Performance Tuning :: How To Decide Partitioning Columns
Mar 28, 2012
What could be the strategy on deciding which columns to create partitions on? I understand for deciding this, first, we need to know the columns we are using in the WHERE clause
consider following scenario assume that emp table is very large
(1)
Query - select * from emp where empno=<pk_value>
what could the partitioning column here?
This is confusing as we access with, quite selective criteria here but we access lot of data. No particular date range Or No particular flag, value to check with! Would hash partition on the pk_column will be useful here?
(2)
select * from emp where empno=<pk_value> and deptno=<some value> what could the partitioning column here? I assume deptno here. Right?
In general what could be the considerations in deciding the partitioning columns? whether the column is not a unique key column Or the column is preferrable if used in joins Or the column is not updateable
Finally will the pruning (take place) if the query spans across multiple partitions, though Not all partitions?
View 21 Replies
ADVERTISEMENT
Jun 16, 2011
How 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?
View 2 Replies
View Related
May 4, 2013
I am doing partitioning in the table ap_invoices_all and i have gone through all the process of i am making a script for a table and process
1. Create the new partitioned table with the same column structure as the original and with the partitions.
2. Insert data from the original table to the partitioned. Use parallel DML.
3. Rename the indexes of the original table
4. Create indexes to the partition table with the same columns as the original indexes.
5. Save the source code of the original table triggers
6. Rename the triggers of the original table to OLD
7. Do the table renaming. Rename original table to OLD and the partitioned table to original.
8. Drop the synonyms for the OLD table and recreate to point to the new partitioned
9. Grant the appropriate privileges to new partitioned table.
10. Create the triggers to the partitioned table
i want to know do i need to copy the constraints of the original table to the partitioned table?
View 10 Replies
View Related
Aug 30, 2011
1) I have 5 Exported Dump files.
2) All of those 5 dump files were taken in different time periods.
3) Many of those Dump files are having the same Partition records.
eg:-
Dump 1:- 01-06-2010 to 31-11-2010
Dump 2:- 01-09-2010 to 31-12-2010
4) Now i want to import all those partitioning data into a single table, without having any duplication.
View 2 Replies
View Related
Apr 4, 2011
I am running a fairly busy Oracle 10gR2 DB, one of the tables has about 120 columns and this table receives on average 1500 insertions per second. The table is partitioned and the partitioning is based on the most important of the two timestamp columns. There are two timestamps, they hold different times.
Out of these 120 columns, about 15 need to be indexed. Out of the 15 two of them are timestamp, at least one of these two timestamp columns is always in the where clause the queries.
Now the challenge is, the queries we run can have any combination of the 13 other columns + one timestamp. In reality the queries never have more than 7 or 8 columns in the where clause but even if we had only 4 columns in the where clause we would still have the same problem.
So if I create one concatenated index for all these columns it will not be very efficient because after the 4th or 5th column the sorting would no longer be very useful and I believe the optimiser would simply not use the rest of the index. So queries that use the leading columns of the index in sequence work well, but if I need to query the 10th column the I have performance issues.
Now, if I create multiple single column indexes oracle will have to work a lot harder to maintain all these indexes and it will create performance issues (I have tried that). Besides, if I have multiple single column indexes the optimiser will do nested loops twice or three times and will hit only the first few columns of the where clause so I think it will kind of be the same as the long concatenated index.
What I am trying to do is exactly what the Bitmap index would do, it would be very good if I could use the AND condition that a Bitmap index uses. This way I could have N number of single column indexes which the optimiser could pick from and serve the query with exactly the ones it needs. But unfortunately using the Bitmap index here is not an option given the large amount of inserts that I get on this table.
I have been looking for alternatives, I have considered creating multiple shorter concatenated indexes but this still would not address the issue since many queries would still not be served properly and therefore would take a very long time to complete.
What I had in mind would be some sort of multidimensional index, I am not even sure if such thing exists. But essentially it would be some sort of index that could serve a query efficiently regardless of the fact that the where clause has the 1st, 3rd and last columns of the index.
So considering how widely used Oracle is and how many super large databases there are out there, this problem must be common.
View 12 Replies
View Related
Mar 5, 2012
I have two tables like below-
CREATE TABLE prod_vendor_record (
vendor_record_seq_no NUMBER NOT NULL,
study_seq_no NUMBER NOT NULL,
vendor_subject_seq_no NUMBER NULL,
control_dataset_seq_no NUMBER NOT NULL,
checksum NUMBER NOT NULL,
processing_flag VARCHAR2(1) NULL,
[code]....
and executing below query on those tables-
insert into prod_temp_vendor(vendor_record_seq_no,checksum,rownumber,transaction_type,iu_flag)
select vr.vendor_record_seq_no, tvr.checksum, tvr.rownumber, tvr.transaction_type, 'U' from
prod_vendor_record vr, prod_temp_vendor_record_20000 tvr
where vr.study_seq_no=25707
and vr.control_dataset_seq_no=3910
and vr.key_hash=tvr.key_hash
and dbms_lob.compare(vr.key_col_val, tvr.key_col_val) = 0
and tvr.error_flag is null;
let me know on which columns of PROD_VENDOR_RECORD table to apply index to make processing faster. As I tried to build index like below-
CREATE INDEX idx_prod_vendor_record
ON prod_vendor_record (
study_seq_no,
control_dataset_seq_no,
key_hash
)
/
But it is not being used by above query (see execution plan)
--------------------------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | TQ |IN-OUT| PQ Distrib |
--------------------------------------------------------------------------------------------------------------------------------------
| 0 | INSERT STATEMENT | | | | 5168 (100)| | | | |
| 1 | PX COORDINATOR | | | | | | | | |
| 2 | PX SEND QC (RANDOM) | :TQ10002 | 212 | 445K| 5168 (1)| 00:01:03 | Q1,02 | P->S | QC (RAND) |
[code]....
View 15 Replies
View Related
Dec 14, 2010
I have been reading Oracle documentaion about access paths, got strucked at the concept 'Leading columns in index'. what is meant by 'Leading columns of an index', how to find/judge them that they are leading columns.
The url where I am reading is[URL]...
View 4 Replies
View Related
Feb 14, 2013
We have a table emp_details with 23772889 records. Our requirement is to increase few of the columns size in the table emp_details. We are following the below alter statement which is taking around 2 hours of time.
ALTER TABLE emp_details
MODIFY
(
address char(90)
,department char(30)
)
/
Is there any way to improve the above query performance?
View 2 Replies
View Related
Mar 30, 2006
we have oracle 8i/win nt. (Prod Server running 24 X7)
On doing a explain plan on long running queries. i realized a couple of columns (that were used in the WHERE condition, were not having any indexes.)
More importantly, here we do not have a Test environment.
I would like to know if i can go ahead and create indexes for those 2 columns by issuing
CREATE INDEX index_name on table_name(Column_name);
on our PDB.
Would this be of any impact on our PDB? Do i check anything more prior to building these indexes. or Do have i create them at a down time of PDB.
View 4 Replies
View Related
Sep 25, 2013
DB Used : Oracle 10g.
A table X : NUM, INST are column names
NUM ----- INST
1234 ----- 23,22,21,78
2235 ----- 20,7,2,1
1298 ----- 23,22,21,65,98
9087 ----- 20,7,2,1
-- Based upon requirement :
1) Split values from "INST" Column : suppose 23
2) Find all values from "NUM" column for above splitted value i.e 23 ,
Eg:
For Inst : 23 ,
It's corresponding "NUM" values are : 1234,1298
3) Save these values into
A table Y : INST, NUM are column names.
INST NUM
23 1234,1298
1) I have a thousand records in Table X , and for all of those records i need to split and save data into Table Y.Hence, I need to do this task with best possible performance.
2) After this whenever a new data comes in Table X, above 'split & save' operation should automatically be called and append corresponding data wherever possible..
View 4 Replies
View Related
Feb 6, 2011
I am trying to update columns of Table A with the columns of Table B. Both these tables have 60,000 rows each. I tried this operation using following 2 queries:
Query 1
Update TableA A
set
(A.col1,A.col2,A.col3)=(select B.col1,B.col2,B.col3
from TableB
where A.CODE=B.CODE)
Query 2
Update TableA A
set
(A.col1,A.col2,A.col3)=(select B.col1,B.col2,B.col3
from TableB
where A.CODE=B.CODE)
where exists
A.code = (select B.code
from TableB B
where A.code=B.code)
When i execute these two above queries, it keeps executing indefinitely.
View 4 Replies
View Related
Nov 20, 2012
I have a big table in which we load about 37M recrods. We have informatica ETL which Loads the data in bulk Mode and creats index after completion. The data load takes about 1Hr and Index Creation takes about 1/2 hr. In total it takes about 90 to 95 Mnts.
Now I thought if Partition and Load paralley, It will improve perfromance. We did 4 partition and and each Partition about 9M records. The data load in Bulk mode is completing in 25 Mnts. Again When I am creating index over it, It is taking about 40 Mnts. and in Total Load time is 65 Mnts.
Is there way I can better performance to complete the load in 1/2 hr ?
View 2 Replies
View Related
Jul 12, 2010
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?
View 1 Replies
View Related
Oct 31, 2011
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,
[code].....
View 39 Replies
View Related
Sep 30, 2010
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'.
View 24 Replies
View Related
Jun 16, 2010
I 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?
View 2 Replies
View Related
Oct 20, 2010
There 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 ?
View 6 Replies
View Related
Nov 15, 2010
Testing 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?
View 13 Replies
View Related
Apr 12, 2013
I 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.
View 13 Replies
View Related
Aug 9, 2010
Somewhere 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.
View 6 Replies
View Related
Dec 6, 2011
I 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?
View 1 Replies
View Related
Oct 17, 2011
The 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]...
View 9 Replies
View Related
Sep 3, 2010
what the principal things to look at when we have for the same query different performance results are?I have 2 different bases: the plan and data are the same but performance results are very differents.
View 10 Replies
View Related
Mar 17, 2012
are the most important performance keys we have to calculate or take in account to preserve or to increase the DB performance in terms of response times, and whatsoever according to performance ?
View 8 Replies
View Related
Apr 4, 2013
I have problem to transfer data in non partitioning table to partitioning table.
I have non partitioning table and i create new table partitioning that have same column and type like in non partitioning. So how can i transfer data from table in non partitioning to table in partitioning?
View 10 Replies
View Related
Mar 27, 2013
I am working on an assignement where client is using Oracle 10g but stuck to using RBO Now the application team, from the GUI available to them build dynamic queries and some of them run very slow.
Neither the code can not be changed to tune the queries nor do we get the exact step in the plan which is an issue (being RBO).For some long running queries the Tuning advisor is not producing any recommendations.
Another hurdle is that all the application users are using same application user id so we can not write a logon trigger to use CBO for some particular queries to see what is happening in the background!
View 11 Replies
View Related
Jul 4, 2012
I want to tuning the next sql sentence. In this sql I want to get the hash_value and sql_text of the sentences that it's causing TX blocks. Is it possible?. This sentence works fine but sometimes It's slow.
SELECT DISTINCT hash_value,
sql_text
FROM gv$sql sq
WHERE hash_value IN (SELECT DISTINCT prev_hash_value
FROM gv$session se
WHERE sid IN (SELECT sid
FROM gv$lock l
WHERE type = 'TX'
AND ctime >= 2000
AND l.inst_id = se.inst_id
AND l.sid = se.sid)
AND sq.inst_id = se.inst_id);
[code]....
View 7 Replies
View Related
Nov 2, 2012
I see one of my SQL's which is ran by the user on a 10.2.0.3 database changing its SQL_ID after some runs even if the query is not changed a bit! However the HASH VALUE for this query remains the same.
how a same query can have different SQL_ID's but same HASH_VALUE?
Note: Statistics are not modified on the base tables of this query.
View 10 Replies
View Related
Aug 10, 2011
I am running Oracle 10.2.0.1.0 on MS Windows 2003 server 64-bit with 16G RAM.
Here is the findings for my Oracle database.
SQL> select * * from v$sgainfo;
NAME BYTES RES
-------------------------------- ---------- ---
Fixed SGA Size 1293560 No
Redo Buffers 7094272 No
Buffer Cache Size 830472192 Yes
[code]...
I find that the SGA component "Buffer Cache" is decreasing from the start "1.8G" and down to now 0.8G. On the other hand, the component "Shared Pool" is increasing from the start 0.3G to now 1.2G. I noticed that there are 100 operations of shrinking of "Buffer cache" and growth of "Shared Pool" in Oracle every day.Is it a indicator that I should raise up the SGA_MAX_SIZE?
I tried to increase the SGA_MAX_SIZE to 4G. But I cannot start the Oracle afterward.Is it a limitation of MS Windows(OS) or Oracle?I set the SGA_MAX_SIZE to 3G. This time, I can startup Oracle.What is the optimum/maximum I can set to SGA_MAX_SIZE?Is there any adverse effect/concern when setting the SGA_MAX_SIZE more than 2G?
View 6 Replies
View Related
Jul 11, 2012
Here i have three tier application. I want to know it host name from sid or sqlid . I want to know which query run on which host. Because i have one user from application to database. So i want to know which query consume more time on which host ?
View 19 Replies
View Related
