Seagate ST43401N/ND Instalační příručka stáhnout pdf (Strana 48)

If Your Version is 11.5

This sections covers the following topics:

• Changes to Locking

• Changes to Error Checking

• 11.9.2 Query Processing Changes

Changes to Locking

Release 11.9.2 introduced several changes to locking, including support for

row-level and page-level locking. Some of these changes require you to make

application or configuration changes to avoid performance issues.

Data-only Locking

Sybase now supports new locking methods called “data-only” locking. In

previous releases, all locking happened at the page level. When you upgrade,

by default, your server performs page-level locking. However, you may change

the locking scheme on your existing tables with the

alter table command.

The new locking schemes are:

• Datapages locking

• Datarows locking, also known as row-level locking

If you intend to use the data-only locking feature, you need to be aware of the

following system and application issues:

• The number of locks required for your applications may increase, and you

may need to change the number of locks configuration parameter.

• On data-only-locked tables with clustered indexes, the default behavior of

disallowing duplicate rows and the

ignore_dup_row option are not

enforced during inserts and updates. This changes the behavior of

commands that insert duplicate rows and may change the behavior of

create clustered index if the table contains duplicate rows.

• On data-only-locked tables, the

sorted_data option to create index can be

used only immediately following a bulk copy operation that copies into an

existing table. Use of the

sorted_data option is prohibited once additional

page allocation operations have been made for the table.

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Seagate ST43401N/ND Instalační příručka Strana 48