HHH-19508 efficient detection of pending deletions for CollectionUpdateActions

Author: gavinking

hibernate-core/src/main/java/org/hibernate/action/internal/CollectionUpdateAction.java

@@ -108,13 +108,17 @@ else if ( collection.needsRecreate( persister ) ) {
 		}
 	}
 
+	/**
+	 * Sort update actions with deletions to the start of the line
+	 * in order to limit the chance of a unique key violation.
+	 */
 	@Override
 	public int compareTo(ComparableExecutable executable) {
 		if ( executable instanceof CollectionUpdateAction that
 				&& getPrimarySortClassifier().equals( executable.getPrimarySortClassifier() ) ) {
 			final CollectionPersister persister = getPersister();
-			boolean hasDeletes = this.getCollection().getDeletes( persister, false ).hasNext();
-			boolean otherHasDeletes = that.getCollection().getDeletes( persister, false ).hasNext();
+			final boolean hasDeletes = this.getCollection().hasDeletes( persister );
+			final boolean otherHasDeletes = that.getCollection().hasDeletes( persister );
 			if ( hasDeletes && !otherHasDeletes ) {
 				return -1;
 			}

hibernate-core/src/main/java/org/hibernate/collection/spi/PersistentArrayHolder.java

@@ -219,7 +219,7 @@ public Object getValue() {
 	}
 
 	@Override
-	public Iterator getDeletes(CollectionPersister persister, boolean indexIsFormula) throws HibernateException {
+	public Iterator<?> getDeletes(CollectionPersister persister, boolean indexIsFormula) throws HibernateException {
 		final List<Integer> deletes = new ArrayList<>();
 		final Serializable sn = getSnapshot();
 		final int snSize = Array.getLength( sn );
@@ -242,6 +242,22 @@ public Iterator getDeletes(CollectionPersister persister, boolean indexIsFormula
 		return deletes.iterator();
 	}
 
+	@Override
+	public boolean hasDeletes(CollectionPersister persister) throws HibernateException {
+		final Serializable sn = getSnapshot();
+		final int snSize = Array.getLength( sn );
+		final int arraySize = Array.getLength( array );
+		if ( snSize > arraySize ) {
+			return true;
+		}
+		for ( int i=0; i<snSize; i++ ) {
+			if ( Array.get( array, i ) == null && Array.get( sn, i ) != null ) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 	@Override
 	public boolean needsInserting(Object entry, int i, Type elemType) throws HibernateException {
 		final Serializable sn = getSnapshot();

hibernate-core/src/main/java/org/hibernate/collection/spi/PersistentBag.java

@@ -331,6 +331,38 @@ public Iterator<?> getDeletes(CollectionPersister persister, boolean indexIsForm
 		return deletes.iterator();
 	}
 
+	@Override
+	public boolean hasDeletes(CollectionPersister persister) {
+		final Type elementType = persister.getElementType();
+		final List<?> sn = (List<?>) getSnapshot();
+		final Iterator<?> olditer = sn.iterator();
+		int i = 0;
+		final Iterator<E> bagiter = collection.iterator();
+		while ( olditer.hasNext() ) {
+			final Object old = olditer.next();
+			final Iterator<E> newiter = collection.iterator();
+			boolean found = false;
+			if ( collection.size() > i && i++ > 0 && elementType.isSame( old, bagiter.next() ) ) {
+				//a shortcut if its location didn't change!
+				found = true;
+			}
+			else {
+				//search for it
+				//note that this code is incorrect for other than one-to-many
+				while ( newiter.hasNext() ) {
+					if ( elementType.isSame( old, newiter.next() ) ) {
+						found = true;
+						break;
+					}
+				}
+			}
+			if ( !found ) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 	@Override
 	public boolean needsInserting(Object entry, int i, Type elemType) throws HibernateException {
 		final List<?> sn = (List<?>) getSnapshot();

hibernate-core/src/main/java/org/hibernate/collection/spi/PersistentCollection.java

@@ -316,6 +316,17 @@ default boolean needsUpdating(
 	 */
 	Iterator<?> getDeletes(CollectionPersister persister, boolean indexIsFormula);
 
+	/**
+	 * Does this collection have any elements which must be deleted?
+	 *
+	 * @param persister The collection persister
+	 *
+	 * @return {@code true} if elements were removed
+	 *
+	 * @since 7
+	 */
+	boolean hasDeletes(CollectionPersister persister);
+
 	/**
 	 * Is this the wrapper for the given collection instance?
 	 *

hibernate-core/src/main/java/org/hibernate/collection/spi/PersistentIdentifierBag.java

@@ -299,6 +299,18 @@ public Iterator<?> getDeletes(CollectionPersister persister, boolean indexIsForm
 		return deletes.iterator();
 	}
 
+	@Override
+	public boolean hasDeletes(CollectionPersister persister) {
+		final Map<?,?> snap = (Map<?,?>) getSnapshot();
+		int deletes = snap.size();
+		for ( E value : collection ) {
+			if ( value != null ) {
+				deletes --;
+			}
+		}
+		return deletes > 0;
+	}
+
 	@Override
 	public Object getIndex(Object entry, int i, CollectionPersister persister) {
 		throw new UnsupportedOperationException("Bags don't have indexes");

hibernate-core/src/main/java/org/hibernate/collection/spi/PersistentList.java

@@ -410,14 +410,15 @@ public Iterator<?> getDeletes(CollectionPersister persister, boolean indexIsForm
 		final List<Object> deletes = new ArrayList<>();
 		final List<?> sn = (List<?>) getSnapshot();
 		int end;
-		if ( sn.size() > list.size() ) {
-			for ( int i=list.size(); i<sn.size(); i++ ) {
+		final int snSize = sn.size();
+		if ( snSize > list.size() ) {
+			for ( int i = list.size(); i < snSize; i++ ) {
 				deletes.add( indexIsFormula ? sn.get( i ) : i );
 			}
 			end = list.size();
 		}
 		else {
-			end = sn.size();
+			end = snSize;
 		}
 		for ( int i=0; i<end; i++ ) {
 			final Object item = list.get( i );
@@ -429,6 +430,21 @@ public Iterator<?> getDeletes(CollectionPersister persister, boolean indexIsForm
 		return deletes.iterator();
 	}
 
+	@Override
+	public boolean hasDeletes(CollectionPersister persister) {
+		final List<?> sn = (List<?>) getSnapshot();
+		int snSize = sn.size();
+		if ( snSize > list.size() ) {
+			return true;
+		}
+		for ( int i=0; i<snSize; i++ ) {
+			if ( list.get( i ) == null && sn.get( i ) != null ) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 	@Override
 	public boolean needsInserting(Object entry, int i, Type elemType) throws HibernateException {
 		final List<?> sn = (List<?>) getSnapshot();

hibernate-core/src/main/java/org/hibernate/collection/spi/PersistentMap.java

@@ -447,6 +447,16 @@ public Iterator<?> getDeletes(CollectionPersister persister, boolean indexIsForm
 		return deletes.iterator();
 	}
 
+	@Override
+	public boolean hasDeletes(CollectionPersister persister) {
+		for ( Entry<?,?> e : ((Map<?,?>) getSnapshot()).entrySet() ) {
+			if ( e.getValue() != null && map.get( e.getKey() ) == null ) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 	@Override
 	public boolean needsInserting(Object entry, int i, Type elemType) throws HibernateException {
 		final Map<?,?> sn = (Map<?,?>) getSnapshot();

hibernate-core/src/main/java/org/hibernate/collection/spi/PersistentSet.java

@@ -360,6 +360,32 @@ public Iterator<?> getDeletes(CollectionPersister persister, boolean indexIsForm
 		return deletes.iterator();
 	}
 
+	@Override
+	public boolean hasDeletes(CollectionPersister persister) {
+		final Type elementType = persister.getElementType();
+		final java.util.Map<?,?> sn = (java.util.Map<?,?>) getSnapshot();
+
+		Iterator<?> itr = sn.keySet().iterator();
+		while ( itr.hasNext() ) {
+			if ( !set.contains( itr.next() ) ) {
+				// the element has been removed from the set
+				return true;
+			}
+		}
+
+		itr = set.iterator();
+		while ( itr.hasNext() ) {
+			final Object test = itr.next();
+			final Object oldValue = sn.get( test );
+			if ( oldValue!=null && elementType.isDirty( test, oldValue, getSession() ) ) {
+				// the element has changed
+				return true;
+			}
+		}
+
+		return false;
+	}
+
 	@Override
 	public boolean needsInserting(Object entry, int i, Type elemType) throws HibernateException {
 		final Object oldValue = ( (java.util.Map<?,?>) getSnapshot() ).get( entry );