The short answer satisfies my doubt. this type of change, for SapDB, what is importance to export and reimport the data?
TIA Cl�vis Wichoski Supridatta >>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< On 22/03/02, 03:51:43, "Zabach, Elke" <[EMAIL PROTECTED]> wrote regarding RE: what is effect of changing size of PRIMARY KEY: > Cl�vis Wichoski wrote: > > All tables in my system have one PRIMARY KEY field of type > > VARCHAR(8), if > > change all fields to VARCHAR(16), how the performance of > > database will be affected? > What answer do you expect? > Your rows will be a little bit longer (8 bytes). If your rows have > been 24 bytes before, your table will increase its size by 1/3. > if your rows have been 6000 bytes before, forget the difference. > If a row needs more space, you will need more pages to store > the table. If your table will fit in the datacache and will remain there > --> no additional I/O when it has been read once. In any other case > a little bit more I/O will be done or 1/3 more I/O (see above). > Your indexes will need more space. Depending on the size of > your secondary key,... same as above. > Short answer: it depends. > Searching the table will not be faster than before. But usually you > will not be able to measure the time difference. > Elke > SAP Labs Berlin > _______________________________________________ > sapdb.general mailing list > [EMAIL PROTECTED] > http://listserv.sap.com/mailman/listinfo/sapdb.general _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
