cbo/rbo: full blob-table scan..

hi,

we've got a table like

create table templates(
  name varchar(50),
  releasedate date,
  data long raw,
  primary key(name,releasedate));

and are interested in obtaining

select name,max(realeasedate)
  from templates
  group by name;

usually this select will retrieve about 1/3 of the records in templates and could be satisfied by use of the pk.

cbo and rbo decide to make a full table scan which under normal circumstances might be quite a good idea, but as templates.data holds blobs of about 4k-40k we encounter severe thrashing due to the table scans..

what can we do? we use ora 7.3.4

is createing a templateswithoutdata-table, maintained by triggers, the only way to go?

ciao, jan

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