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https://issues.apache.org/jira/browse/CASSANDRA-18796?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17759942#comment-17759942
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Mike Adamson commented on CASSANDRA-18796:
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I'm assuming that, like any guardrail, it can be disabled, so we only really
need to decide on a good default. From observation, we have seen that queries
on large clusters start to falter when the number of sstables gets in the
hundreds, so a fail threshold of 128 seems reasonable, but I'd question
starting to warn at 16 because we regularly test with this number without
issue.
I'd also be opposed to guardrail that just prevented non-partitioned restricted
queries. Is this suggested to go with the threshold guardrail or that they be
an either or?
> Optionally fail when a non-partition-restricted query is issued against a
> storage-attached index with a backing table using LCS
> -------------------------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-18796
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18796
> Project: Cassandra
> Issue Type: Improvement
> Components: Feature/2i Index, Feature/SAI, Local/Compaction/LCS
> Reporter: Caleb Rackliffe
> Assignee: Caleb Rackliffe
> Priority: Normal
> Fix For: 5.0.x, 5.x
>
>
> With LCS, we will have potentially thousands of SSTables for a given user
> table. Storage-attached also means SSTable-attached, and searching thousands
> of attached indexes is not going to scale well at all locally, due to the
> sheer number of searches and amount of postings list merging involved. We
> should have a guardrail to prohibit this by default.
> Partition-restricted queries, the use-case SAI is broadly designed for,
> should be very efficient.
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