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From "T Jake Luciani (JIRA)" <>
Subject [jira] Commented: (CASSANDRA-1267) Improve performance of cached row slices
Date Sat, 17 Jul 2010 00:35:50 GMT


T Jake Luciani commented on CASSANDRA-1267:

1) I see.  I thought  the logic was redundant QueryFilter.isRelevant call so I moved the increment
the counter after this call.
2) awesome. this will remove the rest of the latency I was seeing.
3 & 4) sure.

I see you also removed the optimizations made to ColumnFamilyStore removeDeletedStandard()
and removeDeletedSuper() 
The supplied approach is definatly faster because it avoids the following call

IColumn c = cf.getColumnsMap().get(cname);

For rows with millions of columns this is very slow compared to getEntrySet() pair approach.

> Improve performance of cached row slices
> ----------------------------------------
>                 Key: CASSANDRA-1267
>                 URL:
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: T Jake Luciani
>            Assignee: T Jake Luciani
>            Priority: Minor
>             Fix For: 0.7
>         Attachments: 1267-v2.txt, cached-row-slice-perf-patch-1.txt
> In Lucandra, I have a use case to pull all columns for a given row.  
> I've noticed that for rows with large numbers of columns this takes much longer than
I would think since row caching is enabled.
> After looking into this I see that the cached row is rebuilt and pruned even though I
want all columns.  
> This patch skips this use case and in my case has improved performance significantly.
> From ~400ms to ~50ms

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