Creating sequence without cach

how can i create a sequence without cach to reduce the possibility of gabs

http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96540/statements_615a.htm#2067096
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Similar Messages

How to create sequence when minvalue is unknown?

I am currently migrating a lot of tables (that already have data) over to using sequences. I'd like to have a script that creates these sequences without having to hardcode the minimum value that the sequence should start at.
I am trying to do something like this:
create sequence mySeq minvalue (select max(id)+1 from table) increment BY 1 cache 20;
This always gives the error "Invalid number". Can anyone provide some guidance on how to solve this problem?

Like this..?
SQL> declare
2   min_val number;
3   str varchar2(1000);
4 begin
5   select nvl(max(empno),0)+1
6   into min_val
7   from emp;
8   str := 'create sequence seq1 start with '||min_val||' increment by 1 cache 20';
9   execute immediate str;
10 end;
11 /
PL/SQL procedure successfully completed.
SQL> select seq1.nextval
2 from dual;
   NEXTVAL
      7935
http://download-uk.oracle.com/docs/cd/B19306_01/appdev.102/b14251/adfns_dynamic_sql.htm#i1006172

Proving that sequence is cached in SGA

Hello,
I spent all day researching this yesterday without an answer - the information must be out there somewhere but I can't find it!
We know that when a sequence is created with CACHE 20 the values are generated 20 at a time and stored in the SGA. We also know that Oracle may choose to age these values out of SGA if the sequence is infrequently used (and for other reasons too).
I am trying to understand how to prove that a set of values is currently being cached for a particular sequence. I expect to be able to see a difference somewhere in memory between a sequence with CACHE 20 and a sequence created with NOCACHE - this is reproduceable. I also wish to be able to prove whether or not a sequence created with the CACHE option has been aged out of the SGA (this is more difficult to reproduce).
I looked in v$bh but this does not seem to contain sequences (I believe they are cached in library cache since Oracle 8?).
V$db_object_cache seems to contain a row for the sequence regardless or whether it was created with the CACHE option and there does not seem to be a pattern in the value of SHARABLE_MEM.
There are views available to see the contents of the buffer cache right down to the block level - is there something similar for the pool which contains sequences?
Thanks.

Hi Dom,
I'm hoping to write a script which I can run for a current point in time snapshot, rather than something I need to configure and monitor.
For example I use v$bh to see the buffer cache contents (right down to block level if necessary). I just assume there must be a data dictionary view somewhere that will contain a row for the sequence if it has values cached in the library and no row if there are no values cached.
I am assuming that the information is in the dictionary somewhere and I just don't know where to look, but perhaps it isn't there at all. Oracle internals can obviously track whether it needs to get nextval from memory or via a latch to disk but perhaps this information hasn't been opened up for us to see.

Sequence losting cache

Hi, I have some sequences in cache and i'm losing the cache with the instance "ON".
I'm using 10g.
The sequence's cache uses LRU list? What can I do?
Thanks.

The sequence cache is in the library cache.
You will loose sequences by bouncing the instance amongst other.
This is not a problem, as sequences are used for surrogate keys, and as surrogate keys don't have a meaning (except for bean counters), you can have a surrogate key with holes.
If you want to minimize the impact create your sequences with the nocache clause.
If you want a surrogate without holes, revert to the sequence table. Remember this 'solution' scales badly.
Sybrand Bakker
Senior Oracle DBA

CREATE SEQUENCE from a stored procedure

Hello,
Is it possible, to create a sequence object from an own written stored procedure? Can I reinitialize the actual value of a sequence object without recreating it from a stored procedure?
Thank you for recommendations,
Matthias Schoelzel
EDV Studio ALINA GmbH
Bad Oeynhausen

maybe this example might be of some help.
SQL> create or replace procedure dy_sequence (pSeqName varchar2,
2                                           pStart number,
3                                           pIncrement number) as
4    vCnt     number := 0;
5 begin
6    select count(*) into vCnt
7      from all_sequences
8     where sequence_name = upper(pSeqName);
9
10    if vCnt = 0 then
11      execute immediate 'create sequence '||pSeqName||
12                        ' start with '||to_char(pStart)||
13                        ' increment by '||to_char(pIncrement);
14    else
15      execute immediate 'alter sequence '||pSeqName||' increment by '||to_char(pIncrement);
16    end if;
17 end;
18 /
Procedure created.
SQL> -- create the sequence by calling the dy_sequence procedure
SQL> execute dy_sequence ('test_sequence',1,1);
PL/SQL procedure successfully completed.
SQL> select test_sequence.nextval from dual;
   NEXTVAL
         1
SQL> -- alter the sequence to increment by 2
SQL> execute dy_sequence ('test_sequence',0,2);
PL/SQL procedure successfully completed.
SQL> select test_sequence.nextval from dual;
   NEXTVAL
         3
SQL>

Assigning a 'dynamically created sequence' value to a variable

in my procedure i am creating a sequence on the fly, i am preparing the name with some passed parameters like below
v_seq_name := 'seq_'||loadid||v_table_name;
execute immediate 'CREATE SEQUENCE '||v_seq_name||' MINVALUE 1 MAXVALUE 999999999999999999999999999 START WITH 1 increment by 1 cache 20';
and now after doing some operations i need to assign the current value of sequence to a number variable i tried following but not working
1) v_curr_value : = v_seq_name.currval ;
2) select v_seq_name||'.nextval' into v_curr_value from dual;
can you please suggest me how i can get the value in plsql block.

DIVI wrote:
in my procedure i am creating a sequence on the fly, i am preparing the name with some passed parameters like below
v_seq_name := 'seq_'||loadid||v_table_name;
execute immediate 'CREATE SEQUENCE '||v_seq_name||' MINVALUE 1 MAXVALUE 999999999999999999999999999 START WITH 1 increment by 1 cache 20';
and now after doing some operations i need to assign the current value of sequence to a number variable i tried following but not working
1) v_curr_value : = v_seq_name.currval ;
2) select v_seq_name||'.nextval' into v_curr_value from dual;
can you please suggest me how i can get the value in plsql block.Well, you haven't given the error you are getting but I guess the procedure isn't compiling? You need to execute immediate any reference to the sequence.
Having said that, your architecture is probably wrong if you are dynamically creating things in a procedure.
Why do you need to create them dynamically?

Issue in creating Sequence

Hi All,
I am using
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bi
PL/SQL Release 10.2.0.1.0 - Production
CORE 10.2.0.1.0 Production
TNS for Linux: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - ProductionI have schema with following roles
ALTER ANY OUTLINE
CREATE ANY OUTLINE
CREATE ANY SYNONYM
CREATE DATABASE LINK
CREATE MATERIALIZED VIEW
CREATE PUBLIC DATABASE LINK
CREATE VIEW
DROP ANY OUTLINE
DROP PUBLIC DATABASE LINK
SELECT ANY TABLE
UNLIMITED TABLESPACE
CONNECT
DBA
EXP_FULL_DATABASE
IMP_FULL_DATABASE
OEM_MONITOR
RESOURCEI can able create a sequence through SQLPLUS as well as from toad.
SQL> CREATE SEQUENCE ROLE_ACTIVITY_SEQ START WITH 225006249 INCREMENT BY 1 MAXVALUE 9999999999999999999 MINVALUE 225006249 NOCYCLE CACHE 100 ORDER;
Sequence created.
SQL>when i try to create sequence dynamically through PL/SQL procedure getting error
SQL> execute PROC_CLONE_BU;
BEGIN PROC_CLONE_BU; END;
ERROR at line 1:
ORA-01031: insufficient privileges
ORA-06512: at "SUPERNOVA.PROC_CLONE_BU", line 19
ORA-06512: at line 1
SQL>Even though I have DBA role for the schema. I don't know what privileges oracle still excepting..
Pls guide me to resolve it..
Thanks & Regards
Sami

Hi All,
As said early creating sequence through dynamic SQL
its creating sequence fine but when i try to use sequence in same procedure then procedure getting error..
create or replace procedure proc_seq_genrate as
begin
EXECUTE IMMEDIATE 'CREATE SEQUENCE BU_ROLE_DSK_ITEM_SEQ START WITH 100 INCREMENT BY 1 MAXVALUE 9999999999999999999 '||
'MINVALUE 100 NOCYCLE CACHE 100 ORDER';--- hard coded value 100 will changed according to PK max value of the table .. for getting max value i will write SQL Query
end;
Procedure created.
create or replace procedure proc_seq_genrate as
begin
EXECUTE IMMEDIATE 'CREATE SEQUENCE BU_ROLE_DSK_ITEM_SEQ START WITH 100 INCREMENT BY 1 MAXVALUE 9999999999999999999 '||
'MINVALUE 100 NOCYCLE CACHE 100 ORDER';--- hard coded value 100 will changed according to PK max value of the table .. for getting max value i will write SQL Query
INSERT INTO ROLE_ACTIVITY (SELECT ROLE_ACTIVITY_SEQ.NEXTVAL, -98, ACTIVITY_CD, REC_ST, 1, ROW_TS, USER_ID, CREATE_DT, SYS_CREATE_TS, CREATED_BY FROM ROLE_ACTIVITY WHERE ROLE_ID=-99 );
end;
7 35 PL/SQL: ORA-02289: sequence does not existI have understood that its looking for Sequence but
pls any one explain me why its looking sequence in compile time itself.. any way we are going to use the sequence only at run time right.. i would like to know is there any technical reason behind this..
Thanks & regards
Sami.

Creating sequences for all tables in the database at a time

Hi ,
I need to create sequences for all the tables in my database.
i can create individually ,using toad and sqlplus.
Can any one give me a code for creating the sequences dynamically at a time for all the tables.
it is urgent ..
Regards.

I need to create sequences for majority of the tables that are having ID column
which is sequences."The majority" is not the same as all. So you probably want to drive your generation script off the ALL_TAB_COLUMNS view...
where column_name = 'ID'You need to think about this carefully. You might want different CACHE sizes or different INCREMENT BY clauses for certain tables. You might even (whisper it) want a sequence to be shared by more than one table.
Code generation is a useful technique, but it is a rare application where one case fits all.
Cheers, APC
Blog : http://radiofreetooting.blogspot.com/

Create Sequence Number with Select Query

Hi All,
I would like to create a sequence number in oracle but instead of hard coding the "start with" I want to select the max value of the primary key of a table and add 1 and use this instead:
So what I want is:
CREATE SEQUENCE crg_mrec_seq
MINVALUE 1
MAXVALUE 999999999999999999999999999
START WITH select max(primarykey)+1 from table1
INCREMENT BY 1
CACHE 20;I'm guessing I need to pass this max value as a variable into the create sequence number but I'm not sure what syntax to use.
Thanks,
Ed

spalato76 wrote:
Hi All,
I would like to create a sequence number in oracle but instead of hard coding the "start with" I want to select the max value of the primary key of a table and add 1 and use this instead:
So what I want is:
CREATE SEQUENCE crg_mrec_seq
MINVALUE 1
MAXVALUE 999999999999999999999999999
START WITH select max(primarykey)+1 from table1
INCREMENT BY 1
CACHE 20;I'm guessing I need to pass this max value as a variable into the create sequence number but I'm not sure what syntax to use.
Thanks,
Edconstruct SQL statement & then EXECUTE IMMEDIATE

Create sequence on report

Help please.
I am trying to create sequence on the report. I wrote following PLSQL on the field emp_no in order to show sequence number (1,2,3...)on the employee_no column. It did not work.
CREATE SEQUENCE Emp_sequence
INCREMENT BY 1
START WITH 1
NOMAXVALUE
NOCYCLE
CACHE 10;
is this correct PLSQL? should we put the PLSQL on trigger or field?
Thank's in advance!

Sequence is an DDL. So dynamic sql utility package
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by antony:
Help please.
I am trying to create sequence on the report. I wrote following PLSQL on the field emp_no in order to show sequence number (1,2,3...)on the employee_no column. It did not work.
CREATE SEQUENCE Emp_sequence
INCREMENT BY 1
START WITH 1
NOMAXVALUE
NOCYCLE
CACHE 10;
is this correct PLSQL? should we put the PLSQL on trigger or field?
Thank's in advance!<HR></BLOCKQUOTE>
null

Cannot create sequence with nocache

hi there,
actual I try Raptor build 919 and I have a problem with creating sequences with NOCACHE using the wizzard.
When I want to create a sequence with NOCACHE, the DDL shown in the wizzard is: CREATE SEQUENCE SEQUENCE1 INCREMENT BY 1 START WITH 1 MAXVALUE 10 MINVALUE 1 ;
So the sequence is created with CACHE and cache size 20. After creating it is possible to switch the sequence to NOCACHE.

I just checked in our bug database and this was fixed in our development version 1060 so it will be fixed in our next Early Adopter release (post v919).
-- Sharon

Create sequence

in create sequence statement what z the use of cache/nocache?please tell me briefly.

810045 wrote:
in create sequence statement what z the use of cache/nocache?please tell me briefly.Fortunately this is described in the manuals that you refuse to read.
http://download.oracle.com/docs/cd/E11882_01/server.112/e17118/statements_6015.htm#i2067093
>
CACHE
Specify how many values of the sequence the database preallocates and keeps in memory for faster access. This integer value can have 28 or fewer digits. The minimum value for this parameter is 2. For sequences that cycle, this value must be less than the number of values in the cycle. You cannot cache more values than will fit in a given cycle of sequence numbers. Therefore, the maximum value allowed for CACHE must be less than the value determined by the following formula:
(CEIL (MAXVALUE - MINVALUE)) / ABS (INCREMENT)
If a system failure occurs, then all cached sequence values that have not been used in committed DML statements are lost. The potential number of lost values is equal to the value of the CACHE parameter.
Note:
Oracle recommends using the CACHE setting to enhance performance if you are using sequences in an Oracle Real Application Clusters environment.
NOCACHE
Specify NOCACHE to indicate that values of the sequence are not preallocated. If you omit both CACHE and NOCACHE, then the database caches 20 sequence numbers by default.

Sequence and Cache

I created a sequence:
SQL> create sequence s
increment by 1
start with 1;
then,
SQL> select s.nextval from dual;
1
SQL> select s.nextval from dual;
2
it works fine.
But when I shutdown my Windows2000 Server (where Oracle 9i is installed) and restart it again...
SQL> select s.nextval from dual;
32
The default cache for sequence is 20.
After reboot, the cahched sequence number are lost!
Is there any way to keep the cached sequence number after reboot?
What if I do the following: "SQL> alter sequence s cache 0; " ???
What if the side-effect if I set the cache to 0 ??? Do you suggest to set it to zero ?
thank you very much.
Chu Ka Keong

Just to elaborate a bit on Don's post.
If you want to minimize the number of holes in a sequence, you must use the NOCACHE option when creating the sequence (or alter it that way). Be aware that this will NOT eliminate holes in the sequence. Any transaction that gets a value from the the sequence, and then rolls back, or otherwise does not write to the table, will "waste" a sequence number.
Having said that, who really cares. The only, and I emphasise only, use for a sequence is to generate a guaranteed unique number for some purpose, either an ID, or a sequential number to make an otherwise duplicated key unique. Personally, I see absolutely no reason for a sequence in the second case.
If you expect multiple users, and frequent "hits" to your sequence, use a big cache (I have some that cache 500) and damm the holes.

Why is an OST created even if Cached Exchange mode is disabled?

We have run into performance issues on our VDI environment which have been traced to Outlook. By default Cached Exchange Mode is enabled, this obviously creates an OST file. However, if this is disabled, either by GPO or in the registry and the OST file
is deleted, it creates another one anyway. The problem is we use non persistent with persona machines, so every time a user logs on it pulls a new machine, creates the OST in their persona then copies this OST to the C drive. This results in up to 10 minutes
between pulling the machine and being able to do anything.
Looking deeper into it there is another setting needed in the GPO or DWORD in the registry to not allow creation of an OST, see below
My question is why on earth is an OST created even if Cached Exchange mode is disabled? Why is this second setting even there? By definition if you are not using Cached Exchange mode, you do not need to have an OST so this just seems redundant and annoying.

Hi,
Outlook has one Online mode but two offline modes: Exchange Cached mode and Offline Folders. Although Outlook 2013 doesn't use true offline folders, only cached mode, you need to disable offline folders along with cached mode to prevent it and older versions
of Outlook from creating an OST file for offline use.
I think it should work if you have applied the GPO, or the registry values below:
Important
This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the
registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry,
http://windows.microsoft.com/en-US/windows7/Back-up-the-registry
HKEY_CURRENT_USER\Software\Policies\Microsoft\office\15.0\outlook\cached mode
DWORD: enable
Value: 0
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\OST
DWORD: NoOST
Value: 2
NoOst value specifies whether or not an OST is created at startup. Setting the
NoOst value to 2 will prevent the use of OST files. A value of 3 will allow OST files for cached mode but won't create one when online mode is used.
The explanation above is quoted from Diane Poremsky's article:
http://www.slipstick.com/exchange/outlook-online-mode-creates-ost-file/
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
Regards,
Melon Chen
Forum Support
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Reg:Creating Sequence

hi
can you anyone please tell me how to create sequence in xmii suppose if i use syntax like this
   CREATE SEQUENCE supplier_seq
    MINVALUE 1
    MAXVALUE 999999999999999999999999999
    START WITH 1
    INCREMENT BY 1
    CACHE 20;
its showing an error
<b>A SQL Error has occurred on query, ORA-00911: invalid character
Thanks in advance

Hi DevaKrishnan,
                             u can use the same as used first , that is
                                  CREATE SEQUENCE supplier_seq
                                   MINVALUE 1
                                   MAXVALUE 999999999999999999999999999
                                   START WITH 1
                                   INCREMENT BY 1
                                   CACHE 20
   and choosing the same mode(command) the only difference is remove the semicolon then it works fine.
Regards,
chaitanya

Creating sequence without cach

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