HHH-10563 : Significant String use/duplication associated with subselect fetch

(cherry picked from commit 3f37fff04aab09e136d9e24c2bf6a4841170552c)

Conflicts:
	hibernate-core/src/main/java/org/hibernate/engine/spi/SubselectFetch.java
	hibernate-core/src/main/java/org/hibernate/loader/Loader.java
	hibernate-core/src/main/java/org/hibernate/loader/plan/exec/process/internal/ResultSetProcessingContextImpl.java

hibernate-core/src/main/java/org/hibernate/engine/spi/SubselectFetch.java

@@ -48,30 +48,92 @@ public class SubselectFetch {
 	private final QueryParameters queryParameters;
 	private final Map namedParameterLocMap;
 
+	/**
+	 * Construct a SubselectFetch instance. The subselect fetch query fragment is generated by
+	 * {@link #createSubselectFetchQueryFragment}.
+	 *
+	 * If the same value for {@code queryParameters} is to be used when constructing multiple
+	 * SubselectFetch objects, then it is preferable to generate the subselect fetch query
+	 * fragment using {@link #createSubselectFetchQueryFragment}, and pass the result as an
+	 * argument to constructor {@link #SubselectFetch(String, String, Loadable, QueryParameters, Set, Map)}.
+	 *
+	 * @param alias - the table alias used in the subselect fetch query fragment
+	 * (to be generated by {@link #createSubselectFetchQueryFragment(QueryParameters)} that
+	 * corresponds to {@code loadable};
+	 * @param loadable - the {@link Loadable} for the associated entities to be subselect fetched;
+	 * @param queryParameters - the query parameters;
+	 * @param resultingEntityKeys - the {@link EntityKey} objects for the entities to be subselect fetched;
+	 * @param namedParameterLocMap - mapping from named parameter to the parameter index located in the
+	 * subselect fetch query fragment.
+	 *
+	 * @see #SubselectFetch(String, String, Loadable, QueryParameters, Set, Map)
+	 */
 	public SubselectFetch(
-		//final String queryString,
+			final String alias,
-		final String alias,
+			final Loadable loadable,
-		final Loadable loadable,
+			final QueryParameters queryParameters,
-		final QueryParameters queryParameters,
+			final Set resultingEntityKeys,
-		final Set resultingEntityKeys,
+			final Map namedParameterLocMap) {
-		final Map namedParameterLocMap
+		this(
-	) {
+				createSubselectFetchQueryFragment( queryParameters ),
+				alias,
+				loadable,
+				queryParameters,
+				resultingEntityKeys,
+				namedParameterLocMap
+		);
+	}
+
+	/**
+	 * Construct a SubselectFetch instance using the provided subselect fetch query fragment,
+	 * {@code subselectFetchQueryFragment}. It is assumed that {@code subselectFetchQueryFragment}
+	 * is the result of calling {@link #createSubselectFetchQueryFragment} with the same value
+	 * provided for {@code queryParameters}.
+	 *
+	 * @param subselectFetchQueryFragment - the subselect fetch query fragment;
+	 * @param alias - the table alias used in {@code subselectFetchQueryFragment} that
+	 * corresponds to {@code loadable};
+	 * @param loadable - the {@link Loadable} for the associated entities to be subselect fetched;
+	 * @param queryParameters - the query parameters;
+	 * @param resultingEntityKeys - the {@link EntityKey} objects for the entities to be subselect fetched;
+	 * @param namedParameterLocMap - mapping from named parameter to the parameter index located in the
+	 * subselect fetch query fragment.
+	 */
+	public SubselectFetch(
+			final String subselectFetchQueryFragment,
+			final String alias,
+			final Loadable loadable,
+			final QueryParameters queryParameters,
+			final Set resultingEntityKeys,
+			final Map namedParameterLocMap) {
 		this.resultingEntityKeys = resultingEntityKeys;
 		this.queryParameters = queryParameters;
 		this.namedParameterLocMap = namedParameterLocMap;
 		this.loadable = loadable;
 		this.alias = alias;
 
+		this.queryString = subselectFetchQueryFragment;
+	}
+
+	/**
+	 * Create the subselect fetch query fragment for the provided {@link QueryParameters}
+	 * with SELECT and ORDER BY clauses removed.
+	 *
+	 * @param queryParameters -the query parameters.
+	 * @return the subselect fetch query fragment.
+	 */
+	public static String createSubselectFetchQueryFragment(QueryParameters queryParameters) {
 		//TODO: ugly here:
 		final String queryString = queryParameters.getFilteredSQL();
 		int fromIndex = queryString.indexOf(" from ");
 		int orderByIndex = queryString.lastIndexOf("order by");
-		this.queryString = orderByIndex>0 ?
+		final String subselectQueryFragment =  orderByIndex > 0
-				queryString.substring(fromIndex, orderByIndex) :
+				? queryString.substring( fromIndex, orderByIndex )
-				queryString.substring(fromIndex);
+				: queryString.substring( fromIndex );
 		if ( LOG.isTraceEnabled() ) {
-			LOG.tracef( "Generated SubselectFetch query: %s", queryString );
+			LOG.tracef( "SubselectFetch query fragment: %s", subselectQueryFragment );
 		}
+		return subselectQueryFragment;
 	}
 
 	public QueryParameters getQueryParameters() {

hibernate-core/src/main/java/org/hibernate/loader/Loader.java

@@ -63,7 +63,6 @@
 import org.hibernate.engine.internal.CacheHelper;
 import org.hibernate.engine.internal.TwoPhaseLoad;
 import org.hibernate.engine.jdbc.ColumnNameCache;
-import org.hibernate.engine.jdbc.spi.ResultSetWrapper;
 import org.hibernate.engine.spi.EntityEntry;
 import org.hibernate.engine.spi.EntityKey;
 import org.hibernate.engine.spi.EntityUniqueKey;
@@ -1014,6 +1013,9 @@ private void createSubselects(List keys, QueryParameters queryParameters, Sessio
 
 			final Loadable[] loadables = getEntityPersisters();
 			final String[] aliases = getAliases();
+			final String subselectQueryString = SubselectFetch.createSubselectFetchQueryFragment(
+					queryParameters
+			);
 			final Iterator iter = keys.iterator();
 			while ( iter.hasNext() ) {
 
@@ -1023,7 +1025,7 @@ private void createSubselects(List keys, QueryParameters queryParameters, Sessio
 					if ( rowKeys[i]!=null && loadables[i].hasSubselectLoadableCollections() ) {
 
 						SubselectFetch subselectFetch = new SubselectFetch(
-								//getSQLString(),
+								subselectQueryString,
 								aliases[i],
 								loadables[i],
 								queryParameters,