Idoc Hit ratio and Idoc Table

Hi
We would like to monitor the idoc hit ratio (No of idocs posted successfully in the first instance/Total No of Idocs) to see the success rate of our interfaces.
What is the best way to get this data?
Is there any table which gives all the statuses of the idocs. For eg If a idoc had initially failed (status 51) and then it was reprocessed and was successfully posted (status 53), is there any table which gives us this data?
Thanks in advance.
Mick

Thanks Sergey.
I checked one idoc, which was created on 29.01.2010 (29th January 2010). However when I use table EDIDS, with field CREDAT as 10.02.2010 (10th Feb, 2010), it shows me 2 entries for the above mentioned idoc. This is because it was reprocessed on 10th of Feb.
Is there any way to get the idocs created on say for eg 0n the 1st of Feb, 2010 along with the entire history of statuses on the 1st of Feb (all the statuses that the idoc went through on the 1st of Feb)?
Mick

Similar Messages

Any link having various Hit ratios and SQL's to calculate them

Hi
Can an ybody give me the link having various Hit ratios in Oacle9i and SQl's to calulate them????How about using advisors than calclating the Hit ratios??
Regards
Gagan

Please be aware that ratios are only helpful in tuning in a relatively small set of circumstances. For instance, if you have just set up a new database and need to montitor the effectiveness of certain init.ora parameters. Ratios can be useful in diagnosing system wide problems but only if you have sufficient understanding of your system to know what is a "good" value. A buffer cache hit ratio of 95% might be bad, a hit ratio of 70% might be great, it really depends on the nature of you application. There is a useful little piece by Jonathan Lewis on his site which compares the value of mining the underlying data for information about the system over looking at the headline ratios. Find out more.
The standard Oracle tools - such as OEM and Statspack - include ratios as part of their offering.
Cheers, APC

Buffer Cache hit Ratio

Hi All,
My DB Version: 10.2.0
OS: Windows Server 2003
I run the following script to get Hit ratio's
SELECT cur.inst_id, 'Buffer Cache Hit Ratio ' "Ratio", to_char(ROUND((1-(phy.value / (cur.value + con.value)))*100,2)) "Value"
FROM gv$sysstat cur, gv$sysstat con, gv$sysstat phy
WHERE cur.name = 'db block gets'
AND con.name = 'consistent gets'
AND phy.name = 'physical reads'
and phy.inst_id=1
and cur.inst_id=1
and con.inst_id=1
union all
SELECT cur.inst_id,'Buffer Cache Hit Ratio ' "Ratio", to_char(ROUND((1-(phy.value / (cur.value + con.value)))*100,2)) "Buffer Cache Hit Ratio"
FROM gv$sysstat cur, gv$sysstat con, gv$sysstat phy
WHERE cur.name = 'db block gets'
AND con.name = 'consistent gets'
AND phy.name = 'physical reads'
and phy.inst_id=2
and cur.inst_id=2
and con.inst_id=2
union
SELECT inst_id, 'Library Cache Hit Ratio ' "Ratio", to_char(Round(sum(pins) / (sum(pins)+sum(reloads)) * 100,2)) "Library Cache Hit Ratio"
FROM gv$librarycache group by inst_id
union
SELECT inst_id,'Dictionary Cache Hit Ratio ' "Ratio", to_char(ROUND ((1 - (SUM (getmisses) / SUM (gets))) * 100, 2)) "Percentage"
FROM gv$rowcache group by inst_id
union
Select inst_id, 'Get Hit Ratio ' "Ratio",to_char(round((sum(GETHITRATIO))*100,2)) "Get Hit"--, round((sum(PINHITRATIO))*100,2)"Pin Hit"
FROM GV$librarycache
where namespace in ('SQL AREA')
group by inst_id
union
Select inst_id, 'Pin Hit Ratio ' "Ratio", to_char(round((sum(PINHITRATIO))*100,2))"Pin Hit"
FROM GV$librarycache
where namespace in ('SQL AREA')
group by inst_id
union
select a.inst_id,'Soft-Parse Ratio ' "Ratio", to_char(round(100 * ((a.value - b.value) / a.value ),2)) "Soft-Parse Ratio"
from (select inst_id,value from gv$sysstat where name like 'parse count (total)') a,
(select inst_id, value from gv$sysstat where name like 'parse count (hard)') b
where a.inst_id = b.inst_id
union
select a.inst_id,'Execute Parse Ratio ' "Ratio", to_char(round(100 - ((a.value / b.value)* 100),2)) "Execute Parse Ratio"
from (Select inst_id, value from gv$sysstat where name like 'parse count (total)') a,
(select inst_id, value from gv$sysstat where name like 'execute count') b
where a.inst_id = b.inst_id
union
select a.inst_id,'Parse CPU to Elapsed Ratio ' "Ratio", to_char(round((a.value / b.value)* 100,2)) "Parse CPU to Elapsed Ratio"
from (Select inst_id, value from gv$sysstat where name like 'parse time cpu') a,
(select inst_id, value from gv$sysstat where name like 'parse time elapsed') b
where a.inst_id = b.inst_id
union
Select a.inst_id,'Chained Row Ratio ' "Ratio", to_char(round((a.val/b.val)*100,2)) "Chained Row Ratio"
from (SELECT inst_id, SUM(value) val FROM gV$SYSSTAT WHERE name = 'table fetch continued row' group by inst_id) a,
(SELECT inst_id, SUM(value) val FROM gV$SYSSTAT WHERE name IN ('table scan rows gotten', 'table fetch by rowid') group by inst_id) b
where a.inst_id = b.inst_id
union
Select inst_id,'Latch Hit Ratio ' "Ratio", to_char(round(((sum(gets) - sum(misses))/sum(gets))*100,2)) "Latch Hit Ratio"
from gv$latch
group by inst_id
/* Available from 10g
union
select inst_id, metric_name, to_char(value)
from gv$sysmetric
where metric_name in ( 'Database Wait Time Ratio', 'Database CPU Time Ratio')
and intsize_csec = (select max(intsize_csec) from gv$sysmetric)
order by inst_id
What i am getting after this is:
INST_ID Ratio Value
1 Buffer Cache Hit Ratio .83
1 Chained Row Ratio 0
1 Dictionary Cache Hit Ratio 77.5
1 Execute Parse Ratio 45.32
1 Get Hit Ratio 75.88
1 Latch Hit Ratio 100
1 Library Cache Hit Ratio 99.52
1 Parse CPU to Elapsed Ratio 24.35
1 Pin Hit Ratio 95.24
1 Soft-Parse Ratio 89.73
i have a doubt with buffer cache hit ratio, can anyone please help me to understand this

Buffer Cache Hit Ratio .83Quite weird value. It seems your system is doing all physical reads, which seems unrealistic.
I had a 10.2.0.1 database where i saw this kind of result for cache hit ratio and after patching it to 10.2.0.4, it started showing results correctly.
Probably it could be some Oracle 10g bug which made this odd display of hit ratio information in data dictionary. Can you try patching your database to latest 10g PSU, or contact Oracle support for a one-off patch for this problem
Salman

Buffer cache hit ratio query

Hi,
I would appreciate some advice please.
My Oracle 10.2.0.4.0 database starts off in the day with a buffer cache hit ratio of almost 100% but this drops gradually in the course of the day as the system gets busier. Is this something I need to be concerned about if no performance problem has been reported by the users?
I would have thought this should be a normal situation, i.e. as the system gets busier, I would expect that less number of calls to the buffer cache will be satisfied because many more calls are using up the memory?
Please note that I've done some reading up on this but would like some suggestions from more experienced people than myself on what I should normally expect and what should or should not be a concern.
thanks

user8869798 wrote:
hi,
thanks again for your response and apologies for not being able to get back yesterday.No problem :) .
>
- What i am doing and how - it is the backend database r our Finance application, many users with various transactions.Okay , that sounds like a "normal" database with normal workload.
- configuring buffer cache size - I haven't done anything manually yet, it's all been as installed, this is what I'm trying to figure out whether it is something I should be looking into doing simply because of the dropping hit ratio and not because of any reported performance problem.If you don't have much of the knowledge, its the best to take use of the advisories which would tell you in a better and in a graphical way that whether you should or shouldn't be worries. Look at the view v$db_cache_advice which can suggest to you that whether you would need to tweak the buffer cache or not.
>
- looking at the queries - What is the easiest way of doing this in an environment where many users are running different queries? What's the easiest way to identify queries that we may need to have a closer look at?Easiest way? Well, let the users come back to you ;-) .
>
- Basically, I'm just trying to ascertain whether or not I need to be concerned that my hit ratio drops below 89% even though no performance problem has been reported. If it is something that I should look into, then what is the best way to go about it?
I believe that's answered by couple of us already, nope.
Aman....

Oracle Buffer Hit Ratio

I m using this query to find Oracle Buffer Hit ratio .Is this query right.Is there some other way of getting more accurate ratio
select trunc((1-(sum(decode(name,'physical reads',value,0))/(sum(decode(name,'db block gets',value,0)) + (sum(decode(name,'consistent gets',value,0)))))) * 100) from v$sysstat

Asif,
Too bad we couldn't meet when I happened to come to Bdesh coz if we could , we would had talked about the same topic for hours. If you are using this hit ratio as the tuning technique than you are not alone. There are so many dbas who are using hit ratio and loose sleep seeing not to a particular %. It was a method that was given years ago by Oracle reason being that at that time, databases , their loads, they were not too much. But now things have changed so should be the troubleshooting techniques. Search over this forum for the same topic and you would see some "cool" threads where some top-notch experts are talking about the same issue.
Aman....

Buffer, library,dictionary, shared pool, redo log buffer chache hit ratios

Can please one provide information and sql queries to calculate Buffer, library,dictionary, shared pool, redo log buffer chache hit ratios and if any other ratio for investigation of performance issues in oracle 10g database (10g.1 and 10g.2 both). thanks in advance.

In and by themselves most of the standard ratio calculations are useless to misleading. All the ratios should always be considered in relation to other data such as total requests for a resource, existence of any outlying values in the associated events, etc ....
The proper warning being given then you can find most of the standard ratios mentioned with SQL for their calculation in the Performance and Tuning manual for your version of Oracle.
HTH -- Mark D Powell --

Calculate cache hit ratio

Hi,
How to calculate cache hit ratio and execution time for the below query
Select * from tab;
Nirmal

Fnord. Cache hit ratio is meaningless in the context of a single query. Come to that, it's meaningless in any context. Check out this handy utility from Connor McDonald which allows us to set the cache hit ratio to any value that pleases us.
So what is the actual problem that is troubling you?
Cheers, APC

What is the name of the IDoc table

Can anyone tell me what the name of the IDoc table is

Janice,
Go to WE16 transaction and give the table name. If you dont know the table name just search out for it with all.
---Satish

Default Buffer Pool Busy Waits and Default Buffer Pool Hit Ratio

Hi experts,
I am having oracle database with version 11gR2 on windows server 2003 platform.
I am continuously getting alerts related to "Default Buffer Pool Busy Waits" and "Default Buffer Pool Hit Ratio."
I have fired some of the queries(which contain view like v$session_wait) to get information of sessions that causing the same issue,but unable to get it.
Please help me to resolve the same issue.

Hi - Try this query for Buffer busy wait
COL class FORM a10
COL total_waits FORM 9,999,999,999
COL "WAITS %" FORM 9999999
COL time_waited FORM 9999999
COL "TIME %" FORM 9999999
COL event FORM a24
COL avg_wait FORM 9999.99
SELECT a.event event, substr(c.wait_class,1,9) class,
a.total_waits total_waits, a.time_waited/100 time_waited,
a.average_wait avg_wait
-- a.average_wait/100 avg_wait -- displays seconds instead of 100s
FROM v$system_event a, v$event_name b, v$system_wait_class c
WHERE a.event_id=b.event_id
AND b.wait_class#=c.wait_class#
AND a.time_waited/100 > 0
AND (event LIKE '%HW%' OR event = 'buffer busy waits')
-- AND c.wait_class in ('Application','Concurrency','User I/O')
ORDER BY 1 DESC;

IDOC Tables with Errors Post System Refresh

Hi Everyone,
Is there any Report or other way through which one can get List of IDOC Tables with Errors Post System Refresh.
Thanks,
Regards,
- Ishan

Hi,
While selecting the Infopackage to run the INIT load, it is taking me to the ECC login screen. Once i enter my credentials, its showing a dump with the message:
Short text of error message:
No RFC authorization for user XXXXX ( RSA8 ).
Long text of error message:
Technical information about the message:
Message class....... "RSAR"
Number.............. 051
Variable 1.......... "No RFC authorization for user XXXXX ( RSA8 )."
Variable 2.......... " "
Variable 3.......... " "
Variable 4.......... " "
Please advice.
Regards
sneha

Dimension and Fact table Ratios

Hi All,
I have loaded some test data into my Cube and executed the program "SAP_INFOCUBE_DESIGNS" to get the ratios of Dimension tables to Fact table. I found that 1 dimension is almost equal to the fact table. but, as far as my knowledge, a dimension table should not exceed 30% of the fact table, please correct me if I am wrong.
To decrease the size of the dimension table, I have created another dimension and included some of the chars, from the bigger dimension, in it. I have loaded the data again and ran the program again. But, the program result is still showing the same as previous i.e the ratio has not been changed and even the newly added dimension is not being showed. Do I need to refresh something to get the new ratios?
Thanks,
RPK.

Hi Paolo,
I tried as you suggested but unfortunately no luck. Below are the steps I performed.
RC on the cube->Manage->Performance tab->Click on "Refresh Statistics".
I also tried:
RC on the cube->Manage->Performance tab->Click on "Create Statistics(Btch)".
What could be wrong?
Thanks,
RPK.

Ratio between Fact table and Dimention table for a Infocube

Hi All,
How can we reduce the Ratio between Fact table and Dimention table for a Infocube below 20%.??
please give suggestions

Hi
Reduce Ratio??
The Ratios are dependent on the Fact Table, and the Dimension table that is modeled for your Cube.
You cannot change ratio individually, but can set the Line Item Dimension , provided you have only one char object is taking much space and bulky with much percentage, based on your requirement. You can always use fine tuning objects.
Please be more specific while posting, to get right help from sdn.
Hope it helps

BAPI FOR Deleting a Schedule Line Item from EKES and EKET tables

Dear All,
I would like to for deleting one of the line item from EKES (Po Confirmation ) and the respective line item from the EKET(PO Schedule Line Item Table).
Assume that am allowing the user to select the lineitem from zprogram screen and collecting the PO and Its LIne Item details in an internal table.
Can i Use
<b>BAPI_PO_Change</b> , if so , can anybody tell me the steps to follow to use this bapi for deleting the PO lineItems, since i m going to try BAPI for First time.
pls help me out
Message was edited by: Raja K.P

Hi raja ,
loop at iekko1.
    w_index = sy-tabix.
    item-po_item   = itemx-po_item   = iekko1-ebelp.
    item-quantity = iekko1-mng01.
    itemx-quantity = iekko1-mng01.
    if iekko1-wamng = iekko1-wemng.
    itemx-no_more_gr = item-no_more_gr = 'X'.
    else.
    itemx-no_more_gr = item-no_more_gr = ''.
    endif.
    append item.
    append itemx.
      clear return[].
      call function 'BAPI_PO_CHANGE'
           exporting
                purchaseorder = iekko1-ebeln
           tables
                return        = return
                poitem        = item
                poitemx       = itemx.
      if return[] is initial.
      commit work and wait.
      call function 'DEQUEUE_ALL'.
search for deletion fields which u have to mark 'X'.
before calling this BAPi u have to lock the PO by using ENQUEUE.
<b>
FU BAPI_PO_CHANGE
Text
Change purchase order
Functionality
Function module BAPI_PO_CHANGE enables you to change purchase orders. The Change method uses the technology behind the online transaction ME22N.
Alternatively, the IDoc type PORDCH1 is available. The data from this IDoc populates the interface parameters of the function module BAPI_PO_CHANGE.
Functionality in Detail
Authorization
When you create (activity 02) an Enjoy purchase order, the following authorization objects are checked:
M_BEST_BSA (document type in PO)
M_BEST_EKG (purchasing group in PO)
M_BEST_EKO (purchasing organization in PO)
M_BEST_WRK (plant in PO)
Controlling adoption of field values via X bar
For most tables, you can use your own parameters in the associated X bar (e.g. PoItemX) to determine whether fields are to be set initial, values inserted via the interface, or default values adopted from Customizing or master records, etc. (for example, it is not mandatory to adopt the material group from an underlying requisition - you can change it with the BAPI).
Transfer
Purchase order number
The PurchaseOrder field uniquely identifies a purchase order. This field must be populated in order to carry out the Change method.
Header data
The header data of the Enjoy purchase order is transferred in table PoHeader.
Item data
The item data of the Enjoy purchase order is stored in the tables PoItem (general item data). Changes regarding quantity and delivery date are to be made in the table PoSchedule.
Use the table PoAccount to change the account assignment information.
Services and limits
Changes to existing items cannot be carried out with the Change method. It is only possible to create new items.
Conditions
Conditions are transferred in the table PoCond; header conditions in the table PoCondHeader. A new price determination process can be initiated via the parameter CALCTYPE in the table PoItem.
Vendor and delivery address
The vendor address in the table PoAddrVendor and the delivery address in the table PoAddrDelivery can only be replaced by another address number that already exists in the system (table ADRC). Changes to address details can only be made using the method BAPI_ADDRESSORG_CHANGE.
Partner roles
You can change all partners except the partner role "vendor" via the table PoPartner.
Export/import data
Export/import data can be specified per item in the table PoExpImpItem. Foreign trade data can only be transferred as default data for new items. Changes to the export/import data of existing items are not possible.
Texts
Header and item texts can be transferred in the tables PoTextHeader and PoTextItem. Texts for services are imported in the table PoServicesText. Texts can only be replaced completely.
Version Management
You can make use of the Version Management facility via the table AllVersions.
Return
If the PO was changed successfully, the header and item tables are populated with the information from the PO.
Return messages
Messages are returned in the parameter Return. This also contains information as to whether interface data has been wrongly or probably wrongly (heuristical interface check) populated. If a PO has been successfully created, the PO number is also placed in the return table with the appropriate message.
Restrictions
With this function module, it is not possible to:
Create subcontracting components (you can only use existing ones)
Create configurations (you can only use existing ones)
Change message records (table NAST) and additional message data (this data can only be determined via the message determination facility (Customizing))
Attach documents to the purchase order
Change foreign trade data
Change service data
Change or reexplode BOMs
A firewall prevents the manipulation of data that is not changeable in Purchasing according to the business logic of the purchase order (e.g. PO number, vendor, etc.).
PO items with an invoicing plan cannot be created or changed using the BAPIs
In this connection, please refer to current information in Note 197958.
To change addresses with numbers from Business Address Services (cantral address management), please use the function module BAPI_ADDRESSORG_CHANGE.
To change variant configurations, please use the function module BAPI_UI_CHANGE. More information is available in the BAPI Explorer under the Logistics General node.
In the case of changes that are to be made via the BAPI_PO_CHANGE, a firewall first checks whether the relevant fields are changeable. This approach follows that of the online transaction. Here it is not possible to change the vendor or the document type, for example.
Example
Example of changes made to a purchase order with:
1. Change in header data
2. Change in item
3. Change in delivery schedule
4. Change in account assignment
5. Change in conditions
6. Change in partners
Parameter: PURCHASEORDER 4500049596
Parameter: POHEADER
PMNTTRMS = 0002
PUR_GROUP = 002
Parameter: POHEADERX
PMNTTRMS = X
PUR_GROUP = X
Parameter: POITEM
PO_ITEM = 00001
CONF_CTRL = 0001
Parameter: POITEMX
PO_ITEM = 00001
PO_ITEMX = X
CONF_CTRL = X
Parameter: POSCHEDULE
PO_ITEM = 00001
SCHED_LINE = 0001
QUANTITY = 10.000
PO_ITEM = 00001
SCHED_LINE = 0003
DELETE_IND = X
Parameter: POSCHEDULEX
PO_ITEM = 00001
SCHED_LINE = 0001
PO_ITEMX = X
SCHED_LINEX = X
QUANTITY = X
PO_ITEM = 00001
SCHED_LINE = 0003
PO_ITEMX = X
SCHED_LINEX = X
DELETE_IND = X
Parameter: POACCOUNT
PO_ITEM = 00001
SERIAL_NO = 01
GL_ACCOUNT = 0000400020
Parameter: POACCOUNTX
PO_ITEM = 00001
SERIAL_NO = 01
PO_ITEMX = X
SERIAL_NOX = X
GL_ACCOUNT = X
Parameter: POCOND
ITM_NUMBER = 000001
COND_TYPE = RA02
COND_VALUE = 2.110000000
CURRENCY = %
CHANGE_ID = U
Parameter: POCONDX
ITM_NUMBER = 000001
COND_ST_NO = 001
ITM_NUMBERX = X
COND_ST_NOX = X
COND_TYPE = X
COND_VALUE = X
CURRENCY = X
CHANGE_ID = X
Parameter: POPARTNER
PARTNERDESC = GS
LANGU = EN
BUSPARTNO = 0000001000
Help in the Case of Problems
1. Note 197958 lists answers to frequently asked questions (FAQs). (Note 499626 contains answers to FAQs relating to External Services Management.)
2. If you have detected an error in the function of a BAPI, kindly create a reproducible example in the test data directory in the Function Builder (transaction code SE37). Note 375886 tells you how to do this.
3. If the problem persists, please create a Customer Problem Message for the componente MM-PUR-PO-BAPI, and document the reproducible example where necessary.
Customer Enhancements
The following user exits (function modules) are available for the BAPI BAPI_PO_CREATE1:
EXIT_SAPL2012_001 (at start of BAPI)
EXIT_SAPL2012_003 (at end of BAPI)
The following user exits (function modules) are available for the BAPI BAPI BAPI_PO_CHANGE:
EXIT_SAPL2012_002 (at start of BAPI)
EXIT_SAPL2012_004 (at end of BAPI)
These exits belong to the enhancement SAPL2012 (see also transaction codes SMOD and CMOD).
There is also the option of populating customer-specific fields for header, item, or account assignment data via the parameter EXTENSIONIN.
Further Information
1. Note 197958 contains up-to-date information on the purchase order BAPIs.
2. If you test the BAPIs BAPI_PO_CREATE1 or BAPI_PO_CHANGE in the Function Builder (transaction code SE37), no database updates will be carried out. If you need this function, please take a look at Note 420646.
3. The BAPI BAPI_PO_GETDETAIL serves to read the details of a purchase order. The BAPI cannot read all details (e.g. conditions). However, you can use the BAPI BAPI_PO_CHANGE for this purpose if only the document number is populated and the initiator has change authorizations for purchase orders.
4. Frequently used BAPIs for purchase orders are BAPI_PO_CREATE, BAPI_PO_CREATE1, BAPI_PO_CHANGE, BAPI_PO_GETDETAIL, BAPI_PO_GETITEMS, BAPI_PO_GETITEMSREL, and BAPI_PO_GETRELINFO.
5. For more information on purchase orders, refer to the SAP library (under MM Purchasing -> Purchase Orders) or the Help for the Enjoy Purchase Order, or choose the path Tools -> ABAP Workbench -> Overview -> BAPI Explorer from the SAP menu.
Parameters
PURCHASEORDER
POHEADER
POHEADERX
POADDRVENDOR
TESTRUN
MEMORY_UNCOMPLETE
MEMORY_COMPLETE
POEXPIMPHEADER
POEXPIMPHEADERX
VERSIONS
NO_MESSAGING
NO_MESSAGE_REQ
NO_AUTHORITY
NO_PRICE_FROM_PO
EXPHEADER
EXPPOEXPIMPHEADER
RETURN
POITEM
POITEMX
POADDRDELIVERY
POSCHEDULE
POSCHEDULEX
POACCOUNT
POACCOUNTPROFITSEGMENT
POACCOUNTX
POCONDHEADER
POCONDHEADERX
POCOND
POCONDX
POLIMITS
POCONTRACTLIMITS
POSERVICES
POSRVACCESSVALUES
POSERVICESTEXT
EXTENSIONIN
EXTENSIONOUT
POEXPIMPITEM
POEXPIMPITEMX
POTEXTHEADER
POTEXTITEM
ALLVERSIONS
POPARTNER
Exceptions
Function Group
2012
</b>
regards
prabhu
Message was edited by: Prabhu Peram

Problem with the cache hit ratio

Hello,
I ma having a problem with the cache hit ratio I am geting. I am sure, 100% sure, that something has got to be wrong with the cache hit ratio I am fetching!
1) I will post the code that I am using to retrieve the cache hit ratio. I've seen about a thousand different equations, all equivalent in the end.
In oracle cache hit ratio seems to be:
cache hits / cache lookups,
where cache hits <=> logica IO - physical reads
cache lookups <=> logical IO
Now some people use the session logical Reads stat, from teh view v$sysstat; others use db block gets + db consistent gets; whatever. At the end of the day its all the same, and this is what i Use:
SELECT (P1.value + P2.value - P3.value) AS CACHE_HITS, (P1.value + P2.value) AS CACHE_LOOKUPS, P4.value AS MAX_BUFFS_SIZEB
FROM v$sysstat P1, v$sysstat P2, v$sysstat P3, V$PARAMETER P4
WHERE
P1.name = 'db block gets' AND
P2.name = 'consistent gets' AND
P3.name = 'physical reads' AND
P4.name = 'sga_max_size'
2) The problem:
The cache hit ratio I am retrieving cannot be correct. In this case i was benchamarking a HUGELY inneficient query, consisting of the Union of 5 Projections over the same source table, and Oracle is configured with a relatively small SGA of 300 MB. They query plan is awful, the database will read the source database table 5 times.
And I can see in the physical data statistics of the source tablespace, that total Bytes read is aproximatly 5 times the size of the text file that I used to bulk load data into the databse.
Some of the relevant stats, wait events:
db file scattered read     1129,93 seconds
Elapsed time: 1311,9 seconds
CPU time: 179,84
SGA max Size: 314572800 Bytes
And total bytes read: 77771964416 B (aproximatly 72 Gga bytes)
the source txt loaded to the database was aprox 16 G
Number of reads was like 4.5 times the source datafile.
I would say this, given the difference between CPU time and Elapsed Time, it is clear that the query spent almost all of its time doin DB file scattered reads. How is it possible that i get the following cache hit ratio:
Cache hit Ratio: 0,92
Cache hits: 109680186
Cache lookups: 119173819
I mean only 8% of that Logical I/O corresponded to physical I/O? It is just not possible.
3) Procedure of taking stats:
Now to retrieve these stats I snapshot the system 2 times. One before the query, one after the query.
But: this is not done in a single session. In total 3 sessions are created. One session two retrieve the stats before the query, one session to run the query, a last session to snapshot after the query.
Could the problem, assuming there is one, be related to this:
"The V$SESSTAT view contains statistics on a per-session basis and is only valid for the session currently connected. When a session disconnects all statistics for the session are updated in V$SYSSTAT. The values for the statistics are cleared until the next session uses them."
What does this paragraph mean. Does it mean that the v$sysstat only shows you the stats of the last session that closed? Or does it mean thtat v$sysstat is increamented with the statistics of each v$sessionstat once a session terminates? If so, then my procedure for gathering those stats should be correct.
Can anyone help me sort out the origin of such a high cache hit ratio, with so much I/O being done?

sono99 wrote:
Hi,s
first of, let me start by saying that there were many things in your post that you mentioned that I could no understand. 1. Because i am not an Oracle Expert, i use whatever RDBMS whenever i need to. 2. Because another problem has come up and, right now, i cannot inform myself to be able to comprehend it all.Well, could it be that you need to understand the database you are working on in order to comprehend it? That is why we strongly advise you to read the concepts manual first, you need to understand the architecture that Oracle uses, as well as the basic concepts of how oracle does locking and maintains read consistency. It does these different than other database engines, and some things become nonsense if looked at from the viewpoint of a single user.
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quote:
It would be useful to see the execution plan jhust in case you have simplified the problem so much that a critical detail is missing.
First, the query code:
2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:>SQL> CREATE TABLE FAVFRIEND
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 2 NOLOGGING TABLESPACE TARGET
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 3 AS
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 4 SELECT ID as USRID, FAVF1 as FAVF FROM PROFILE
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 5 UNION ALL
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 6 SELECT ID as USRID, FAVF2 AS FAVF FROM PROFILE
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 7 UNION ALL
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 8 SELECT ID as USRID, FAVF3 AS FAVF FROM PROFILE
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 9 UNION ALL
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 10 SELECT ID as USRID, FAVF4 AS FAVF FROM PROFILE
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 11 UNION ALL
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 12 SELECT ID as USRID, FAVF5 AS FAVF FROM PROFILE
[2009-10-20 15:11:59,141 INFO]: OUTPUT_GOBLER:> 13 ;
Now, Althought it is clear from the query that the statement is executed with the NOLOGGiNG, i have disabled the logging entirely for the tablespace.There are certain rules about nologging that may not be obvious. Again, this derives from the basic Oracle architecture, and if you use the wrong definitions of things like logging, you will be led down the primrose path to confusion.
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Futhermore, yes, the RDBMS is a test RDBMS... I have droped the database a few times... And I am constantly deleting an re-inserting data into the source database table named PROFILE.>
I also make sure do check all the datafile statistics, and for this query the amount of RedoLog, Undo "Log", Templife used is negligible, practically zero.Create table is DDL, which has implied commits before and afterwards. There is a lot going on, some of it dependent on the volume of data returned. The Oracle database writer writes things out when it feels like it, there are situations where it might just leave it in memory for a while. With nologging, Oracle may not care that you can't perform recovery if it is interrupted. So you might want to look into statspack or EM to tell you what is going on, the datafile statistics may not be all that informative for this case.
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Most of the I/O is reading, a few of the I/O is writing.
My idea is not to optimize this query, it is to understand how it performs. Well, have you read the Concepts manual?
I have other implementations to test, namely I having trouble with one of them.
Furthermore, I doubt the query Plan Oracle is using actually involves tablescans (as I I'd like it to do); because in the Wait Events, most of the wait time for this query is spent doing "db file scattered read". And I think this is different from a tablescan.Please look up the definition of [db file scattered read|http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/instance_tune.htm#sthref703].
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Do you really have to use sessions external to the query session ? Can you query v$mystat joined to v$statname from the session itself.
No, I don't want to that!
I avoid as much as possible having the code I execute being implemented in java. Why do you think java has anything to do with this? In your session, desc v$mystat and v$statname, these are views you can look at.
When i can avoid it I don't query the database directly through JDBC, i use the RDBMS command line client, which is supposed to be very robust. Er, is that sqlplus?
So yes, I only connect to the database with JDBC... in very last session.
Of course, I Could Have put both the gather stats before query and gathers stats after query a single script: the script that would be also runing the query.
But that would cause me a number of problems, namely some of the SQL i build has to be implemented dynamically. And I don't want to be replicating the snapshoting code into every query script I make. This way I have one sql with the snapshoting scripts; and multiple scripts for running each query. I avoid code replication in this manner.Instrumentation is a large subject; dynamic sql generation is something to be avoided if possible. Remember, Oracle is written with the idea that many people are going to be sharing code and the database, so it is optimized in that way. For SQL parsing in particular, if every SQL is different, you get a performance problem called "hard parsing." You can (and generally should, and sometimes can't avoid) use bind variables so that Oracle doesn't need to hard parse every SQL. In fact, this is one of those things that applies to other engines besides Oracle. I would recommend you read Tom Kyte's books, he explains what is going on in detail, including in some places the non-Oracle viewpoint.
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Furthermore, Since the database is not a production database, it is there so I can do my tests. I don't have to be concerned with what other sessions may be doing to my system. There are only the sessions I control.No, there are sessions Oracle controls. If you are on unix, you can easily see this, but there are ways to see it on Windows, too. In some cases, your own sessions can affect themselves.
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then what it the array fetch size ? If the array fetch size is large enough the number of block visits would be similar to the number of physical block reads.
I don't know what the arraysize you mention is. i have not touched that parameter. So whatever it is, it's the default.You should find out! You can go to http://tahiti.oracle.com and type array fetch size into the search box. You can also go to http://asktom.oracle.com and do the same thing, with some more interesting detail.
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By the way, I don't get the query results into my client, the query results are dumped into a target output table.
So, if the arraysize has something to do with the number of rows that Oracle is returning the client in each step... I think it doesn't matter.You may hear this phrase a lot:
"It depends."
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As for the query plan, If i am not mistaken you can't get get query plans for queries that are: create table as select.What?
JG@TTST> explain plan for create table jjj as select * from product_master;
Explained.
JG@TTST> select count(*) from plan_table;
COUNT(*)
         3
I can however commit the create table part and just call for the evalution of the Select part of the query; i believe it should be same.
"Optimizer"     "Cost"     "Cardinality"     "Bytes"     "Partition Start"     "Partition Stop"     "Partition Id"     "ACCESS PREDICATES"     "FILTER PREDICATES"
"SELECT STATEMENT"     "ALL_ROWS"     "2563"     "586110"     "15238860"     ""     ""     ""     ""     ""
"UNION-ALL"     ""     ""     ""     ""     ""     ""     ""     ""     ""
"TABLE ACCESS(FULL) SONO99.PROFILE"     ""     "512"     "117222"     "3047772"     ""     ""     ""     ""     ""
"TABLE ACCESS(FULL) SONO99.PROFILE"     ""     "513"     "117222"     "3047772"     ""     ""     ""     ""     ""
"TABLE ACCESS(FULL) SONO99.PROFILE"     ""     "513"     "117222"     "3047772"     ""     ""     ""     ""     ""
"TABLE ACCESS(FULL) SONO99.PROFILE"     ""     "513"     "117222"     "3047772"     ""     ""     ""     ""     ""
"TABLE ACCESS(FULL) SONO99.PROFILE"     ""     "513"     "117222"     "3047772"     ""     ""     ""     ""     ""
This query plan was taken from sql developer, exported to txt, and the PROFILE table here has only 100k tuples.
Right now I am more concerned with testing the MODEL query. Which Oracle doesn't seem to be able any more... but that is a matter for another thread.
Regarding this plan. The Union ALL seems to be more than just a binary Operator... IT seems to be Neray.
The union all on that execution plan seems to be taking as leaf tables 5 99sono.Profile tables, and be making a table scan to them all. So I'd say that the RDBMS should only scan each database block once and not 5 times.
But: It doesn't seem to be so. IT seems like what oracle is doing is scanning completly each the table, and then moving on to next select statement in the UNION ALL. Because given the amount of source table that was read, 5 times greater than the size of the source table. Oracle didn't reuse read blocks.
But this is just my feeling.Your feeling is uninteresting. Telling us what you really hope to accomplish might be more interesting.
Anyway, in terms of consistent gets, how many consistent gets should the RDBMS be doing? 5
One for each table block?It depends.
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My best regards,
Nuno (99sono xp).

Low buffer hit ratio

Hi all,
could anyone please let me know how I can improve upon the buffer hit ratio in Oracle 8.0
I have increased my buffer size by 40% in the init.ora parameters but there has been no gain at all in the buffer hit ratio after the system has been bounced and up by 42 hrs so could any let me know..
Thanks
Akkama

Why don't u try pinning the objects accessed frequently - even pinning tables are possible.

Idoc Hit ratio and Idoc Table

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