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https://issues.apache.org/jira/browse/CASSANDRA-2893?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis updated CASSANDRA-2893:
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Attachment: 2893-pauses.txt
I can also reproduce the apparently atomic insert behavior in 1.0. I'm not
sure what quirk of Java optimization is causing it, to be honest. But I'm not
worried about it because when I forced pauses between the columns being added
("pauses" patch attached) then I did see the counts change. (Specifically, I
initialized the row first with "stress -t 1 -n 1 -c 1 -K 1", then sent 10000
columns with "stress -t 1 -n 1 -c 10000 -K 1".)
So whatever is making the updates highly likely to be isolated does not
*guarantee* it, so I'm comfortable that our mental model of the 1.0 Memtable is
valid.
> Add row-level isolation
> -----------------------
>
> Key: CASSANDRA-2893
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2893
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Jonathan Ellis
> Assignee: Sylvain Lebresne
> Priority: Minor
> Fix For: 1.1
>
> Attachments: 0001-Move-deletion-infos-into-ISortedColumns-v2.patch,
> 0001-Move-deletion-infos-into-ISortedColumns.patch,
> 0002-Make-memtable-use-CF.addAll-v2.patch,
> 0002-Make-memtable-use-CF.addAll.patch,
> 0003-Add-AtomicSortedColumn-and-snapTree-v2.patch,
> 0003-Add-AtomicSortedColumn-and-snapTree.patch, 2893-pauses.txt,
> latency-plain.svg, latency.svg, row_isolation_test.py,
> snaptree-0.1-SNAPSHOT.jar
>
>
> This could be done using an the atomic ConcurrentMap operations from the
> Memtable and something like http://code.google.com/p/pcollections/ to replace
> the ConcurrentSkipListMap in ThreadSafeSortedColumns. The trick is that
> pcollections does not provide a SortedMap, so we probably need to write our
> own.
> Googling [persistent sortedmap] I found
> http://code.google.com/p/actord/source/browse/trunk/actord/src/main/scala/ff/collection
> (in scala) and http://clojure.org/data_structures#Data Structures-Maps.
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