[ https://issues.apache.org/jira/browse/CASSANDRA-2635?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Vijay updated CASSANDRA-2635: ----------------------------- Attachment: 0001-CASSANDRA-2635-v3.patch Attached patch includes jonathan's feedback with some renames. I am still wondering how i missed that :/ > make cache skipping optional > ---------------------------- > > Key: CASSANDRA-2635 > URL: https://issues.apache.org/jira/browse/CASSANDRA-2635 > Project: Cassandra > Issue Type: Improvement > Reporter: Peter Schuller > Assignee: Harish Doddi > Priority: Minor > Attachments: 0001-CASSANDRA-2635-v3.patch, CASSANDRA-2635-075.txt, > CASSANDRA-2635-trunk-1.txt, CASSANDRA-2635-trunk.txt > > > We've applied this patch locally in order to turn of page skipping; not > completely but only for compaction/repair situations where it can be directly > detrimental in the sense of causing data to become cold even though your > entire data set fits in memory. > It's better than completely disabling DONTNEED because the cache skipping > does make sense and has no relevant (that I can see) detrimental effects in > some cases, like when dumping caches. > The patch is against 0.7.5 right now but if the change is desired I can make > a patch for trunk. Also, the name of the configuration option is dubious > since saying 'false' does not actually turn it off completely. I wasn't able > to figure out a good name that conveyed the functionality in a short brief > name however. > A related concern as discussed in CASSANDRA-1902 is that the cache skipping > isn't fsync:ing and so won't work reliably on writes. If the feature is to be > retained that's something to fix in a different ticket. > A question is also whether to retain the default to true or change it to > false. I'm kinda leaning to false since it's detrimental in the "easy" cases > of little data. In "big" cases with lots of data people will have to think > and tweak anyway, so better to put the burden on that end. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira