[jira] [Commented] (CASSANDRA-15641) No error if consistency_level = SERIAL and unqualified select
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https://issues.apache.org/jira/browse/CASSANDRA-15641?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17073535#comment-17073535
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Massimiliano Tomassi commented on CASSANDRA-15641:
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Hi [~Osipov], as already explained by [~samt] in the slack channel, the
behaviour depends on how the select statement is implemented. When paging is
turned off, the query you are trying (filtering with an IN clause), results in
a single multi-partition read (in which case the query would fail if SERIAL
consistency is used), while if paging is turned on it will result in separate
single-partition reads each executed with SERIAL consistency, therefore no
exception is thrown.
Here you can see the query failed with paging turned off and SERIAL consistency:
{code:java}
cqlsh> SELECT * FROM test.t where a in (1,2);
InvalidRequest: Error from server: code=2200 [Invalid query]
message="SERIAL/LOCAL_SERIAL consistency may only be requested for one
partition at a time"
{code}
I'm going to close this ticket as it doesn't categorise as a bug.
> No error if consistency_level = SERIAL and unqualified select
> -
>
> Key: CASSANDRA-15641
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15641
> Project: Cassandra
> Issue Type: Bug
> Components: CQL/Semantics
>Reporter: Konstantin
>Assignee: Massimiliano Tomassi
>Priority: Normal
> Fix For: 4.0-rc
>
> Attachments: test.py
>
>
> The attached test program produces no errors, while doesn't provide serial
> consistency. There is no exception that the consistency level is incorrect.
> It's simply silently downgraded. The issue is not documented either.
> kostja@atlas ~ % python test.py
> Row(a=1, b=1)
> Row(a=0, b=0)
> Row(a=2, b=2)
> Row(a=3, b=3)
> Row(a=1, b=1)
> Row(a=2, b=2)
> The behavior is contrary to the original intent by LWT author, since the code
> has the following check:
>if (group.queries.size() > 1)
> throw new InvalidRequestException("SERIAL/LOCAL_SERIAL
> consistency may only be requested for one partition at a time");
> https://github.com/apache/cassandra/blob/cassandra-3.11/src/java/org/apache/cassandra/service/StorageProxy.java#L1593
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[jira] [Commented] (CASSANDRA-15641) No error if consistency_level = SERIAL and unqualified select
[
https://issues.apache.org/jira/browse/CASSANDRA-15641?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17058951#comment-17058951
]
Konstantin commented on CASSANDRA-15641:
Konstantin Osipov
what I am curious about though, is there any way to hit the code path I
highlighted? I can't build a relevant query
beobal 8:38 PM
@Konstantin Osipov session.execute(SimpleStatement("select * from ks.t where a
in (1, 2) ", fetch_size=-1, consistency_level=ConsistencyLevel.SERIAL))
Konstantin Osipov 8:39 PM
why does fetch_size matter? there is only a handful of rows in the table
anyway..
beobal 8:41 PM
fetch_size=-1 disables paging. With paging enabled the multiple single
partition reads are executed separately (and paged), but disabling it shortcuts
that and goes straight to StorageProxy::read with a group of size 2
> No error if consistency_level = SERIAL and unqualified select
> -
>
> Key: CASSANDRA-15641
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15641
> Project: Cassandra
> Issue Type: Bug
> Components: CQL/Semantics
>Reporter: Konstantin
>Priority: Normal
> Attachments: test.py
>
>
> The attached test program produces no errors, while doesn't provide serial
> consistency. There is no exception that the consistency level is incorrect.
> It's simply silently downgraded. The issue is not documented either.
> kostja@atlas ~ % python test.py
> Row(a=1, b=1)
> Row(a=0, b=0)
> Row(a=2, b=2)
> Row(a=3, b=3)
> Row(a=1, b=1)
> Row(a=2, b=2)
> The behavior is contrary to the original intent by LWT author, since the code
> has the following check:
>if (group.queries.size() > 1)
> throw new InvalidRequestException("SERIAL/LOCAL_SERIAL
> consistency may only be requested for one partition at a time");
> https://github.com/apache/cassandra/blob/cassandra-3.11/src/java/org/apache/cassandra/service/StorageProxy.java#L1593
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