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Benedict commented on CASSANDRA-9486: ------------------------------------- LGTM. There's a double "in" (i.e. "in in") in one of your comment modifications. Also, {{insertBefore}} doesn't need to call {{next()}} for the behaviour here, but not at all fussed since the semantics of an arbitrary method labelled {{insertBefore}} might well want to do so. > LazilyCompactedRow accumulates all expired RangeTombstones > ---------------------------------------------------------- > > Key: CASSANDRA-9486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-9486 > Project: Cassandra > Issue Type: Bug > Components: Core > Reporter: Benedict > Assignee: Sylvain Lebresne > Priority: Critical > Fix For: 3.x, 2.1.x, 2.0.x, 2.2.x, 1.2.x > > Attachments: 0001-9486.patch > > > LazilyCompactedRow initializes a ColumnIndex.Builder to use its > RangeTombstone.Tracker, but it only calls update() with a RT argument, never > an atom. The Tracker only ever _adds_ if it receives a RT, never removes. So > all the RT ever seen for the partition (that have expired) remain in memory > until the compaction completes. To make matters worse, this then forces a > linear scan of all of these RT for each live cell we add, so this extra load > hangs around for a long time, and compactions stall. > This issue is biting one of our users badly (at least, it seems likely to be > this issue), and there may be others. This user is not even making use of RT > extensively themselves, only collections (presumably with a complete > overwrite of the contents of the collection, resulting in a RT being > generated). > Probably the best solution is to make the RT addition itself remove any > already present that are no longer helpful. -- This message was sent by Atlassian JIRA (v6.3.4#6332)