Index hints: Lookup for indexes only once + other minor improvements.

h2/src/main/org/h2/command/Parser.java

@@ -1263,7 +1263,7 @@ public class Parser {
         // for backward compatibility, handle case where USE is a table alias
         if (readIf("USE")) {
             if (readIf("INDEX")) {
-                indexHints = parseUseIndexList();
+                indexHints = parseIndexHints(table);
             } else {
                 alias = "USE";
             }
@@ -1273,7 +1273,7 @@ public class Parser {
                 // if alias present, a second chance to parse index hints
                 if (readIf("USE")) {
                     read("INDEX");
-                    indexHints = parseUseIndexList();
+                    indexHints = parseIndexHints(table);
                 }
             }
         }
@@ -1281,18 +1281,20 @@ public class Parser {
                 currentSelect, orderInFrom++, indexHints);
     }
 
-
-    private IndexHints parseUseIndexList() {
+    private IndexHints parseIndexHints(Table table) {
+        if (table == null) {
+            throw getSyntaxError();
+        }
         read("(");
-
         LinkedHashSet<String> indexNames = new LinkedHashSet<>();
         if (!readIf(")")) {
             do {
-                indexNames.add(readIdentifierWithSchema());
+                String indexName = readIdentifierWithSchema();
+                Index index = table.getIndex(indexName);
+                indexNames.add(index.getName());
             } while (readIf(","));
             read(")");
         }
-
         return IndexHints.createUseIndexHints(indexNames);
     }
 

h2/src/main/org/h2/table/Table.java

@@ -246,6 +246,25 @@ public abstract class Table extends SchemaObjectBase {
      */
     public abstract ArrayList<Index> getIndexes();
 
+    /**
+     * Get an index by name.
+     *
+     * @param indexName the index name to search for
+     * @return the found index
+     */
+    public Index getIndex(String indexName) {
+        ArrayList<Index> indexes = getIndexes();
+        if (indexes != null) {
+            for (int i = 0; i < indexes.size(); i++) {
+                Index index = indexes.get(i);
+                if (index.getName().equals(indexName)) {
+                    return index;
+                }
+            }
+        }
+        throw DbException.get(ErrorCode.INDEX_NOT_FOUND_1, indexName);
+    }
+
     /**
      * Check if this table is locked exclusively.
      *
@@ -693,7 +712,7 @@ public abstract class Table extends SchemaObjectBase {
                     item.cost, item.getIndex().getPlanSQL());
         }
         ArrayList<Index> indexes = getIndexes();
-        IndexHints indexHints = getIndexHints(session, filters, filter);
+        IndexHints indexHints = getIndexHints(filters, filter);
 
         if (indexes != null && masks != null) {
             for (int i = 1, size = indexes.size(); i < size; i++) {
@@ -718,27 +737,12 @@ public abstract class Table extends SchemaObjectBase {
         return item;
     }
 
-    private boolean isIndexExcludedByHints(IndexHints indexHints, Index index) {
+    private static boolean isIndexExcludedByHints(IndexHints indexHints, Index index) {
         return indexHints != null && !indexHints.allowIndex(index);
     }
 
-    private IndexHints getIndexHints(Session session, TableFilter[] filters, int filter) {
-        if (filters == null) {
-            return null;
-        }
-
-        IndexHints indexHints = filters[filter].getIndexHints();
-        if (indexHints == null) {
-            return null;
-        }
-        // check all index names in hints are valid indexes
-        for (String indexName : indexHints.getAllowedIndexes()) {
-            Index index = getSchema().findIndex(session, indexName);
-            if (index == null) {
-                throw DbException.get(ErrorCode.INDEX_NOT_FOUND_1, indexName);
-            }
-        }
-        return indexHints;
+    private static IndexHints getIndexHints(TableFilter[] filters, int filter) {
+        return filters == null ? null : filters[filter].getIndexHints();
     }
 
     /**

h2/src/test/org/h2/test/db/TestIndexHints.java

@@ -5,6 +5,7 @@
  */
 package org.h2.test.db;
 
+import org.h2.api.ErrorCode;
 import org.h2.test.TestBase;
 
 import java.sql.Connection;
@@ -126,10 +127,9 @@ public class TestIndexHints extends TestBase {
             fail("Expected exception: "
                     + "Index \"IDX_DOESNT_EXIST\" not found");
         } catch (SQLException e) {
-            assert(e.getErrorCode() == 1);
+            assertEquals(ErrorCode.INDEX_NOT_FOUND_1, e.getErrorCode());
         } finally {
             conn.close();
-
         }
     }