Performance Tuning :: How To Set Commit_write Parameter To (BATCH) In Another Session
May 16, 2013How to set commit_write parameter to 'BATCH' in another session.
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Performance Tuning :: Looking For More Than Last 16 Operations For Session
May 25, 2010Doing some data conversion at the moment and using V$SESSION_LONGOPS to predict when the current task will be finished so I can run the next one.
V$SESSION_LONGOPS seems to have only the last 16 long operations for the session. Older operations are automatically purged. My bigger tables have 32 partitions, so after the first 16 are processed, I cannot tell which partition I am up to.
Googling "old longops" and "longops history" didn't work, nor did the same searches on this site. The Oracle Reference manual section on V$SESSION_LONGOPS did not mention that older entries are purged.
Performance Tuning :: SID Column In V$SESSION?
Dec 12, 2010Even though the users are not logged in why the V$SESSOIN shows the SID and why many times?
View 2 Replies View RelatedPerformance Tuning :: TKPROF Output For Session
Jun 9, 2010understanding the TKPROF output for the session that was executing an insert statement(inserting 70 lakh data) on which a row level trigger get fired and select from following table.The trace was run for 1 hour.
Table name - > GS_MAP_RCC_CCIT
This table is having 37 rows as in on single block and having primary key index on RCC_NUM that is also contained on single block.We are getting maximum wait events on db_file_sequential_read.
As per my understanding this is due to the contention for the same block because for each row these queries get fired.
Performance Tuning :: Session Doing FTS Not Appearing In Longops?
Apr 4, 2012dbo is a table with 1M records and structure similar to dba_objects
The following queries which does FTS, access same number of blocks as observed in v$session_longops
select * from dbo;
and
select * from dbo where object_type='VIEW';
Ex.
select * from dbo where object_type='VIEW';
select * from table(dbms_xplan.display_CURSOR(null,null,'ALLSTATS LAST'));
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------
------------------------------------------------------------------------------
SQL_ID 5mh418w9stax2, child number 0
-------------------------------------
select * from dbo where object_type in('VIEW')
Plan hash value: 2675347415
-------------------------------------------
| Id | Operation | Name | E-Rows |
-------------------------------------------
|* 1 | TABLE ACCESS FULL| DBO | 77611 |
-------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("OBJECT_TYPE"='VIEW')
I understand that because the query is accessing large number of blocks which exceeds 6 seconds threshold, the session appears in v$session_longops And this has nothing to do with the time spent in displaying the records on the screen
Now, why the following query does not appear in v$session_longops?
select /*+ full(dbo) */ count(*) from dbo;
select /*+ full(dbo) */ count(*) from dbo;
COUNT(*)
----------
1006525
Elapsed: 00:00:01.36
dv3_erie-dev_08 >select * from table(dbms_xplan.display_CURSOR(null,null,'ALLSTATS LAST'));
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------
SQL_ID 4mgjwp3tv70db, child number 0
-------------------------------------
select /*+ full(dbo) */ count(*) from dbo
Plan hash value: 1423969929
--------------------------------------------
| Id | Operation | Name | E-Rows |
--------------------------------------------
| 1 | SORT AGGREGATE | | 1 |
| 2 | TABLE ACCESS FULL| DBO | 1007K|
--------------------------------------------
The table has all nullable columns and thus I assume the index on ID can't be used for this COUNT Thus ideally it shall be accessing same number of blocks and thus shall appear in v$session_longops
Performance Tuning :: Session Tracing For Shared Servers
Jan 12, 2011How to enable tracing for sessions connected using shared servers ?
View 1 Replies View RelatedPerformance Tuning :: How To Trace Different Session From Current With LEVEL 4
Jun 13, 2012I've been searching the web for examples of how to run a trace.It's needed for a session different then current in trace LEVEL 4 (I need the bind variables values in the trace).
Unfortunately, I couldn't trace with DBMS_SUPPORT.START_TRACE_IN_SESSION, I understand that this is because it was only introduced in Oracle 11g.
how can i trace a session in level 4 on Oracle 10g for another session?
Performance Tuning :: SQL ID And Text - No Record Being Found At Session Level
Feb 22, 2012At my prod instance one sql query ran for about 9 hours.Now the sql query completed with success.Suddenly our ops team want to know the which sql query was running for 9 hours.As the query got success no record is being found at session level.
I know the SID.How Do I get the SQL query ?
Performance Tuning :: How To Find Out Session Consuming High Resource In Past
Mar 28, 2013How can I find out the particular oracle session which was consuming high memory in the past?
I can't get the data in v$sessstat
Unable to get the information in AWR
dba_hist_active_session_history do not have field which indicate memory related information
Shall I concetrate on EVENT in dba_hist_active_session_history which continuosly had sort, direct path read
Or
Locate sql_id from dba_hist_sqlstat with high SORTS_DELTA for snapshots belonging to problematic time period and then using the sql_id query dba_hist_active_session_history
which approach I shall take to find out the session which consumed most memory in the past?
Performance Tuning :: SGA / PGA Parameter Settings?
Nov 27, 2011we are ruining oracle 9i in windows 2000 server, oracle is the only database running in the server. The RAM capacity is 4GB but the sga showing is as below
Total System Global Area 118255568 bytes
Fixed Size 282576 bytes
Variable Size 83886080 bytes
Database Buffers 33554432 bytes
Redo Buffers 532480 bytes
pga size
NAME VALUE
---------------------------------------------------------------- ----------
aggregate PGA auto target 0
global memory bound 0
total expected memory 0
total PGA inuse 19937280
[code]...
how can we using the 4gb RAM deducing 20% for OS Sometimes users are complaining slow process.
Performance Tuning :: How To Configure SGA_MAX_SIZE Parameter
Sep 24, 2013The Memory tuning advisor has recommended that I increase the size of the SGA_TARGET to 5G, from my current size of 3G.
SQL> select * from v$sga_target_advice order by sga_size;
SGA_SIZE SGA_SIZE_FACTOR ESTD_DB_TIME ESTD_DB_TIME_FACTOR ESTD_PHYSICAL_READS
---------- --------------- ------------ ------------------- -------------------
1536 .5 1555141 1.667 7251211
2304 .75 949130 1.0174 4572127
3072 1 932898 1 2258733
3840 1.25 930939 .9979 2168835
4608 1.5 929819 .9967 2005529
5376 1.75 929166 .996 2005529
6144 2 928980 .9958 2005529
7 rows selected.However, the SGA_MAX_SIZE parameter is set to 3G, so when I do:
SQL> ALTER SYSTEM SET sga_target=5376M scope=both;
ALTER SYSTEM SET sga_target=5376M scope=both
*
ERROR at line 1:
ORA-02097: parameter cannot be modified because specified value is invalid
ORA-00823: Specified value of sga_target greater than sga_max_size
My database used spfile. I know that the procedure to change this is the following: Create pfile from spfile, shutdown immediate, change value in pfile, startup with pfile..However, the pfile does not have any parameter called max_sga_size. It only has the following:
<dbsid>.__sga_target=3221225472
*.sga_target=3221225472
how to change sga_max_size?
Performance Tuning :: Pass 4000 - 5000 Parameter In IN Clause?
Mar 2, 2011In my below query example , i have to pass more than 4000-5000 paramter in "a1.num" in below query. what is the best way to handle this, also if I pass more than 2000 paramter , the query takes a long time to execute. How can we solve the performance issue as well how I can pass more parameter.
SELECT c1, c2,
TO_CHAR (c3, 'HH24:MI'),
c4,
c5,
[code]...
Performance In Batch Run
Sep 15, 2012We are having a major issues with the batch run. we are using oracle 11g db. We run the scripts to populate the tables and then call scripts to run the extractions. The issue here each time we run the sql it takes so much inconsistent time.We have created index and run the db stats then run the extractions.The sql sometimes takes 10 minutes or sometimes takes hours to run? This is major show stopper of the project.
View 3 Replies View RelatedTuning SQLs In A Batch Process
Mar 18, 2013I'm having an issue with stale optimizer statistics for some SQLs that are run in a batch process. The problem is that the process runs many times during the day - sometimes 20 to 30 times. And each time, the tables are updated, i.e. rows are inserted or deleted, etc.
So eventually the optimizer statistics for those tables become stale and the performance of the SQLs start to slow down (a lot). How best to gather the optimizer stats on the tables so they don't become stale when the batch process runs each time? The problem is that I also can't add/modify the code in the batch process because it is delivered by the vendor as is.
Critical Application Batch Performance
Sep 21, 2012We have a critical application batch that runs daily and had a 7.5 hr window after which the application needs to come online. During the peak batch times the truncates are running very slow leading to slow down of the batch jobs quite considerably due to which the batch is going beyond the window.
Technical details:
Database version: 11.2.0.2
OS: HP-UX 11.31
The wait events that show up when the truncates are running are local write wait
enq: RO fast object reuse
enq: CR block range reuse ckpt
db file parallel write
The ASH reports show that the top sessions are those executing DMLs(insert, merge, update) and DDLs(Create/alter index & truncate). In addition to this it also shows that the blocking sessions are background wait events: CKPT and DBWR. Changes to DB configuration done with respect to addressing these issues are:
1) We have increased the DBWR processes to 2
2) Reduced the buffer cache size to 20G(from the original 30G)
3) Flushing the buffer cache before the batch begins in order to reduce the load on DBWR during the batch peak time
4) Set the parameter filessytem_io to SETALL(from none)
5) Tuned the EVA(SAN storage) to improve its performance - by distributing the loads evenly between the controllers, reducing the IO transfer block size, etc
6) Suggested using the reuse storage clause to improve truncate performance.
All of these have worked bring a semblance of control but the fact remains that the batch is generating more jobs(hence increasing data volume) over time due to it being the peak season. This causes an inevitable increase in the number of sessions all running DMLs and DDLs which are IO intensive operations.
Suggestions pending from our end:
1) Increase DBWR beyond 2. For this we need a H/W upgrade since we have maxed out the maximum number of DBWR that can be configured
2) Implementing asynchronous IO for DBWR which on HP-UX requires moving to raw disks. Hence have suggested using ASM.
3) Tuning the application to either reduce the IO generated or redistribute the jobs such that those with maximum loads don't run together
instead of truncating tables, can we rename the tables and delete them later . will this improve performance ?
Tuning Searching Into Clob In Batch Operation?
Jul 3, 2012My application runs a batch procedure weekly once for searching 'A_Text' from a column in Table1 in a clob column in Table2 and inserts accordingly into another Table3.
code snippet is like this -
---
CURSOR cr_sn
IS
SELECT serial_number
[Code]....
TABLE1 will have at least 1.1 Million rows but not significantly more than this.
This procedure takes 24+ hours to complete. I tried -
1. putting parallel hint ( INSERT /*+ PARALLEL*/INTO Table3)
2. partitioning TABLE2 based on last_update_date and putting a where clause in the above query last_update_date ( last_update_date between date1 and date2)
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?
Server Administration :: Initialization Parameter File - Currently In Effect For Session
Jan 31, 2012I have a question about spfile.
SQL> SELECT COUNT(*) FROM v$parameter WHERE value IS NOT NULL;
COUNT(*)
----------
246
SQL> SELECT COUNT(*) FROM v$spparameter WHERE value IS NOT NULL;
COUNT(*)
----------
20
v$parameter displays information about the initialization parameters that are currently in effect for the session,but v$spparameter displays information about the contents of the spfile.I want to know why the count of parameters whose values are not null in v$parameter is greater.where are they from? My initialization parameter file is spfile.
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]...
Performance Tuning :: Same Data But Different Performance Results
Sep 3, 2010what 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 RelatedPerformance Tuning :: DB Performance Keys?
Mar 17, 2012are 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
