keith-turner commented on a change in pull request #2293:
URL: https://github.com/apache/accumulo/pull/2293#discussion_r733215474
##########
File path:
server/gc/src/main/java/org/apache/accumulo/gc/GarbageCollectionAlgorithm.java
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@@ -217,11 +221,43 @@ private void confirmDeletes(GarbageCollectionEnvironment
gce,
throw new RuntimeException(
"Scanner over metadata table returned unexpected column : " +
entry.getKey());
}
+ Set<String> tableIdsAfter = gce.getTableIDs();
+ ensureAllTablesChecked(Collections.unmodifiableSet(tableIdsBefore),
+ Collections.unmodifiableSet(tableIdsSeen),
Collections.unmodifiableSet(tableIdsAfter));
confirmDeletesFromReplication(gce.getReplicationNeededIterator(),
candidateMap.entrySet().iterator());
}
+ @VisibleForTesting
+ /**
+ *
+ */
+ protected void ensureAllTablesChecked(Set<String> tableIdsBefore,
Set<String> tableIdsSeen,
+ Set<String> tableIdsAfter) {
+
+ // if a table was added or deleted during this run, it is acceptable to not
+ // have seen those tables ids when scanning the metadata table. So get the
intersection
+ Set<String> tableIdsMustHaveSeen = new HashSet<>(tableIdsBefore);
+ tableIdsMustHaveSeen.retainAll(tableIdsAfter);
+
+ if (tableIdsMustHaveSeen.isEmpty() && !tableIdsSeen.isEmpty()) {
+ // we saw no table ids in ZK but did in the metadata table. This is
unexpected.
+ throw new RuntimeException(
+ "Saw no table ids in ZK but did see table ids in metadata table: " +
tableIdsSeen);
+ }
+
+ // From that intersection, remove all the table ids that were seen.
+ tableIdsMustHaveSeen.removeAll(tableIdsSeen);
Review comment:
> What I think we want is that tableIdsMustHaveSeem is equivalent to
tableIdsSeen.
This would mean GC would not run if tables were added or delete during the
GC scan process. If we did this it would make the check much stronger, however
it could lead to starvation of GC where it never runs if tables are constantly
added and deleted.
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