Performance Tuning :: Snapshot Skipped In Between Scheduled Time?
Sep 11, 2013
Yesterday, there were performance issue at server. So today, when i am generating report for that particular period, found snapshot id sequence is serially but with skipped hourly timed. Instead of generating report at 15:30, it generated at 16:30.
Enter value for num_days: 2
Listing the last 2 days of Completed Snapshots
Snap
Instance DB Name Snap Id Snap Started Level
------------ ------------ --------- ------------------ -----
tagidev TAGIDEV 2857 10 Sep 2013 00:30 1
2858 10 Sep 2013 01:30 1
2859 10 Sep 2013 02:30 1
2860 10 Sep 2013 03:30 1
2861 10 Sep 2013 04:30 1
2862 10 Sep 2013 05:31 1
[code]....
Below are the details at alert log -
Tue Sep 10 14:28:20 2013
Thread 1 cannot allocate new log, sequence 7029
Checkpoint not complete
Current log# 2 seq# 7028 mem# 0: E:APPORACLEORADATATAGIDEVREDO02.LOG
Thread 1 advanced to log sequence 7029 (LGWR switch)
[code]....
1) why snap didn't started at 15:30?
2) since database just started at the scheduled time of AWR snap time. But generated at 16:32 instead of 16:30, though last services "SMCO" is started at 16:42. How it snap id generated for this particular time?
3) what does "kewastUnPackStats(): bad magic 1 (0x000000001B3CE48D, 0)" mean?
I am trying to generate AWR report for database observation. But I am not getting any snapshot listed there. below is the output of my awrrpt.sql
SQL> @?/rdbms/admin/awrrpt.sql
Current Instance ~~~~~~~~~~~~~~~~ DB Id DB Name Inst Num Instance ----------- ------------ -------- ------------ 1140984076 AFCCV 1 afccv
Specify the Report Type ~~~~~~~~~~~~~~~~~~~~~~~ Would you like an HTML report, or a plain text report?
Enter 'html' for an HTML report, or 'text' for plain text Defaults to 'html'
Enter value for report_type: html
Type Specified: html
Instances in this Workload Repository schema ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DB Id Inst Num DB Name Instance Host ------------ -------- ------------ ------------ ------------ * 1140984076 1 AFCCV afccv SERVICEDB1
Using 1140984076 for database Id Using 1 for instance number
Specify the number of days of snapshots to choose from ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Entering the number of days (n) will result in the most recent (n) days of snapshots being listed. Pressing <return> without specifying a number lists all completed snapshots.
Enter value for num_days: 3
Listing the last 3 days of Completed Snapshots
Specify the Begin and End Snapshot Ids ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Enter value for begin_snap:
How can i check the avg time taken by an execution plan. Actually i have a very big query and it changes its execution plan very often, we would like to lock the best execution plan and to find it , i would like to know the Average Execution Time the query takes when it runs using different different execution plans.
elapsed time = time spent on waits + time CPU was used
Total time during snaps = Elapsed time + (may be) time waited for CPU...In AWR is it possible to draw such equation? I can see that the AWR report has following elements
1) End Snap time - Begin Snap time 2) DB time - as mentioned at the top of AWR report 3) DB CPU - in "Top 5 Timed Foreground Events" (I assume this is 'CPU used by sesson timing' in statspack) 4) Total of time for all Statistics in "Time Model Statistics" 5) BUSY_TIME + IDLE_TIME - "Operating System Statistics"
Time between 2 snapshots? or what else? Also for which seconds to multiply to 'DB Time(s)' per second and 'DB CPU(s)' per second in Load Profile to get the db time and CPU time?
For example, we have a table ACCOUNT (snowflake dimension containing other dimension keys) and I have many fact tables based on this dimension. Normally data warehouse load happens like first dimensions needs to be loaded and then facts. Our frequency of loads is 30 mins.
To increase the rate in which the data will be available in the facts (as its a financial application), am considering to have two batches one with dimension and another one with fact (came to this conclusion as there is no dependency like first dimensions to be loaded then only fact) just the update might get missed sometimes. But if I do that, when dimension gets loaded, it will be read in the facts in another session. Will this affect the performance ?
LOADING (insert/update) and selecting data from table at the same time. Will it affect the performance in any way.
I understand that when data is read from the disk, I/O is done..And When computations are done then CPU is used..Then where the following equation fits?
On AWR, I see two script that are out of ordinary, and I want to make sure that I interpret them correctly.
1) "Elap per Exec (s)" shows 3263.49 with 1 "Executions". 2) "Elap per Exec (s)" shows 3180.17 each execution with 2 "Executions".
Does this mean that this script ran for ~ 54 minutes (3263.49 / 60 seconds) for 1 "Execution" and ~ 53 minutes (3180.17 / 60 seconds) per each execution? I need to understand "Elapsed Time (s),CPU Time (s),Executions ,Elap per Exec (s), % Total DB Time" represent.
BEGIN dbms_scheduler.create_schedule( schedule_name => 'INTERVAL_EVERY_1_MINUTES', start_date => trunc(sysdate)+18/24, repeat_interval => 'freq=MINUTELY;interval=1', comments => 'Runtime: Every day all 1 minutes'); END;-- program code BEGIN
[code]....
all above three code compiled successfully . but it is not running automatically and not run every 1 minute.
I try to run this manuall by using following code
BEGIN dbms_scheduler.run_job('JOB_FEED_UK_DATA',TRUE); END;
It works fine..
create or replace PROCEDURE LOAD_CUSTOMERS_UK IS BEGIN Insert into CUSTOMERS_UK (ID, NAME, CITY) VALUES (1,'SMITH','LONDON'); Insert into CUSTOMERS_UK (ID, NAME, CITY) VALUES (2,'JONES','LONDON'); Insert into CUSTOMERS_UK (ID, NAME, CITY) VALUES (3,'BROWN','BRIGHTON');
I have a table which contains 8,21,177 amount of data totally.Now I am trying to delete around 4,84,000 of data from this table by using just one filter i.e. my query is something like below
DELETE /*+ parallel(resource,4) */ FROM resource where created_by = 'MIGN'
This is going to delete 4,84,000 rows of data . But my current issue is this is taking lots of time to delete the data . To be precise , its almost taking 25 hours to delete this data..The created_by column is indexed .
Execution Plan ---------------------------------------------------------- Plan hash value: 2389236532
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | --------------------------------------------------------------------------------
- First time to execute: Using all indexes on 2 tables
- Second time to execute: Using only indexes on first table, full table scan on the other
- Third time to execute: Do FTS on both of tables.
Now, I show the objects and relate information here:
The Tables:
system@dbwap> select count(*) from my_wap.news_relation;
COUNT(*) ---------- 272708
system@dbwap> select count(*) from my_wap.news_content;
COUNT(*) ---------- 95092
system@dbwap> desc my_wap.news_content; Name Null? Type ----------------------------------------------------- -------- ---------------- ID NOT NULL NUMBER(11) SUBJECT NOT NULL VARCHAR2(500) TITLE VARCHAR2(4000) STATE NUMBER(1) IMGPATH VARCHAR2(500) ALIGN VARCHAR2(10)
Is there any way to reduce the index creation time. I have one table which has 7700000 records and every day this table get truncate and we create with create table as select statement and then create the 4 indexes and each index took 5 minutes so in totality it took 20 minutes in index creation.
Elapsed Time (s) CPU Time (s) Executions Elap per Exec (s) % Total DB Time SQL Id SQL Module SQL Text 2,423 1 3,919 0.62 1.83 gt49gg0fnc5x8 srv_dr@ahs (TNS V1-V3) UPDATE /*+ CCL<OENDB_FILE... 2,227 14 1 2227.16 1.68 bggfx8a04prj9 SQL*Plus select * from (select n.source... .........
On [SQL ordered by Elapsed Time], [SQL Module] shows an indication that a SQL was executed by which process (i.e. srv_dr@ahs)outside of SQL*PLUS.If [SQL Modeule] shows as [SQL*Plus], does it mean the query was run in SQL*PLUS manually or directly?I have the SQL ID. How do I find out who, how, and exactly what time it was run?
In my insert query, Window sort takes longer time i.e. 93% of total execution time, How do i reduce this time? are there any tuning parameters availabe for this?
In my code I am using delete statement which is taking too much time to execute.
Statement is as follow:
DELETE FROM TRADE_ORDER_EMP_ALLOCATION T WHERE (ARTEMIS_SOURCE_SYSTEM_ID,NM_ARTEMIS_SOURCE_SYSTEM,CD_BOOK_KEY,ACTIVITY_DT) IN (SELECT ARTEMIS_SOURCE_SYSTEM_ID,NM_ARTEMIS_SOURCE_SYSTEM,CD_BOOK_KEY,ACTIVITY_DT FROM LOAD_TRADE_ORDER WHERE IND_IS_BAD_RECORD='N');
Every column in "IN" clause and select clause is containing index on it
Every time no of rows which to be deleted is vary (May be in hundred ,thousand or hundred thousand )so that I am Unable to use "BITMAP" index on the table "LOAD_TRADE_ORDER" column "IND_IS_BAD_RECORD" though it is containing distinct record in it.
Even table "TRADE_ORDER_EMP_ALLOCATION" is containing "RANGE" PARTITION over it on the column "ARTEMIS_SOURCE_SYSTEM_ID". With this I am enclosing table scripts with Indexes and Partitions over it.
way for fast execution in of above delete statement?
I have a Query(report) which is running in <5 mins in one Scheme, where as the same is running for a long time in second schema. I have identified that an Index is scanning for more than 2000 Millions of records in second Schema, but this is scanning only 440 Millions in First Schema and hence it is fast. I am expecting the same to be done in Second schema.
I have verified the following All records in tables in 2 schemas are same. All indexes are same Analyzed the tables Gathered Histogram on all the columns as per the first schema.
But now i still have the same problem, don't know what could be the problem.
I executed a query which executed quickly (1.7 seconds) but since its output took time in displaying on the console the time shown by 'set timing on was 39.5 seconds
also I took trace (tkprof) for the same.My query is why the timings under 'Total Waited' (43.19 and 1.69) are not added to the elapsed time 1.83 seconds
here we have an scenario where we want to find out all the sql statements that are executed in a particular time. The sql statements are executed via our application. I tried in awr report but it shows only the sql query which has taken long time to execute. and i even tried in V$session and V$sqlarea. how to view the executed sql statements in a particular session/current session
We have a big hierarchical query which is now running for a long time (around 6 hours. earlier it was running for 3 hours). We have to tune this query so that we run the jobs within a stipulated time frame.
The query below inserts around 42 million records in to the table WK_ACCT_WSTORE. I have attached in the text file.
Our application servers will be running a SELECT which returns zero rows all the time.This SELECT is put into a package and this package will be called by application servers very frequently which is causing unnecessary CPU.
Original query and plan
SQL> SELECT SEGMENT_JOB_ID, SEGMENT_SET_JOB_ID, SEGMENT_ID, TARGET_VERSION FROM AIMUSER.SEGMENT_JOBS WHERE SEGMENT_JOB_ID NOT IN (SELECT SEGMENT_JOB_ID FROM AIMUSER.SEGMENT_JOBS) 2 3 4 5 ; [code]....
Which option will be better or do we have other options?They need to pass the column's with zero rows to a ref cursor.
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'm planning to decrease the time taken to execute data by managing the redo log file but I'm kinda stuck in some aspect : > Why is my OPTIMAL_LOGFILE_SIZE is showing NULL ? > I'm trying to resize the LOGFILE capacity from 100M to 200M and I'm also adding 1 more LOG GROUP with 200M capacity too but turned out that didn't decrease my execution time.
I wish to run a SQL query and measure elapsed time, then compare the values to other Oracle DBs from other companies. That will give me a feeling if our DB performs well.For example in UNIX world, you can create a random 4GB file to measure throughput I/O and compare the values (for example 4MB/sec).
What's the simplest way to compare DB response time from forum members to our own DB? I don't need 100% accurate numbers.
I've got a query running a select count (*) over a table. The default plan takes in the order of 15 minutes to return, a hinted plan to use a different index takes 3 minutes to return.
Unfortunately I cant get at the index stats and a few other areas which I suspect may be key here.When running autotrace against the two queries I see fairly different values as one would expect.
Query
select count (*) from fulfilmentitem bfi where created >= sysdate-30 AND bfi.status = 'FA' AND bfi.fulfilmentmethod = 'D' Slow run PLAN_TABLE_OUTPUT ----------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| ---------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | 15 | 33119 (1)| | 1 | SORT AGGREGATE | | 1 | 15 | | |* 2 | TABLE ACCESS BY INDEX ROWID| FULFILMENTITEM | 12525 | 183K| 33119 (1)| |* 3 | INDEX RANGE SCAN | IDX_FULFIL_METHODSTATUS | 250K| | 1786 (1)| ---------------------------------------------------------------------------------------------- [code]....
IDX_FULFIL_METHODSTATUS is across FULFILMENTMETHOD & STATUS in that order. IDX_BFI_CREATED is on CREATED and is approx 70% of the size of the other index
The row counts estimated in the explain plan are out, the count(*) comes in at 32.8k rows.As you will have seen, the fast run shows a pretty significant consistent get increase compared to the slow run and a decent though not dramatic physical read drop.
My uncertainty is around if these changes in consistent get/phys read values would typically be enough to suggest the real time improvements I'm observing or if other (albeit perhaps temporary) factors are involved. It is a prod OLTP environment so the data will be rapidly changing and that may be a factor.
I know it can never be an exact science without intimately knowing the hardware/current loads etc but I also know that there's enough experience on these boards to have a loose handle on if the time shifts between queries are likely (or not) to be reflective of the stat changes or if those differences alone shouldn't (or typically wouldn't account) for it.
I'm thinking about instructing the query to ignore its original plan but am hesitant to do so without being a little more confident that it's not just a timing thing or something other than the change of index approach which may be causing the improvement. the autotrace stat changes observed I couldn't put my hand on heart say "yup - that change is good, ignore the default index all the time for this job".
