Who will generate hash value

Hi Everyone,
I need some information about hash value getting generated for every new SQl
I think that PGA will generate hash value every time
thanks in advance
Shareef

912856 wrote:
Hi Everyone,
I need some information about hash value getting generated for every new SQl
I think that PGA will generate hash value every time
PGA would "generate" the value? Isn't it that the hash-values are generated by hash functions ? If you want information about how the parsing works, please read,
http://docs.oracle.com/cd/E11882_01/server.112/e16638/optimops.htm#i21299
And,
http://docs.oracle.com/cd/E11882_01/server.112/e25789/sqllangu.htm#CNCPT1740
Aman....

Similar Messages

Generating MD5 hash value for any specific flat file

Hi experts,
I am developing a program that will generate flat files and also I should generate the MD5 Hash value for each and every flat files. My question is how can I generate the MD5 hash value for the generated .txt files.
Thanks in advance
Shabir

You can use functions
MD5_CALCULATE_HASH_FOR_CHAR for text file
MD5_CALCULATE_HASH_FOR_RAW for binary

Generate Sequential values for a column

Hi,
I had a column in named 'ID' in the block of my form. I want to generate sequential values for the column without using sequence. Suppose if the table does not have any data it has display the starting value what i am providing.(ex. 101).If the data is there in the table If i am executing the query in the last null record it has to show the maxvalue+1 for that column. where can I write the code to get this logic? How to write the code? Can any body please solve my problem?
Thanks in advance
user1

Why don't you want to use a sequence? Do the ORDID values have to be sequential without any gaps in between?
If so, this requirement is quite hard to achieve in multi-user environment.
Some approaches:
Select the next available value from the database when creating a new record , e.g. in the WHEN-CREATE-RECORD-Trigger:
DECLARE
CURSOR crMax IS
SELECT NVL(MAX(ORDID), 0)+1
FROM ORD;
BEGIN
OPEN crMax;
FETCh crMax INTO :ORD.ORDID;
CLOSE crMax;
END;Pros: The user can see the new value when he starts entering the data.
Contras: When another user uses the same form to create a new record between the point of time user 1 starts entering the record and the point of time he saves, the same number will be taken again which will fail on insert for the second user (i assume there is a Unique Key on ORDID).
Result: This approach is not suitable in a multi-user environment.
Second approach:
Use the same logic as in approach 1, but select the next available number in the PRE-INSERT-trigger of the block:
Pros: The problem of approach 1 with two users getting the same number gets much more unlikely, for in general the COMMIT goes quite short after the PRE-INSERT has fired, so there will only be problems if both users save at the same moment.
Contras: Problem with duplicate numbers can still occur iunder special circumstances. The number is not shown until the Insert is issued against the database.
Result: This approach is possible, but you have to decide if the restrictions are bearable for your situation.
Further approaches:
Create a "Number table" either with just one record and one column which contains the next suitable number (lets say TAB_ORDID with column NEXT_ORDID) or with a number of records containing the next suitable numbers.
Then with the usage of SELECT FOR UPDATE you can lock a record, take the number from it and either update the row to the next value (one row apporach)or delete the row retrieved (multi row approach). Both cases require some more complex logic for retrieving the next number and can cause some trouble in multi-user-environments (ending up in all users who want to create records waiting for the one user who started and did not save correctly) if the locks are not handled correctly.

DBMS_CRYPTO MD5 hash value does not match 3rd party MD5 free tool

Hello,
I am using Oracle Version: 11.2.4.
I have a problem where the MD5 value from DBMS_CRYPTO does not match the hash value from 3rd party MD5 free tool (MD5 Checksum Calculator 0.0.5.58 or WinMD5Free v1.20) and also the MD5 hash value calculated by an ingestion tool where I am transferring files to. The MD5 hash value that the ingestion tool calculates is the same as the 3rd party MD5 free tools I have. This occurs only on some of the XML files that I generate using XSQL(xmlserialize, xmlagg, xmlelement, etc.) and DBMS_XSLPROCESSOR on a Linux OS. The XML files are transferred from the Unix OS to my Windows 7 OS via filezilla.
I found a thread on this forum that also had a similar issue so I copy/paste the java functions. They are listed below(both are the same expect for the character set):
create or replace java source named "MD5_UTF_8" as
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.sql.Clob;
import java.sql.Blob;
public class MD5_UTF_8 {
private static final byte [] hexDigit = {
'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
/** Converts a byte array to a hex string
* Returns an empty string if the byte array is null
public static final String toHexString(byte [] bytes) {
if (bytes == null) return new String("");
StringBuffer buf = new StringBuffer(bytes.length * 2);
for (int i = 0; i < bytes.length; i++) {
buf.append((char) hexDigit[((bytes >>> 4) & 0x0F)]);
buf.append((char) hexDigit[(bytes & 0x0F)]);
return buf.toString();
// Convert Hex String to Byte Array
public static final byte[] byteArrayFromHexString(String str) {
byte[] bytes = new byte[str.length() / 2];
for (int i = 0; i < bytes.length; i++)
bytes = (byte) Integer.parseInt(str.substring(2 * i, 2 * i + 2), 16);
return bytes;
public static String getMD5HashFromClob(Clob inhalt) throws Exception{
MessageDigest algorithm;
StringBuffer hexString;
String s = null;
String salida = null;
int i;
byte[] digest;
String tepFordigest = inhalt.getSubString(1L, (int)inhalt.length());
try {
algorithm = MessageDigest.getInstance("MD5_UTF_8");
algorithm.reset();
algorithm.update(tepFordigest.getBytes("UTF-8"));
digest = algorithm.digest();
s = toHexString(digest);
} catch (java.security.NoSuchAlgorithmException nsae) {
s = "No es posible cifrar MD5";
return s;
sho err
alter java source "MD5_UTF_8" compile
sho err
CREATE OR REPLACE FUNCTION get_md5_UTF_8_CLOB(inhalt CLOB) RETURN VARCHAR2 DETERMINISTIC
AS LANGUAGE JAVA
name 'MD5_UTF_8.getMD5HashFromClob(java.sql.Clob) return java.lang.String';
create or replace java source named "MD5" as
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.sql.Clob;
import java.sql.Blob;
public class MD5 {
private static final byte [] hexDigit = {
'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
/** Converts a byte array to a hex string
* Returns an empty string if the byte array is null
public static final String toHexString(byte [] bytes) {
if (bytes == null) return new String("");
StringBuffer buf = new StringBuffer(bytes.length * 2);
for (int i = 0; i < bytes.length; i++) {
buf.append((char) hexDigit[((bytes >>> 4) & 0x0F)]);
buf.append((char) hexDigit[(bytes & 0x0F)]);
return buf.toString();
// Convert Hex String to Byte Array
public static final byte[] byteArrayFromHexString(String str) {
byte[] bytes = new byte[str.length() / 2];
for (int i = 0; i < bytes.length; i++)
bytes = (byte) Integer.parseInt(str.substring(2 * i, 2 * i + 2), 16);
return bytes;
public static String getMD5HashFromClob(Clob inhalt) throws Exception{
MessageDigest algorithm;
StringBuffer hexString;
String s = null;
String salida = null;
int i;
byte[] digest;
String tepFordigest = inhalt.getSubString(1L, (int)inhalt.length());
try {
algorithm = MessageDigest.getInstance("MD5");
algorithm.reset();
algorithm.update(tepFordigest.getBytes());
digest = algorithm.digest();
s = toHexString(digest);
} catch (java.security.NoSuchAlgorithmException nsae) {
s = "No es posible cifrar MD5";
return s;
sho err
alter java source "MD5" compile
sho err
CREATE OR REPLACE FUNCTION get_md5_CLOB(inhalt CLOB) RETURN VARCHAR2 DETERMINISTIC
AS LANGUAGE JAVA
name 'MD5.getMD5HashFromClob(java.sql.Clob) return java.lang.String';
I created the above java functions and added the calls to them in my package to see what hash values they would produce but I am getting "ORA-29532: Java call terminated by uncaught Java exception: java.nio.BufferOverflowException " the XML is about 60mb.
package code sniippets:
declare
l_hash raw(2000);
l_checksum_md5 varchar2(2000);
l_checksum_md5_utf_8 varchar2(2000);
Begin
t_checksum := lower(RAWTOHEX(dbms_crypto.hash(src=>l_clob,typ=>dbms_crypto.hash_md5)));
l_hash := get_md5_CLOB (l_clob);
l_checksum_md5 := lower(rawtohex(l_hash));
l_hash := get_md5_UTF_8_CLOB (l_clob);
l_checksum_md5_UTF_8 := lower(rawtohex(l_hash));Please help,
Thank You in advance
Don
Edited by: 972551 on Nov 21, 2012 12:18 PM
Edited by: sabre150 on Nov 21, 2012 11:06 PM
Moderator action : added [code ] tags to format properly. In future please add them yourself.

>
I have a problem where the MD5 value from DBMS_CRYPTO does not match the hash value from 3rd party MD5 free tool (MD5 Checksum Calculator 0.0.5.58 or WinMD5Free v1.20) and also the MD5 hash value calculated by an ingestion tool where I am transferring files to. The MD5 hash value that the ingestion tool calculates is the same as the 3rd party MD5 free tools I have.
I found a thread on this forum that also had a similar issue so I copy/paste the java functions.
>
And in that thread (Re: MD5 HASH computed from DBMS_CRYPTO does not match .NET MD5 I provided the reason why DBMS_CRYPTO may not match hashes produced by other methodologies.
I have no idea why you copied and posted all of that Java code the other poster and I provided since code has NOTHING to do with the problem you say you are having. Thte other poster's question was how to write Java code that would produce the same result as DBMS_CRYPTO.
You said your problem was understanding why DBMS_CRYPTO 'does not match the hash value from 3rd party MD5 free tool ...'. and I answered that in the other forum.
>
The Crypto package always converts everything to AL32UTF8 before hashing so if the .NET character set is different the hash will likely be different.
See DBMS_CRYPTO in the PL/SQL Packages and Types doc
http://docs.oracle.com/cd/B28359_01/appdev.111/b28419/d_crypto.htm
If you look at the spec header for the DBMS_CRYPTO package it shows this note:
-- Prior to encryption, hashing or keyed hashing, CLOB datatype is
-- converted to AL32UTF8. This allows cryptographic data to be
-- transferred and understood between databases with different
-- character sets, across character set changes and between
-- separate processes (for example, Java programs).
-- If your 3rd party MD5 free tool (MD5 Checksum Calculator 0.0.5.58 or WinMD5Free v1.20) do not use the AL32UTF8 character set then the hashes will likely be different. You can't modify DBMS_CRYPTO so if the hashes need to match you need to use 3rd party tools that either use the correct character set or can be configured to use the correct character set.
The problem in the other thread was how to WRITE Java code that uses the correct character set and I showed that OP how to do that.
So unless you are writing your own Java code all of that code you copied and pasted is useless for your use case.

Hash Values in BODS

Hello Experts,
I am a newbie to Data Services. We are using Data Services XI 3.0 Premium. I was given a task to identify duplicates by using hash values so that there is no loss of data and at the same time we can identify the duplicates. I was able to find that functionality in Oracle. But client wants the functionality in Data Services, before it loads into Oracle. I looked everywhere, couldn't find the right information. Help would be really appreciated. Please let me know if any further information needed.
Thank you for going through my post. I really appreciate your time.
Thank you,
Sandeep.

Hi
As per your statement "to identify duplicates considering bunch of columns together" you can implement logic using BODS built in function "gen_row_num_by_group"
create new column in query transformation say "Dup_find" with data type int
write logic in mapping tab as below
gen_row_num_by_group( field1 || field2 || field3 || ....... ) and drag the subsequent fields in group by tab as well
the above logic will return the row ids per group
example
FIELD1     FIELD2     FIELD3     DUP_FIELD
A                    B                    C                    1
A                    B                    C                    2
A                    B                    C                    3
D                    E                    F                    1
G                    H                    I                     1
take two query transformations in parallel
In first query transformation, you have to filter the duplicate records using "WHERE" clause
WHERE DUP_FIELD > 1 ( map this to one temp table to catch duplicate records )
in second query transformation, you can consider only unique records using "WHERE" clause
WHERE DUP_FIELD = 1 ( map this to second temp table to catch unique records )
hope it helps in your requirement
Thanks
Ahalya

Who will assign the prices for refurbished & faulty & on which basis

Dear Friends
while implementing this refurbishment process
the pricing for c2 repaired & faulty c3 who will decide & on which basis
since every time we cannot have same fault for c3 (sometimes winding burn ,sometimes bearing faulty then for all how it will have same value as c3)
& in case of c2 what about depriciation
can you focus more
Regards
chandrashekhar Ingole

Dear Vinay & thagrajan
Thanks for your reply
Now it is clear that faulty c3 has the value low which pm person will assist to mm&fi people
Regarding c2 which we be repaired but it has depriciated value as copmare to new .
But how will utlimately give in sap wherther mmor fi whose work is this exactly
I am rewarding you with points but answer to my question please
Regads
chanrda

Delete hash value row in Bex report output

Hi All,
Can anybody suggest how can i remove hash value(not assigned) row in Bex report out put.
my report looks like this:
rows
project position
(hierarchy)
WBS element
(hierarchy)
Order
For each Project position and WBS element hierarchies, i did supress the " not assigned" tick in hiearchy attributes in RSH1.
but in colums i have budget as one of the column.
this budget comes from project position nodes to last node of WBS element but not in order, for order it will be blank but after this order a new row coming up with bold" Not assigned" with that budget amount against this not assigned.
My problem is how can i get rid of this not assinged entire row. I search so many links in SDN, they talk about just to replace the not assigned to some other value as blank or something like that.
Please suggest me how can i get rid of this.
i did tried to restrict Order with "#" but then the whole budget column getting blank.
Regards
Robyn.

HI Arun,
As i mentioned earlier, i have gone through these links, they just talk about replacing # value or Not Assigned to some other value or blank.
my issue is i need to get rid of that entire row.
when i drop proj def hierarchy ,then wbs hierachy starts, sometimes at the end of wbs hierarchy i get row with #
and sometimes after wbs hierarchy ,then order row then # row is coming.
even after i tick supress unassigned nodes in both Projdef and wbs hierarchies.
i am not supposed to simply replace #( not assigned) symbol or text with some other symbol or text ( thats what they discussing in these links).
i created that macro they said in those links but its just deleting # symbol to blank not the whole row.
hope i made my issue clear.
i have seen so many other links as well
[Re: Bex macros]
Regards
Robyn.

Hash values coming in extraction,how to rectify

Dear All,
During Extraction we are getting hash values,for which our extraction is getting failed,we manually edit the psa and doing the load from PSA to Cube,is there a way where we can restrict this hash values
so our extraction din failed,in rskc all values are maintaide including hash.
pls suggest.
Thanks,
Sapta

Hi,
Characters whose hexadecimal value is 00-1F these will be displayed as # and we think this is maintained in RSKC and even then the load is failed... the invalid characters are displayed as # and there by u need to stop them . Even With ALL_CAPITAL u will not be able and it wont be good to use ALL_CAPITAL in rskc. this is part of code which i used to eliminate such cases.........and this is absolutely working fine... it will be invalid characters....
DATA: L_S_ERRORLOG TYPE RSSM_S_ERRORLOG_INT,
G_ALLOWED_CHAR(300) TYPE C.
IF G_ALLOWED_CHAR IS INITIAL.
CALL FUNCTION 'RSKC_ALLOWED_CHAR_GET'
IMPORTING
E_ALLOWED_CHAR = G_ALLOWED_CHAR.
ENDIF.
concatenate G_ALLOWED_CHAR 'abcdefghijklmnopqrstuvwxyz£Ö@[]' into G_ALLOWED_CHAR.
in the above concatentate statement add all the characters which u want to allow apart from the allowed characters .....**
do.
if not RESULT co g_allowed_char.
shift RESULT+sy-fdpos left.
else.
exit.
endif.
enddo.
Here result is the field for which say invalid characters are coming ...above is the code to remoce invalid characters from the field Result.....
Regards
vamsi

Hash value in report

Hi sdn,
I'm getting hash value in report for one infoobject,that is for 0customer .Could you pls let me know how to remove that particular problem.
thanks
R

Hi
So u have records as follows:
ckf Customer Text Value
Base # Not Assigned -59,286.60
value
So as for the above...if there is no data as the JR.. said,it will display in that row as # or Not Assigned.
1.So if u want dont want to display it & then u can EXCLUDE that # values in ur FILTER as other guy says.
2.Do as per JR..
3. U cannot totally remove tht frm ur report...becoz..where there is dependent char. which has data
Hope this helps.

Generating next value in a custom 2 character sequence

I am working on a customer project for creating a web portal that needs to write data back to an ancient legacy backend mainframe system. I have never used sql server sequences before but I believe that is what I will need to use.
Each vendor in this application has a char(3) vendor code field. Each transaction a vendor does is identified by a char(2) transaction code field. The char(2) transaction code field for the legacy system is what I am trying to generate.
This transaction code field is 2 character alpha-numeric sequence. I need to create a store proc to give me the next available transaction code for that vendor. The sequence got numbers 0-9 then letters A-Z as follows:
00,01,02....0A,0B...0Y,0Z,10,12....ZZ
In the stored proc to get me the next available transaction code for a vender, I need to take the 3 character vendor code as in input parameter, then check the vendor transactions table to see which transaction codes exist and return the next one from the
sequence to use next.
Here is a very basic table def. and some sample data:
CREATE TABLE vendor_trans
vendor_cd char(3),
trans_cd char(2)
INSERT INTO [dbo].[vendor_trans] ([vendor_cd] ,[trans_cd]) VALUES ( 'ABC' ,'00' )
GO
INSERT INTO [dbo].[vendor_trans] ([vendor_cd] ,[trans_cd]) VALUES ( 'ABC' ,'01' )
GO
INSERT INTO [dbo].[vendor_trans] ([vendor_cd] ,[trans_cd]) VALUES ( 'ABC' ,'02' )
GO
INSERT INTO [dbo].[vendor_trans] ([vendor_cd] ,[trans_cd]) VALUES ( 'ABC' ,'04' )
GO
INSERT INTO [dbo].[vendor_trans] ([vendor_cd] ,[trans_cd]) VALUES ( 'ABC' ,'0A' )
GO
INSERT INTO [dbo].[vendor_trans] ([vendor_cd] ,[trans_cd]) VALUES ( 'ABC' ,'0C' )
GO

Just create a scalar function that will give you the next character sequence.
Then use it on the max transaction code for the given vendor, to get their next code.
IF EXISTS (SELECT * FROM dbo.sysobjects WHERE ID = OBJECT_ID('dbo.funNextCode') AND XTYPE IN ('FN', 'IF', 'TF'))
DROP FUNCTION dbo.funNextCode
GO
CREATE FUNCTION dbo.funNextCode (@Code char(2))
RETURNS char(2)
AS
BEGIN
DECLARE @NewCode char(2)
SELECT @NewCode = CASE WHEN RIGHT(@Code,1) != 'Z'
THEN LEFT(@Code,1)
ELSE CHAR(CASE LEFT(@Code,1) WHEN '9' THEN 64
WHEN 'Z' THEN 47
ELSE ASCII(LEFT(@Code,1))
END + 1)
END
+ CHAR(CASE RIGHT(@Code,1) WHEN '9' THEN 64
WHEN 'Z' THEN 47
ELSE ASCII(RIGHT(@Code,1))
END + 1)
RETURN @NewCode
END
GO
-- UNIT TEST funNextCode
DECLARE @TableOfCodes TABLE (idx int IDENTITY(1,1), Code char(2))
DECLARE @Code char(2) = 'ZZ'
,@Count int = 0
WHILE @Count < ((36 * 36) + 1)
BEGIN
SELECT @Code = dbo.funNextCode(@Code)
INSERT @TableOfCodes SELECT @Code
SELECT @Count = @Count + 1
END
SELECT * FROM @TableOfCodes ORDER BY idx
--SELECT * FROM @TableOfCodes ORDER BY Code
-- Using funNextCode with vendors
DECLARE @VendorTransactions TABLE (VendorCode char(3), TransCode char(2))
INSERT @VendorTransactions VALUES ('ABC', '00'), ('ABC', '01'), ('ABC', '02')
,('ABC', '04'), ('ABC', '0A'), ('ABC', '0C')
DECLARE @VendorCode char(3)
,@LastCode char(2)
SELECT @VendorCode = 'ABC'
-- Get the last code for the given vendor
SELECT @LastCode = MAX(TransCode)
FROM @VendorTransactions
WHERE VendorCode = @VendorCode
-- If no code exists, then set it so funNextCode will generate the starting code as '00'
SELECT @LastCode = ISNULL(@LastCode, 'ZZ')
SELECT dbo.funNextCode(@LastCode) as [NextCode]

Who will have access to data grid

do end user can have access to Data Grid.
general who will have access to data grid i.e both end user and hfm developer can access to the data grid in real time.
Can any one pls tell
Thanx

Access to datagrids is controlled by the "Security Class" which is selected when saving the datagrid. By default this value is [Default]. Security classes are defined within shared services, and users or groups are subsequently given rights to security classes.
A user can access a datagrid if he has "Read" or "All" access level on the datagrid's security class.
Different kinds of users, whether end users, power users, key users, developers etc, are given access to grids (and other hfm objects like forms, documents, reports, dimension members etc) according to the above mechanism.
Kostas

Who will write the SOAP message

when wrting simple Webservice .Who will write the SOAP message?
weather it generate automatically? or we need write?
is there any automatic tools are there to generte the SOAP message?
Please send me a Simple Webservice Example?
Thanks in advance
Raju

Check out http://jax-ws.dev.java.net and look at the samples provided. Netbeans 5.5 beta also makes it very easy to publish a web service. All of the hard work is done for you automatically, to you as a developer it looks just like you are makiing an normal method invocaiton, the framework underneath converts that invocation to/from a soap message.

Ora_hash - Same hash value for different inputs (Urgent)

Hi,
Trying to use ora_hash to join between tables but i noticed that in some cases, when working on different input value the ora_hash function generates same results.
select ora_hash('oomeroe03|6NU3|LS006P|7884|1|17-JUL-13 13.18.22.528000|0005043|'),ora_hash('GSAHFFXTK|GCQ3|A6253S|12765|1|17-JUL-13 17.26.26.853000|0136423|')
from dual
Output value : 1387341941
Oracle version is 11gR2.
Thanks

Why would anyone limit the hash distribution to three buckets ?
However, one must understand that the default seed is 0. So one input repeated gets the same hash value unless the seed is changed.
SQL> select ora_hash(rn) , rn
2 from
3 (Select rownum as rn from dual connect by level < 11)
4 order by rn;
ORA_HASH(RN)         RN
2342552567          1
2064090006          2
2706503459          3
3217185531          4
   365452098          5
1021760792          6
   738226831          7
3510633070          8
1706589901          9
1237562873         10
10 rows selected.
SQL> l
1 select ora_hash(rn) , rn
2 from
3 (Select rownum as rn from dual connect by level < 11)
4* order by rn
SQL> /
ORA_HASH(RN)         RN
2342552567          1
2064090006          2
2706503459          3
3217185531          4
   365452098          5
1021760792          6
   738226831          7
3510633070          8
1706589901          9
1237562873         10
10 rows selected.
SQL> /
ORA_HASH(RN)         RN
2342552567          1
2064090006          2
2706503459          3
3217185531          4
   365452098          5
1021760792          6
   738226831          7
3510633070          8
1706589901          9
1237562873         10
10 rows selected.
SQL>
Hemant K Chitale

If the data is not available in R/3 systems(Ex: MM), who will load the data

Hi All,
Can anybody tell me that if the data is not available in R/3 systems(Ex: MM), who will load the data into that?
Need Helpful Answers....
Regards,
Kiran Telkar

Hi kiran,
The data is generated in the R/3 when the business transactions take place.
No one loads the data into R/3 as it done with BW. R/3 is a OLTP(online transactional processing) system which aides the day to day transactions of a business & theese transactions are stored in the R/3 in there respective tables in the form of records, so one record is generated for each transaction done.
For example there will be record generated in different modules when there is an order placed or when a material is delivered against an order.
Hope this helps,
regards.

Plan hash value for two queries!

Hi,
DB : Oracle 11g (11.2.0.3.0)
OS: RHEL 5
I have two question:
1. Can two queries have same plan hash value? I mean I have below two queries:
SELECT /+ NO_MERGE */ MIN(payor.next_review_date)*
* FROM payor*
* WHERE payor.review_complete = 0*
* AND payor.closing_date IS NULL*
* AND payor.patient_key = 10;*
and
SELECT MIN(payor.next_review_date)
* FROM payor*
* WHERE payor.review_complete = 0*
* AND payor.closing_date IS NULL*
* AND payor.patient_key = 10;*
When I tried to review the execution plan for both queries, the plan hash value remain same. Does it mean that execution plan for both queries are same? If yes, then how Oracle understands or changes the execution plan based on hint. If no then what plan hash value represents?
2. If the execution plan with hint and without hint is same except for a given query except no.of rows and bytes. Does it mean that query with less rows and bytes scanned is better?
Thanks in advance
-Onkar

Hi,
there are two different things. One is EXPLAIN PLAN, which is how the optimizer thinks the query will be executed. It contains some estimates of cost, cardinalities etc. There is also EXECUTION PLAN. It also contains all this information regarding the optimizer estimates, but on the top of that, it also contains information about actual I/O incurred, actual cardinalities, actual timings etc.
So if a hint is changing optimizer estimates, but the plan stays the same, then impact on query's performance is zero.
If the actual numbers are changing, this is probably also irrelevant to the hint (e.g. you can have less physical reads because more blocks are found in the buffer cache the second time you're running the query, or you less work because you don't have to parse the statement etc.).
Actually, most of optimizer hints don't affect optimizer estimates; rather, they try to get the optimizer to use a certain access method or a certain join order etc. regardless of the cost. So you must be talking about such hints as cardinality, dynamic_sampling etc. If that's not the case -- please clarify, because this means that something wrong is going on here (e.g. an INDEX hint may work or it may fail to work, but if it fails, optimizer estimates shouldn't change).
Best regards,
Nikolay

Who will generate hash value

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