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https://issues.apache.org/jira/browse/CASSANDRA-17189?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17457359#comment-17457359
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Bartlomiej commented on CASSANDRA-17189:
----------------------------------------
{code:java}
Why would it crash?{code}
that was because, in forPaging method, state was null
{code:java}
public DataLimits forPaging(int pageSize)
{
Guardrails.pageSize.guard(pageSize, "?", null);
return new CQLLimits(pageSize, perPartitionLimit, isDistinct);
}{code}
so guard was also applied for super user
{code:java}
(state == null || state.isOrdinaryUser()); {code}
Now it is not the case anymore because in execute I am able to get state and
super users are not aborded :)
{code:java}
By the way, that SelectStatement#columnFamily method uses the old terminology
for tables, which were originally called column families. Maybe we can rename
the method to table(). {code}
as you suggested I changed two method to table() :)
I also had to move guard call from
{code:java}
public ResultMessage.Rows execute() {code}
to
{code:java}
private ResultMessage.Rows execute(){code}
because otherwise
{code:java}
public ResultMessage.Rows executeInternal() {code}
would stay without guard check or this guard call would have be duplicated.
Now, after reading the code, I understand that all Select statements will be
handled by that guard. Please check what you think about my change, if it is
"lets say ok" I will write tests :)
Thanks !
> Guardrail for page size
> -----------------------
>
> Key: CASSANDRA-17189
> URL: https://issues.apache.org/jira/browse/CASSANDRA-17189
> Project: Cassandra
> Issue Type: New Feature
> Components: Feature/Guardrails
> Reporter: Andres de la Peña
> Assignee: Bartlomiej
> Priority: Normal
> Labels: AdventCalendar2021, lhf
> Fix For: 4.1
>
> Attachments: CASSANDRA-17189-trunk.diff
>
>
> Add guardrail limiting the query page size, for example:
> {code}
> # Guardrail to warn about or reject page sizes greater than threshold.
> # The two thresholds default to -1 to disable.
> page_size:
> warn_threshold: -1
> abort_threshold: -1
> {code}
> Initially this can be based on the specified number of rows used as page
> size, although it would be ideal to also limit the actual size in bytes of
> the returned pages.
> +Additional information for newcomers:+
> # Add the configuration for the new guardrail on page size in the guardrails
> section of cassandra.yaml.
> # Add a getPageSize method in GuardrailsConfig returning a Threshold.Config
> object
> # Implement that method in GuardrailsOptions, which is the default yaml-based
> implementation of GuardrailsConfig
> # Add a Threshold guardrail named pageSize in Guardrails, using the
> previously created config
> # Define JMX-friendly getters and setters for the previously created config
> in GuardrailsMBean
> # Implement the JMX-friendly getters and setters in Guardrails
> # Now that we have the guardrail ready, it’s time to use it. We should search
> for a place to invoke the Guardrails.pageSize#guard method with the page size
> that each query is going to use. The DataLimits#forPaging methods look like
> good candidates for this.
> # Finally, add some tests for the new guardrail. Given that the new guardrail
> is a Threshold, our new test should probably extend ThresholdTester.
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