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https://issues.apache.org/jira/browse/IOTDB-736?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17124886#comment-17124886
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Xiangdong Huang commented on IOTDB-736:
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Hi,
> At least for metrics to get metrics about query durations.
Yes it is useful.
> How does tracing on work exactly in Cassandra? Does it have a separate log
>with timing informations?
At the end of
[https://docs.datastax.com/en/cql-oss/3.3/cql/cql_reference/cqlshTracing.html],
there is an example.
> Query performance tracing
> -------------------------
>
> Key: IOTDB-736
> URL: https://issues.apache.org/jira/browse/IOTDB-736
> Project: Apache IoTDB
> Issue Type: New Feature
> Components: Core/Engine
> Reporter: Xiangdong Huang
> Priority: Major
>
> Hi,
> Today I run a `select count(s1) from root.some_time_series`, while there is
> no un-sequence data. The data type is text and there is 1.5TB data totally
> and the time series has about 15GB data, then it spends 17s.
>
> is that possible to trace the query process for debugging the performance?
> Like what Cassandra provides, `tracing on`, and then how many sstables or
> tombstone are read and the time cost is clear.
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