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HBASE-29835: Fix typos and inconsistencies in CacheAwareLoadBalancer #7644

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Merged
lfrancke merged 2 commits into from
Jan 20, 2026
+6 −12
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HBASE-29835: Fix typos and inconsistencies in CacheAwareLoadBalancer #7644

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HBASE-29835: Fix typos and inconsistencies in CacheAwareLoadBalancer
lfrancke Jan 19, 2026
34bf291
Remove unused import
lfrancke Jan 19, 2026
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18 changes: 6 additions & 12 deletions ...alancer/src/main/java/org/apache/hadoop/hbase/master/balancer/CacheAwareLoadBalancer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -23,12 +23,11 @@
* periodically and restores the cache when it is restarted. This balancer implements a mechanism
* where it maintains the amount by which a region is cached on a region server. During balancer
* run, a region plan is generated that takes into account this cache information and tries to
* move the regions so that the cache minimally impacted.
* move the regions so that the cache is minimally impacted.
*/

import static org.apache.hadoop.hbase.HConstants.BUCKET_CACHE_PERSISTENT_PATH_KEY;

import java.text.DecimalFormat;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
Expand Down Expand Up @@ -130,7 +129,7 @@ private void updateRegionLoad() {
int regionSizeMB = (int) rm.getRegionSizeMB().get(Size.Unit.MEGABYTE);

rload.add(new BalancerRegionLoad(rm));
// Maintain a map of region and it's total size. This is needed to calculate the cache
// Maintain a map of region and its total size. This is needed to calculate the cache
// ratios for the regions cached on old region servers
regionCacheRatioOnCurrentServerMap.put(regionEncodedName, new Pair<>(sn, regionSizeMB));
loads.put(regionEncodedName, rload);
Expand Down Expand Up @@ -285,9 +284,6 @@ private boolean moveRegionToOldServer(BalancerClusterState cluster, int regionIn
return false;
}

DecimalFormat df = new DecimalFormat("#");
df.setMaximumFractionDigits(4);

float cacheRatioDiffThreshold = 0.6f;

// Conditions for moving the region
Expand All @@ -307,7 +303,7 @@ private boolean moveRegionToOldServer(BalancerClusterState cluster, int regionIn
LOG.debug(
"Region {} moved from {} to {} as the region is cached {} equally on both servers",
cluster.regions[regionIndex].getEncodedName(), cluster.servers[currentServerIndex],
cluster.servers[oldServerIndex], df.format(cacheRatioOnCurrentServer));
cluster.servers[oldServerIndex], cacheRatioOnCurrentServer);
}
return true;
}
Expand All @@ -324,8 +320,7 @@ private boolean moveRegionToOldServer(BalancerClusterState cluster, int regionIn
"Region {} moved from {} to {} as region cache ratio {} is better than the current "
+ "cache ratio {}",
cluster.regions[regionIndex].getEncodedName(), cluster.servers[currentServerIndex],
cluster.servers[oldServerIndex], cacheRatioOnCurrentServer,
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@lfrancke lfrancke Jan 19, 2026

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Note that it would log current ratio twice

df.format(cacheRatioOnCurrentServer));
cluster.servers[oldServerIndex], cacheRatioOnOldServer, cacheRatioOnCurrentServer);
}
return true;
}
Expand All @@ -334,8 +329,7 @@ private boolean moveRegionToOldServer(BalancerClusterState cluster, int regionIn
LOG.debug(
"Region {} not moved from {} to {} with current cache ratio {} and old cache ratio {}",
cluster.regions[regionIndex], cluster.servers[currentServerIndex],
cluster.servers[oldServerIndex], cacheRatioOnCurrentServer,
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@lfrancke lfrancke Jan 19, 2026

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Note that it would log current server ratio twice.

df.format(cacheRatioOnCurrentServer));
cluster.servers[oldServerIndex], cacheRatioOnCurrentServer, cacheRatioOnOldServer);
}
return false;
}
Expand Down Expand Up @@ -391,7 +385,7 @@ BalanceAction pickRandomRegions(BalancerClusterState cluster, int thisServer, in
if (LOG.isDebugEnabled()) {
LOG.debug(
"CacheAwareSkewnessCandidateGenerator: Region {} moved from {} to {} as it "
+ "was hosted their earlier",
+ "was hosted there earlier",
regionEncodedName, cluster.servers[thisServer].getHostname(),
cluster.servers[otherServer].getHostname());
}
Expand Down