I have DEV DB and QA DB , both located in USA. There is a table called Customer which contains the respective index , pk, constraints, etc which is available in
both the environments. Now In DEV DB we have Customer table with 1000 records, but in QA DB we have about 50000 records.
Now in DEV DB when i take a explain plan the columns are not going for a FULL table scan but in QA DB it is going for a full table scan? Why there is a discrepancies? Is it because of the number of records in QA is more than DEV? I hope that wont be a problem as Oracle CBO/RBO will optimize the query by itself for both the cases using the index, etc. If that is the case I am wondering what might me the problem. Whether we need to inform the Oracle using the hints? Please shed some light into this.