multi threading batch giving error

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Posted on by rohit1900

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I am facing issue in multi-threading and it is giving following

Actually here I am creating multiple packing slip for a single PO based on the delivery notes in the staging table and getting the above error message

Before I have checked with the technical team and found that in purchtable properties-> OCC was yes and changed in to No and table locking was not there in multi threading but it created some issue in normal PO creation

So now it has been reverted back to yes and my multi-threading batch is throwing the old error message.

I would to invite the team members to express their thought in this issue so that both thing can work simultaneously.

Thanks,

Rohit

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André Arnaud de Cal... 301,069 Super User 2025 Season 2 on at

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Hi Rohit,

Are you using standard features or a customization to get purchase orders posted in batch? Please provide more details what you have done. Otherwise it would be guessing only.

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enricoariel 60 on at

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Without looking at your code I can only guess that maybe it has to do with the way you select records. in a multi thread it might be updating the same record simultaneously multiple times thus failing all threads. that could be the reason why when you set the table locking to pessimistic lock it worked.

I suggest you look to this great post, http://dev.goshoom.net/en/2011/10/pessimistic-locking/ if you can figure out what is the cause.

Otherwise try to share some code.

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rohit1900 439 on at

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/// /// Contains the code that does the actual job of the class. /// public void run() { #OCCRetryCount SON_PalettiSummaryInvoice SON_PalettiSummaryInvoice; AifInfoLog aifInfoLog = new AifInfoLog(); PurchId lastpurchid; exceptionID = ''; try { SON_PalettiPOPackMultithread::ElmoPopackingnew(purchTable,deliveryNote); purchTable.reread(); if(purchTable.PurchStatus == PurchStatus::Received) { ttsBegin; select firstonly forUpdate PurchStatus from SON_PalettiSummaryInvoice where SON_PalettiSummaryInvoice.InvoiceNumber == purchTable.SON_SummaryInvoiceNo; SON_PalettiSummaryInvoice.PurchStatus = purchTable.PurchStatus; SON_PalettiSummaryInvoice.doUpdate(); ttsCommit; } } catch(Exception::Error) { this.geterror(aifInfoLog); info(strFmt("packing slip cancelled for the delivery note %1",deliveryNote)); } catch (Exception::Deadlock) { retry; } catch (Exception::UpdateConflict) { if (appl.ttsLevel() == 0) { if (xSession::currentRetryCount() >= #RetryNum) { throw Exception::UpdateConflictNotRecovered; } else { retry; } } else { throw Exception::UpdateConflict; } } }

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rohit1900 439 on at

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multi-thread-PO-packing-slip.txt multi-thread-PO-packing-slip.txt

sorry for the wrong formatting above thread i have pasted by code in the notepad and attached here , in the first run method I am calling multiple delivery note(product receipt) for a single PO.

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rohit1900 439 on at

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you are right that same PO it is trying to access in the different thread and trying to create product receipt I have discussed and introduced sleep(3000) before retry in the catch but still I am getting the error.

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rohit1900 439 on at

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2248.multi-thread-PO-packing-slip.txt run-method.txt

I have added the below code in there also

_purchtable.concurrencyModel();

and

select pessimisticLock PurchTableloc where PurchTableloc.PurchId == purchTable.PurchId;
SON_PalettiPOPackMultithread::ElmoPopackingnew(PurchTableloc,deliveryNote);
//SON_PalettiPOPackMultithread::ElmoPopackingnew(purchTable,deliveryNote);

after making those changes I have generated IL but still getting those errors.

but still getting same error after changing I am incrementing IL.

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Khushhal Garg 1,514 on at

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Rohit,

Create dependency tasks so that it doesn't create packing slips for same PO in parallel. Task should wait for one packing slip to be created on a PO before it can start to create another packing slip on same PO.

OR

Lock purchase order (PurchTable) so parallel tasks are waiting for lock to be released from task that has locked it first. I am not seeing ttsbegin at the beginning of the process to lock PurchTable in run method. do ttsbegin and select frupdate purchtable or purchtable.selectforupdate(true)

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enricoariel 60 on at

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Hi, the reason is very simple, you have a while inside a transaction. look at the article I pointed you: it says

ttsBegin;

while select forUpdate myTable

{

myTable.MyField = 'something';

myTable.update();

}

ttsCommit;

potentially locks a large amount of records.

that is what happens to you. besides other implication that it might have in production to other processes that might start failing because of these locks obviously if you do it in a multi thread it fails unless you lock the table with pessimistic concurrency, but that is certainly not a good idea.

i will try to rewrite the logic of this method and post it later

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enricoariel 60 on at

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I'm not sure if it will fix the issue, but in the run method can you try to comment the select line and replace it with the following

//select pessimisticLock PurchTableloc where PurchTableloc.PurchId == purchTable.PurchId;

PurchTableloc.setTmp();

buf2Buf(PurchTable::find(purchTable.PurchId), PurchTableloc);

PurchTableloc.doInsert();

SON_PalettiPOPackMultithread::ElmoPopackingnew(PurchTableloc,deliveryNote);

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