When to Partition a Table and an Index
2010-01-25 22:48
363 查看
1. Global indexes can be unique. Local indexes can only be unique if the partitioning key is a part of the index key.
2. Note: All partitions of a partitioned object must reside in tablespaces of a single block size.
3. Any table can be partitioned into a million separate partitions except those tables containing columns with LONG or LONG RAW data types. You can, however, use tables containing columns with CLOB or BLOB data types.
4. Note:To reduce disk usage and memory usage (specifically, the buffer cache), you can store tables and partitions of a partitioned table in a compressed format inside the database. This often leads to a better scaleup for read-only operations. Table compression can also speed up query execution. There is, however, a slight cost in CPU overhead.
5. When to Partition a Table;
Here are some suggestions for when to partition a table:
Tables greater than 2 GB should always be considered as candidates for partitioning.
Tables containing historical data, in which new data is added into the newest partition. A typical example is a historical table where only the current month's data is updatable and the other 11 months are read only.
When the contents of a table need to be distributed across different types of storage devices.
6. When to Partition an Index:
Here are some suggestions for when to consider partitioning an index:
Avoid rebuilding the entire index when data is removed.
Perform maintenance on parts of the data without invalidating the entire index.
Reduce the impact of index skew caused by an index on a column with a monotonically increasing value.
2. Note: All partitions of a partitioned object must reside in tablespaces of a single block size.
3. Any table can be partitioned into a million separate partitions except those tables containing columns with LONG or LONG RAW data types. You can, however, use tables containing columns with CLOB or BLOB data types.
4. Note:To reduce disk usage and memory usage (specifically, the buffer cache), you can store tables and partitions of a partitioned table in a compressed format inside the database. This often leads to a better scaleup for read-only operations. Table compression can also speed up query execution. There is, however, a slight cost in CPU overhead.
5. When to Partition a Table;
Here are some suggestions for when to partition a table:
Tables greater than 2 GB should always be considered as candidates for partitioning.
Tables containing historical data, in which new data is added into the newest partition. A typical example is a historical table where only the current month's data is updatable and the other 11 months are read only.
When the contents of a table need to be distributed across different types of storage devices.
6. When to Partition an Index:
Here are some suggestions for when to consider partitioning an index:
Avoid rebuilding the entire index when data is removed.
Perform maintenance on parts of the data without invalidating the entire index.
Reduce the impact of index skew caused by an index on a column with a monotonically increasing value.
相关文章推荐
- An Introduction to Clustered and Non-Clustered Index Data Structures
- ORA-14452: attempt to create, alter or drop an index on temporary table already in use
- Error message when you try to modify or to delete an alternate access mapping in Windows SharePoint Services 3.0: "An update conflict has occurred, and you must re-try this action"
- Java Project提示"Errors occurred during the build. Excepted to find an object at table index”
- What is Local Index and Global Index in Partition Table? What is Prefix Index and Nonprefix Index in table?
- How To Reclaim Wasted Space on The Segment (Table, Index and LOB) and Tablespace Levels (文档 ID 16827
- When to use LinkedList and When to use ArrayList- An answer in StackOverFlow
- Asktom Oracle: Partition table and index .
- How To Reclaim Wasted Space on The Segment (Table, Index and LOB) and Tablespace Levels (文档 ID 16827
- When and how to trace who and when alter the table
- An explicit value for the identity column in table can only be specified when a column list is used and IDENTITY_INSERT is ON
- ORA-14452: attempt to create, alter or drop an index on temporary table already in use
- How To Build Multi-control Components when Inheriting from an Existing Control (Intro and TextBox Example)
- SharePoint Error - An unrecognized HTTP response was received when attempting to crawl this item
- So When Does An Oracle B-Tree Index Increase In Height ? (Almost Grown)
- how to deal with fdisk error: Re-reading the partition table failed with error 16: Device or resource busy.
- 面试题:What will happen when you attempt to compile and run the following code
- Use iterators and [] rather than at() when you want to optimize speed;
- An introduction to JAX-RS and JAXB
- Zend Server 错误:The server encountered an internal error or misconfiguration and was unable to comple