FORALL indx IN 1 .. l_tab.COUNT
update repair_part_bp_r5 bp
set is_deleted='Y'
where 1=1
and bp.repair_part_id = l_tab(indx)
and bp.batch_id=p_batch_id;
It is waiting on latch: redo writing as the volume of update is 120011.
Would it help breaking it down into smaller chunk during the update ?
If so pls help with code sample?
any other idea ?
If you have declared the data type of l_tab in SQL using CREATE TYPE then you do not need a loop and can use the MEMBER OF operator:
update repair_part_bp_r5 bp
set is_deleted='Y'
where bp.repair_part_id MEMBER OF l_tab
and bp.batch_id=p_batch_id;
There is such redo work optimization like "array update" (read more details in "Oracle Core" by Jonathan Lewis). Most probably that it doesn't work for such FORALL updates. So I'd suggest to use MERGE with using (select column_value as repair_part_id from TABLE(ltab) s ON (bp.batch_id=p_batch_id and bp.repair_part_id =s.repair_part_id) or simply
update repair_part_bp_r5 bp
set is_deleted='Y'
where bp.repair_part_id in (select * from table(l_tab))
and bp.batch_id=p_batch_id;
nb: ltab must be a collection type defined on schema or package level.
Related
I'm trying to update a table based on another one's information:
Source_Table (Table 1) columns:
TABLE_ROW_ID (Based on trigger-sequence when insert)
REP_ID
SOFT_ASSIGNMENT
Description (Table 2) columns:
REP_ID
NEW_SOFT_ASSIGNMENT
This is my loop statement:
SELECT count(table_row_id) INTO V_ROWS_APPROVED FROM Source_Table;
FOR i IN 1..V_ROWS_APPROVED LOOP
SELECT REQUESTED_SOFT_MAPPING INTO V_SOFT FROM Source_Table WHERE ROW_ID = i;
SELECT REP_ID INTO V_REP_ID FROM Source_Table WHERE ROW_ID = i;
UPDATE Description_Table D
SET D.NEW_SOFT_ASSIGNMENT = V_SOFT
WHERE D.REP_ID = V_REP_ID;
END LOOP;
END;
The ending result of this loop is a beautiful ''504 Gateway Time-out''.
I know the issue is on the Update query but there's no other way (I can think about) of doing it.
Can someone give me a hand please?
Thanks
Unless your row_id values are contiguous - i.e. count(row_id) == max(row_id) - then this will get a no-data-found. Sequences aren't gapless, so this seems fairly likely. We have no way of telling if that is happening and somehow that is leaving your connection hanging until it times out, or if it's just taking a long time because you're doing a lot of individual queries and updates over a large data set. (And you may be squashing any errors that do occur, though you haven't shown that.)
You don't need to query and update in a loop though, or even use PL/SQL; you can apply all the values in the source table to the description table with a single update or merge:
merge into description_table d
using source_table s
on (s.rep_id = d.rep_id)
when matched then
update set d.new_soft_assignment = s.requested_soft_mapping;
db<>fiddle with some dummy data, including a non-contiguous row_id to show that erroring.
Is there a hint to generate execution plan ignoring the existing one from the shared pool?
There is not a hint to create an execution plan that ignores plans in the shared pool. A more common way of phrasing this question is: how do I get Oracle to always perform a hard parse?
There are a few weird situations where this behavior is required. It would be helpful to fully explain your reason for needing this, as the solution varies depending why you need it.
Strange performance problem. Oracle performs some dynamic re-optimization of SQL statements after the first run, like adaptive cursor sharing and cardinality feedback. In the rare case when those features backfire you might want to disable them.
Dynamic query. You have a dynamic query that used Oracle data cartridge to fetch data in the parse step, but Oracle won't execute the parse step because the query looks static to Oracle.
Misunderstanding. Something has gone wrong and this is an XY problem.
Solutions
The simplest way to solve this problem are by using Thorsten Kettner's solution of changing the query each time.
If that's not an option, the second simplest solution is to flush the query from the shared pool, like this:
--This only works one node at a time.
begin
for statements in
(
select distinct address, hash_value
from gv$sql
where sql_id = '33t9pk44udr4x'
order by 1,2
) loop
sys.dbms_shared_pool.purge(statements.address||','||statements.hash_value, 'C');
end loop;
end;
/
If you have no control over the SQL, and need to fix the problem using a side-effect style solution, Jonathan Lewis and Randolf Geist have a solution using Virtual Private Database, that adds a unique predicate to each SQL statement on a specific table. You asked for something weird, here's a weird solution. Buckle up.
-- Create a random predicate for each query on a specific table.
create table hard_parse_test_rand as
select * from all_objects
where rownum <= 1000;
begin
dbms_stats.gather_table_stats(null, 'hard_parse_test_rand');
end;
/
create or replace package pkg_rls_force_hard_parse_rand is
function force_hard_parse (in_schema varchar2, in_object varchar2) return varchar2;
end pkg_rls_force_hard_parse_rand;
/
create or replace package body pkg_rls_force_hard_parse_rand is
function force_hard_parse (in_schema varchar2, in_object varchar2) return varchar2
is
s_predicate varchar2(100);
n_random pls_integer;
begin
n_random := round(dbms_random.value(1, 1000000));
-- s_predicate := '1 = 1';
s_predicate := to_char(n_random, 'TM') || ' = ' || to_char(n_random, 'TM');
-- s_predicate := 'object_type = ''TABLE''';
return s_predicate;
end force_hard_parse;
end pkg_rls_force_hard_parse_rand;
/
begin
DBMS_RLS.ADD_POLICY (USER, 'hard_parse_test_rand', 'hard_parse_policy', USER, 'pkg_rls_force_hard_parse_rand.force_hard_parse', 'select');
end;
/
alter system flush shared_pool;
You can see the hard-parsing in action by running the same query multiple times:
select * from hard_parse_test_rand;
select * from hard_parse_test_rand;
select * from hard_parse_test_rand;
select * from hard_parse_test_rand;
Now there are three entries in GV$SQL for each execution. There's some odd behavior in Virtual Private Database that parses the query multiple times, even though the final text looks the same.
select *
from gv$sql
where sql_text like '%hard_parse_test_rand%'
and sql_text not like '%quine%'
order by 1;
I think there is no hint indicating that Oracle shall find a new execution plan everytime it runs the query.
This is something we'd want for select * from mytable where is_active = :active, with is_active being 1 for very few rows and 0 for maybe billions of other rows. We'd want an index access for :active = 1 and a full table scan for :active = 0 then. Two different plans.
As far as I know, Oracle uses bind variable peeking in later versions, so with a look at the statistics it really comes up with different execution plans for different bind varibale content. But in older versions it did not, and thus we'd want some hint saying "make a new plan" there.
Oracle only re-used an execution plan for exactly the same query. It sufficed to add a mere blank to get a new plan. Hence a solution might be to generate the query everytime you want to run it with a random number included in a comment:
select /* 1234567 */ * from mytable where is_active = :active;
Or just don't use bind variables, if this is the problem you want to address:
select * from mytable where is_active = 0;
select * from mytable where is_active = 1;
This question already has an answer here:
Oracle: Dynamic query with IN clause using cursor
(1 answer)
Closed 8 years ago.
SELECT * FROM EMPLOYEE
WHERE EMP_NAME IN (:EMP_NAME);
This is my query and now the EMP_NAME parameter I would like to send it as a list of strings.
When I run this query in SQL developer it is asked to send the EMP_NAME as a parameter, Now I want to send 'Kiran','Joshi' (Basically, I want to fetch the details of the employee with employee name either Kiran or Joshi. How should I pass the value during the execution of the query?
It works when I use the value Kiran alone, but when I concatenate with any other string it won't work. Any pointers in this?
I tried the one below
'Kiran','Joshi'
The above way doesn't work as understood this is a single parameter it tries the employee with the name as 'Kiran',Joshi' which won't come. Understandable, but in order to achieve this thing, how can I go ahead?
Any help would be really appreciated.
Thanks to the people who helped me in solving this problem.
I could get the solution using the way proposed, below is the approach
SELECT * FROM EMPLOYEE WHERE EMP_NAME IN (&EMP_NAME)
I have tried in this way and following are the scenarios which I have tested and they are working fine.
Scenario 1:
To fetch details of only "Kiran", then in this case the value of EMP_NAME when sql developer prompts is given as Kiran. It worked.
Scenario 2:
To fetch details of either "Kiran" or "Joshi", then the value of EMP_NAME is sent as
Kiran','Joshi
It worked in this case also.
Thanks Kedarnath for helping me in achieving the solution :)
IN clause would be implicitly converted into multiple OR conditions.. and the limit is 1000.. Also query with bind variable means, the execution plan will be reused.. Supporting bind variables for IN clause will hence affect the bind variable's basic usage, and hence oracle limits it at syntax level itself.
Only way is like name in (:1,:2) and bind the other values..
for this, you might dynamic SQL constructing the in clause bind variables in a loop.
Other way is, calling a procedure or function(pl/sql)
DECLARE
v_mystring VARCHAR(50);
v_my_ref_cursor sys_refcursor;
in_string varchar2='''Kiran'',''Joshi''';
id2 varchar2(10):='123'; --- if some other value you have to compare
myrecord tablename%rowtype;
BEGIN
v_mystring := 'SELECT a.*... from tablename a where name= :id2 and
id in('||in_string||')';
OPEN v_my_ref_cursor FOR v_mystring USING id2;
LOOP
FETCH v_my_ref_cursor INTO myrecord;
EXIT WHEN v_my_ref_cursor%NOTFOUND;
..
-- your processing
END LOOP;
CLOSE v_my_ref_cursor;
END;
IN clause supports maximum of 1000 items. You can always use a table to join instead. That table might be a Global Temporary Table(GTT) whose data is visible to thats particular session.
Still you can use a nested table also for it(like PL/SQL table)
TABLE() will convert a PL/Sql table as a SQL understandable table object(an object actually)
A simple example of it below.
CREATE TYPE pr AS OBJECT
(pr NUMBER);
/
CREATE TYPE prList AS TABLE OF pr;
/
declare
myPrList prList := prList ();
cursor lc is
select *
from (select a.*
from yourtable a
TABLE(CAST(myPrList as prList)) my_list
where
a.pr = my_list.pr
order by a.pr desc) ;
rec lc%ROWTYPE;
BEGIN
/*Populate the Nested Table, with whatever collection you have */
myPrList := prList ( pr(91),
pr(80));
/*
Sample code: for populating from your TABLE OF NUMBER type
FOR I IN 1..your_input_array.COUNT
LOOP
myPrList.EXTEND;
myPrList(I) := pr(your_input_array(I));
END LOOP;
*/
open lc;
loop
FETCH lc into rec;
exit when lc%NOTFOUND; -- Your Exit WHEN condition should be checked afte FETCH iyself!
dbms_output.put_line(rec.pr);
end loop;
close lc;
END;
/
I would like to have your advise how to implement the plsql. Below is the situation that i want to do..
select * from table A
loop - get each records from #1 step, and execute the store procedure, processMe(a.field1,a.field2,a.field3 || "test",a.field4);
i dont have any idea how to implement something like this. Below is sample parameter for processMe
processMe(
number_name IN VARCHAR,
location IN VARCHAR,
name_test IN VARCHAR,
gender IN VARCHAR )
Begin
select objId into obj_Id from tableUser where name = number_name ;
select locId into loc_Id from tableLoc where loc = location;
insert into tableOther(obj_id,loc_id,name_test,gender)
values (obj_Id ,loc_Id, name_test, gender)
End;
FOR rec IN (SELECT *
FROM table a)
LOOP
processMe( rec.field1,
rec.field2,
rec.field3 || 'test',
rec.field4 );
END LOOP;
does what you ask. You probably want to explicitly list the columns you actually want in the SELECT list rather than doing a SELECT * (particularly if there is an index on the four columns you actually want that could be used rather than doing a table scan or if there are columns you don't need that contain a large amount of data). Depending on the data volume, it would probably be more efficient if a version of processMe were defined that could accept collections rather than processing data on a row-by-row bases as well.
i just add some process. but this is just a sample. By the way, why
you said that this is not a good idea using loop? i interested to know
Performance wise, If you can avoid looping through a result set executing some other DMLs inside a loop, do it.
There is PL/SQL engine and there is SQL engine. Every time PL/SQL engine stumbles upon a SQL statement, whether it's a select, insert, or any other DML statement, it has to send it to the SQL engine for the execution. It calls context switching. Placing DML statement inside a loop will cause the switch(for each DML statement if there are more than one of them) as many times as many times the body of a loop has to be executed. It can be a cause of a serious performance degradation. if you have to loop, say, through a collection, use foreach loop, it minimizes context switching by executing DML statements in batches.
Luckily, your code can be rewritten as a single SQL statement, avoiding for loop entirely:
insert into tableOther(obj_id,loc_id,name_test,gender)
select tu.objId
, tl.locid
, concat(a.field3, 'test')
, a.field4
from table a
join tableUser tu
on (a.field1 = tu.name)
join tableLoc tl
on (tu.field2 = tl.loc)
You can put that insert statement into a procedure, if you want. PL/SQL will have to sent this SQL statement to the SQL engine anyway, but it will only be one call.
You can use a variable declared using a cursor rowtype. Something like this:
declare
cursor my_cursor is
select * from table;
reg my_cursor%rowtype;
begin
for reg in my_cursor loop
--
processMe(reg.field1, reg.field2, reg.field3 || "test", reg.field4);
--
end loop;
end;
There are plenty of stored procedure on 10g platform . ( Almost 500 SPs)
Each SP might have loop, fetch and etc.
I'd like to ask you if there is a cool method to control all the SPs which are currently running on 10g, and guarantee that it works on 11 g.
I have a development server 1 which is 10 g and the other development server is 11 g.
I can use both of them to testify the propose above.
For instance I know that on 10 g if you use loop, and during the loop the update statements do not affect the loop data but 11g.
There might be more cases that I have to consider. Please tell me if you have any brillant idea , otherwise I will check them up one by one manually and it is a lot of time and human control might be weak sometimes.
important note: It is said that if you select some data from a table or tables, and if you use it in a loop, then during de loop, if you update and commit between loop case, it affects the selected data in cursor.(#11g) But this did not happen #10g version. Please correct me if you heard something like that.
The Example Case;
CREATE TABLE vty_musteri(
musterino NUMBER NOT NULL,
subeadi VARCHAR2(61),
kayitzamani VARCHAR2(20)
);
INSERT INTO vty_musteri (musterino, subeadi, kayitzamani )
VALUES (12345, 'AMSTERDAM', '05/30/2012 15:11:13');
COMMIT;
CREATE UNIQUE INDEX vty_musteri_idx ON vty_musteri (musterino);
SELECT * FROM vty_musteri;
CREATE OR REPLACE PROCEDURE krd_upd_silseomusteri_sp(RC1 in out SYS_REFCURSOR) AS
v_musterino NUMBER := 12345;
BEGIN
OPEN RC1 FOR
SELECT m.musterino, m.subeadi, m.kayitzamani
FROM vty_musteri m
WHERE m.musterino = v_musterino;
update vty_musteri
set subeadi = 'PORTO',
kayitzamani = (SELECT TO_CHAR(SYSDATE, 'MM/DD/YYYY HH24:MI:SS')
FROM dual)
where musterino = v_musterino;
COMMIT;
After all run this test on PLSQL:
DECLARE
--test
vRecTip SYS_REFCURSOR;
TYPE vRecTipK IS RECORD(
musterino NUMBER,
subeadi VARCHAR2(61),
kayitzamani VARCHAR2(20)
);
v_SeoTip vRecTipK;
BEGIN
krd_upd_silseomusteri_sp(rc1 => vRecTip);
IF vRecTip%ISOPEN THEN
LOOP
FETCH vRecTip
INTO v_SeoTip;
EXIT WHEN vRecTip%NOTFOUND;
dbms_output.put_line('The Value : ' || v_SeoTip.musterino || ' - ' || v_SeoTip.subeadi || ' - ' || v_SeoTip.kayitzamani);
END LOOP;
END IF;
COMMIT;
END;
END;
If you run this on 10g you will see AMSTERDAM, but on 11G, it is PORTO.
To fix it; I put a hint in the sp like the following:
SELECT /*+ full(m)*/ m.musterino, m.subeadi, m.kayitzamani
Isn't it weird? any alternative sugesstion to get AMSTERDAM ?
One thing we stumbled upon during a migration were queries that weren't supposed to work on 10.x (but did anyway) did no longer work on 11.x
This happens if you have ambigous column references in your query.
Something like this:
SELECT name,
f.some_col,
b.other_col
FROM foo f,
JOIN bar b ON f.id = b.fid
If the column name exists in both tables, 10.x would run the statement - which was a bug.
This bug (BugID: 6760937) was fixed and makes the statement (rightfully) fail in 11.x
Basic PLSQL structures should work exactly the same. Some pitfalls are listed here:
http://www.help2ora.com/index.php/2011/08/04/be-careful-when-migrating-difference-between-oracle-10g-and-11g/
To fix it; I put a hint in the sp like the following:
SELECT /+ full(m)/ m.musterino, m.subeadi, m.kayitzamani
Recently I have done migration to Oracle 11g. Faced few unprecedented issues. I have written a blog post on this. Have a look http://learncodewrite.blogspot.in/2017/04/migrating-to-oracle-11g-from-oracle-10g.html?m=1.