@Override
public void planSkipped(HRegionInfo hri, PlanType type) {
skippedCount[type.ordinal()]++;
}
/**
* Simple implementation of region normalizer.
*
* <p>Logic in use:
*
* <ol>
* <li>get all regions of a given table
* <li>get avg size S of each region (by total size of store files reported in RegionLoad)
* <li>If biggest region is bigger than S * 2, it is kindly requested to split, and normalization
* stops
* <li>Otherwise, two smallest region R1 and its smallest neighbor R2 are kindly requested to
* merge, if R1 + R1 < S, and normalization stops
* <li>Otherwise, no action is performed
* </ol>
*
* <p>Region sizes are coarse and approximate on the order of megabytes. Additionally, "empty"
* regions (less than 1MB, with the previous note) are not merged away. This is by design to prevent
* normalization from undoing the pre-splitting of a table.
*/
@InterfaceAudience.Private
public class SimpleRegionNormalizer implements RegionNormalizer {
private static final Log LOG = LogFactory.getLog(SimpleRegionNormalizer.class);
private static final int MIN_REGION_COUNT = 3;
private MasterServices masterServices;
private static long[] skippedCount = new long[PlanType.values().length];
/**
* Set the master service.
*
* @param masterServices inject instance of MasterServices
*/
@Override
public void setMasterServices(MasterServices masterServices) {
this.masterServices = masterServices;
}
@Override
public void planSkipped(HRegionInfo hri, PlanType type) {
skippedCount[type.ordinal()]++;
}
@Override
public long getSkippedCount(NormalizationPlan.PlanType type) {
return skippedCount[type.ordinal()];
}
// Comparator that gives higher priority to region Split plan
private Comparator<NormalizationPlan> planComparator =
new Comparator<NormalizationPlan>() {
@Override
public int compare(NormalizationPlan plan, NormalizationPlan plan2) {
if (plan instanceof SplitNormalizationPlan) return -1;
if (plan2 instanceof SplitNormalizationPlan) return 1;
return 0;
}
};
/**
* Computes next most "urgent" normalization action on the table. Action may be either a split, or
* a merge, or no action.
*
* @param table table to normalize
* @param types desired types of NormalizationPlan
* @return normalization plan to execute
*/
@Override
public List<NormalizationPlan> computePlanForTable(TableName table, List<PlanType> types)
throws HBaseIOException {
if (table == null || table.isSystemTable()) {
LOG.debug("Normalization of system table " + table + " isn't allowed");
return null;
}
List<NormalizationPlan> plans = new ArrayList<NormalizationPlan>();
List<HRegionInfo> tableRegions =
masterServices.getAssignmentManager().getRegionStates().getRegionsOfTable(table);
// TODO: should we make min number of regions a config param?
if (tableRegions == null || tableRegions.size() < MIN_REGION_COUNT) {
int nrRegions = tableRegions == null ? 0 : tableRegions.size();
LOG.debug(
"Table "
+ table
+ " has "
+ nrRegions
+ " regions, required min number"
+ " of regions for normalizer to run is "
+ MIN_REGION_COUNT
+ ", not running normalizer");
return null;
}
LOG.debug(
"Computing normalization plan for table: "
+ table
+ ", number of regions: "
+ tableRegions.size());
long totalSizeMb = 0;
for (int i = 0; i < tableRegions.size(); i++) {
HRegionInfo hri = tableRegions.get(i);
long regionSize = getRegionSize(hri);
totalSizeMb += regionSize;
}
double avgRegionSize = totalSizeMb / (double) tableRegions.size();
LOG.debug("Table " + table + ", total aggregated regions size: " + totalSizeMb);
LOG.debug("Table " + table + ", average region size: " + avgRegionSize);
int candidateIdx = 0;
while (candidateIdx < tableRegions.size()) {
HRegionInfo hri = tableRegions.get(candidateIdx);
long regionSize = getRegionSize(hri);
// if the region is > 2 times larger than average, we split it, split
// is more high priority normalization action than merge.
if (types.contains(PlanType.SPLIT) && regionSize > 2 * avgRegionSize) {
LOG.debug(
"Table "
+ table
+ ", large region "
+ hri.getRegionNameAsString()
+ " has size "
+ regionSize
+ ", more than twice avg size, splitting");
plans.add(new SplitNormalizationPlan(hri, null));
} else {
if (candidateIdx == tableRegions.size() - 1) {
break;
}
HRegionInfo hri2 = tableRegions.get(candidateIdx + 1);
long regionSize2 = getRegionSize(hri2);
if (types.contains(PlanType.MERGE) && regionSize + regionSize2 < avgRegionSize) {
LOG.debug(
"Table "
+ table
+ ", small region size: "
+ regionSize
+ " plus its neighbor size: "
+ regionSize2
+ ", less than the avg size "
+ avgRegionSize
+ ", merging them");
plans.add(new MergeNormalizationPlan(hri, hri2));
candidateIdx++;
}
}
candidateIdx++;
}
if (plans.isEmpty()) {
LOG.debug("No normalization needed, regions look good for table: " + table);
return null;
}
Collections.sort(plans, planComparator);
return plans;
}
private long getRegionSize(HRegionInfo hri) {
ServerName sn =
masterServices.getAssignmentManager().getRegionStates().getRegionServerOfRegion(hri);
RegionLoad regionLoad =
masterServices.getServerManager().getLoad(sn).getRegionsLoad().get(hri.getRegionName());
return regionLoad.getStorefileSizeMB();
}
}
