Seagate ST43401N/ND Technical Information PDF herunterladen (Seite 98)

6-18 Implement: Making Required Database Administration Changes

If Your Current Version is 4.x, 10.x or 11.0.x Adaptive Server Enterprise 11.5

which to extend the database, be sure to extend the log segment onto

the new device. When you extend a database to a separate device

with the

alter database command, the command extends only the data

segment, not the log segment. This can cause out-of-space errors for

the log.

See the installation guide for more information about this database.

See also the Upgrade topic in the Technical Information Library for

stored procedure database issues.

Optional Space Considerations

A number of processing changes between 11.0.x and 11.5 which

contribute to improved performance require additional resources.

These changes include true parallel processing on partitioned tables,

new index scans, and improved prefetch. As a result, you will

probably need to add resources to the Adaptive Server environment

to maintain the same performance.

Partitioned Tables and Parallel Processing

Adaptive Server now supports true parallel query processing. You

may want to plan to place your tables differently on Adaptive Server

11.5 to take advantage of this feature, particularly if you use

partitioned tables already. While you do not have to implement this

now, you may want to plan for additional devices.

Here are some considerations for planning table-partition-to-device

placement:

Heavy I/O. In an environment where many users are accessing a

table to perform inserts, deletes, and queries, I/O is the performance

bottleneck. Place your table partitions on multiple devices with

different controllers so that I/O, as well as processing, can be

performed in parallel. For example, if you have four available

devices and you place four tables partitions on them, you should get

an increase in speed of almost four times, assuming no other factors

are affecting performance.

High concurrency for inserts. If the limiting factor on performance

is contention for locks while performing inserts, you could partition

a heap table into many partitions, so that each would have its own

last page of the page chain on which to perform inserts. For example,

if you had four available devices, you could place ten partitions on

each, for 40 total partitions. Inserts would wait for I/O, but they

wouldn’t block each other for locks.

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Seagate ST43401N/ND Technical Information Seite 98