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ADDM suggested
SQL statements consuming significant database time were found.
RECOMMENDATION 1: SQL Tuning, 17% benefit (698 seconds)
ACTION: Run SQL Tuning Advisor on the SQL statement with SQL_ID
"2zcnyf9ypc2g7".
RELEVANT OBJECT: SQL statement with SQL_ID 2zcnyf9ypc2g7 and
PLAN_HASH 1170350465
SELECT user_id, relation,status, to_char(ctime, :"SYS_B_0") as
creation_at, to_char(utime, :"SYS_B_1") as last_modified_date
FROM page_user WHERE page_id = :"SYS_B_2" AND upper(relation) =
sys_context(:"SYS_B_3", :"SYS_B_4") AND upper(relation) =
sys_context(:"SYS_B_5", :"SYS_B_6") AND upper(status) =
sys_context(:"SYS_B_7", :"SYS_B_8") order by utime DESC
Recommendations for SQL ID:2zcnyf9ypc2g7
Only one recommendation should be implemented.
SQL Text
SELECT user_id, relation,status, to_char(ctime, :"SYS_B_0") as creation_at, to_char(utime, :"SYS_B_1") as last_modified_date FROM page_user WHERE page_id = :"SYS_B_2" AND upper(relation) = sys_contex...
Select Recommendation
Select     Type     Findings     Recommendations     Rationale     Benefit (%)     New Explain Plan     Compare Explain Plans
     Restructure SQL     The predicate UPPER("PAGE_USER"."RELATION")=SYS_CONTEXT(:B1,:B2) used at line ID 3 of the execution plan contains an expression on indexed column "RELATION". This expression prevents the optimizer from efficiently using indices on table "PAGES"."PAGE_USER".     Rewrite the predicate into an equivalent form to take advantage of indices. Alternatively, create a function-based index on the expression.     The optimizer is unable to use an index if the predicate is an inequality condition or if there is an expression or an implicit data type conversion on the indexed column.     
Text
     SELECT user_id, relation,status, to_char(ctime, :"SYS_B_0") as creation_at, to_char(utime, :"SYS_B_1") as last_modified_date
FROM page_user WHERE page_id = :"SYS_B_2" AND upper(relation) = sys_context(:"SYS_B_3", :"SYS_B_4") AND upper(relation) = sys_context(:"SYS_B_5", :"SYS_B_6") AND upper(status) = sys_context(:"SYS_B_7", :"SYS_B_8") order by utime DESC
Details
Select the plan hash value to see the details below.          Plan Hash Value     
     Statistics     Activity     
     Plan     
     Tuning Information     
     Data Source          Snapshot (4413)
     Capture Time          12-Mar-2010 16:30:33
     Parsing Schema          PAGES
     Optimizer Mode          ALL_ROWS
Expand All | Collapse All
Operation     Object     Object Type     Order     Rows     Size (KB)     Cost     Time (sec)     CPU Cost     I/O Cost
[Select to collapse] SELECT STATEMENT
     5     0     0.000     5     0     0     0
[Select to collapse] FILTER
     4     0     0.000     0     0     0     0
[Select to collapse] SORT ORDER BY
     3     1     0.039     5     1     19,417,919     4
[Select to collapse] TABLE ACCESS BY INDEX ROWID
     PAGE_USER     TABLE     2     1     0.039     4     1     37,794     4
INDEX RANGE SCAN
     USER_PAGE_UK1     INDEX (UNIQUE)     1     1     0.000     3     1     30,364     3

Answer 1

user8764012 wrote:
Sir,
Asking how to implement the advise provided by ADDM or also if you have a better suggestion to decrease the cost of the query
SELECT user_id, relation,status, to_char(ctime, :"SYS_B_0") as
creation_at, to_char(utime, :"SYS_B_1") as last_modified_date
FROM page_user WHERE page_id = :"SYS_B_2" AND upper(relation) =
sys_context(:"SYS_B_3", :"SYS_B_4") AND upper(relation) =
sys_context(:"SYS_B_5", :"SYS_B_6") AND upper(status) =
sys_context(:"SYS_B_7", :"SYS_B_8") order by utime DESC
Restructure SQLThe predicate UPPER("PAGE_USER"."RELATION")=SYS_CONTEXT(:B1,:B2) used at line ID 3 of the execution plan contains an expression on
indexed column "RELATION". This expression prevents the optimizer from efficiently using indices on table "PAGES"."PAGE_USER".     Rewrite the
predicate into an equivalent form to take advantage of indices. Alternatively, create a function-based index on the expression.     The optimizer is unable to use an
index if the predicate is an inequality condition or if there is an expression or an implicit data type conversion on the indexed column.The message is tellong you that although you have an index on RELATION the idex can't be used because you are changing the value with a function. You can do a couple of things:
1. remove the UPPER() function from the RELATION clause elements (predicates) finding another way to force the columns to match
2. use a function based index, based on upper(relation) something like (untested)
create index fb_index on page_user (upper(relation));This may or may not help in the long run as function-based indexes only work when certain intialization parmeters are set (QUERY_REWRITE_ENABLED). You can read about function-based indexes in the documentation.