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https://issues.apache.org/jira/browse/CASSANDRA-18937?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Henrik Ingo updated CASSANDRA-18937:
------------------------------------
Resolution: Invalid
Status: Resolved (was: Triage Needed)
Closing: Bug was in code added by myself.
> Two accord transactions have the exact same transaction id
> ----------------------------------------------------------
>
> Key: CASSANDRA-18937
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18937
> Project: Cassandra
> Issue Type: Bug
> Components: Accord
> Reporter: Henrik Ingo
> Priority: Normal
>
> When testing solutions for CASSANDRA-18798 I noticed that two independent
> transactions running at the same time in two parallel threads ended up having
> the exact same transaction id:
> {code}
> public void testListAddition() throws Exception
> {
> SHARED_CLUSTER.schemaChange("CREATE TABLE " + currentTable + " (k int
> PRIMARY KEY, l list<int>)");
> SHARED_CLUSTER.forEach(node -> node.runOnInstance(() ->
> AccordService.instance().setCacheSize(0)));
> CountDownLatch latch = CountDownLatch.newCountDownLatch(1);
> Vector<Integer> completionOrder = new Vector<>();
> try
> {
> for (int i=0; i<100; i++)
> {
> ForkJoinTask<?> add1 = ForkJoinPool.commonPool().submit(() ->
> {
> latch.awaitThrowUncheckedOnInterrupt();
> SHARED_CLUSTER.get(1).executeInternal("BEGIN TRANSACTION
> " +
> "UPDATE " + currentTable + " SET l = l + [1]
> WHERE k = 1; " +
> "COMMIT TRANSACTION");
> completionOrder.add(1);
> });
> ForkJoinTask<?> add2 = ForkJoinPool.commonPool().submit(() ->
> {
> try {
> Thread.sleep(0);
> {code}
> Adding some logging in TxnWrite.java reveals the two threads ave identical
> executeAt and unix timestamps:
> {noformat}
> lastmicros 0
> DEBUG [node2_Messaging-EventLoop-3-4] node2 2023-10-18 18:26:08,954
> AccordVerbHandler.java:54 - Receiving Apply{kind:Minimal,
> txnId:[10,1697642767659000,10,1], deps:[distributed_test_keyspace:[(-Inf,-1],
> (-1,9223372036854775805], (9223372036854775805,+Inf]]]:{}, {},
> executeAt:[10,1697642767659000,10,1],
> writes:TxnWrites{executeAt:[10,1697642767659000,10,1],
> keys:[distributed_test_keyspace:DecoratedKey(-4069959284402364209,
> 00000001)], write:TxnWrite{}}, result:accord.api.Result$1@253c102e} from
> /127.0.0.1:7012
> raw 0 (NO_LAST_EXECUTED_HLC=-9223372036854775808
> lastExecutedTimestamp [0,0,0,0]
> lastmicros 1697642767659000
> raw -9223372036854775808 (NO_LAST_EXECUTED_HLC=-9223372036854775808
> lastExecutedTimestamp [10,1697642767659000,10,1]
> DEBUG [node2_CommandStore[1]:1] node2 2023-10-18 18:26:09,023
> AccordMessageSink.java:167 - Replying ACCORD_APPLY_RSP ApplyApplied to
> /127.0.0.1:7012
> lastmicros 0
> raw 0 (NO_LAST_EXECUTED_HLC=-9223372036854775808
> lastExecutedTimestamp [0,0,0,0]
> lastmicros 1697642767659000
> raw -9223372036854775808 (NO_LAST_EXECUTED_HLC=-9223372036854775808
> lastExecutedTimestamp [10,1697642767659000,10,1]
> timestamp 1697642767659000 executeAt[10,1697642767659000,10,1]
> timestamp 1697642767659000 executeAt[10,1697642767659000,10,1]
> {noformat}
> Increasing the Thread.sleep() to9 or 10 helps so that the transactions have
> different IDs.
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