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Optimizer Improvements
Oracle8i introduced the DBMS_STATS package, that
gathers more detailed statistics on database objects. Indeed, Oracle
recommends the use of DBMS_STATS over the ANALYZE command.
Outlines are supported in Oracle8i. Outlines
allow you to store and reuse execution plans related to Oracle SQL
statements. This can stabilize certain SQL statements where
performance tends to vary due to plan changes after a database
analysis.
Tablespace Improvements
Locally managed tablespaces (LMT) are now
available in Oracle8i. Dictionary managed tablespaces are still the
default though. LMT’s can reduce data dictionary activity related to
internal Oracle tablespace space management. There are two different
ways of managing extents in LMT’s, either uniform or system managed.
With Uniform extent size management, Oracle will create equi-sized
extents of a size you define when you create the tablespace. With
system managed, Oracle will allocate the extent sizes on it’s own,
starting with 64k extents on each object. As extents are added,
Oracle will increase the size of the extents.
Transportable tablespaces are introduced in
Oracle8i. This feature allows you to transport tablespaces between
different Oracle databases. Several restrictions exist on this
feature however.
Other Improvements
The alter table move command allows you to move
a table to a new tablespace. This command is not an online command,
so this can cause your database to experience a long outage.
You can drop columns in tables using the
alter table drop column.
The V$SESSION_LONGOPS view is new in Oracle8i.
This view allows you to estimate the completion of some long running
operations. Unfortunately, many Remote DBA kinds of operations never show
up in this view.
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