Re: Tablescan or TableSPACEscan

Hi,

"Michiel Brunt" <mbrunt_at_inergy.nl> wrote in message news:9nhoam$qdu$1_at_scavenger.euro.net...

> I have a tablespace that contains two tables: a very large one and a small
> one.
>
> If a query on the small table results in a full tablescan, does this mean
> that only the table data is scanned, or does the database have to scan
> through all bits that are stored in de tablespace that holds the table?
> How should the database know where the records of the small table are
> physically stored?
>
> Thanks
> Michiel Brunt

as I suppose (someone should correct me if I'm wrong), Oracle do really a TABLE -SCAN, not a TABLEspace-SCAN (opposite to DB2, at least in Version 4 on MVS).
Oracle internally stores data about tables where to find them. In dba_extents / dba_segments you see FILE_ID / BLOCK_ID or HEADER_FILE / HEADER_BLOCK.
With this informations, oracle knows where to look.

Hope that I say some right :-)

Thomas

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