Performance Tuning :: Check Count For Each Partition?
May 2, 2012We have 525 partitions and we want find out partition wise total count. finding partitionwise count in a particular table.
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Performance Tuning :: Select Partition Table With Non-partition Key Condition?
Jun 26, 2010I have a table that partitioned into six partitions. each partitions placed in different table space and every two table space placed it on a different hardisk
when I will do query select with the non-partition keys condition, how the search process ? whether the sequence (scan sequentially from partition 1 to partition 6) or partition in a hardisk is accessed at the same time with other partition in other hardisk. ( in the image, partition 1,4 accessed at the same time with partition 2,5 and 3,6)
Performance Tuning :: Partition Of Table
Jun 28, 2010What are the factors that decide on which column we should partition the table and which partition method we should chose.
View 2 Replies View RelatedPerformance Tuning :: Against Count With Group By Clause
Mar 31, 2012This query is taking 7 hours to execute as I am retrieving data from history table dept_hist.
select count(distinct empid), e.group_nm, d.date,
from emp e, dept_hist d
where e.deptno = d.deptno
and e.up_ts > sysdate -30
[Code]...
Its taking 7 hours to execute.restructing this query.
Performance Tuning :: How To Partition Tables And Indexes
Jan 12, 2011So our situation is pretty simple. We have 3 tables.
A, B and C
the model is A->>B->>C
Currently A, B and C are range partitioned on a key created_date however it's typical that only C is every qualfied with created date. There is a foreign key from B -> A and C -> Bhave many queries where the data is identified by state that is indexed currently non partitioned on columns in A ... there are also indexes on the foreign keys that get from C -> B -> A. Again these are non partitioned indexes at this time.
It is typical that we qualifier A on either account or user or both. There are indexes (non partitioned on these) We have a problem with now because many of the queries use leading wildcards ie. account like '%ACCOUNT' etc. This often results in large full table scans. Our solution has been to remove the leading wildcard.
We are wondering how we can benefit from partitioning and or sub partitioning table A. since it's partitioned on created_date but rarely qualified by that. We are also wondering where and how we can benefit from either global partitioned index or local partitioned indexes on tables A. We suspect that the index on the foreign key from C to B could be a local partitioned index.
Performance Tuning :: How To Check Table Has Changed 10% In Database
Dec 13, 2011By default the DBMS_STATS package runs once every 24 hours to collect statistics for database objects and Oracle collects new statistics when enough of the data (about 10%) has changed.
My question here is how to check the table has changed 10% in database?
Performance Tuning :: How To Check SQL Queries Run By Application At Backend
Oct 28, 2010Name some database tool from which I can check the SQL Queries which my application is running.
NOTE: I do not want to check the queries which I am executing at the SQL command prompt but queries that are being run by my application at the backend.
Performance Tuning :: How To Assure Partition Table Is Better Than Non-partition Table
Mar 25, 2011I think that performance better partition table than non-partition table. How to assure partition table is better than non-partition table at SELECT operation?
I have compare a specific query EXPLAIN PLAN at partition table and non-partition table. both tables data is same. Is it true way or not?
Performance Tuning :: Collection Count High In Memory
Feb 13, 2013I have two tables with same columns(15 of them), I am trying to find difference between two tables using minus operator and then insert in stage table using below code
Issue is table1 has 50 million records
table2 is empty
so when first time when we execute this v_collection1,v_collection2 collection will have 50 million records in it which will go in memory, I think this is not good, because going in memory will eat memory and resources while sorting and other activities ?
After fetching records in collection we are inserting that in stage table and then COMMIT so i think that wont be good because committing 50 million will generate large amount of redo?
below is snippet of my code
DECLARE
type lst_collection1
IS
TABLE OF table1.col1%type INDEX BY binary_integer;
type lst_collection2
IS
[code].......
Performance Tuning :: Two UNION ALL - Modify Index Or Partition
Jan 27, 2012We have a large customer table so first thought was to partition.Also we see two union alls in the plan - can we introduce parallelism? Below is the plan - have attached a text file if difficult to read
SELECT V_IDENTIFIER_LOOKUP.UID_V_IDENTIFIER_LOOKUP AS "UID",
V_IDENTIFIER_LOOKUP.ABA, V_IDENTIFIER_LOOKUP.ADDRESS1,
V_IDENTIFIER_LOOKUP.ADDRESS2, V_IDENTIFIER_LOOKUP.ADDRESS3,
V_IDENTIFIER_LOOKUP.ADDRESS4, V_IDENTIFIER_LOOKUP.ALIAS,
V_IDENTIFIER_LOOKUP.CITY, V_IDENTIFIER_LOOKUP.COUNTRYCODE,
V_IDENTIFIER_LOOKUP.CUST_CODE, V_IDENTIFIER_LOOKUP.CUST_NAME,
V_IDENTIFIER_LOOKUP.HEAD_OFFICE_IN,
V_IDENTIFIER_LOOKUP.IDENTIFIER,
V_IDENTIFIER_LOOKUP.IDENTIFIER_TYPE,
[code]...
Performance Tuning :: Possible To Build Index Partition In Parallel
Jul 8, 2010Is it possible to build index partition in parallel?I tried following command
alter index <index_name> rebuild partition <partition name> online parallel 5;
It executed without complaining, but want to know if index partitions can be build in parallel?
Performance Tuning :: How To Check If Paging Happening While Running The Query
Sep 26, 2013How can i check if paging happening while running the query. As i have 4gb of PGA target but the query is taking long time in parallel and has hash join.
how to check paging in 11gr2
Performance Tuning :: Create Hash Partition On Fact Tables?
Aug 5, 2010I have to create a hash partition on fact tables.. we can use temp tablespace or permanent tablespace.
View 10 Replies View RelatedPerformance Tuning :: Select Partition - Oracle To Scan Blocks
Sep 15, 2011I was confused by partitioed table, when i select a partition of table, how does oracle to scan blocks? it scan all blocks of table or scan a single partition blocks only?
SQL> Explain Plan For
2 Select Count(1) From Tb_Hxl_List Partition(p_L3);
Explained.
SQL> Select * From Table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 18 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | | |
| 2 | PARTITION LIST SINGLE| | 33115 | 18 (0)| 00:00:01 |
| 3 | TABLE ACCESS FULL | TB_HXL_LIST | 33115 | 18 (0)| 00:00:01 |
Performance Tuning :: Difficulty In Using Bind Variable To Check Explain Plan
Dec 12, 2011since the optimizer (during explain plan) assumes all bind variable to be of varchar type, while checking plan for SQL statement using bind variable of numeric and date type shall we convert (typecast) it as following?
variable n_sal number
variable dt_joining date
exec n_sal:= 1000
exec dt_joining := '12-dec-2005'
select first_name from emp_data where sal=to_number(n_sal) and joining=to_date(dt_joining);
Performance Tuning :: Converted Non-partitioned Table (1 Million Data) Into Range-partition
Mar 28, 2013As per Article mentioned in Oracle Base,I have converted non-partitioned table (1 million data) into range-partition table,but,I don't see performance improvement in explain .
View 9 Replies View RelatedPL/SQL :: Check For Any Duplicate Values In COUNT() Column
May 13, 2013I'm going to do some testing, and for that I require to retrieve some data based on a single column e.g test_data_col, which -
1. Has 3 or more count(test_data_col) for a given set of group by columns e.g grp_col1, grp_col2, grp_col3
2. Within the set of rows retrieved, that particular column holds some duplicate values. I don't need the duplicates displayed, just know if duplicates exist or not.
This might explain what I'm trying to do -
grp_col1, grp_col2, grp_col3, test_data_col
1, A, xyz, HELLO
1, A, xyz, HELLO
1, A, xyz, BYE
1, A, xyz, GOODBYE
2, C, pqr, WELCOME
2, C, pqr, GOOD MORNING
2, C, pqr, BAD MORNING
So for condition 1, I do something like this -
SELECT COUNT(test_data_col) cnt, grp_col_1, grp_col2, grp_col3
FROM test_tab
GROUP BY grp_col_1, grp_col2, grp_col3
HAVING COUNT(test_data_col) >= 3;
In this same query, I want to do something that will tell me if the aggregate COUNT(test_data_col) has any duplicate values within it. Again, displaying the duplicates is not important here.
SELECT COUNT(test_data_col) cnt, grp_col_1, grp_col2, grp_col3,
/*some logic*/ dup_val
FROM test_tab
GROUP BY grp_col_1, grp_col2, grp_col3
HAVING COUNT(test_data_col) >= 3;With the proper coding to replace /*some logic*/, I get following values -
cnt, grp_col_1, grp_col2, grp_col3, dup_val
4, 1, A, xyz, Y
3, 2, C, pqr, N
I just gave dup_val column to explain what I'm trying to achieve.. any other way to know the existence of duplicates in the count aggregate will be fine.My Oracle version is Oracle Database 11g Enterprise Edition Release 11.1.0.7.0
SQL & PL/SQL :: How To Count Rows Of Partition Table
Apr 9, 2013I have tried to execute this query
select partition_name, num_rows from dba_tab_partitions where table_name='Partisi_Book_Issue';
it display 0 num_rows. But i have made non partitioned table to partitioned table with the same number of rows. how to display number of record in each partition in any table?
Server Administration :: How To Check A Partition Have Been Compressed
Oct 20, 2011How can i check a partition whether it has been compressed? just as flowing test,i can not get the information about partition P_L1 whether been compressed.
SQL> Select
2 aa.compression,
3 aa.partition_name
4 From dba_tab_partitions aa
5 Where aa.table_name = 'TB_HXL_LIST';
COMPRESS PARTITION_NAME
-------- ------------------------------
DISABLED P_L1
DISABLED P_L2
DISABLED P_L3
DISABLED P_L4
SQL> Alter Table tb_hxl_list compress;
Table altered.
SQL> Alter Table TB_HXL_LIST
2 Move Partition P_L1 compress;
Table altered.
SQL> Select
2 aa.compression,
3 aa.partition_name
4 From dba_tab_partitions aa
5 Where aa.table_name = 'TB_HXL_LIST';
COMPRESS PARTITION_NAME
-------- ------------------------------
ENABLED P_L1
ENABLED P_L2
ENABLED P_L3
ENABLED P_L4
Performance Tuning :: Tools For Database Tuning And Instance Tuning
Jul 12, 2010Looking 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?
Performance Tuning :: Merge Statement Tuning For 100M Records In Table?
Oct 31, 2011I 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,
[code].....
Performance Tuning :: How Length Of Column Width Effects Index Performance
Sep 30, 2010How 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'.
Performance Tuning :: Fragmentation Can Reduce Performance In Query Times
Jun 16, 2010I have a question about database fragmentation.I know that fragmentation can reduce performance in query times. The blocks are distributed in many extents and scans process takes a long time. Oracle engine have to locate the address of the next extent..
I want to know if there is any system view in which you can check if your table or index has high fragmentation. If it's needed I will have to re-create, move or rebulid the table or index, but before I want to know if the degree of fragmentation is high.
Any useful script or query to do this, any interesting oracle system view?
Performance Tuning :: Method Of Tuning Database - Row Reduction?
Oct 20, 2010There is a simple way to increase the performance of a query by reducing the row-size of the table it hits. I used it in the past by dividing the table into smaller parts and querying respective smaller table in each query.
what is this method called ? just forgot the method and can't recall it. what this type of row-reduction optimization is called ?
Performance Tuning :: Performance Standard Edition Without Partitioning?
Jun 16, 2011How many records could I have in a single table without performance degradation with Standard Edition without partitioning with cutting-edge server (8 or 12 cores, 72 GB RAM, FC 4 Gbit, etc...) and good storage?
300 Millions in only one table with 500K transactions / day is too much?
Simple database with simple schema.
How many records begin to be too many?
Performance Tuning :: Procedure Performance On New Database Import?
Nov 15, 2010Testing our 9i to 11g upgrade, we've imported the entire DB into the new machine.We've found that certain procedures are really suffering performance problems. BUT, we've also found, that if we check out a production copy of the procedure from our source code control, and reinstall it, the performance issue goes away. Just alter the procedure and recompiling does NOT work.
The new machine where the 11g database exists is slightly different than the source, but it's not like we have this problem with every procedure. It's only a couple.
any possible reason that we'd have to re-install a procedure to correct a performance problem?
Performance Tuning :: Checking Delete Performance In Package
Apr 12, 2013I need to check the package performance and need to improve the package performance.
1. how to check the package performance(each and every statement in the package)?
2. In the package using the delete statement to delete all records and observed that delete is taking long time to delete all the records in the table(Table records 7000000). This table is like staging table.Daily need to clean the data before inserting the data into it. what can I use instead of Delete.
Performance Tuning :: Query Performance Gain Using Statistics?
Aug 9, 2010Somewhere I read that we should not use hints in Oracle production environments, but we can use hints in the development environment and on achieving the desired execution plan we can adjust the 'statistics' to follow that plan without hints.
Q1. If it is true what statistics do we adjust for influencing the execution plan and how?
For example, I have the following simple query:
select e.empid, e.ename, d.dname
from emp e, dept d
where e.deptno=d.deptno;
emp.empid, emp.deptno and dep.deptno columns have indexes and the tables have the standard structure as found in the basic oracle examples.
If I look at the execution plan of the above query then I see that the driving table is empand the driven table is dept.Also the type of join that is taking place is 'Nested Loop'.
Questions: With respect to the above query,
Q 2. If I want to make dept the driving table and emp the driven table then how can I adjust the statistics to achieve that?
Q 3. If I want to use hash join instead of a nested loop join then then how can I adjust the statistics to achieve that?
I can put the ordered and the use_hash hint to effect this but again I have heard that altering statistics is a more robust way to control an execution plan as compared to hints.
Performance Tuning :: How To Improve The Performance Of Export Job (expdp)
Dec 6, 2011I have an issue with export(expdp).
When i exporting an user using expdp utility, the load the on the server is going up-to 5. The size of the database is 180GB. Below is the command that i use for export.
expdp sys/xxxx directory=dbpdump dumpfile=expdp_trk_backup.dmp logfile=expdp_trk_backup.log exclude=statistics schemas=trk
Do i need any look into any memory parameters for this?
Performance Tuning :: DECODE In WHERE CLAUSE Performance?
Oct 17, 2011The following query gets input parameter from the Front End application, which User queries to get Reports.There are many drop down boxes like LOB, FAMILY, BRAND etc., The user may or may not select values from drop down boxes.
If the user select any one or more values ( against each drop down box) it has to fetch all matching values from DB. If the user does'nt select any values it has to fetch all the records, in this case application will send a value 'DEFAULT' (which is not a value in DB ) so that the DB will fetch all the records.
For getting this I wrote a query like below using DECODE, which colleague suggested that will hamper performance.From the below query all the variables V_ are defined in procedure which gets the values selected by user as a comma separated string here V_SELLOB and LOB_DESC is column in DB.
DECODE (V_SELLOB, 'DEFAULT', V_SELLOB, LOB_DESC) IN
OPEN v_refcursor FOR
SELECT /*+ FULL(a) PARALLEL(a, 5) */
*
FROM items a
WHERE a.sku_status = 'A'
[code]...