ctubbsii commented on code in PR #5421:
URL: https://github.com/apache/accumulo/pull/5421#discussion_r2017622266
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core/src/main/java/org/apache/accumulo/core/clientImpl/ClientContext.java:
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@@ -1088,9 +1098,43 @@ public NamespaceMapping getNamespaces() {
return namespaces;
}
- public HashMap<TableId,ClientTabletCache> tabletCaches() {
+ public ClientTabletCache getTabletLocationCache(TableId tableId) {
ensureOpen();
- return tabletCaches;
+ return
tabletLocationCache.get(DataLevel.of(tableId)).computeIfAbsent(tableId,
+ (TableId key) -> {
+ var lockChecker = getTServerLockChecker();
+ if (AccumuloTable.ROOT.tableId().equals(tableId)) {
+ return new RootClientTabletCache(lockChecker);
+ }
+ var mlo = new MetadataCachedTabletObtainer();
+ if (AccumuloTable.METADATA.tableId().equals(tableId)) {
+ return new ClientTabletCacheImpl(AccumuloTable.METADATA.tableId(),
+ getTabletLocationCache(AccumuloTable.ROOT.tableId()), mlo,
lockChecker);
+ } else {
+ return new ClientTabletCacheImpl(tableId,
+ getTabletLocationCache(AccumuloTable.METADATA.tableId()), mlo,
lockChecker);
+ }
+ });
+ }
+
+ /**
+ * Clear the currently cached tablet locations. The use of ConcurrentHashMap
ensures this is
+ * thread-safe. However, since the ConcurrentHashMap iterator is weakly
consistent, it does not
+ * block new locations from being cached. If new locations are added while
this is executing, they
+ * may be immediately invalidated by this code. Multiple calls to this
method in different threads
+ * may cause some location caches to be invalidated multiple times. That is
okay, because cache
+ * invalidation is idempotent.
+ */
+ public void clearTabletLocationCache() {
+ tabletLocationCache.forEach((dataLevel, map) -> {
+ // use iter.remove() instead of calling clear() on the map, to prevent
clearing entries that
+ // may not have been invalidated
+ var iter = map.values().iterator();
+ while (iter.hasNext()) {
+ iter.next().invalidate();
+ iter.remove();
Review Comment:
It's probably okay to have a reference to the old cache, but only if it
notices that it was invalidated and replaces it before it tries to use it again.
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