Oracle Query Rewrite Alias Problem

Question

Hi,
The problem desribed below is regarding the use of oracle aggregate awareness through the use of query rewrite.
2 materialized views exist (one agg per day, one agg per month) and 1 dimension exists for time (date - month - quarter - year)
Query rewrite seems to be working fine for a query as such (alias sql = alias mv):
select DDFPC.MONTH_NO
from BIDATA_MAIN.DF_REPOSITORY_SUBSET DF2, BIDATA_MAIN.DD_TIME DDFPC
where DF2.FINANCIAL_PROCCESSING_DATE_ID = DDFPC.DATE_ID and DF2.ROUTING_CODE_ISS IN ('FPC','NCC')
group by DDFPC.MONTH_NO
However, considering our reporting tool generates aliases on the fly, we could get the following query (alias sql <> alias mv):
select T2.MONTH_NO
from BIDATA_MAIN.DF_REPOSITORY_SUBSET DF2, BIDATA_MAIN.DD_TIME T2
where DF2.FINANCIAL_PROCCESSING_DATE_ID = T2.DATE_ID and DF2.ROUTING_CODE_ISS IN ('FPC','NCC')
group by T2.MONTH_NO
--> for the second query, query rewrite refuses to correctly use the dimension – it’ll rewrite to the DD (daily) aggregate, but not to the MM (monthly) aggregate
Investigation gives: QSM-01072: materialized view, DA_REPOSITORY_MERCHANT_MM, and query have different joins between tables, DF_REPOSITORY_SUBSET and DD_TIME
So*: How can query rewrite be forced to take place with different aliases between query & materialized view – taken into account a dimension is used for aggregation-awareness?
This seems to indicate it should work...

Answer 1

You are missing a join on the file_id column
i.e.
select sum(f.BLOCKS), sum(d.BLOCKS) from dba_free_space f ,dba_data_files d where f.TABLESPACE_NAME=d.TABLESPACE_NAME and f.TABLESPACE_NAME like SUBSTR('KU_TSD_1',0,10)
and f.file_id = d.file_id
This might have been easier to detect if you had removed the sum aggregation and looked at the data coming back from the raw query.