Performance Tuning :: Slow Join Between Dba_tab_cols And Dba_types
Nov 14, 2012
The product I work on requires a query to tell us what tables are dependent on certain types.
SELECT dba_tab_cols.owner,
dba_tab_cols.table_name,
dba_tab_cols.data_type_owner,
dba_tab_cols.data_type
FROM dba_tab_cols
JOIN dba_types
ON dba_types.owner = dba_tab_cols.data_type_owner
AND dba_types.type_name = dba_tab_cols.data_type
WHERE (dba_types.owner IN ('SCHEMA1', 'SCHEMA2'......))
I find this query to be pretty slow. I think it is because data_type_owner in dba_tab_cols is not indexed. Adding an index is not an option because users expect our product to read-only.
I am running one simple delete statement in one table with rownum<10000 but it is taking nearly 10 to 15 mins.Table doesn't have any child table rows and triggers.
We have a MV which fetches data from around 27 tables containing 26 joins out of which 25 are outer joins. Some tables in the query are being referred multiple times through different alias names and hence the actual no of physical tables used is 18. This MV takes about 50 mins to refresh through complete refresh mechanism. We decided to make it fast refresh and thus made these configurations:
- Created MV logs based on rowid for each of the base tables. - Recreated MV using FAST refresh,with primary key option enabled - Pulled rowid for all these tables in the select column statement.
Even after making all the recommendations suggested by Oracle for fast refresh MV's we are still getting refresh time of around 65 mins(refresh time increased!!!).We already have indexes built on all the join columns of the base tables. What else do we need to do to make this a "fast" refresh MV ?
I'm extracting/retrieving the data from the oracle database using Java application it's bit slow. However, when I retrieve from the SQL server it's faster than oracle.
My ERP Application is responding fast while running reports or saving entries, if Oracle 10g Express Edition (XE) is installed. But in Oracle 10g Enterprise Edition or Standard Editions the same application is running very slow.
If a table(have a primary key) is empty(after truncate),the sql of dml(insert,update) is very quickly,but if the table have many rows about 10,000,000 rows, the dml is very slowly,why?
we are using oracle 9i on AIX Server. When Customer were accessing the database, accidentally power was shut down. we restarted the Server,and Oracle database. all resumed successfully.
However while doing "Payments by the customer" it takes a lot of time to insert even a single payment record on database.The database is Live and our customer are very much frustrated,
Few days ago, My database server no access to StorageBox then I reboot it then after works fine. But, know DB import process is too slow. Before 100GB DB import process completed within 10 hours when server normal running. Now 2 day working, but not complete
How to investigate this issue? Maybe I miss increase some parameters on the Server or Oracle?
Here is my server brief info:
RAM is 16GB, SWAP size is 16GB, CPU 12 cores
SQL> show sga;
Total System Global Area 4294967296 bytes Fixed Size 1984144 bytes Variable Size 369105264 bytes Database Buffers 3909091328 bytes Redo Buffers 14786560 bytes
I have an Oracle database (9.2.0.7) installed on a HP-UX server.When trying to access this database from another HP-UX or Linux server, connection is fine. But when trying to connect from a Windows based client, connection is very slow (almost 1 minute to return the result of a 'select count(*)' like query, which is immediate from the Linux client).
Here are some facts I can add :
- Clients and servers are on the same network segment (it is not a network matter)
- No matter which client version I use, there no difference
- I tried to know what happens on the Oracle server when performing my sample query using tusc command : the result is that the server is performing exactly the same actions when sending my query from a Linux client or a Windows client
- The only relevant difference seems to be the client OS
I have a query which takes 5 minutes when run through the java app which uses hibernate. I've cut and pasted the SQL directly from hiberate trace file and run it in sqlplus/sqldeveloper and it runs instantly (0.01 seconds)(uses the index all ok and explain plan looks good - see below.) I don't know how to get the explain plan when it's running through the app or why it should be any different anyway as the query is identical.
My query is as follows:
SELECT /*+ INDEX (SPD SPD_SEQ_CODE) */ SPD.* FROM SEQ_ADDR_DATA SPD, SEQ_ADDR_LEVELS SPL WHERE SPD.SPVR_ID = '10' AND SPL.SPLE_ID = SPD.SPLE_ID AND SPL.SPLE_LEVEL <= '2' AND SPDA_ID NOT IN [code]....
I have to do the optimization of a query that has the following characteristics:
- Takes 3 hours to process - Performs the inner join with 30 tables - Produces an output of 280 million records with 450 fields
First of all it is not feasible to make 30 updates (one for each table) to 280 million records.
The best solution that I had found so far was to create 3 temporary tables, where each of them to do the join with 1/3 of the 30 tables, and in the end I make the join between the main table and these three tables temporary.
I know that you will ask (or maybe not) to the query and samples, but it is impossible to create 30 examples.
how to optimize this type of querys that perform the join with multiple tables and produce a large output with (too) many columns.
I'm looking to see if there is a way (fully expecting it to be an underscore, or two...) to force the optimizer to keep churning until all permutations are exhausted.I'm aware that it, to paraphrase, cuts out when it's spent more time parsing than it would just running it based on it's estimates.
I've got some irritating problems with xml rewrite, xml indexes and access paths/cardinalities etc and I'm really needing the entire thing considered as a one off for debugging this. I've already cranked up the maximum permutations to the max but it's not enough, it shorts out after 5041 permutations (I'd set that to 80000 max).
I know you'd not want to do this in the real world but I cant get the damned thing to run the plan I want in a 10053 so I can see the values it has there. I know I can hint it, but I'm trying to ascertain why it's not even considering it in a "normal" parse.
however I was able to identify a poorly performing query that seemed to be maxing out our CPU. I have been trying to understand the Explain Plan. The plan below is from our test system which has considerably less information in the tables than our PROD system.
I can see there are a bunch of table scans at the end which may indicate missing indexes, but I am unclear on whether this is actually a problem as the %CPU seems to be worse for the JOIN near the top of the plan.
------------------------------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time | Inst |IN-OUT| ------------------------------------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1870M| 3018G| | 677M (1)|999:59:59 | | | | 1 | SORT ORDER BY | | 1870M| 3018G| 3567G| 677M (1)|999:59:59 | | |
Having production system: 11.2.0.1 on Windows Server x64 Test system: 9.2.0.1 on Windows XP
Problem preface: to get all unique CASEID which should be checked up by biometric system.What i should check - all CASEs for different PERSONs having same PHONEs at least among one phone type (1..4).Real table contains little bit more than 10 million records.I made test scripts.
Below the DDL for test table creation: ------------------------------------------ -- Create CASEINFO test table ------------------------------------------ DROP TABLE CASEINFO; CREATE TABLE CASEINFO
[code]...
Below i've put SQL/DLL to make test data.number of records inserted 2 millions. PERSON_COUNT := #/8; ------------------------------------------ -- fill CASEINFO with sample data ------------------------------------------ DECLARE I INTEGER;
[code]...
Below SQL select to check the data in created table. ------------------------------------------ -- Check test data counters ------------------------------------------ SELECT 'TOTAL',count(*) from CASEINFO UNION ALL SELECT 'LEGAL',count(*) from CASEINFO where
[code]...
The PROBLEM is that i am experiencing HUGE perfomance problems on both test and production systems with that query:
select distinct b.caseid from CASEINFO a, CASEINFO b where (a.person<>b.person) and (a.sex=b.sex) and ( (a.phone1=b.phone1) or (a.phone1=b.phone2) or (a.phone1=b.phone3) or
[code]...
This query takes almost 90 minutes to execute.And i do not know how to avoid this.Full SQL file to make test attached.
I want to make sure I am describing correctly what happens in a query where there is distributed database access and it is participating in a NESTED LOOPS JOIN. Below is an example query, the query plan output, and the remote SQL information for such a case. Of particular note are line#4 (NESTED LOOPS) and line#11 (REMOTE TABLE_0002).
What I want to know is more detail on how this NESTED LOOPS JOIN handles the remote operation. For example, for each row that comes out of line#5 and is thus going into the NESTED LOOPS JOIN operation @line#4, does the database jump across the network to do the remote loopkup? Thus if there are 1 million rows, does that mean 1 million network hops? Does batchsize play a role? For example, if the database batches in groups of 100 then does that mean 10 thousand network hops?
I think each row that comes out of line#5 means a network hop to the remote database. But I do not know for a fact.I have done some abbreviating in the plan in an attempt to make it fit on the page (line#7 TA = TABLE ACCESS).
explain plan for select count(*) from orders, lineitem where o_orderkey= l_orderkey.
The trace 10053 (as shown below) for this query shows nested loop join with Lineitem as outer table and Orders as inner table. It is effectively join on composite index (pk_lineitem) of Lineitem and unique index(Pk_orderkey) of Orders table. The cost calculation formula as given in the book as "outer table cost + cardinality of outer table * inner table cost " fails here. I am not able to understand this.
I want to know how the Oracle optimizer choose joins and apply them while executing the query. So that I will insure about optimizer join before writing any query.
we are busy updating one databasee from a windows platform 2003 oracle 10G to a linux and oracle 11r2
We exported/imported the data and it looks ok Explain plans look the same . but our heavy batches are twice slower than on the windows box ,the two top events are disk related, sequential and scattered reads there are 90% of the time of the batch job , i read some white paper and found that using ASM can be bad in some cases the same with the linux for this particular kind of scattered reads , i was just wondering if just changing the SGA to 10GB instead of 4GB to get more cache and speedup the things .
I am trying to insert huge data into another huge table which is almost taking around 2-3 hrs. See my below query
INSERT /*+ APPEND *//*+ NOLOGGING */ INTO DB1.Table1 SELECT * FROM DB2.Table2 ; COMMIT;
Both Table1 and Table2 have same structure and table1 is master table having 100 Billion records and table2 having 30 Million records. This is a direct insert where each day this operation carried.
Looking to understand the difference between instance tuning and database tuning.
What is the difference between these two tuning exercises? I understand that an instance is memory based structures (logical) where as database consists of physical structures.
However, how does one tune a database the physical structure? Does it have to do with file placements/block sizes etc. Would you agree that a lot of that is taken care by ASM now in 11g? What tools are required/available (third party as well as oracle supplied) for these types of tuning scenarios?
I am using 11gR2 on windows server. This is the query that runs many times a day and effect badly the performance of database. I don't have much idea about this query.
SELECT TO_CHAR(current_timestamp AT TIME ZONE 'GMT', 'YYYY-MM-DD HH24:MI:SS TZD') AS curr_timestamp, COUNT(username) AS failed_count FROM sys.dba_audit_session WHERE returncode != 0 AND TO_CHAR(timestamp, 'YYYY-MM-DD HH24:MI:SS') >= TO_CHAR(current_timestamp - TO_DSINTERVAL('0 0:30:00'), 'YYYY-MM-DD HH24:MI:SS')
I just trying to import some informations from excel to Oracle using OLE2 over Oracle Forms 6i, but It´s very slow when I have import under then 10k lines. anything to optimize that ? Follow the code used...
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,
How the length of column width effects index performance?
For example if i had IOT table emp_iot with columns: (id number, job varchar2(20), time date, plan number)
Table key consist of(id, job, time)
Column JOB has fixed list of distinct values ('ANALYST', 'NIGHT_WORKED', etc...).
What performance increase i could expect if in column "job" i would store not names but concrete numbers identifying job names. For e.g. i would store "1" instead 'ANALYST' and "2" instead 'NIGHT_WORKED'.
