In article <366811A5.B020A276_at_step.de>,
Jochen Joerg <joj_at_step.de> wrote:
> hello,
>
> I have the following question:
>
> When the Oracle server wants to retrieve the data he first looks up in
> the DB-block buffer of the SGA if the corresponding database blocks are
> loaded.
> If not the Oracle Server Process has to load the corresponding database
> blocks in the DB block buffer.
>
> Here my question occurs:
>
> From where does the oracle server process get the information what
> databse blocks do contain the data which is requested for ?
>
> Where is the information stored about what datafiles contains which
> database blocks?
> I suppose that the information is stored in the data dictionary. But
> also for accessing the data dictionary the server has to get the
> information what database blocks to access and where these database
> blocks are located.
>
> Maybe somebody does know an answer. Thanks in advance.
> Jochen
>
>
During the instance startup process, dictionary is open and enough of it is
loaded into shared pool that any further valid query can be resolved. There
is a structure called boot segment which contains the information how and
where from to load the data dictionary.
--
Mladen Gogala
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Received on Sun Dec 06 1998 - 00:00:00 CST
