Slightly reduce the memory cost of View metadata, helps with people who have…

Slightly reduce the memory cost of View metadata, helps with people who have lots and lots of views, and there is no real performance gain in caching the plan SQL string

h2/src/docsrc/html/changelog.html

@@ -41,6 +41,7 @@ Change Log
     was to be inserted. Patch from Jean-Francois Noel.
 </li><li>Issue 522: Treat empty strings like NULL in Oracle compatibility mode, patch by Daniel Gredler.
 </li><li>Issue 527: Oracle compatibility mode: incorrect scale behavior, patch by Daniel Gredler.
+</li><li>Slightly reduce the memory cost of View metadata.
 </li></ul>
 
 <h2>Version 1.3.174 (2013-10-19)</h2>

h2/src/main/org/h2/index/ViewIndex.java

@@ -44,7 +44,6 @@ public class ViewIndex extends BaseIndex {
         SmallLRUCache.newInstance(Constants.VIEW_INDEX_CACHE_SIZE);
     private boolean recursive;
     private final int[] indexMasks;
-    private String planSQL;
     private Query query;
     private final Session createSession;
 
@@ -70,7 +69,6 @@ public class ViewIndex extends BaseIndex {
         columns = new Column[0];
         if (!recursive) {
             query = getQuery(session, masks);
-            planSQL =  query.getPlanSQL();
         }
     }
 
@@ -80,7 +78,7 @@ public class ViewIndex extends BaseIndex {
 
     @Override
     public String getPlanSQL() {
-        return planSQL;
+        return query == null ? null : query.getPlanSQL();
     }
 
     @Override
@@ -178,7 +176,6 @@ public class ViewIndex extends BaseIndex {
             }
             if (query == null) {
                 query = (Query) createSession.prepare(querySQL, true);
-                planSQL =  query.getPlanSQL();
             }
             if (!(query instanceof SelectUnion)) {
                 throw DbException.get(ErrorCode.SYNTAX_ERROR_2, "recursive queries without UNION ALL");

h2/src/test/org/h2/test/testScript.sql

@@ -6644,8 +6644,8 @@ SELECT * FROM V_UNION WHERE ID=1;
 
 EXPLAIN SELECT * FROM V_UNION WHERE ID=1;
 > PLAN
-> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT V_UNION.ID, V_UNION.NAME, V_UNION.CLASS FROM PUBLIC.V_UNION /* (SELECT CHILDREN.ID, CHILDREN.NAME, CHILDREN.CLASS FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID IS ?1 ++/ WHERE CHILDREN.ID IS ?1) UNION ALL (SELECT CHILDREN.ID, CHILDREN.NAME, CHILDREN.CLASS FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID IS ?1 ++/ WHERE CHILDREN.ID IS ?1): ID = 1 */ WHERE ID = 1
+> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT V_UNION.ID, V_UNION.NAME, V_UNION.CLASS FROM PUBLIC.V_UNION /* (SELECT CHILDREN.ID, CHILDREN.NAME, CHILDREN.CLASS FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID IS ?1 ++/ /++ scanCount: 2 ++/ WHERE CHILDREN.ID IS ?1) UNION ALL (SELECT CHILDREN.ID, CHILDREN.NAME, CHILDREN.CLASS FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID IS ?1 ++/ /++ scanCount: 2 ++/ WHERE CHILDREN.ID IS ?1): ID = 1 */ WHERE ID = 1
 > rows: 1
 
 CREATE VIEW V_EXCEPT AS SELECT * FROM CHILDREN EXCEPT SELECT * FROM CHILDREN WHERE ID=2;
@@ -6659,8 +6659,8 @@ SELECT * FROM V_EXCEPT WHERE ID=1;
 
 EXPLAIN SELECT * FROM V_EXCEPT WHERE ID=1;
 > PLAN
-> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT V_EXCEPT.ID, V_EXCEPT.NAME, V_EXCEPT.CLASS FROM PUBLIC.V_EXCEPT /* (SELECT CHILDREN.ID, CHILDREN.NAME, CHILDREN.CLASS FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID IS ?1 ++/ WHERE CHILDREN.ID IS ?1) EXCEPT (SELECT CHILDREN.ID, CHILDREN.NAME, CHILDREN.CLASS FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID = 2 ++/ WHERE ID = 2): ID = 1 */ WHERE ID = 1
+> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT V_EXCEPT.ID, V_EXCEPT.NAME, V_EXCEPT.CLASS FROM PUBLIC.V_EXCEPT /* (SELECT DISTINCT CHILDREN.ID, CHILDREN.NAME, CHILDREN.CLASS FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID IS ?1 ++/ /++ scanCount: 2 ++/ WHERE CHILDREN.ID IS ?1) EXCEPT (SELECT DISTINCT CHILDREN.ID, CHILDREN.NAME, CHILDREN.CLASS FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID = 2 ++/ /++ scanCount: 2 ++/ WHERE ID = 2): ID = 1 */ WHERE ID = 1
 > rows: 1
 
 CREATE VIEW V_INTERSECT AS SELECT ID, NAME FROM CHILDREN INTERSECT SELECT * FROM CLASSES;
@@ -6673,8 +6673,8 @@ SELECT * FROM V_INTERSECT WHERE ID=1;
 
 EXPLAIN SELECT * FROM V_INTERSECT WHERE ID=1;
 > PLAN
-> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT V_INTERSECT.ID, V_INTERSECT.NAME FROM PUBLIC.V_INTERSECT /* (SELECT ID, NAME FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID IS ?1 ++/ WHERE ID IS ?1) INTERSECT (SELECT CLASSES.ID, CLASSES.NAME FROM PUBLIC.CLASSES /++ PUBLIC.PRIMARY_KEY_5: ID IS ?1 ++/ WHERE CLASSES.ID IS ?1): ID = 1 */ WHERE ID = 1
+> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT V_INTERSECT.ID, V_INTERSECT.NAME FROM PUBLIC.V_INTERSECT /* (SELECT DISTINCT ID, NAME FROM PUBLIC.CHILDREN /++ PUBLIC.PRIMARY_KEY_9: ID IS ?1 ++/ /++ scanCount: 2 ++/ WHERE ID IS ?1) INTERSECT (SELECT DISTINCT CLASSES.ID, CLASSES.NAME FROM PUBLIC.CLASSES /++ PUBLIC.PRIMARY_KEY_5: ID IS ?1 ++/ /++ scanCount: 2 ++/ WHERE CLASSES.ID IS ?1): ID = 1 */ WHERE ID = 1
 > rows: 1
 
 DROP VIEW V_UNION;