ndimiduk commented on a change in pull request #2490:
URL: https://github.com/apache/hbase/pull/2490#discussion_r509692111
##########
File path:
hbase-server/src/main/java/org/apache/hadoop/hbase/master/normalizer/SimpleRegionNormalizer.java
##########
@@ -315,35 +316,60 @@ private boolean skipForMerge(final RegionStates
regionStates, final RegionInfo r
* towards target average or target region count.
*/
private List<NormalizationPlan> computeMergeNormalizationPlans(final
NormalizeContext ctx) {
- if (ctx.getTableRegions().size() < minRegionCount) {
+ if (isEmpty(ctx.getTableRegions()) || ctx.getTableRegions().size() <
minRegionCount) {
LOG.debug("Table {} has {} regions, required min number of regions for
normalizer to run"
+ " is {}, not computing merge plans.", ctx.getTableName(),
ctx.getTableRegions().size(),
minRegionCount);
return Collections.emptyList();
}
- final double avgRegionSizeMb = ctx.getAverageRegionSizeMb();
+ final long avgRegionSizeMb = (long) ctx.getAverageRegionSizeMb();
+ if (avgRegionSizeMb < mergeMinRegionSizeMb) {
+ return Collections.emptyList();
+ }
LOG.debug("Computing normalization plan for table {}. average region size:
{}, number of"
+ " regions: {}.", ctx.getTableName(), avgRegionSizeMb,
ctx.getTableRegions().size());
- final List<NormalizationPlan> plans = new ArrayList<>();
- for (int candidateIdx = 0; candidateIdx < ctx.getTableRegions().size() -
1; candidateIdx++) {
- final RegionInfo current = ctx.getTableRegions().get(candidateIdx);
- final RegionInfo next = ctx.getTableRegions().get(candidateIdx + 1);
- if (skipForMerge(ctx.getRegionStates(), current)
- || skipForMerge(ctx.getRegionStates(), next)) {
- continue;
+ // this nested loop walks the table's region chain once, looking for
contiguous sequences of
+ // regions that meet the criteria for merge. The outer loop tracks the
starting point of the
+ // next sequence, the inner loop looks for the end of that sequence. A
single sequence becomes
+ // an instance of MergeNormalizationPlan.
+
+ final List<NormalizationPlan> plans = new LinkedList<>();
+ final List<NormalizationTarget> rangeMembers = new LinkedList<>();
+ long sumRangeMembersSizeMb;
+ int current = 0;
+ for (int rangeStart = 0;
+ rangeStart < ctx.getTableRegions().size() - 1 && current <
ctx.getTableRegions().size();) {
+ // walk the region chain looking for contiguous sequences of regions
that can be merged.
+ rangeMembers.clear();
+ sumRangeMembersSizeMb = 0;
+ for (current = rangeStart; current < ctx.getTableRegions().size();
current++) {
+ final RegionInfo regionInfo = ctx.getTableRegions().get(current);
+ final long regionSizeMb = getRegionSizeMB(regionInfo);
+ if (skipForMerge(ctx.getRegionStates(), regionInfo)) {
+ // this region cannot participate in a range. resume the outer loop.
+ rangeStart = Math.max(current, rangeStart + 1);
Review comment:
This line of questions convinces me you really read the code. Thank you
for the thoughtful review!
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