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https://issues.apache.org/jira/browse/CASSANDRA-18798?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17774270#comment-17774270
]
Henrik Ingo commented on CASSANDRA-18798:
-----------------------------------------
Confirmed:
First run --list-append on an old branch of cep-15-accord:
{code}
hingo@odysseus:~/Documents/github/accordclient$ java -jar
elle-cli/target/elle-cli-0.1.6-standalone.jar --model list-append --anomalies
G0 --consistency-models strict-serializable --directory out-la --verbose
test-la.edn
java.lang.AssertionError: Assert failed: No transaction wrote 5 12
t2
at
elle.list_append$dirty_update_cases$fn__1930$fn__1935.invoke(list_append.clj:377)
at clojure.lang.PersistentVector.reduce(PersistentVector.java:343)
at clojure.core$reduce.invokeStatic(core.clj:6829)
at clojure.core$reduce.invoke(core.clj:6812)
at
elle.list_append$dirty_update_cases$fn__1930.invoke(list_append.clj:372)
at clojure.core$map$fn__5884.invoke(core.clj:2759)
at clojure.lang.LazySeq.sval(LazySeq.java:42)
at clojure.lang.LazySeq.seq(LazySeq.java:51)
at clojure.lang.Cons.next(Cons.java:39)
at clojure.lang.RT.boundedLength(RT.java:1793)
at clojure.lang.RestFn.applyTo(RestFn.java:130)
at clojure.core$apply.invokeStatic(core.clj:667)
at clojure.core$mapcat.invokeStatic(core.clj:2787)
at clojure.core$mapcat.doInvoke(core.clj:2787)
at clojure.lang.RestFn.invoke(RestFn.java:423)
at elle.list_append$dirty_update_cases.invokeStatic(list_append.clj:370)
at elle.list_append$dirty_update_cases.invoke(list_append.clj:361)
at
elle.list_append$check$dirty_update_task__2257.invoke(list_append.clj:875)
at jepsen.history.task.Task.run(task.clj:282)
at
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:829)
{code}
Then today's checkout of cep-15-accord
{code}
hingo@odysseus:~/Documents/github/accordclient$ java -jar
elle-cli/target/elle-cli-0.1.6-standalone.jar --model list-append --anomalies
G0 --consistency-models strict-serializable --directory out-la --verbose
test-la.edn
{"valid?":true}
{code}
(Full list of steps as in description of this ticket)
> Appending to list in Accord transactions uses insertion timestamp
> -----------------------------------------------------------------
>
> Key: CASSANDRA-18798
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18798
> Project: Cassandra
> Issue Type: Bug
> Components: Accord
> Reporter: Jaroslaw Kijanowski
> Assignee: Henrik Ingo
> Priority: Normal
> Attachments: image-2023-09-26-20-05-25-846.png
>
>
> Given the following schema:
> {code:java}
> CREATE KEYSPACE IF NOT EXISTS accord WITH replication = {'class':
> 'SimpleStrategy', 'replication_factor': 3};
> CREATE TABLE IF NOT EXISTS accord.list_append(id int PRIMARY KEY,contents
> LIST<bigint>);
> TRUNCATE accord.list_append;{code}
> And the following two possible queries executed by 10 threads in parallel:
> {code:java}
> BEGIN TRANSACTION
> LET row = (SELECT * FROM list_append WHERE id = ?);
> SELECT row.contents;
> COMMIT TRANSACTION;"
> BEGIN TRANSACTION
> UPDATE list_append SET contents += ? WHERE id = ?;
> COMMIT TRANSACTION;"
> {code}
> there seems to be an issue with transaction guarantees. Here's an excerpt in
> the edn format from a test.
> {code:java}
> {:type :invoke :process 8 :value [[:append 5 352]] :tid 3 :n 52
> :time 1692607285967116627}
> {:type :invoke :process 9 :value [[:r 5 nil]] :tid 1 :n 54
> :time 1692607286078732473}
> {:type :invoke :process 6 :value [[:append 5 553]] :tid 5 :n 53
> :time 1692607286133833428}
> {:type :invoke :process 7 :value [[:append 5 455]] :tid 4 :n 55
> :time 1692607286149702511}
> {:type :ok :process 8 :value [[:append 5 352]] :tid 3 :n 52
> :time 1692607286156314099}
> {:type :invoke :process 5 :value [[:r 5 nil]] :tid 9 :n 52
> :time 1692607286167090389}
> {:type :ok :process 9 :value [[:r 5 [303 304 604 6 306 509 909 409 912
> 411 514 415 719 419 19 623 22 425 24 926 25 832 130 733 430 533 29 933 333
> 537 934 538 740 139 744 938 544 42 646 749 242 546 547 548 753 450 150 349 48
> 852 352]]] :tid 1 :n 54 :time 1692607286168657534}
> {:type :invoke :process 1 :value [[:r 5 nil]] :tid 0 :n 51
> :time 1692607286201762938}
> {:type :ok :process 7 :value [[:append 5 455]] :tid 4 :n 55
> :time 1692607286245571513}
> {:type :invoke :process 7 :value [[:r 5 nil]] :tid 4 :n 56
> :time 1692607286245655775}
> {:type :ok :process 5 :value [[:r 5 [303 304 604 6 306 509 909 409 912
> 411 514 415 719 419 19 623 22 425 24 926 25 832 130 733 430 533 29 933 333
> 537 934 538 740 139 744 938 544 42 646 749 242 546 547 548 753 450 150 349 48
> 852 352 455]]] :tid 9 :n 52 :time 1692607286253928906}
> {:type :invoke :process 5 :value [[:r 5 nil]] :tid 9 :n 53
> :time 1692607286254095215}
> {:type :ok :process 6 :value [[:append 5 553]] :tid 5 :n 53
> :time 1692607286266263422}
> {:type :ok :process 1 :value [[:r 5 [303 304 604 6 306 509 909 409 912
> 411 514 415 719 419 19 623 22 425 24 926 25 832 130 733 430 533 29 933 333
> 537 934 538 740 139 744 938 544 42 646 749 242 546 547 548 753 450 150 349 48
> 852 352 553 455]]] :tid 0 :n 51 :time 1692607286271617955}
> {:type :ok :process 7 :value [[:r 5 [303 304 604 6 306 509 909 409 912
> 411 514 415 719 419 19 623 22 425 24 926 25 832 130 733 430 533 29 933 333
> 537 934 538 740 139 744 938 544 42 646 749 242 546 547 548 753 450 150 349 48
> 852 352 553 455]]] :tid 4 :n 56 :time 1692607286271816933}
> {:type :ok :process 5 :value [[:r 5 [303 304 604 6 306 509 909 409 912
> 411 514 415 719 419 19 623 22 425 24 926 25 832 130 733 430 533 29 933 333
> 537 934 538 740 139 744 938 544 42 646 749 242 546 547 548 753 450 150 349 48
> 852 352 553 455]]] :tid 9 :n 53 :time 1692607286281483026}
> {:type :invoke :process 9 :value [[:r 5 nil]] :tid 1 :n 56
> :time 1692607286284097561}
> {:type :ok :process 9 :value [[:r 5 [303 304 604 6 306 509 909 409 912
> 411 514 415 719 419 19 623 22 425 24 926 25 832 130 733 430 533 29 933 333
> 537 934 538 740 139 744 938 544 42 646 749 242 546 547 548 753 450 150 349 48
> 852 352 553 455]]] :tid 1 :n 56 :time 1692607286306445242}
> {code}
> Processes process 6 and process 7 are appending the values 553 and 455
> respectively. 455 succeeded and a read by process 5 confirms that. But then
> also 553 is appended and a read by process 1 confirms that as well, however
> it sees 553 before 455.
> process 5 reads [... 852 352 455] where as process 1 reads [... 852 352 553
> 455] and the latter order is returned in subsequent reads as well.
> [~blambov] suggested that one reason for that behavior could be the way how
> unfrozen lists are updated. The backing datatype is a _kind of a map_ which
> uses insertion timestamps as indexes which are used to sort the list when the
> list is composed from chunks from various sources/sstables before being
> returned to the client.
> In such a case it indeed can happen, that process 5 reads [... 852 352 455]
> but later process 1 reads [... 852 352 553 455] because 553 has been
> _appended_ with an earlier timestamp than 455 but it has been _committed_
> with a later timestamp.
> Now with Accord we have the timestamp _of the transaction_ at hand. Could
> Accord use that for the index instead? Which would lead to the correct
> behavior? The value 553 has been appended after 455 and using the transaction
> id/timestamp as the list index would place it properly in the underlying map,
> wouldn't it?
> Steps to reproduce:
>
> {code:java}
> git clone https://github.com/datastax/accordclient.git
> git checkout append-to-list-index
> lein run --list-append -t 10 -r 1,2,3,4,5 -n 1000 -H <host-ips> -s `date
> +%s%N` > test-la.edn
>
> curl -L -o elle-cli.zip
> https://github.com/ligurio/elle-cli/releases/download/0.1.6/elle-cli-bin-0.1.6.zip
> unzip -d elle-cli elle-cli.zip
> java -jar elle-cli/target/elle-cli-0.1.6-standalone.jar --model list-append
> --anomalies G0 --consistency-models strict-serializable --directory out-la
> --verbose test-la.edn
> {code}
>
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