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https://issues.apache.org/jira/browse/CASSANDRA-1155?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Brandon Williams updated CASSANDRA-1155:
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Attachment: 1155-v3.txt
v3 builds on v2, finishing the TODOs in CFS and loading the persistent
statistics on SSTRs when opening an existing SST. This has a deadlock problem
when flushing, where a flush of A goes to write the stats, but meanwhile B has
acquired the flusherlock in preparation to flush, so A can't acquire the lock
to do the stats write, and B can't release the lock because we only allow N
flushes at a time. Because that's pretty hairy, I'm going to go the route of
storing a separate -Statistics.db, but am posting this patch in case it turns
out to be useful later.
> keep persistent row statistics
> ------------------------------
>
> Key: CASSANDRA-1155
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1155
> Project: Cassandra
> Issue Type: Sub-task
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Brandon Williams
> Fix For: 0.7 beta 1
>
> Attachments: 1155-v2.txt, 1155-v3.txt, 1155.txt
>
>
> during flush and compaction we should keep row size statistics using
> EstimatedHistogram (column count, and row size), replacing min/max/total
> sizes in CFS.
> having this detail will let us estimate, given an index CF, how many nodes we
> need to query to get the number of matching rows requested by the client.
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