morningman commented on code in PR #16574:
URL: https://github.com/apache/doris/pull/16574#discussion_r1102668030
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fe/fe-core/src/main/java/org/apache/doris/qe/Coordinator.java:
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@@ -1768,12 +1797,56 @@ public TScanRangeLocation
selectBackendsByRoundRobin(List<TScanRangeLocation> lo
return location;
}
+ private void computeScanRangeAssignmentByConsistentHash(
+ ScanNode scanNode,
+ final List<TScanRangeLocations> locations,
+ FragmentScanRangeAssignment assignment,
+ Map<TNetworkAddress, Long> assignedBytesPerHost,
+ Map<TNetworkAddress, Long> replicaNumPerHost) throws Exception {
+ Collection<Backend> aliveBEs =
idToBackend.values().stream().filter(SimpleScheduler::isAvailable)
+ .collect(Collectors.toList());
+ if (aliveBEs.isEmpty()) {
+ throw new UserException("No available backends");
+ }
+ int virtualNumber = Math.max(Math.min(512 / aliveBEs.size(), 32), 2);
+ ConsistentHash<TScanRangeLocations, Backend> consistentHash = new
ConsistentHash<>(
+ Hashing.murmur3_128(), new ScanRangeHash(), new BackendHash(),
aliveBEs, virtualNumber);
+ for (TScanRangeLocations scanRangeLocations : locations) {
+ TScanRangeLocation minLocation =
scanRangeLocations.locations.get(0);
+ Backend backend = consistentHash.getNode(scanRangeLocations);
+ TNetworkAddress execHostPort = new
TNetworkAddress(backend.getHost(), backend.getBePort());
+ this.addressToBackendID.put(execHostPort, backend.getId());
+ // Why only increase 1 in other implementations ?
Review Comment:
TODO: because the file size of each scan range is same, so we can just use 1
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