Seagate ST43401N/ND Guide d'installation télécharger pdf (Page 67)

CHAPTER 5 Implement: Making Required Application Changes

To see whether you can enable wide data sizes for your client software, go to

the section below that describes your system:

• Both ASE and Open Client are Version 12.5

• Open Client Is an Older Version

• ASE 12.5 Connects to a Remote Pre-12.5 Server

Both ASE and Open

Client are Version

12.5

You should not have any problems if both Adaptive Server and Open Client are

at version 12.5. Perform the following before you use Open Client 12.5 with

Adaptive Server version 12.5:

1 Relink your Open Client application with the 12.5 libraries.

2 Establish the new version number with CS_VERSION.

3 If you are using JConnect, reconnect the drivers.

Open Client Is an

Older Version

If you are running a pre-version 12.5 Open Client application with Adaptive

Server version 12.5, and have relinked your application with 12.5 Open Client,

but have not changed the version of your libraries, the pre-version 12.5

functionality is fine, but the new limits are not enabled. Adaptive Server sends

the data according to the pre-12.5 limits, and will truncate any data that is

beyond these limits.

If you are running pre-version 12.5 Open Client with Adaptive Server version

12.5, but have not relinked your libraries, Adaptive Server sends data according

to the pre-12.5 version, with the same restrictions outlined above.

ASE 12.5 Connects to

a Remote Pre-12.5

Server

If Open Client 12.5 connects to a 12.5 Adaptive Server, which then queries a

remote server which is at an earlier version, the remote server truncates any

wide data before returning results. All servers and clients in a transaction must

be at 12.5 in order to use the new wide limits.

Wide Columns and Optimizer Statistics

When placing statistics on a wide column, the server uses on the first 255 bytes

of data. Even if you place an index on a column created as

char(500), only

the first 255 bytes will contribute towards the column histograms in

sysstatistics. For unichar columns, the first 127 chars will be used to gather

column distributions.

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Seagate ST43401N/ND Guide d'installation Page 67