Extra cleanup for the index scrubbing code (#3317)

Resolve #3315

There where leftover requested changes in PR #3298 that are addressed
here

Author: jjezra

fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/provider/foundationdb/IndexingSubspaces.java

@@ -91,22 +91,36 @@ public static Subspace indexBuildTypeSubspace(@Nonnull FDBRecordStoreBase<?> sto
      * @return subspace
      */
     @Nonnull
-    public static Subspace indexScrubRecordsRangeSubspaceZero(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index) {
+    private static Subspace indexScrubRecordsRangeSubspaceZero(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index) {
         // Backward compatible subspace for range-id zero
         return indexBuildSubspace(store, index, INDEX_SCRUBBED_RECORDS_RANGES_ZERO);
     }
 
     /**
-     * Subspace that stores scrubbed records ranges. This subspace is expected to be followed by a range-id.
+     * Subspace that stores scrubbed records ranges.
      * @param store store
      * @param index index
      * @return subspace
      */
     @Nonnull
-    public static Subspace indexScrubRecordsRangeSubspace(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index) {
+    private static Subspace indexScrubRecordsRangeSubspaceRoot(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index) {
         return indexBuildSubspace(store, index, INDEX_SCRUBBED_RECORDS_RANGES);
     }
 
+    /**
+     * Subspace that stores scrubbed records ranges.
+     * @param store store
+     * @param index index
+     * @return subspace
+     */
+    @Nonnull
+    public static Subspace indexScrubRecordsRangeSubspace(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index, int rangeId) {
+        return rangeId == 0 ?
+               // Backward compatible
+               IndexingSubspaces.indexScrubRecordsRangeSubspaceZero(store, index) :
+               IndexingSubspaces.indexScrubRecordsRangeSubspaceRoot(store, index).subspace(Tuple.from(rangeId));
+    }
+
     /**
      * Subspace that stores scrubbed index entries ranges of the zero range-id. This subspace is backward compatible
      * to index entries ranges scrubbed before range-id was introduced.
@@ -115,7 +129,7 @@ public static Subspace indexScrubRecordsRangeSubspace(@Nonnull FDBRecordStoreBas
      * @return subspace
      */
     @Nonnull
-    public static Subspace indexScrubIndexRangeSubspaceLegacy(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index) {
+    private static Subspace indexScrubIndexRangeSubspaceZero(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index) {
         // Backward compatible subspace for range-id zero
         return indexBuildSubspace(store, index, INDEX_SCRUBBED_INDEX_RANGES_ZERO);
     }
@@ -127,21 +141,36 @@ public static Subspace indexScrubIndexRangeSubspaceLegacy(@Nonnull FDBRecordStor
      * @return subspace
      */
     @Nonnull
-    public static Subspace indexScrubIndexRangeSubspace(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index) {
+    private static Subspace indexScrubIndexRangeSubspaceRoot(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index) {
         return indexBuildSubspace(store, index, INDEX_SCRUBBED_INDEX_RANGES);
     }
 
+    /**
+     * Subspace that stores scrubbed index entries ranges.
+     * @param store store
+     * @param index index
+     * @param rangeId used by the caller to distinct different scrubbing sessions.
+     * @return subspace
+     */
+    @Nonnull
+    public static Subspace indexScrubIndexRangeSubspace(@Nonnull FDBRecordStoreBase<?> store, @Nonnull Index index, int rangeId) {
+        return rangeId == 0 ?
+            // Backward compatible
+            IndexingSubspaces.indexScrubIndexRangeSubspaceZero(store, index) :
+            IndexingSubspaces.indexScrubIndexRangeSubspaceRoot(store, index).subspace(Tuple.from(rangeId));
+    }
+
     /**
      * Erasing all the scrubbing ranges data. After calling this function, there would be no memory of scrubbed ranges.
      * @param context user context - the operation will run within this context
      * @param store store
      * @param index index
      */
     public static void eraseAllIndexingScrubbingData(@Nonnull FDBRecordContext context, @Nonnull FDBRecordStore store, @Nonnull Index index) {
-        context.clear(Range.startsWith(indexScrubIndexRangeSubspaceLegacy(store, index).pack()));
-        context.clear(Range.startsWith(indexScrubIndexRangeSubspace(store, index).pack()));
+        context.clear(Range.startsWith(indexScrubIndexRangeSubspaceZero(store, index).pack()));
+        context.clear(Range.startsWith(indexScrubIndexRangeSubspaceRoot(store, index).pack()));
         context.clear(Range.startsWith(indexScrubRecordsRangeSubspaceZero(store, index).pack()));
-        context.clear(Range.startsWith(indexScrubRecordsRangeSubspace(store, index).pack()));
+        context.clear(Range.startsWith(indexScrubRecordsRangeSubspaceRoot(store, index).pack()));
     }
 
     /**

fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/provider/foundationdb/indexing/IndexingRangeSet.java

@@ -32,7 +32,6 @@
 import com.apple.foundationdb.record.provider.foundationdb.FDBStoreTimer;
 import com.apple.foundationdb.record.provider.foundationdb.IndexingSubspaces;
 import com.apple.foundationdb.subspace.Subspace;
-import com.apple.foundationdb.tuple.Tuple;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -228,13 +227,7 @@ public static IndexingRangeSet forIndexBuild(@Nonnull FDBRecordStore store, @Non
      */
     @Nonnull
     public static IndexingRangeSet forScrubbingIndex(@Nonnull FDBRecordStore store, @Nonnull Index index, int rangeId) {
-        final Subspace subspace;
-        if (rangeId == 0) {
-            // Backward compatible
-            subspace = IndexingSubspaces.indexScrubIndexRangeSubspaceLegacy(store, index);
-        } else {
-            subspace = IndexingSubspaces.indexScrubIndexRangeSubspace(store, index).subspace(Tuple.from(rangeId));
-        }
+        final Subspace subspace = IndexingSubspaces.indexScrubIndexRangeSubspace(store, index, rangeId);
         final RangeSet rangeSet = new RangeSet(subspace);
         return new IndexingRangeSet(store.getRecordContext(), rangeSet);
     }
@@ -251,13 +244,7 @@ public static IndexingRangeSet forScrubbingIndex(@Nonnull FDBRecordStore store,
      */
     @Nonnull
     public static IndexingRangeSet forScrubbingRecords(@Nonnull FDBRecordStore store, @Nonnull Index index, int rangeId) {
-        final Subspace subspace;
-        if (rangeId == 0) {
-            // Backward compatible
-            subspace = IndexingSubspaces.indexScrubRecordsRangeSubspaceZero(store, index);
-        } else {
-            subspace = IndexingSubspaces.indexScrubRecordsRangeSubspace(store, index).subspace(Tuple.from(rangeId));
-        }
+        final Subspace subspace = IndexingSubspaces.indexScrubRecordsRangeSubspace(store, index, rangeId);
         final RangeSet rangeSet = new RangeSet(subspace);
         return new IndexingRangeSet(store.getRecordContext(), rangeSet);
     }