two.
Freelists
Whether it is outdated
With Oracle9i's launch, the management of idle blocks is more intelligent and efficient. If ASSM (Automatic Segment Space Management) is specified in LMT (LOCALLY Managed TableSpaces, you will be ignored for any PCTUSED, FREELISTS, FREELIST GROUPS storage parameters. The method of creating an ASSM table space is as follows:
Create TableSpace Lmtbsb DataFile '/u02/oracle/data/lmtbsb01.dbf' size 50M
Extent Management Local
Segment Space Management Auto;
ASSM benefits from using the bitmaps to manage the idle block in the segment, as for how to manage, that is another article.
In this sense, for the exploration of Freeelists, it is already a bit outdated, but all the databases are not all databases have now been upgraded to Oracle9i, even in some large applications that are most adjustable, often due to the business stability. Take the risk of upgrading to a new version; even if the new app uses the Oracle9i database, if the database administrator does not specify Segment Space Management Auto when the table space is created, then defaults will still use Freelists and FreeElist Groups to manage Free block.
So, there is still a large number of Oracle8i databases and non-automatic space management table spaces, and the research of Freelists still has very practical significance, and because the default Freelists and Freelist Groups are only 1, it is precisely high load. One of the most important parts of the TUNING in the app.
