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POJPA persistence using multiple threads
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  1. POJPA persistence using multiple threads
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    copied!<p>I have a problem when I try to persist objects using <strong>multiple threads</strong>.</p> <p><strong>Details :</strong></p> <p>Suppose I have an object <code>PaymentOrder</code> which has a list of <code>PaymentGroup</code> (One to Many relationship) and <code>PaymentGroup</code> contains a list of <code>CreditTransfer</code>(One to Many Relationship again).</p> <p>Since the number of <code>CreditTransfer</code> is huge (in lakhs), I have grouped it based on <code>PaymentGroup</code>(based on some business logic) and creating <em>WORKER</em> threads(one thread for each PaymentGroup) to form the <code>PaymentOrder</code> objects and commit in database.</p> <p>The problem is, each worker thread is creating one each of <code>PaymentOrder</code>(which contains a unique set of <code>PaymentGroup</code>s). </p> <p>The primary key for all the entitties are auto generated.</p> <p>So there are three tables, 1. PAYMENT_ORDER_MASTER, 2. PAYMENT_GROUPS, 3. CREDIT_TRANSFERS, all are mapped by One to Many relationship.</p> <p>Because of that when the second thread tries to persist its group in database, the framework tries to persist the same <code>PaymentOrder</code>, which previous thread committed,the transaction fails due to some other unique field constraints(the checksum of <code>PaymentOrder</code>). </p> <p>Ideally it must be 1..n..m (<code>PaymentOrder</code> ->PaymentGroup<code>--&gt;</code>CreditTransfer`)</p> <p>What I need to achieve is if there is no entry of <code>PaymentOrder</code> in database make an entry, if its there, dont make entry in <code>PAYMENT_ORDER_MASTER</code>, but only in <code>PAYMENT_GROUPS</code> and <code>CREDIT_TRANSFERS</code>.</p> <p>How can I ovecome this problem, maintaining the split-master-payment-order-using-groups logic and multiple threads?</p>
 

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