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https://issues.apache.org/jira/browse/CASSANDRA-8371?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14224238#comment-14224238
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mck commented on CASSANDRA-8371:
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[~krummas], [~Bj0rn], we don't have logs going back that far. Only a day or
two. (We need to sort out a better logging configuration for c*).
We've switched another table to DTCS, that doesn't have deletes, so once it's
been running a while we will be able to confirm whether it's specific to this
table.
> DateTieredCompactionStrategy is always compacting
> --------------------------------------------------
>
> Key: CASSANDRA-8371
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8371
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: mck
> Assignee: Björn Hegerfors
> Labels: compaction, performance
> Attachments: java_gc_counts_rate-month.png, read-latency.png,
> sstables.png, vg2_iad-month.png
>
>
> Running 2.0.11 and having switched a table to
> [DTCS|https://issues.apache.org/jira/browse/CASSANDRA-6602] we've seen that
> disk IO and gc count increase, along with the number of reads happening in
> the "compaction" hump of cfhistograms.
> Data, and generally performance, looks good, but compactions are always
> happening, and pending compactions are building up.
> The schema for this is
> {code}CREATE TABLE search (
> loginid text,
> searchid timeuuid,
> description text,
> searchkey text,
> searchurl text,
> PRIMARY KEY ((loginid), searchid)
> );{code}
> We're sitting on about 82G (per replica) across 6 nodes in 4 DCs.
> CQL executed against this keyspace, and traffic patterns, can be seen in
> slides 7+8 of https://prezi.com/b9-aj6p2esft
> Attached are sstables-per-read and read-latency graphs from cfhistograms, and
> screenshots of our munin graphs as we have gone from STCS, to LCS (week ~44),
> to DTCS (week ~46).
> These screenshots are also found in the prezi on slides 9-11.
> [~pmcfadin], [~Bj0rn],
> Can this be a consequence of occasional deleted rows, as is described under
> (3) in the description of CASSANDRA-6602 ?
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