SORT_AREA_SIZE Question

Question

Can someone please answer the below questions I have.
- The tables t1 and t2 both have around 1.5 million rows.
- Table t1 has PK defined on col1 and col2
- Table t2 has unique index defined on col1 and col2
1) Does the below query use the SORT_AREA_SIZE while running the query?
2) The below query when explain planned uses NESTED LOOP and FULL TABLE SCAN on table2. I am currently running the below in a cursor for loop to update a blob column on table1. It is taking long time? What are the alternative ways I can tune this query or tune PLSQL to update blob columns in table t1.
SELECT rownum as rec, t1.col1, t1.col2, t2.col1, t2.col2,
replace(replace(t2.col1, 'str1','strn'), 'str2','strn')
FROM table1 t1, table2 t2
where t1.col1 = t2.col1 and t1.col2 = t2.col2

Answer 1

What version of Oracle are you on?
How many rows does the query return?
Nested loops generally perform poorly when the amount of rows returned is very large.
How long does the query take when you run it in sqlplus?
Are statistics on the table current?
SORT_AREA_SIZE and HASH_AREA_SIZE control the maximum amount of memory those operations could use in Oracle 8i and earlier. Since your query is using NESTED LOOPS then I would guess that increasing your SORT_AREA_SIZE parameter will not speed up the query.