Nicolas,
Your proposal for a new method like, "SequenceUtil.getNextSequence(String
key, long staggerMax)" sounds like what I am proposing. Would the
"staggerMax" parameter set the next range of sequence IDs? For example:
Before calling "getNextSequence" method"
SeqName: MySequence
SeqId: 1000
Now call your method: SequenceUtil.getNextSequence("MySequence", 1500)
After the call the SequenceValueItem record has the following:
SeqName: MySequence
SeqId: 2501
We ran into some performance problems for some of our entities (OrderItem,
InventoryItem, etc) when the application servers were generating sequenceIds
for these entities and the default sequence-bank-size was only 10. The
process of getting a new range of sequence IDs from the database is a
locking process and we had multiple servers trying to perform the same
function. This was creating table locks during high loads.
In the entity definition you can specify the "sequence-bank-size" like so:
<entity entity-name=*"ProductSurveyResource" *package-name=*
"org.ofbiz.product.survey" *sequence-bank-size=*"1000"*>
but we couldn't find a way to specify the bank size for non-entity related
sequence IDs. We also use the "sequence-id" simple method a lot but this
only works for entity related sequences and doesn't have a parameter to set
the "staggerMax".
My proposal was simply to add a new column to the SequenceValueItem table
called "sequenceBankSize" (or something like that). Using my example above
the SequenceValueItem table might look like the following:
column names: SeqName, SeqId, SeqBankSize
record values: MySequence, 1000, 1500
Then when the you used the SequenceUtil.getNextSequence("MySequence") or the
simple method "sequence-id" for the first time the sequencer would update
the SequenceValueItem table as follows:
MySequence, 2501, 1500
Subsequent "getNextSequence" calls would continue to return unique IDs
without hitting the database until the bank of 1500 IDs was used up and then
the above process would continue again.
For us the key points we would like to see for the sequencer are as follows:
1. Ability to use non-entity related sequences by just providing a sequence
name.
2. Ability to configure the sequence bank size so we can adjust the
frequency for database updates.
3. Any APIs for the sequence util should be available via simple
methods. We could provide a patch for the simple method support for the new
utils if needed.
Thanks,
Brett
On Thu, Dec 24, 2009 at 8:52 AM, Nicolas Malin <
malin.nico...@librenberry.net> wrote:
> After some reflection on this subject, I arrive to :
> getNextSeqId is use normaly to get an single id that identify an
> entity : Invoice.invoiceId, Order.orderId, Party.partyId etc ...
> It's easier to remove the problematic instruction but bypasses
> getNextSeqId purpose.
>
> For multiple sequence on Entity I suggest to create new function on
> delegator : getNextSequence (String entityName, String diff, long
> staggerMax) that manage sequence as getNextSeqId but analyse just the
> validity of entityName and generate sequenceValueId : entityName.diff.
>
> As this, Delegator continue to work only on entity and not use for other
> not in relation with entitymodel.
>
> For sequence not in relation with entity, I can extend sequenceUtil to
> have a function SequenceUtil.getNextSequence(String key, long
> staggerMax).
>
> Brett can you give me an example for your proposal ? I don't really
> understand your improvement.
>
> If you wait to read, Have a nice end year ;)
> Nicolas
>
>
> Le mercredi 23 décembre 2009 à 13:49 -0700, Brett Palmer a écrit :
> > I confirmed that if you use the delegator.getNextSeqId() you will get
> an
> > exception every time it is used with a complaint that an entity doesn't
> > exist for the sequence you requested. It does give still generate an ID
> but
> > the exception is a little concerning when you are running in a production
> > environment. This exception probably isn't intended but is a consequence
> of
> > the call to look for the entity name.
> >
> > I would prefer we just outputted a warning log and not threw an
> exception.
> >
> > Another request for the sequence generator is the ability to specify the
> gap
> > between the next sequence ID update. This can be configured in the
> entity
> > engine but only for those IDs that have a corresponding entity. If you
> try
> > to use a generic sequencer with no attached entity the default is 10
> which
> > can be low for a production environment with multiple servers. Could we
> add
> > a column to the SequenceValueItem to include the next increment value?
> >
> >
> > Brett
> >
> > Here is the stack trace:
> >
> >
> > ---- exception report
> > ----------------------------------------------------------
> > Error getting entity definition from model
> > Exception: org.ofbiz.entity.GenericModelException
> > Message: Could not find definition for entity name DummySequence
> > ---- stack trace
> > ---------------------------------------------------------------
> > org.ofbiz.entity.GenericModelException: Could not find definition for
> entity
> > name DummySequence
> > org.ofbiz.entity.model.ModelReader.getModelEntity(ModelReader.java:451)
> > org.ofbiz.entity.DelegatorImpl.getModelEntity(DelegatorImpl.java:1544)
> > org.ofbiz.entity.DelegatorImpl.getNextSeqIdLong(DelegatorImpl.java:1693)
> > org.ofbiz.entity.DelegatorImpl.getNextSeqId(DelegatorImpl.java:1655)
> > org.ofbiz.entity.DelegatorImpl.getNextSeqId(DelegatorImpl.java:1651)
> >
> com.automationgroups.pe.util.InventoryContainer.start(InventoryContainer.java:27)
> > org.ofbiz.base.container.ContainerLoader.start(ContainerLoader.java:101)
> > org.ofbiz.base.start.Start.startStartLoaders(Start.java:272)
> > org.ofbiz.base.start.Start.startServer(Start.java:322)
> > org.ofbiz.base.start.Start.start(Start.java:326)
> > org.ofbiz.base.start.Start.main(Start.java:409)
> >
> --------------------------------------------------------------------------------
> >
> > 2009-12-23 13:29:07,218 (main) [ SequenceUtil.java:236:WARN ]
> > [SequenceUtil.SequenceBank.fillBank] first select failed: will try to add
> > new row, result set was empty for sequence [DummySequence]
> > Used SQL: SELECT SEQ_ID FROM SEQUENCE_VALUE_ITEM WHERE
> > SEQ_NAME='DummySequence'
> > Thread Name is: main:Thread[main,5,main]
> > 2009-12-23 13:29:07,312 (main) [ SequenceUtil.java:341:INFO ] Got
> bank
> > of sequenced IDs for [DummySequence]; curSeqId=10000, maxSeqId=10010,
> > bankSize=10
> > 2009-12-23 13:29:07,312 (main) [ InventoryContainer.java:28 :INFO ] Here
> is
> > the sample sequence Id: 10000
> > 2009-12-23 13:29:07,343 (main) [ GenericDispatcher.java:61 :INFO ]
> Creating
> > new dispatcher [RMIDispatcher] (main)
> >
> >
> >
> > On Wed, Dec 23, 2009 at 12:54 PM, Scott Gray <scott.g...@hotwaxmedia.com
> >wrote:
> >
> > > It looks to me as though an exception is being logged rather than
> thrown,
> > > is the id still being generated?
> > >
> > > Regards
> > > Scott
> > >
> > > HotWax Media
> > > http://www.hotwaxmedia.com
> > >
> > >
> > > On 24/12/2009, at 3:31 AM, Nicolas Malin wrote:
> > >
> > > Hi all,
> > >>
> > >> It's possible that this subject has been already discussed here but I
> > >> don't find any trace in the archives.
> > >>
> > >> A long time ago, I used delegator.getNextSeqId to use multiple
> sequences
> > >> in an entity like invoice (SALES, PURCHASE, ...).
> > >> Example : in France we use a sequence for all invoiceType and I call
> the
> > >> delegator this way :
> > >> invoiceId = delegator.getNextSeqId("Invoice." + invoiceTypeId);
> > >> To have :
> > >> for sales : VE10000, VE10001, VE10002, ...
> > >> for purchases : AC10000, AC10001, AC10002, ...
> > >>
> > >> Now when using this, GenericDelegator throws an exception : "Could not
> > >> find definition for entity name Invoice.PURCHASE_INVOICE"
> > >>
> > >> I checked the code (GenericDelegotor.java:3049 on trunk) and found :
> > >> // might be null, but will usually match the entity name
> > >> ModelEntity seqModelEntity = this.getModelEntity(seqName);
> > >>
> > >> I suppose that there are some reasons to check the seqName as an
> > >> entityName but I don't understand why.
> > >>
> > >> To manage many sequences for one entity, do you use directly the
> > >> sequenceUtil ?
> > >>
> > >> Is it possible to add an escape case before checking entity (as add
> test
> > >> if we find a point) ? Or extend getNextSeqId to manage prefix/suffix
> > >> parameters ?
> > >>
> > >> Nicolas
> > >>
> > >> --
> > >> Nicolas MALIN
> > >> Consultant
> > >> Tél : 06.17.66.40.06
> > >> Site projet : http://www.neogia.org/
> > >> -------
> > >> Société LibrenBerry
> > >> Tél : 02.48.02.56.12
> > >> Site : http://www.librenberry.net/
> > >>
> > >>
> > >
> --
> Nicolas MALIN
> Consultant
> Tél : 06.17.66.40.06
> Site projet : http://www.neogia.org/
> -------
> Société LibrenBerry
> Tél : 02.48.02.56.12
> Site : http://www.librenberry.net/
>
>
