Sequence numbers - with no gaps!

I seek some advice from anyone with first hand experience in this area.
My need is simple; generate a new ID number for every order for use as the primary key.
Obviously this simple exercise could be a bottleneck as volumes ramp up, so I was pleased to find the Oracle feature to generate such numbers (efficiently presumably). However, upon closer reading it was apparent that aborted transactions would result in the loss of the number allocated to to that order if another transaction had obtained the next sequence number already (as one would want it to, rather than serializing transactions).
I don't want to have gaps in the sequence as the system needs a high degree of auditability. I am thinking of utilising the Autonomous Transaction feature to write the newly acquired sequence number to the order file with a flag indicating that the record is incomplete, and that record is to be skipped by normal system applications (but available to audit reports which will interpret the reason correctly), then returning to the far more extensive main transaction which updates many tables.
The other alternative is to control sequence numbers within the application itself, or try to get the sequence number as the very last step before writing the new order record, but this probably won't guarantee gapless reliability either. The ID itself has no significance, and it doesn't matter if an ID was used out of strict date/time sequence, so I really don't want to execute these updates serially.
So, my question is this:
a) do most people use the builtin sequence number feature?
b) if so, is there a standard technique for avoiding or accounting for gaps?
c) if the application must take over this task, should the counter for the last used ID be in a single row table to minimise bottlenecks caused by the thisrecord being locked? There will be several such counters for different aspects of the application, and i thought of having each in its own row in a small table, but I'm concerned about the whole table getting locked and freezing out otherwise-unrelated updates.
Thanks for any advice you may have.
CS

user8821725 wrote:
I seek some advice from anyone with first hand experience in this area.
My need is simple; generate a new ID number for every order for use as the primary key.
Obviously this simple exercise could be a bottleneck as volumes ramp up, so I was pleased to find the Oracle feature to generate such numbers (efficiently presumably). However, upon closer reading it was apparent that aborted transactions would result in the loss of the number allocated to to that order if another transaction had obtained the next sequence number already (as one would want it to, rather than serializing transactions).
I don't want to have gaps in the sequence as the system needs a high degree of auditability. One of the very very few reasons for me to have a requirement for "gapless" sequences is if you have a kind of checking mechanism outside of the database that is implemented using this gapless number. I had such a requirement once, when exchanging files with another bank where we had to ensure that each file was transferred correctly and in the right order. Your "high degree of auditability" might be a similiar requirement. Just remember as long as you are still inside the database you can use other mechanisms to increase auditability.
I am thinking of utilising the Autonomous Transaction feature to write the newly acquired sequence number to the order file with a flag indicating that the record is incomplete, and that record is to be skipped by normal system applications (but available to audit reports which will interpret the reason correctly), then returning to the far more extensive main transaction which updates many tables.Hm. I don't see why you want to use Autonomous Transactions for this. It might be useful to lessen locking conflicts , depending how your future sequence mechanism will be built.
>
The other alternative is to control sequence numbers within the application itself, or try to get the sequence number as the very last step before writing the new order record, but this probably won't guarantee gapless reliability either. The ID itself has no significance, and it doesn't matter if an ID was used out of strict date/time sequence, so I really don't want to execute these updates serially.I would go for generating the sequence as the very last step. It needs to be set to NOCACHE of cause. This will garantee that the sequence fetched from mySeq.nextval is gapless. The problem is then in your application. Your application must be built in a way that it ensures to use this sequence, or at least to create a noticable alert when this generated sequence can't be used anymore. In essence this means. Each unhandled (database) error that happens after you fetched the next sequence value must be raised in a way that informs all relevant people about this error.
Example: It might be that you use the sequence to write an order file. What happens if halfway through writing the file your disk runs out of space? This can be such an issue where a sequenced value will be lost. Your organisation must take care of those things.
>
So, my question is this:
a) do most people use the builtin sequence number feature?Yes. But for some tasks a sequence is not the best way, for example if you want a numbering for each item of your order. This "sequence" needs to restart with every new order.
b) if so, is there a standard technique for avoiding or accounting for gaps?NOCACHE => Avoids gaps during generation
Database Trigger => Tries to use the sequence as late as possible
c) if the application must take over this task, should the counter for the last used ID be in a single row table to minimise bottlenecks caused by the thisrecord being locked? There will be several such counters for different aspects of the application, and i thought of having each in its own row in a small table, but I'm concerned about the whole table getting locked and freezing out otherwise-unrelated updates.This is a possibility and the issues you describe are why we avoid such a solution in general. Autonomous transactions help to reduce the locking conflict, but they increase the chance that you produce gaps.
>
Thanks for any advice you may have.
CSOracle can guarantee to produce gapless sequences. But it can't guarantee that your application uses such a sequence in a gapless way.

Similar Messages

Produce a range of numbers with select from the gaps of ID column

(1)
Suppose I have a table t which has rows like this:
A B
2 4
6 7
I would like to use select to produce rows with numbers ranging between A column and B column inclusive
for each row, like this:
select ... from t ...
2
3
4
6
7
(2)
Suppose I have ID column which has gaps, I would like to get lowest <N> available numbers between the gaps.
I did research, and I can find the range of the gaps, but I cannot have the numbers listed individually, that is why
I ask question (1). But is there a direct way to get the list instead of going through ranges and the list.
For example, I have ID column which has
2
5
6
7
9
2000000
I would like to get a select query that produces
select ...
3
4
8
10
11
I have a way to get a list from 2 to 2000000 and then minus what we have to get all the
gap numbers, but that is not efficient and could runs out of memory.
PS: Before I post to this group, I did research already on "connect by", with recursive queries.

First of all, I would like to thank jeneesh and Frank for helpful and correct reply. However, due to the a bug of this forum,
when I mark jeneesh's reply as correct, I cannot mark Frank's reply as correct anymore. Therefore I would like to formally
state here that I have tested both solutions and they are both correct. jeneesh and Frank use different approach, connect by
and less join ( <=, I do not know what is the proper name for it ).
Secondly I would like to report my small findings: use connect by, you control the level from 1 to the max number, so you
do not need to use order by, and the performance is better (0.37 seconds version 0.92 seconds). And also it performs better
if I use an intermediate view to limit the result sets. One line of code is worth one thousand words, now I am posting two
versions of the code and highlighted the points I mentioned here.
I am sorry that either I do not know how to format the code or I do not have the capability when posting on this forum.
The code listing does not look good, but I hope you get the idea. I have "plain text" and I am not if I can use fixed width font
and preserve space. After I used the spelling checker, it becomes double spaced and I have to manually delete the blank lines.
/* I learned about { code } after the post and edited the original post */
Thanks again to both jeneesh and Frank.
"connect by" version:
SQL> VARIABLE new_id_cnt NUMBER
SQL> EXEC        :new_id_cnt := 10;
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.00
SQL> WITH my_table AS
2 (
3     SELECT num
4     FROM   prs_elm
5     WHERE 1=1
6 )
7 ,       my_num   AS
8 (
9 SELECT num, ct
10 FROM   (
11                    SELECT num AS num, LEAD(num) OVER (ORDER BY num) - num - 1 AS ct
12                    FROM   ( SELECT 0 AS num
13                             FROM   DUAL
14                             UNION ALL
15                             SELECT num
16                             FROM   my_table
17                             UNION ALL
18                             SELECT ( MAX(num) + :new_id_cnt + 1 ) AS num
19                             FROM   my_table
20                    )
21          )
22 WHERE      ct >= 1
23 AND         ROWNUM <= :new_id_cnt
24 )
25 SELECT     num + level AS available_id
26 FROM       my_num
27 WHERE      ROWNUM <= :new_id_cnt
28 CONNECT BY level <= ct
29 AND        prior num = num
30 AND        prior sys_guid() is not null
31 ;
AVAILABLE_ID
        3219
        3261
        3264
        3269
        3270
        3275
        3281
        3288
        3289
        3290
10 rows selected.
Elapsed: 00:00:00.37"Less join" version:
SQL> VARIABLE new_id_cnt NUMBER
SQL> EXEC        :new_id_cnt := 10;
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.00
SQL> WITH my_table AS
2 (
3     SELECT num
4     FROM   prs_elm
5     WHERE 1=1
6 )
7 ,       my_num   AS
8 (
9                    SELECT num AS num, LEAD(num) OVER (ORDER BY num) - num - 1 AS ct
10                    FROM   ( SELECT 0 AS num
11                             FROM   DUAL
12                             UNION ALL
13                             SELECT num
14                             FROM   my_table
15                             UNION ALL
16                             SELECT ( MAX(num) + :new_id_cnt + 1 ) AS num
17                             FROM   my_table
18                    )
19 )
20 ,       my_cnt    AS
21 (
22          SELECT LEVEL AS ct
23          FROM    DUAL
24          CONNECT BY    LEVEL <= :new_id_cnt
25 )
26 SELECT     available_id
27 FROM
28 (
29          SELECT    n.num + c.ct AS available_id
30          FROM      my_num n
31          JOIN      my_cnt c ON c.ct <= n.ct
32          WHERE     n.ct >= 1
33          ORDER BY available_id
34 )
35 WHERE      ROWNUM <= :new_id_cnt
36 ;
AVAILABLE_ID
        3219
        3261
        3264
        3269
        3270
        3275
        3281
        3288
        3289
        3290
10 rows selected.
Elapsed: 00:00:00.92PS: In Frank's code, there is a typo, <= should read as <.
Edited by: PuraVidaOTN on 04-feb-2013 22:49
What: To use tags to format the code.
Edited by: PuraVidaOTN on 04-feb-2013 22:56

Alter a column with sequence numbers

Hi to all,
i have a table (sample) with cplumns: sno, sname,dob and so on..........
In this table i have milions of rows with random numbers in column sno
i want to give the give the sequence numbers from 1 to 10000 in the sno column to the begining rows in the table
(Oracle)
could u post the code plese
thanks & Regards
Tangella

Tangella wrote:
Hi to all,
i have a table (sample) with cplumns: sno, sname,dob and so on..........
In this table i have milions of rows with random numbers in column sno
i want to give the give the sequence numbers from 1 to 10000 in the sno column to the begining rows in the table
(Oracle)
could u post the code plese
thanks & Regards
TangellaHow do you define "the beginning rows in the table"? Rows in a relational, heap table have no "order" to them. There is no concept of "first".
And once that is defined, why would you want to assign sequence number to only 10k our of "millions" of rows?

Multiple volumes with sequence numbers

Hello
i see a strange behaviour for some volumes. For instance - i have an external hard drive connected via Firewire 800, where my Time Machine is located.
If i look into the volumes folder i do see several folders with a red button on it named Time Machine, Time Machine 1, Time Machine 2, Time Machine 3. Only Time Machine 4 is displayed as an alias and contains the actual files. All others are empty. The same observation applies to my idisk. It seems that every day my Mac creates a new folder or a new alias. I have now 81 folders!
The behaviour observed does not seem to hurt and the folders can be deleted, but in some applications (for instance Arperture) all these drive are shown as import folders, which is nasty if you have 81 idisks presented.
It seems to me that it all relates to external hard drives. All local volumes have never shown these crazy sequence numbers
The question is now why the systems behaves like this and how it can be avoided.
Help is mostly appreciated. Thanks

Thanks, Andreas for the explanation, which are helpful to get rid of those unwanted items.
However the external firewire drive is always connected to the Mac pro - it is not a mobile device - it's purely for having the Time Machine on an external storage.
And how should i avoid the behaviour with the idisk. The storage is a remote external device, where the connection is built through the Internet.
Any additional ideas ?
Thanks
Michael

Sequence numbers not generated sequentially?

Our situation: We have encountered an issue with our database, where it appears that a sequence has generated a number out of sequence, that is, to fill in a gap left previously. That is, in the affected table, we have records like:
Seq No Date (DD/MM/YY)
1 29/12/08
2 29/12/08
3 4/1/09
4 29/12/08
The code that actually updates the database is from a third party, so I am unable to prove the following, but the vendor assures me that:
1. The sequence numbers are generated using "select message_number.nextval from dual".
2. The Date column is not modified after the record is created. ( Nor is it supposed to be )
The sequence is created by "CREATE SEQUENCE MESSAGE_NUMBER START WITH 10000000 INCREMENT BY 1 MINVALUE 10000000 CACHE 20 NOCYCLE NOORDER"
This was detected only yesterday, after the event, and is very uncommon ( I have not found another instance, but there are over 7,000,000 records, so I haven't performed an exhaustive search). We are relying on the sequence numbers always being generated sequentially, as in each message_number.nextval is greater than the previous one.
I don't think that the date change was due to a user accidentaly changing the date. Related records to '3' are also dated 4/1/09, there is no facility for a user to change the date outside of accessing the database directly, and even the developers do not have write access to this database.
My questions:
1. Is this normal behaviour for a sequence? To go back and fill in a gap like this? If so we'll have to change one of the assumptions of one of our modules.
2. Should the sequence be defined with 'ORDER' rather than 'NOORDER' to stop this?
3. Could this be a bug in the sequence number generation? We are using Oracle 9.2.0.1.0.
4. Is this situation "impossible", and therefore there is a bug in the vendor library that we need to track down.
Thanks for your help,
Wayne.

wayneb wrote:
Our situation: We have encountered an issue with our database, where it appears that a sequence has generated a number out of sequence, that is, to fill in a gap left previously. That is, in the affected table, we have records like:
Seq No Date (DD/MM/YY)
1 29/12/08
2 29/12/08
3 4/1/09
4 29/12/08
The code that actually updates the database is from a third party, so I am unable to prove the following, but the vendor assures me that:
1. The sequence numbers are generated using "select message_number.nextval from dual".
2. The Date column is not modified after the record is created. ( Nor is it supposed to be )There might be a delay between fetching the sequence and storing the sysdate? value in the database.
maybe some user prepared a new record. Then went to some new years eve party and when he came back at the begining of next year he commited the data (record send to database, database is adding date column by some trigger...).
>
The sequence is created by "CREATE SEQUENCE MESSAGE_NUMBER START WITH 10000000 INCREMENT BY 1 MINVALUE 10000000 CACHE 20 NOCYCLE NOORDER"
This was detected only yesterday, after the event, and is very uncommon ( I have not found another instance, but there are over 7,000,000 records, so I haven't performed an exhaustive search). We are relying on the sequence numbers always being generated sequentially, as in each message_number.nextval is greater than the previous one.
I don't think that the date change was due to a user accidentaly changing the date. Related records to '3' are also dated 4/1/09, there is no facility for a user to change the date outside of accessing the database directly, and even the developers do not have write access to this database.
My questions:
1. Is this normal behaviour for a sequence? To go back and fill in a gap like this? If so we'll have to change one of the assumptions of one of our modules.No sequences don't fill gaps. However it is possible to fetch and cache values from a sequence for later usage. Especially in a RAC environment you can get sequence values that are not in order of time.
2. Should the sequence be defined with 'ORDER' rather than 'NOORDER' to stop this?No.
3. Could this be a bug in the sequence number generation? We are using Oracle 9.2.0.1.0.Extremly unlikely, but you can always check Metalink.
4. Is this situation "impossible", and therefore there is a bug in the vendor library that we need to track down.You can create such situations programatically. Whether it is a bug depends on the specifications for the software.
>
Thanks for your help,
Wayne.Edited by: Sven W. on Mar 24, 2009 5:00 PM

Finding missed sequence numbers and rows from a fact table

Finding missed sequence numbers and rows from a fact table
Hi
I am working on an OLAP date cube with the following schema:
As you can see there is a fact transaction with two dimensions called cardNumber and Sequence. Card dimension contains about three million card numbers.
Sequence dimension contains a sequence number from 0 to 255. Fact transaction contains about 400 million transactions of those cards.
Each transaction has a sequence number in 0 to 255 ranges. If sequence number of transactions of a card reaches to 255 the next transaction would get 0 as a sequence number.
For example if a card has 1000 transactions then sequence numbers are as follows;
Transaction 1 to transaction 256 with sequences from 0 to 255
Transaction 257 to transaction 512 with sequences from 0 to 255
Transaction 513 to transaction 768 with sequences from 0 to 255
Transaction 769 to transaction 1000 with sequences from 0 to 231
The problem is that:
Sometimes there are several missed transactions. For example instead of sequence from 0 to 255, sequences are from 0 to 150 and then from 160 to 255. Here 10 transactions have been missed.
How can I find all missed transactions of all cards with a MDX QUERY?
I really appreciate for helps

Thank you Liao
I need to find missed numbers, In this scenario I want the query to tell the missed numbers are: 151,152,153,154,155,156,157,158,159
Relative transactions are also missed, so I think it is impossible to get them by your MDX query
Suppose this:
date
time
sequence
20140701
23:22:00
149
20140701
23:44:00
150
20140702
8:30:00
160
20140702
9:30:00
161
20140702
11:30:00
162
20140702
11:45:00
163
As you can see the sequence number of the last transaction at the 20140701 is 150
We expecting that the first transaction of the next day should be 151 but it is 160. Those 10 transactions are totally missed and we just need to
find missed sequence numbers

LR3 Web Gallery Sequence Numbering bug?

Anyone else getting this problem with sequence numbering in the web HTML templates? Basically, as you jump through photos the photo number is always stuck on #1, never changes when you go to the next photo - should go 1, 2, 3, 4, 5...
I just sent a bug report but, wondering if anyone else found a fix for this yet.
This is in LR3 on Mac - really trying to do this on TTG Highslide gallery but, same problem occurs in default Lightroom HTML gallery.
Thanks.
******BUG******
Concise problem statement:
Steps to reproduce bug:
1. Go to Web Module
2. Choose default HTML Gallery
3. Under Image Info set Caption to Sequence
Results:
Sequence caption always shows 1/total images.
i.e. 1/10, 1/10, 1/10, 1/10
Expected results:
Sequence should increment current image number / total images as you click through images.
i.e. 1/10, 2/10, 3/10, 4/10

Yeah, still have the numbering problem using the Image Info sequence outputs.
But, if you use the standard Lightroom Flash Gallery it has it's own sequence numbering output (that does not use Image Info captions) and it does work correctly. These show up as 1/9, 2/9, 3/9 etc. on each photo down by the back/next buttons.
Also, the Cell Numbering does work when using the Lightroom HTML Gallery - though, those numbers only appear on the index page not on individual photos.
But, haven't seen a good work-around yet for sequence numbering in Image Info area. Only option there seems to be typing numbers manually into the caption. Or, if you need the caption for other info maybe use one of the IPTC fields like Headline to type in your numbers. You can then do a Custom Setting in web module to have those text fields show up with your photos.
Really hoping we will see a LR 3.1 sometime soon with a fix - should be an easy correction for Adobe.

Documents Sequence numbering for each Branch (Branch as segment)

dear Brother's
can help me in this case
Documents Sequence numbering for each Branch (Branch as segment)
Each branch have an own sequence
I implement oracle Business suite ERP for Five Branch ( KSA,INDIA,DUBIA ,JORDAN ,SYRIA )
I want to segregate sequence numbering for each branch, sequence for (
Sales order, invoice, purchase order, Invoice)
Is there a possibility to link sequence with any segment I define it in COA like Branch
Note: I work in single Operating Unit

Hi,
You might be able to adapt this solution to work for your case: https://acrobat.com/#d=*2slxPLc6c-H0U449vA4jQ. It's more about page numbers for different Master Pages, but you may be able to tie it to the different data nodes.
Niall

Deleting specific sequence numbers

Gurus!
I have a scenario in which , I would like to revoke / delete the disabled java.io.filepermissions on a Specific Oracle9i Schema.
i tried to delete the KEY values from DBA_JAVA_POLICY / USER_JAVA_POLICY
then i came to a point that as these both are Views we cannt delete the data.
So I tried to delete a specific sequence numbers ( 71 to 79) for a GRANTEE# number 31 from the base table that is java$policy$ but still am not able to . the errors SQL command terminated improperly ( somehting like that)
Please help me out with this. as I already upset with this.

You are not supposed to mess with the data dictionary, otherwise unexpected results may start to show up.
Granting or revoking privileges must be done with proper commands provided explicilty for that pourpose.
Verify database privileges here.
~ Madrid.

MIRO document sequence numbering

Hi Experts,
We are facing an issue in MIRO document sequence numbering; please see the document numbers with dates:
Document No             Yr      DocTye     Document Date                Posting Date          Entry Date
5105600850              2011            RE      23.02.2011                          11.04.2011          11.04.2011
5105600865              2011            RE     27.03.2011          07.04.2011         07.04.2011
5105600866              2011            RE     27.03.2011          07.04.2011         07.04.2011
5105600866              2011           RE     27.03.2011          07.04.2011         07.04.2011
5105600867              2011           RE     27.03.2011          07.04.2011         07.04.2011
5105600869              2011           RE     29.03.2011          07.04.2011          08.04.2011
From the above document list doc no 5105600850 is been posted on 11.04.2011 but doc no 5105600866 is been posted on 07.04.2011 but still the sequence of the document numbers are not correct, though it doc no 5105600850 posted before the doc no 5105600866.
Why is this behavior of the system? Is there any buffer concept in MIRO posting?
Thanks in advance.
Br,
Shilpa

Please check whether the number range is used up or not.
Sometime system will take the used number range if the range is over.
Or you can check this ling for Buffer
[MIRO document Number range buffering problem |MIRO document Number range buffering problem;

In Numbers, highlighting a gap?

I have a line graph in Numbers with multiple lines to show the trends. But I want to show the gap between the two points. So is there a way to highlight from a point on the first line to a point on the second line?
Hope that makes sense.. not sure if it is possible!

You had to pick that one didn't you?
this is not a feature or anything, it's a trick, a workaround if you will. A real workaround
First it's a scatter plot, I don't think it will work in a line chart at all.
Second, I am on my ipad, so what you see is what you get, maybe SG can answer the line thickness part.
Ok, Scatter plots, they can plot data that isn't continuous, meaning if there isn't a Reading for Tuesday, it won't show zero (like other chart types typically do), it will just draw a line from Monday across Tuesday to the Wednesday point for example. It also will only draw a line between two points if they are one above the other in the table. If there is a blank row, no line between the last value and the next one further down in the table in that column.
I use these two things together to get the result.
So for each vertical section the chart. I am plotting three things, so three columns, but I need to draw a line between two of them, so I need different data in the third column between two rows. This will draw a line in that color between the data points on rows 1 and 2. But I don't want the other points to change so I leave them in place for all three rows. The blank row is there to stop it drawing a yellow line between columns of information in the chart ( put something in and watch the difference.
Look at my table, I typed in values by hand, but it could easily be accomplished using some Formulas.
It actually, plots three dots at 10 and at 15 for value 1 and 2, but it draws a line from the 10 to 15 in the third column, then stops because of the blank row. If you put data there or remove the blank row, you get a yellow line from 15 in counter one data to the 10 in counter 2 data. Try it to see what I mean.

70D changed sequence numbers from 6.. to 5...

Month old 70D was issuing sequnce numbers OK in August 31 in the 600 range but on September 2 (the next time I used the camera) the sequence numbers changed to 5000. I manually changed the date to October but the sequence numbers remained in the 5000 range so it probably had nothing to do with the month change. I did a menu RESET, took a photo and it was just the next number (5102) so no help there. In both cases there is a number 100 and a dash preceding the sequence number. Any suggestions? Thanks
BTW the camera FILE NUMBERING setting is CONTINUOUS
Solved!
Go to Solution.

Hello bob70D,
The most likely culprit with something like this is going to be the card. It is very likely that the camera is reading an old file numbering scheme (could even be from another Canon EOS DSLR) and "picking up" where the numbers leave off.
To test this, and really to resolve this issue, you'd need to format the card. Only do this in the camera and only once you've backed up your pictures. First, set the camera's file numbering to Manual Reset and then Format. It will bring everything back to 0001. Then go back into the Menu and back to file numbering and choose Continuous this time.
Did this answer your question? Please click the Accept as Solution button so that others may find the answer as well.

Enhancement Request: Recalculate Sequence Numbers

Hi
Wherever apex has sequence numbers (for branchs, items, regions etc.), please could we have the ability to recalculate them based on increments of ten so for example items as follows:
P_ITEM1 - sequence = 1
P_ITEM1 - sequence = 11
P_ITEM1 - sequence = 12
P_ITEM1 - sequence = 100
P_ITEM1 - sequence = 120
Would become:
P_ITEM1 - sequence = 10
P_ITEM1 - sequence = 20
P_ITEM1 - sequence = 30
P_ITEM1 - sequence = 40
P_ITEM1 - sequence = 50
The option to exclude items with a sequence number of 999 from the recalculation would also be handy. This can become a bit of a pain when a page has been updated many times and you end up with bunching of sequence number so that if something has to be inserted between them, you have to edit a number of items or whatever to make that happen.
If you could do a page-wide or application-wide recalculation - t'would also be cool.
If this feature is available already, please point me to it.
Cheers
Ben

The Cleanup feature Paul mentioned is new in 4.0 but fyi in any version component sequence numbers accept non-integer values so you can always insert something anywhere without a need to resequence...Thanks! I never knew that! Oh yes. And they can be negative too. We have some very esoteric looking sequences...
Actually the decimals are pretty useful for things like conditional display of regions. If you've got 3 related but mutually exclusive regions, numbering them 20.1, 20.2, and 20.3 indicates the relationship between them. Which brings me to another enhancement request: regions to have separate name and title properties (like pages do), so that where such regions have to have the same title shown to users, it's a lot easier for developers to tell them apart.

Recycled Sequence Numbers

Hi,
We have a requirement of generating sequence numbers for a table and we need to recycle them if some of them is deleted.
For example the following tabe Employee(Id,name)
ID NAME
1 XXX
2 YYY
3 ZZZ
4 AAA
The ID filed should have the next sequence number generated. When I call getnextID now, it should return 5
ID NAME
1 XXX
2 YYY
3 ZZZ
4 AAA
5 BBB
Now Let us assume I delete 3. The contents of the table aare
ID NAME
1 XXX
2 YYY
4 AAA
5 BBB
Now when getNextID, 3 should be returned.
How to achieve this in a best performing way in Oracle? Are there any patterns around it? Please note this should run in a multi user environment.
Thanks,
Rama

I think the answers were based on the fact that you call it incorrectly sequence.
Your ConnectivityID is more as a resource that could be recycled. I see some similarities to the GSM telecom market where a resource(i.e. a phone number or a SIM card no) can be recycled when is not active anymore (under certain conditions however).
Personally I would generate a table of resources having the resource number (ConnectivityID) and resource status.
To simplify it, suppose that you have column status with 2 possible values, 0=available, 1=not available.
When you want to allocate the resource number(ConnectivityId) you will set the status to 1.
When the record is deleted then status will be updated back to 0.
Recycling a ConnectivityID will mean searching in the table for the lowest number having status=0.
Of course you don't expect this to be as fast as a sequence but I think this is a different requirement, IMO.
Regards
Al

Failed to request gap sequence. Thread #: 1, gap sequence: 6859-6859

Dear all,
1.while applying the log manually 6859 it tells that is already registered. then i appplied 6860,6861,6862,6863 its get appplied.
2.But while check on the alertlog it tells
Failed to request gap sequence. Thread #: 1, gap sequence: 6859-6859,All FAL server has been attempted.
Thu May 17 13:04:59 2012
idle dispatcher 'D000' terminated, pid = (11, 18)"
3.the alert logfile from standby is given below
Completed: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DI
Thu May 17 13:04:20 2012
Failed to request gap sequence. Thread #: 1, gap sequence: 6859-6859
All FAL server has been attempted.
Thu May 17 13:04:59 2012
idle dispatcher 'D000' terminated, pid = (11, 18)
thanks in advance,
regards,
DB

Hello again;
12154 is a common error. If this was Oracle 11 i would say check your Standby password file, I assume this is OK.
If not you must copy the password to the standby and rename it. After that you must cancel recovery and shutdown the standby
and START MOUNT on the new password file.
Can you tnsping both servers from the other?
Can you connect from ( sqlplus ) from each server to the other?
Example :
sqlplus sys/password@primary as sysdba (from the standby system)
Most likely your tnsname is missing an entry or has an incorrect entry. Sometimes this is a listener issue, double check your status.
Is your listener setup correctly?
If you do a :
lsnrctl status
The READY status comes from the instance registering with the listener.
The UNKNOWN status comes from the sid list entry in listener.ora.
from standby
$lsnrctl services
And make sure your service is available.
You can compare you tnsnames and listener.ora setup with my short notes :
http://www.visi.com/~mseberg/data_guard_on_oracle_11_step_by_step.html
Best Regards
mseberg

Sequence numbers - with no gaps!

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