Github user JamesRTaylor commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/8#discussion_r16720739
--- 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 --
It's fine to collect it per region. I'm talking about the *usage* of these
guideposts. Instead of driving this per region in this loop, we can just get
back *all* guideposts for a table here and return them. No need to break this
down per region. Thus, I don't think PTable needs to keep a map. All it needs
is all the guideposts for a table. I don't think the logic to get them to
"round-robin" per region server is worth preserving. We can just randomly
shuffle the guideposts and we'll get the same effect. This routine will become
very simple.
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