RegionedPageStore contexts must not unconditionally supportUnboundedF…

engine/table/src/main/java/io/deephaven/engine/table/impl/sources/regioned/ColumnRegion.java

@@ -18,6 +18,15 @@ default long firstRowOffset() {
         return 0;
     }
 
+
+    /**
+     * Do the fill contexts produced by this region support unbounded fill?
+     * @return true if the contexts support unbounded fill; false otherwise
+     */
+    default boolean supportsUnboundedFill() {
+        return true;
+    }
+
     abstract class Null<ATTR extends Any>
             extends GenericColumnRegionBase<ATTR>
             implements ColumnRegion<ATTR>, WithDefaultsForRepeatingValues<ATTR> {

engine/table/src/main/java/io/deephaven/engine/table/impl/sources/regioned/RegionContextHolder.java

@@ -11,17 +11,18 @@
 public class RegionContextHolder implements ChunkSource.FillContext {
     private final int chunkCapacity;
     private final SharedContext sharedContext;
+    private final boolean supportsUnboundedFill;
     private Context innerContext;
 
-    public RegionContextHolder(final int chunkCapacity, @Nullable final SharedContext sharedContext) {
-
+    public RegionContextHolder(final int chunkCapacity, @Nullable final SharedContext sharedContext, boolean supportsUnboundedFill) {
         this.chunkCapacity = chunkCapacity;
         this.sharedContext = sharedContext;
+        this.supportsUnboundedFill = supportsUnboundedFill;
     }
 
     @Override
     public boolean supportsUnboundedFill() {
-        return true;
+        return supportsUnboundedFill;
     }
 
     /**

engine/table/src/main/java/io/deephaven/engine/table/impl/sources/regioned/RegionedColumnSourceArray.java

@@ -33,6 +33,8 @@ interface MakeDeferred<ATTR extends Values, REGION_TYPE extends ColumnRegion<ATT
     private volatile int regionCount = 0;
     private volatile REGION_TYPE[] regions;
 
+    private volatile boolean allRegionsSupportUnbounded = true;
+
     @SuppressWarnings("rawtypes")
     private static final ColumnRegion[] EMPTY = new ColumnRegion[0];
 
@@ -136,7 +138,11 @@ private void maybeExtendRegions() {
      */
     @NotNull
     private synchronized REGION_TYPE updateRegion(final int regionIndex, final REGION_TYPE region) {
-        return regions[regionIndex] = region == null ? nullRegion : region;
+        if (region == null) {
+            return regions[regionIndex] = nullRegion;
+        }
+        allRegionsSupportUnbounded &= region.supportsUnboundedFill();
+        return regions[regionIndex] = region;
     }
 
     @Override
@@ -162,4 +168,9 @@ public void releaseCachedResources() {
     public final REGION_TYPE getNullRegion() {
         return nullRegion;
     }
+
+    @Override
+    public boolean supportsUnboundedFill() {
+        return allRegionsSupportUnbounded;
+    }
 }

engine/table/src/main/java/io/deephaven/engine/table/impl/sources/regioned/RegionedColumnSourceReferencing.java

@@ -90,4 +90,9 @@ public ColumnRegionReferencing.Null<ATTR, NATIVE_REGION_TYPE> getNullRegion() {
     public RegionedColumnSourceBase<NATIVE_DATA_TYPE, ATTR, NATIVE_REGION_TYPE> getNativeSource() {
         return nativeSource;
     }
+
+    @Override
+    public boolean supportsUnboundedFill() {
+        return nativeSource.supportsUnboundedFill();
+    }
 }

engine/table/src/main/java/io/deephaven/engine/table/impl/sources/regioned/RegionedColumnSourceWithDictionary.java

@@ -99,6 +99,11 @@ public int getRegionCount() {
             return RegionedColumnSourceWithDictionary.this.getRegionCount();
         }
 
+        @Override
+        public boolean supportsUnboundedFill() {
+            return RegionedColumnSourceWithDictionary.this.supportsUnboundedFill();
+        }
+
         @Override
         public ColumnRegionLong<DictionaryKeys> getRegion(final int regionIndex) {
             final ColumnRegionObject<DATA_TYPE, Values> sourceRegion =
@@ -124,6 +129,8 @@ public ColumnRegionLong<DictionaryKeys> getRegion(final int regionIndex) {
                 return localWrappers[regionIndex] =
                         ColumnRegionObject.DictionaryKeysWrapper.create(parameters(), regionIndex, sourceRegion);
             }
+
+
         }
 
         @Override
@@ -195,6 +202,11 @@ public ColumnRegionObject<DATA_TYPE, Values> getRegion(final int regionIndex) {
             // so it's fine to call more than once and avoid extra backing storage in the column source.
             return RegionedColumnSourceWithDictionary.this.getRegion(regionIndex).getDictionaryValuesRegion();
         }
+
+        @Override
+        public boolean supportsUnboundedFill() {
+            return RegionedColumnSourceWithDictionary.this.supportsUnboundedFill();
+        }
     }
 
     @Override

engine/table/src/main/java/io/deephaven/engine/table/impl/sources/regioned/RegionedPageStore.java

@@ -13,6 +13,8 @@
 import io.deephaven.util.annotations.FinalDefault;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Arrays;
+
 public interface RegionedPageStore<ATTR extends Any, INNER_ATTR extends ATTR, REGION_TYPE extends Page<INNER_ATTR>>
         extends PageStore<ATTR, INNER_ATTR, REGION_TYPE> {
 
@@ -72,6 +74,14 @@ default int getRegionIndex(final long elementIndex) {
      */
     REGION_TYPE getRegion(int regionIndex);
 
+    /**
+     *  Whether this page store supports an unbounded fill operation.
+     *
+     * @return true if unbounded fill is supported.
+     */
+    boolean supportsUnboundedFill();
+
+
     /**
      * Perform region lookup for an element row key.
      *
@@ -92,7 +102,7 @@ default REGION_TYPE getPageContaining(final FillContext fillContext, final long
 
     @Override
     default FillContext makeFillContext(final int chunkCapacity, final SharedContext sharedContext) {
-        return new RegionContextHolder(chunkCapacity, sharedContext);
+        return new RegionContextHolder(chunkCapacity, sharedContext, supportsUnboundedFill());
     }
 
     /**
@@ -133,11 +143,12 @@ private static long validateMask(final long mask, final String name) {
     /**
      * A regioned page store for use when the full set of regions and their sizes are known.
      */
-    abstract class Static<ATTR extends Any, INNER_ATTR extends ATTR, REGION_TYPE extends Page<INNER_ATTR>>
+    abstract class Static<ATTR extends Any, INNER_ATTR extends ATTR, REGION_TYPE extends ColumnRegion<INNER_ATTR>>
             implements RegionedPageStore<ATTR, INNER_ATTR, REGION_TYPE> {
 
         private final Parameters parameters;
         private final REGION_TYPE[] regions;
+        private final boolean supportsUnboundedFill;
 
         /**
          * @param parameters Mask and shift parameters
@@ -152,6 +163,7 @@ public Static(@NotNull final Parameters parameters,
             for (final REGION_TYPE region : regions) {
                 Require.eq(region.mask(), "region.mask()", parameters.regionMask, "parameters.regionMask");
             }
+            supportsUnboundedFill = Arrays.stream(regions).allMatch(ColumnRegion::supportsUnboundedFill);
         }
 
         @Override
@@ -168,5 +180,10 @@ public final int getRegionCount() {
         public final REGION_TYPE getRegion(final int regionIndex) {
             return regions[regionIndex];
         }
+
+        @Override
+        public boolean supportsUnboundedFill() {
+            return supportsUnboundedFill;
+        }
     }
 }