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Sylvain Lebresne commented on CASSANDRA-3912: --------------------------------------------- bq. What if we dropped our philosophy that client timestamps aren't necessarily timestamps? I can't think of anyone actually using non-clock-based timestamps. Then we could usefully compare server time to data timestamps and create a tree of "data inserted before repair beginning." That wouldn't fully solves it because in-memtable resolution is lossy. In other words, even if timestamps are clock-based, you cannot get correct snapshot of in-memory data which is what we would need. > support incremental repair controlled by external agent > ------------------------------------------------------- > > Key: CASSANDRA-3912 > URL: https://issues.apache.org/jira/browse/CASSANDRA-3912 > Project: Cassandra > Issue Type: Improvement > Components: Core > Reporter: Peter Schuller > Assignee: Peter Schuller > Fix For: 1.2 > > Attachments: CASSANDRA-3912-trunk-v1.txt, > CASSANDRA-3912-v2-001-add-nodetool-commands.txt, > CASSANDRA-3912-v2-002-fix-antientropyservice.txt > > > As a poor man's pre-cursor to CASSANDRA-2699, exposing the ability to repair > small parts of a range is extremely useful because it allows (with external > scripting logic) to slowly repair a node's content over time. Other than > avoiding the bulkyness of complete repairs, it means that you can safely do > repairs even if you absolutely cannot afford e.g. disk spaces spikes (see > CASSANDRA-2699 for what the issues are). > Attaching a patch that exposes a "repairincremental" command to nodetool, > where you specify a step and the number of total steps. Incrementally > performing a repair in 100 steps, for example, would be done by: > {code} > nodetool repairincremental 0 100 > nodetool repairincremental 1 100 > ... > nodetool repairincremental 99 100 > {code} > An external script can be used to keep track of what has been repaired and > when. This should allow (1) allow incremental repair to happen now/soon, and > (2) allow experimentation and evaluation for an implementation of > CASSANDRA-2699 which I still think is a good idea. This patch does nothing to > help the average deployment, but at least makes incremental repair possible > given sufficient effort spent on external scripting. > The big "no-no" about the patch is that it is entirely specific to > RandomPartitioner and BigIntegerToken. If someone can suggest a way to > implement this command generically using the Range/Token abstractions, I'd be > happy to hear suggestions. > An alternative would be to provide a nodetool command that allows you to > simply specify the specific token ranges on the command line. It makes using > it a bit more difficult, but would mean that it works for any partitioner and > token type. > Unless someone can suggest a better way to do this, I think I'll provide a > patch that does this. I'm still leaning towards supporting the simple "step N > out of M" form though. -- 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