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https://issues.apache.org/jira/browse/IMPALA-13491?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18054283#comment-18054283
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Arnab Karmakar commented on IMPALA-13491:
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Thanks for the tip [~stigahuang]
I wanted to discuss how do we check "if the limit and fairness are enforced"?
Few thoughts come to my mind but I'd appreciate if you could choose one:
1. We can parse catalogd logs during the test and verify the sequence of permit
acquisitions.
2. We could expose some metrics: getActiveLoadOperationsCount(),
getLoadOperationQueueLength()
3. Query profiles analysis that contain timeline events. We can check for
events "Acquiring load operation permit" and "Acquired load operation permit"
4. We can use some timing based tests. eg: Use debug action delay of 2 secs for
REFRESH, trigger 6 such operations with the flag value set as 2. It should
process the ops in 3 batches that should ideally take (3 * 2s) ~6s instead ~2s
when all ops execute parallelly in 1 batch and assert on time.
> Add config on catalogd for controlling the number of concurrent
> loading/refresh commands
> ----------------------------------------------------------------------------------------
>
> Key: IMPALA-13491
> URL: https://issues.apache.org/jira/browse/IMPALA-13491
> Project: IMPALA
> Issue Type: Improvement
> Reporter: Manish Maheshwari
> Assignee: Arnab Karmakar
> Priority: Critical
>
> When running Table Loading or Refresh commands, catalogd requires working
> memory in proportion to the number of tables been refreshed. While we have a
> table level lock, we dont have a config to control concurrent load/refresh
> operations.
> In case of customers that run refresh in parallel in multiple threads, the
> number of load/refresh command can cause OOM on the catalog due to running
> out of working memory.
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