Issue#573 Remove temp views for CTEs in WITH statement

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

@@ -7,6 +7,8 @@ package org.h2.command;
 
 import java.sql.SQLException;
 import java.util.ArrayList;
+import java.util.List;
+
 import org.h2.api.ErrorCode;
 import org.h2.engine.Constants;
 import org.h2.engine.Database;
@@ -45,6 +47,8 @@ public abstract class Command implements CommandInterface {
 
     private boolean canReuse;
 
+    private List<Runnable> cleanupCallbacks;
+
     Command(Parser parser, String sql) {
         this.session = parser.getSession();
         this.sql = sql;
@@ -228,6 +232,7 @@ public abstract class Command implements CommandInterface {
                 throw e;
             } finally {
                 if (callStop) {
+                    commandCleanup();
                     stop();
                 }
                 if (writing) {
@@ -287,6 +292,7 @@ public abstract class Command implements CommandInterface {
             } finally {
                 try {
                     if (callStop) {
+                        commandCleanup();
                         stop();
                     }
                 } finally {
@@ -298,6 +304,17 @@ public abstract class Command implements CommandInterface {
         }
     }
 
+    private void commandCleanup() {
+        if (cleanupCallbacks!=null){
+            for(Runnable eachCleanup:cleanupCallbacks){
+                eachCleanup.run();
+                // clean up done - must restart query (and dependency construction) to reuse
+                canReuse = false;
+            }
+            cleanupCallbacks.clear();
+        }
+    }
+
     private long filterConcurrentUpdate(DbException e, long start) {
         int errorCode = e.getErrorCode();
         if (errorCode != ErrorCode.CONCURRENT_UPDATE_1 &&
@@ -370,4 +387,8 @@ public abstract class Command implements CommandInterface {
         }
     }
     
+    public void setCleanupCallbacks(List<Runnable> cleanupCallbacks) {
+        this.cleanupCallbacks = cleanupCallbacks;
+    }
+
 }

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

@@ -4899,6 +4899,26 @@ public class Parser {
 
         Query q = parseSelectUnion();
         q.setPrepareAlways(true);
+        List<Runnable> cleanupCallbacks = new ArrayList<Runnable>();
+
+        // clean up temp views starting with last to first (in case of dependencies)
+        Collections.reverse(viewsCreated);
+
+        for (TableView view : viewsCreated){
+            if(view==null){
+                continue;
+            }
+            cleanupCallbacks.add(new Runnable(){
+                @Override
+                public void run() {
+                    // check if view was previously deleted as their name is set to null
+                    if(view.getName()!=null) {
+                        session.removeLocalTempTable(view);
+                    }
+                }
+            });
+        }
+        q.setCleanupCallbacks(cleanupCallbacks);
         return q;
     }
 

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

@@ -6,6 +6,8 @@
 package org.h2.command;
 
 import java.util.ArrayList;
+import java.util.List;
+
 import org.h2.api.DatabaseEventListener;
 import org.h2.api.ErrorCode;
 import org.h2.engine.Database;
@@ -55,6 +57,7 @@ public abstract class Prepared {
     private int objectId;
     private int currentRowNumber;
     private int rowScanCount;
+    private List<Runnable> cleanupCallbacks;
 
     /**
      * Create a new object.
@@ -173,6 +176,9 @@ public abstract class Prepared {
      */
     public void setCommand(Command command) {
         this.command = command;
+        if(command!=null && cleanupCallbacks!=null){
+            command.setCleanupCallbacks(cleanupCallbacks);
+        }
     }
 
     /**
@@ -434,4 +440,13 @@ public abstract class Prepared {
         return false;
     }
 
+    public List<Runnable> getCleanupCallbacks() {
+        return cleanupCallbacks;
+    }
+
+    public void setCleanupCallbacks(List<Runnable> cleanupCallbacks) {
+        this.cleanupCallbacks = cleanupCallbacks;
+    }
+
+
 }

h2/src/main/org/h2/res/help.csv

@@ -381,6 +381,12 @@ SET BINARY_COLLATION
 ","
 Sets the collation used for comparing BINARY columns, the default is SIGNED
 for version 1."
+"Commands (Other)","SET BUILTIN_ALIAS_OVERRIDE","
+SET BUILTIN_ALIAS_OVERRIDE
+{ TRUE | FALSE } ] }
+","
+Allows the overriding of the builtin system date/time functions
+for unit testing purposes."
 "Commands (Other)","SET COLLATION","
 SET [ DATABASE ] COLLATION
 { OFF | collationName [ STRENGTH { PRIMARY | SECONDARY | TERTIARY | IDENTICAL } ] }

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

@@ -9,6 +9,8 @@ import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.Statement;
+
+import org.h2.jdbc.JdbcSQLException;
 import org.h2.test.TestBase;
 
 /**
@@ -186,6 +188,8 @@ public class TestGeneralCommonTableQueries extends TestBase {
         PreparedStatement prep;
         ResultSet rs;
 
+        conn.setAutoCommit(false);
+
         prep = conn.prepareStatement("WITH t1 AS ("
             +"     SELECT R.X, 'T1' FROM SYSTEM_RANGE(?1,?2) R"
             +"),"
@@ -210,6 +214,16 @@ public class TestGeneralCommonTableQueries extends TestBase {
 
         assertFalse(rs.next());
 
+        try{
+            prep = conn.prepareStatement("SELECT * FROM t1 UNION ALL SELECT * FROM t2 UNION ALL SELECT X, 'Q' FROM SYSTEM_RANGE(5,6)");
+            rs = prep.executeQuery();
+            fail("Temp view T1 was accessible after previous WITH statement finished - but should not have been.");
+        }
+        catch(JdbcSQLException e){
+             // ensure the T1 table has been removed even without auto commit
+             assertContains(e.getMessage(),"Table \"T1\" not found;");
+        }
+
         conn.close();
         deleteDb("commonTableExpressionQueries");
     }