CNDB-12342 Fix query view builder inifinite loop

src/java/org/apache/cassandra/index/sai/StorageAttachedIndex.java

@@ -801,7 +801,7 @@ private synchronized List<SSTableReader> findNonIndexedSSTables(ColumnFamilyStor
             //   1. The current view does not contain the SSTable
             //   2. The SSTable is not marked compacted
             //   3. The column index does not have a completion marker
-            if (!view.hasIndexForSSTable(sstable)
+            if (!view.containsSSTableIndex(sstable.descriptor)
                 && !sstable.isMarkedCompacted()
                 && !IndexDescriptor.isIndexBuildCompleteOnDisk(sstable, indexContext))
             {

src/java/org/apache/cassandra/index/sai/plan/QueryView.java

@@ -189,7 +189,6 @@ else if (indexContext.isDropped())
                         {
                             // Index was dropped deliberately by the user.
                             // We cannot recover here.
-                            refViewFragment.release();
                             throw new MissingIndexException(indexContext, "Index " + indexContext.getIndexName() +
                                                                           " not found for memtable: " + memtable);
                         }
@@ -217,10 +216,14 @@ else if (!processedMemtables.contains(memtable))
                     // Lookup and reference the indexes corresponding to the sstables:
                     for (SSTableReader sstable : refViewFragment.sstables)
                     {
+                        // Empty sstables are ok to not have the index.
+                        if (sstable.getTotalRows() == 0)
+                            continue;
+
                         // If the IndexViewManager never saw this sstable, then we need to spin.
                         // Let's hope in the next iteration we get the indexView based on the same sstable set
                         // as the refViewFragment.
-                        if (!indexView.containsSSTable(sstable))
+                        if (!indexView.isAwareOfSSTable(sstable.descriptor))
                         {
                             if (MonotonicClock.approxTime.isAfter(start + 100))
                                 NoSpamLogger.log(logger, NoSpamLogger.Level.WARN, 1, TimeUnit.SECONDS,

src/java/org/apache/cassandra/index/sai/view/View.java

@@ -108,11 +108,6 @@ public Collection<SSTableIndex> getIndexes()
         return view.values();
     }
 
-    public boolean containsSSTable(SSTableReader sstable)
-    {
-        return sstables.contains(sstable.descriptor);
-    }
-
     public int size()
     {
         return view.size();
@@ -122,10 +117,30 @@ public int size()
     {
         return view.get(descriptor);
     }
+
+    /**
+     * Tells if an index for the given sstable exists.
+     * It's equivalent to {@code getSSTableIndex(descriptor) != null }.
+     * @param descriptor identifies the sstable
+     */
+    public boolean containsSSTableIndex(Descriptor descriptor)
+    {
+        return view.containsKey(descriptor);
+    }
 
-    public boolean hasIndexForSSTable(SSTableReader sstable)
+    /**
+     * Returns true if this view has been based on the Cassandra view containing given sstable.
+     * In other words, it tells if SAI was given a chance to load the index for the given sstable.
+     * It does not determine if the index exists and was actually loaded.
+     * To check the existence of the index, use {@link #containsSSTableIndex(Descriptor)}.
+     * <p>
+     * This method allows to distinguish a situation when the sstable has no index, the index is
+     * invalid, or was not loaded for whatever reason,
+     * from a situation where the view hasn't been updated yet to reflect the newly added sstable.
+     */
+    public boolean isAwareOfSSTable(Descriptor descriptor)
     {
-        return view.containsKey(sstable.descriptor);
+        return sstables.contains(descriptor);
     }
 
     /**