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From JamesRTaylor <...@git.apache.org>
Subject [GitHub] phoenix pull request: Phoenix 180
Date Tue, 26 Aug 2014 04:05:54 GMT
Github user JamesRTaylor commented on a diff in the pull request:

    https://github.com/apache/phoenix/pull/8#discussion_r16694959
  
    --- Diff: phoenix-core/src/main/java/org/apache/phoenix/iterate/DefaultParallelIteratorRegionSplitter.java
---
    @@ -138,14 +146,10 @@ public boolean apply(HRegionLocation location) {
             //    split each region in s splits such that:
             //    s = max(x) where s * x < t
             //
    -        // The idea is to align splits with region boundaries. If rows are not evenly
    -        // distributed across regions, using this scheme compensates for regions that
    -        // have more rows than others, by applying tighter splits and therefore spawning
    -        // off more scans over the overloaded regions.
    -        int splitsPerRegion = getSplitsPerRegion(regions.size());
             // Create a multi-map of ServerName to List<KeyRange> which we'll use to
round robin from to ensure
             // that we keep each region server busy for each query.
    -        ListMultimap<HRegionLocation,KeyRange> keyRangesPerRegion = ArrayListMultimap.create(regions.size(),regions.size()
* splitsPerRegion);;
    +        int splitsPerRegion = getSplitsPerRegion(regions.size());
    +        ListMultimap<HRegionLocation,KeyRange> keyRangesPerRegion = ArrayListMultimap.create(regions.size(),regions.size()
* splitsPerRegion);
    --- End diff --
    
    I forgot to mention this before, but it's important that we always use the guide posts
here to determine the set of work that will be done. We'll get rid of the hint for not splitting
up work. I'm not super keen on falling back to using Bytes.split(), but not sure what a better
alternative would be. I suppose when a table is initially created this will be the case for
a while. We should at a minimum log a warning if we fallback to this. Any ideas here?


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