yangzhg commented on a change in pull request #8553:
URL: https://github.com/apache/incubator-doris/pull/8553#discussion_r831857583
##########
File path:
fe/fe-core/src/main/java/org/apache/doris/clone/BackendLoadStatistic.java
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@@ -315,6 +315,60 @@ public BalanceStatus isFit(long tabletSize, TStorageMedium
medium,
return status;
}
+ /*
+ * Check whether the backend can be more balance if we migrate a tablet
with size 'tabletSize' from
+ * `srcPath` to 'destPath'
+ * 1. recalculate the load score of src and dest path after migrate the
tablet.
+ * 2. if the summary of the diff between the new score and average score
becomes smaller, we consider it
+ * as more balance.
+ */
+ public boolean isMoreBalanced(long srcPath, long destPath, long tabletId,
long tabletSize,
+ TStorageMedium medium) {
+ long totalCapacity = 0;
+ long totalUsedCapacity = 0;
+ RootPathLoadStatistic srcPathStat = null;
+ RootPathLoadStatistic destPathStat = null;
+ for (RootPathLoadStatistic pathStat : pathStatistics) {
+ if (pathStat.getStorageMedium() == medium) {
+ totalCapacity += pathStat.getCapacityB();
+ totalUsedCapacity += pathStat.getUsedCapacityB();
+ if (pathStat.getPathHash() == srcPath) {
+ srcPathStat = pathStat;
+ } else if (pathStat.getPathHash() == destPath) {
+ destPathStat = pathStat;
+ }
+ }
+ }
+ if (srcPathStat == null || destPathStat == null) {
+ LOG.info("migrate {}(size: {}) from {} to {} failed, medium: {},
src or dest path stat does not exist.",
+ tabletId, tabletSize, srcPath, destPath, medium);
+ return false;
+ }
+ double avgUsedPercent = totalCapacity == 0 ? 0.0 : totalUsedCapacity /
(double) totalCapacity;
+ double currentSrcPathScore = srcPathStat.getCapacityB() == 0
+ ? 0.0 : srcPathStat.getUsedCapacityB() / (double)
srcPathStat.getCapacityB();
+ double currentDestPathScore = destPathStat.getCapacityB() == 0
+ ? 0.0 : destPathStat.getUsedCapacityB() / (double)
destPathStat.getCapacityB();
+
+ double newSrcPathScore = srcPathStat.getCapacityB() == 0
+ ? 0.0 : (srcPathStat.getUsedCapacityB() - tabletSize) / (double)
srcPathStat.getCapacityB();
+ double newDestPathScore = destPathStat.getCapacityB() == 0
+ ? 0.0 : (destPathStat.getUsedCapacityB() + tabletSize) / (double)
destPathStat.getCapacityB();
+
+ double currentDiff = Math.abs(currentSrcPathScore - avgUsedPercent)
+ + Math.abs(currentDestPathScore - avgUsedPercent);
+ double newDiff = Math.abs(newSrcPathScore - avgUsedPercent) +
Math.abs(newDestPathScore - avgUsedPercent);
+
+ LOG.info("after migrate {}(size: {}) from {} to {}, medium: {}, the
load score changed."
Review comment:
should this be debug level?
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