Re: Ingres to Oracle Conversion

In <32482944.3FC_at_rrds.co.uk>, Ron Ekins <R.Ekins_at_rrds.co.uk> writes:
>Has anyone any experience in moving a large Ingres database to Oracle ?
>The Ingres database is mainly compressed BTREE tables, will this therefor
>give us a problem with disk space & performance.
>
>Regards
>
>Ron Ekins

Ingres only compresses integer, float, date & money fields if they contain a null value. Varchars (& chars, I think) are only "compressed" in that the full length of the field is not stored.
i.e. a varchar(200) not null field with a row containing "XYZ" will be stored in 3 bytes (+1? for the length) if the table is compressed, rather than 200 (+1) if not compressed.

As far as I'm aware, Oracle's varchar2 behaves like Ingres varchar on a compressed table, so space should not be a problem.

As far as performance goes... lets just say that for, our application, Oracle was faster than Ingres. For your application, this may not be the case (benchmark, if you get the chance).

Cheers,
Liam

-- 

    Liam McCauley                Email: Liam_McCauley_at_QSP.co.uk
    Database Administrator       Tel  : (0191)402 3283
    Quality Software Products
    Gateshead
    UK                             Views expressed are my own