[ https://issues.apache.org/jira/browse/CASSANDRA-16158?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Caleb Rackliffe reassigned CASSANDRA-16158: ------------------------------------------- Assignee: Caleb Rackliffe > Avoid Unnecessary Chunk Cache Usage During Compaction > ----------------------------------------------------- > > Key: CASSANDRA-16158 > URL: https://issues.apache.org/jira/browse/CASSANDRA-16158 > Project: Cassandra > Issue Type: Improvement > Components: Feature/Compression, Feature/Encryption, Local/Compaction > Reporter: Caleb Rackliffe > Assignee: Caleb Rackliffe > Priority: Normal > Fix For: 5.x > > > We have at least some evidence from CASSANDRA-16036 that compaction can cause > significant churn in the chunk cache for a mixed workloads. Conceptually, > this makes sense, as the files compaction is scanning are destined for > deletion. It seems like we could avoid most of the cache churn mess by having > the {{ISSTableScanner}} implementations returned by {{SSTableReader}} during > compaction use file handles that don't use {{CachingRebufferer}}. > {{FileHandle.Builder#complete()}} already seems to roughly have the logic we > would need to produce the correct (uncached) {{RebuffererFactory}}. > (NOTE: {{SSTableReader#getScanner(ColumnFilter, DataRange, > SSTableReadsListener)}} is used on the read path, and we likely don't want to > touch it here.) > Given that CASSANDRA-16036 settled on disabling the chunk cache by default in > 4.0, CASSANDRA-15229 further segregates the negative effects of this, and it > isn't entirely clear that the decompression/decryption cache is actually > adding measurable value for any workload, this may not be a critical priority > for 4.0. -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org