SQL & PL/SQL :: Select Statement Is Blocking A Delete Statement
Jan 11, 2012
I am using JDBC to run a few queries from my Java program (multi-threaded one).I am facing an issue where a select statement is blocking a delete statement. From the java code point of view, there are 2 different threads accessing the same tables (whith different DB connection objects).
When the block occurs (which i was able to find out from the java thread dump that there is a lock on oracle), the below is the output:
SQL> SELECT TO_CHAR(sysdate, 'DD-MON-YYYY HH24:MI:SS')
2 || ' User '||s1.username || '@' || s1.machine
3 || ' ( SID= ' || s1.sid || ' ) with the statement: ' || sqlt2.sql_text
||' is blocking the SQL statement on '|| s2.username || '@'
4 5 || s2.machine || ' ( SID=' || s2.sid || ' ) blocked SQL -> '
6 ||sqlt1.sql_text AS blocking_status FROM v$lock l1, v$session s1, v$lock l2 ,
7 v$session s2,v$sql sqlt1, v$sql sqlt2
8 WHERE s1.sid =l1.sid
9 AND s2.sid =l2.sid AND sqlt1.sql_id= s2.sql_id
AND sqlt2.sql_id= s1.prev_sql_id AND l1.BLOCK =1
10 AND l2.request > 0 AND l1.id1 = l2.id1 AND l2.id2 = l2.id2;
[code]...
From the above it can be seen that a select statement is blocking a delete. Unless the select is select for Update, it should not block other statements is not it ?
In the following merge statement in the USINg clause...I am using a select stament of one schema WEDB.But that same select statement should take data from 30 schemeas and then check the condition below condition
ON(source.DNO = target.DNO AND source.BNO=target.BNO);
I thought that using UNIONALL for select statement of the schemas as below.
I am trying to run following sql query,but it is throwing following error.
SQL> delete from b$gc_count_temp a INNER JOIN COMPLEMENTS ON b$gc_count_temp.CON NECTION_ID_TEMP=COMPLEMENTS.feature_conn_id 2 WHERE a.current_designation is null and a.current_low is null and a.current _high is null;
delete from b$gc_count_temp a INNER JOIN COMPLEMENTS ON b$gc_count_temp.CONNECTI ON_ID_TEMP=COMPLEMENTS.feature_conn_id * ERROR at line 1: ORA-00933: SQL command not properly ended
I am getting ORA-00933 after running below mentioned delete statement;
DELETE FROM REPOSITORY.MEDIASEGMENT MS INNER JOIN REPOSITORY.ROUTINGEVENT RE ON TRIM(MS.Segment_Key) = TRIM(RE.uuid) INNER JOIN REPOSITORY.TEMPCONTACT TC ON TRIM(RE.Contact_Key) = TRIM(TC.vduid) WHERE TC.CREATETIME BETWEEN (TO_DATE('04/24/2008 00:00:00','MM/DD/YYYY, HH24:MI:SS')) AND (TO_DATE('04/30/2008 23:59:00','MM/DD/YYYY, HH24:MI:SS'))
I have a session on a system here that has been stuck on a DELETE statement for a very long time and the session is pegging the CPU. Using TOAD here is the "current statement":
DELETE FROM WORKFLOW WHERE ID = :B1
ID is the primary key of the table.Here are some relevant stats, also from TOAD's session browser:
Elapsed time = 35507986900 CPU time = 35531815481 Buffer gets = 972040769 Disk reads = 951289273 Executions = 71462
I'm not sure I understand "executions" because from the information I have from the people who initiated this, this particular delete should only be occurring 30 times... maybe that stat means something other than what I think it does.I also ran a trace for 30 seconds using:
TKPROF: Release 11.2.0.1.0 - Development on Wed Feb 27 04:04:50 2013 Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved. [root@localhost trace]#
The resulting file is attached. Now the offending query in the tkprof, based on my interpretation, is the select from the CMTE00 table, which contains 2344482 rows and no index on the workflow_id column. The relationship between CMTE00 and WORKFLOW tables are 1 to 1. There is a foreign key on CMTE00 pointing to the primary key of WORKFLOW which is what I assume initiated this query - I assume this is oracle checking the referential integrity since our code is not executing that statement. Also of interest, prior to this delete statement, the corresponding entry in CMTE00 was deleted in the same transaction. Google searching "db scattered file read" lead me to one of your (Don - if you read this) articles and appears to indicate that individual blocks are being fetched off the disk and this is what is taking up all the time.
DELETE FROM sre_t WHERE TO_CHAR(end_dt,'yyyy')<'2000' or TO_CHAR(start_dt)<'yyyy')<'2000';
It's executing for 15 to 20 minutes after that i got the error "session timed out"..The table is having four crore records.The delete statement is deleting 12,00000 records.
In my code I am using delete statement which is taking too much time to execute.
Statement is as follow:
DELETE FROM TRADE_ORDER_EMP_ALLOCATION T WHERE (ARTEMIS_SOURCE_SYSTEM_ID,NM_ARTEMIS_SOURCE_SYSTEM,CD_BOOK_KEY,ACTIVITY_DT) IN (SELECT ARTEMIS_SOURCE_SYSTEM_ID,NM_ARTEMIS_SOURCE_SYSTEM,CD_BOOK_KEY,ACTIVITY_DT FROM LOAD_TRADE_ORDER WHERE IND_IS_BAD_RECORD='N');
Every column in "IN" clause and select clause is containing index on it
Every time no of rows which to be deleted is vary (May be in hundred ,thousand or hundred thousand )so that I am Unable to use "BITMAP" index on the table "LOAD_TRADE_ORDER" column "IND_IS_BAD_RECORD" though it is containing distinct record in it.
Even table "TRADE_ORDER_EMP_ALLOCATION" is containing "RANGE" PARTITION over it on the column "ARTEMIS_SOURCE_SYSTEM_ID". With this I am enclosing table scripts with Indexes and Partitions over it.
way for fast execution in of above delete statement?
HOW to use variable P_TMPLID in following statement
TYPE typ_unrecon IS TABLE OF REC_' || P_TMPLID ||'_UNRECON%ROWTYPE index by binary_integer;
because its throwing error while compiling
and also in statement FORALL i IN unrecondata.FIRST .. unrecondata.LAST SAVE EXCEPTIONS --STRSQL := ''; --STRSQL := ' INSERT INTO REC_' || P_TMPLID ||'_UNRECON VALUES ' || unrecondata(i); -- EXECUTE IMMEDIATE STRSQL; INSERT INTO REC_' || P_TMPLID ||'_UNRECON VALUES unrecondata(i);---throwing error on this statement commit; --dbms_output.put_line(unrecondata(2).TRANSID); EXCEPTION
I have a question about select statements, as I am new to them and don't know how to work all the commands yet.
I'm making a select statement that is about half right... it is shown below:
select t.warehouse_id, t.quantity_on_hand, c.product_name from pahtest3.inventories t join pahtest3.product_information c using (product_id) WHERE warehouse_id in (7);
I need to take this select statement and make it so it shows all the products that don't have any quantities in the warehouse in addition to the ones that are already being shown in that select statement.
how to set the timing on for all SELECT statements in a procudeure...and i want that should come as a output for very SELECT statement slong with my original output.
I have a need to use the Alias name of a column within the same select statement( because I can't have another select statement using the first select as table - BO tool limitation).
Ex:
Select dept_id, agency, sum(quantity) as "sum_qty" where sum_qty > 500;
Currently oracle won't allow using alias name Sum_qty in the same select statement. Is there a way to use alias within the same select statement?
I'm trying to write a simple query so I can do some testing on my application. I am trying to do something like this:
SELECT Location, LEVEL,
FROM S_ORG_EXT
where Location = 'North America' and LEVEL ='Software' OR location = 'North America' and Active = 'N'
in the where statement, I have put in the 'Active' that isn't a column. I want to be able to be able to change that in the select part. But I am not able to do so.
this is what I have tried: SELECT Location, LEVEL, Active = 'N' --I want to change this in the to N or Y so I can get different results.
FROM S_ORG_EXT
where Location = 'North America' and LEVEL ='Software' OR location = 'North America' and Active = 'N'
insert into lookups values ('Rent' , 500); insert into lookups values ('Breakpoint' , 10);
create table products (id number, cost number, year varchar2(4));
insert into products values (1, 1000, '2011'); insert into products values (1, 2000, '2011'); insert into products values (2, 100, '2011'); insert into products values (3, 50, '2011');
commit;
I want to write a query which lists the IDs and the sum(cost), and a Y/N indicator which is set to 'Y' IF sum(cost) > ( (lookups.rent value) * (100 - lookups.breakpoint value))/100
I have written this query:
SELECT id, sum(cost)cost, year, CASE WHEN cost > ((SELECT amount [code]....... ORDER BY id;
This returns
ID COST YEAR YN --------- ---------- ---- - 1 1000 2011 Y 1 2000 2011 Y 2 100 2011 N 3 50 2011 N
The YN is correct, but it needs to sum the amounts. So there should only be one row for id1 = 3000.e.g.
ID COST YEAR YN --------- ---------- ---- - 1 3000 2011 Y 2 100 2011 N 3 50 2011 N
I am not sure how to do this. Or is there a better way of doing this than using CASE.
Quote: select a.contact, b.db_name from MOM.db_contacts@DB_LINK a, MOM.databases@DB_LINK b, where a.DB_ID=b.DB_ID and b.DB_name=(SELECT unique substr(upper(t.target_name), 1, instr(t.target_name,'_',1,1)-1) FROM mgmt_targets t JOIN mgmt_current_severity s ON s.target_guid = t.target_guid WHERE t.target_type = 'oracle_database' and UPPER(t.target_name) like '%11GDB%');
How can I add two more columns into the select statement and the two columns are in the tables that were in the sub query..I would like to have something like this:
Quote: select a.contact, b.db_name, COLUM1, COLUMN2 from MOM.db_contacts@DB_LINK a, MOM.databases@DB_LINK b, mgmt_targets t, mgmt_current_severity s where a.DB_ID=b.DB_ID and b.DB_name=(SELECT unique substr(upper(t.target_name), 1, instr(t.target_name,'_',1,1)-1) FROM mgmt_targets t JOIN mgmt_current_severity s ON s.target_guid = t.target_guid WHERE t.target_type = 'oracle_database' and UPPER(t.target_name) like '%11GDB%');
I have a cursor in a procedure that selects columns from a table on a remote Oracle database using a database link. It all works fine when the table name and database link name is 'hard coded' into the procedure but what I would like to achieve is have the select statement lookup the table name and database link name from a column in another table. See example below
CURSOR c_total_bookings IS SELECT personnel_id, surname, forenames, birth_date,
[code]...
What I would like to do is replacecompany_bookings@remote.linkwith a variable that takes its value from another table.
I was given a SQL query to develop another query that will need to do something similar. The query I was given I believe is a stored procedure. It is PL/SQL and has a SELECT statement that looks like
SELECT :var1 AS var1 FROM t1 WHERE :var1 = 1
In the past I have seen where variables can be used in the WHERE clause like
SELECT c1 FROM t1 WHERE c1 = :my_column_valueand this makes sense to me.
Usually :my_column_value is declared in the DECLARE block of the PL/SQL. In the query I was given, :my_column_value is not declared in any DECLARE blocks (maybe I wasn't given the entire code??). But even if it was, that would be even more confusing because in the DECLARE block it could be assigned one value and then set to another value in the WHERE clause???
The first query doesn't make sense to me and when I run it as plain SQL I get an error like "SP2-0552: Bind variable "var1" not declared. I am guessing that such a syntax is not valid for regular SQL?
The only thing I can gather that the first query does is something along the lines of
SELECT 1 as var1
so it will output a 1 for every row. Not always that interesting of a query, but it is needed sometimes, I know. But I still don't understand this type of assignment.
So what's going on here? I'd be happy to look it up and read about it myself, but I don't know what to search for.
i want a select statement to retrieve the last name added into the "ename" column .i mean :if i insert "jack" into "ename" column , i want to write a select statement to retrieve that last name while i do not know it is jack or any other name ?
