SQL & PL/SQL :: ORA-30926 Occurs Only With PARALLEL Hint On MERGE Statement
Jun 26, 2013
I am writing below MERGE statement. In this cardinality between table_a and table_b is 1:2. I.e. each record in table_b corresponds to 2 records in table_a based on columns in ON clause.
Well this query throws below error.
----Error---
ORA-12801: error signaled in parallel query server P011
ORA-30926: unable to get a stable set of rows in the source tables
However, the same statement executes successfully when PARALLEL hint is removed altogether. (There are no duplicates in table_b based on unit,group,loc columns.)
-----Query--------
MERGE /*+ PARALLEL(8) */
INTO table_a a
USING table_b b
ON (a.unit = b.unit AND a.group = b.group AND a.loc = b.loc)
I have been told that i should use multiple's of 4 as degree in the parallel hint to get maximum performance, so i am wondering is it true? that i should always use multiples of 4 or i can use any number inside the parallel hint.
Does parallel hint works in cursor queries? The cursor query is something like :
cursor c is select /*+ parallel(s,8) */ from table ref_tab s ---- >> <where condition>;
The table ref_tab hold data for a single day at any point of time and gets truncate before loading the next days data.On average the table holds around 7 million rows and doesn't contains any index (think that's fine as all together we are loading the whole set).And, we are using bulk logic with save exceptions to open the cursor and load the data into the target table.
select serialnumber from product where productid in (select /*+ full parallel(producttask 16) */productid from producttask where startedtimestamp > to_date('2013-07-04 00:00:00', 'YYYY-MM-DD HH24:MI:SS') and startedtimestamp < to_date('2013-07-05 00:00:00', 'YYYY-MM-DD HH24:MI:SS') and producttasktypeid in
I have been asked to rewrite the following update statement without using the hint BYPASS_UJVC.
l_new_CFT_ID CASHFLOW_TYPE.CFT_ID%TYPE;
if (l_Record > 0) then -- since at least 1 loan was found with the old type, process the actual update update /*+BYPASS_UJVC*/ ( select cfa.CFA_CFT_ID [code]......
I think I am supposed to be using the Merge statement but I am not sure on how to go about 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'm running Oracle EE 11.2.0.2 and when I look in OEM SQL Monitoring, it shows nearly every sql statement running with a degree of parallelism of *2*.
I've checked dba_tables and the 'degree' for all tables is only 1. I look at the actual sql statement, and there are no hints to tell it to use parallelism. So why and how is the database using parallelism?
I do see that parallel_threads_per_cpu is set to 2, but this is default for our Solaris 10 operating system.
REF: (for 11.2) =========== PARALLEL_THREADS_PER_CPU specifies the default degree of parallelism for the instance and determines the parallel adaptive and load balancing algorithms. The parameter describes the number of parallel execution processes or threads that a CPU can handle during parallel execution.
The default is platform-dependent and is adequate in most cases. You should decrease the value of this parameter if the machine appears to be overloaded when a representative parallel query is executed. You should increase the value if the system is I/O bound.
how to tell if my database is actually IO bound or not?
how to use the MERGE Statement. actually I've used oracle Merge Statement before and it works very well. However today I tried to use and perform a command like that:
Merge into myTable mt using ( select 'data' field1, 'data2' field2, ect from dual union select 'data' field1, 'data2' field2, ect from dual union
[code]...
This has not worked.What am I doing wrong?What could I do to solve this problem and axecute this statement sucessfully?
I have two tables have almost the same columns, how can I use merge statement to update the target table only when there is difference between source and target table. Is there any easier way not compare each column one by one? I am using Oracle 11.2
Here is the MERGE statement:
Merge into tb_trgt trgt using tb_src src on (src.id = trgt.id) when not matched then insert (trgt.id, trgt.nm, trgt.addr) values (src.id, src.nm, src.nm) when matched then update set trgt.nm = src.nm, trgt.addr = src.addr where trgt.nm <> src.nm or trgt.addr <> src.addr ;
Is there any easier way to specify the where clause in the NOT MATCHED? I don't want compare each column of the tables. Since I may have many columns in the tables.
CREATE TABLE TEST11(TNO NUMBER(5), TVAL VARCHAR2(100), TID VARCHAR2(10)); INSERT INTO TEST11 VALUES(1,'VIJAYA','TEST'); INSERT INTO TEST11 VALUES(2,'VIJAYA','TEST'); INSERT INTO TEST11 VALUES(3,'VIJAYA','TEST'); INSERT INTO TEST11 VALUES(4,'VIJAYA',''); INSERT INTO TEST11 VALUES(5,'VIJAYA','');
[Code]....
My requiremen is if record is exists then i wan to update some value, if record not existes the i wan to insert new record
mbr has 60,000 rows and member has 60,000 rows approx. two tables have indexes on ssn, and citi_no on them.
PK of mbr : mbr_id PK of member : mbr_id
other columns are not PK, and have no index on it.
I'm wondering why the statment doesn't use index while ssn and citi_no have index.
MERGE INTO mbr t USING (SELECT mbr_id,citi_no FROM member) a ON (t.ssn = a.citi_no) WHEN MATCHED THEN UPDATE SET t.asis_mbr_id = a.mbr_id where t.ssn not in(select ssn from mbr group by ssn having count(*) > 1)
I am getting a (PL/SQL: ORA-00903: invalid table name) compile error in a procedure using a merge statement. I have seen many examples using this technique and am at a loss as to why I can't compile.
the pipelined function is:
FUNCTION f_crcli_pipe(pi_source_data IN sys_refcursor, pi_limit_size IN PLS_INTEGER DEFAULT pkg_crcli_variables.c_cursor_limit_def) RETURN CRCLI_AA PIPELINED PARALLEL_ENABLE(PARTITION pi_source_data BY ANY) IS
[code].....
the error is pointing to the TABLE function in the USING clause of the merge statement.
If we have not set parallel degree for a table then we can ( try to ) force parallel execution on a table using a parallel hint Does this 'parallelism' works on the index search in the query as well?
In which situations non-parallel non-partitioned table but parallel index (degree>2) will facilitate a query?
I have two tables with 113M records in DWH_BILL_DET & 103M in prd_rerate_chg_que and Im running following merge query, which is running for 13 hrs to update records, which is quiet longer time.
SQL> explain plan for MERGE /*+ parallel (rq, 16) */ INTO DWH_BILL_DET rq USING (SELECT rated_que_rowid, detail_rerate_flag_code, rerate_sel_key,
The block size of my db(10gr2) is 8k, and the db is on the raw device file system on a aix machine.
OS block size is 512k.
How much block will be read from disk when a single oracle io call occurs? Which one is currect, 8K or 512K?
If the block size for a single io call depends on the os block size (512k), I think os block size need to be tuned for oracle block size (8k). If we use raw device file system, os level block size has no meaning?
We have occurrences of enq : TX - index contentions in the database. Using the SQL ID, we have identified the INSERT statement and the table which they are trying to insert.
This table has almost 25 different indexes, some of which are unique as well.I am wondering how to identify the actual index causing issue, out of these 25 indexes.
Is there any way to pin point to the name of index which is causing the lock?My plan is, once the index is identified, I would like to check the extents and inittrans and other attributes of this index to fix.
I'm very happy about materialize hint and I use it a lot. But is it possible to set some hint indicating that I want to materialize some inline view results (temp table transformation) as IOT (index organized table)?
IOT must have primary key. Ok, could it be all the columns in listing order? That would convenient. I know I can use global temporary with index, but this forces me to split one statement into parts.
I've got SQL code generated by an HP tool to make an update of itself. This code is not modifiable because was execute 'in background' from the tool updater.
The macro operations made by the updater (through sql code) are:
--create a copy of actual table and rename with '_old' suffix --create new table, with indexes and constraints --insert data into new table from old tables
Now, only in one table, when the data were inserted, an ORA-00001: unique constraint (ASSET_SVIL.CFG_CFGSECTIONCFGE) violated, appear.
To insert data is used an insert/select statement with an HINT /* APPEND */. We verify all the data existing in the old table (that is the data to 'migrate') but there aren't duplicate record!
BUT IF WE REMOVE THE HINT /* APPEND */, THE INSERT/SELECT STATEMENT WORKS WITHOUT GENERATE ERRORS!!
