you know that most of your workload is index seeks, you may benefit from a 8k block size on the SAN - good luck convincing your SAN team of this
•        If you are doing mostly very large table scans and you have enterprise edition, then it is possible that a 1MB block size may be most performant.
•        If you are not running enterprise edition, then a 1MB block size will never be optimal as the maximum IO size SQL Server will issue is 256k, so a minimum of three quarters of your I/O will be wasted.
Operation         Random / Sequential        Read / Write        Size Range
OLTP – Log        Sequential        Write         Sector Aligned Up to 60K
OLTP – Log        Sequential         Read        Sector Aligned Up to 120K
OLTP – Data (Index Seeks)        Random        Read         8K
OLTP - Lazy Writer (scatter gather)        Random        Write         Any multiple of 8K up to 256K
OLTP – Checkpoint (scatter gather)        Random        Write         Any multiple of 8K up to 256K
Read Ahead (DSS, Index/Table Scans)        Sequential         Read        Any multiple of 8KB up to 256K (1024 Enterprise Edition)
Bulk Insert         Sequential         Write        Any multiple of 8K up to 128K

This secondary table is useful as trivia, but we rarely optimise storage for these operations. One  observation is that backup and restore can issue up to 4MB IO sizes, and the importance of instant file initialisation in helping create database performance (or file growth).
Operation         Random / Sequential        Read / Write        Size Range
CREATE DATABASE (or file growth)        Sequential         Write         512KB (SQL 2000) , Up to 4MB (SQL2005+)
(Only log file is initialized in SQL Server 2005+ if instant file initialisation is enabled)
BACKUP         Sequential         Read/Write        Multiple of 64K (up to 4MB)
RESTORE        Sequential         Read/Write        Multiple of 64K (up to 4MB)
DBCC – CHECKDB        Sequential         Read        8K – 64K
ALTER INDEX REBUILD - replaces DBREINDEX
(Read Phase)        Sequential         Read        Any multiple of 8KB up to 256K
ALTER INDEX REBUILD - replaces DBREINDEX
(Write Phase)         Sequential         Write        Any multiple of 8K up to 128K
DBCC – SHOWCONTIG (deprecated, use sys.dm_db_index_physical_stats)        Sequential         Read        8K – 64K

无牙

啥结论，懒的看了。

yddll

啥结论，懒的看了。
无牙 发表于 2010-11-29 16:29

    Bulk Insert         Sequential         Write        Any multiple of 8K up to 128K