The optimization for IN(...) is now only used if comparing a column with an index.

h2/src/main/org/h2/expression/ConditionIn.java

@@ -13,6 +13,7 @@ import org.h2.constant.SysProperties;
 import org.h2.engine.Constants;
 import org.h2.engine.Database;
 import org.h2.engine.Session;
+import org.h2.index.Index;
 import org.h2.index.IndexCondition;
 import org.h2.schema.Schema;
 import org.h2.table.Column;
@@ -215,6 +216,14 @@ public class ConditionIn extends Condition {
         if (!areAllValues(ExpressionVisitor.get(ExpressionVisitor.EVALUATABLE))) {
             return this;
         }
+        if (!(left instanceof ExpressionColumn)) {
+            return this;
+        }
+        ExpressionColumn ec = (ExpressionColumn) left;
+        Index index = ec.getTableFilter().getTable().getIndexForColumn(ec.getColumn(), false);
+        if (index == null) {
+            return this;
+        }
         Database db = session.getDatabase();
         Schema mainSchema = db.getSchema(Constants.SCHEMA_MAIN);
         int rowCount = values.size();
@@ -233,7 +242,7 @@ public class ConditionIn extends Condition {
         Column col = new Column(columnName, dataType);
         columns.add(col);
         function.setColumns(columns);
-        FunctionTable table = new FunctionTable(mainSchema, session, function);
+        FunctionTable table = new FunctionTable(mainSchema, session, function, function);
         String viewName = session.getNextSystemIdentifier(select.getSQL());
         TableFilter filter = new TableFilter(session, table, viewName, false, select);
         select.addTableFilter(filter, true);

h2/src/main/org/h2/expression/ConditionInSelect.java

@@ -13,6 +13,7 @@ import org.h2.command.dml.Select;
 import org.h2.constant.ErrorCode;
 import org.h2.engine.Database;
 import org.h2.engine.Session;
+import org.h2.index.Index;
 import org.h2.message.Message;
 import org.h2.result.LocalResult;
 import org.h2.table.ColumnResolver;
@@ -128,6 +129,7 @@ public class ConditionInSelect extends Condition {
     }
 
     public Expression optimizeInJoin(Session session, Select select) throws SQLException {
+        query.setDistinct(true);
         if (all || compareType != Comparison.EQUAL) {
             return this;
         }
@@ -135,10 +137,17 @@ public class ConditionInSelect extends Condition {
             return this;
         }
         String alias = query.getFirstColumnAlias(session);
-        query.setDistinct(true);
         if (alias == null) {
             return this;
         }
+        if (!(left instanceof ExpressionColumn)) {
+            return this;
+        }
+        ExpressionColumn ec = (ExpressionColumn) left;
+        Index index = ec.getTableFilter().getTable().getIndexForColumn(ec.getColumn(), false);
+        if (index == null) {
+            return this;
+        }
         String name = session.getNextSystemIdentifier(select.getSQL());
         TableView view = TableView.createTempView(session, session.getUser(), name, query, select);
         TableFilter filter = new TableFilter(session, view, name, false, select);

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

@@ -12,6 +12,7 @@ import org.h2.message.Message;
 import org.h2.result.LocalResult;
 import org.h2.result.Row;
 import org.h2.result.SearchRow;
+import org.h2.value.Value;
 
 /**
  * A cursor for a function that returns a result set.
@@ -19,6 +20,7 @@ import org.h2.result.SearchRow;
 public class FunctionCursor implements Cursor {
 
     private LocalResult result;
+    private Value[] values;
     private Row row;
 
     FunctionCursor(LocalResult result) {
@@ -26,11 +28,17 @@ public class FunctionCursor implements Cursor {
     }
 
     public Row get() {
+        if (values == null) {
+            return null;
+        }
+        if (row == null) {
+            row = new Row(values, 0);
+        }
         return row;
     }
 
     public SearchRow getSearchRow() {
-        return row;
+        return get();
     }
 
     public int getPos() {
@@ -38,12 +46,13 @@ public class FunctionCursor implements Cursor {
     }
 
     public boolean next() throws SQLException {
+        row = null;
         if (result.next()) {
-            row = new Row(result.currentRow(), 0);
+            values = result.currentRow();
         } else {
-            row = null;
+            values = null;
         }
-        return row != null;
+        return values != null;
     }
 
     public boolean previous() {

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

@@ -35,9 +35,13 @@ public class FunctionTable extends Table {
 
     private final FunctionCall function;
     private final long rowCount;
+    private Expression functionExpr;
+    private LocalResult cachedResult;
+    private Value cachedValue;
 
-    public FunctionTable(Schema schema, Session session, FunctionCall function) throws SQLException {
+    public FunctionTable(Schema schema, Session session, Expression functionExpr, FunctionCall function) throws SQLException {
         super(schema, 0, function.getName(), false);
+        this.functionExpr = functionExpr;
         this.function = function;
         if (function instanceof TableFunction) {
             rowCount = ((TableFunction) function).getRowCount();
@@ -151,14 +155,23 @@ public class FunctionTable extends Table {
      * @return the result set
      */
     public LocalResult getResult(Session session) throws SQLException {
-        function.optimize(session);
-        Value v = function.getValue(session);
+        functionExpr = functionExpr.optimize(session);
+        Value v = functionExpr.getValue(session);
+        if (cachedResult != null && cachedValue == v) {
+            cachedResult.reset();
+            return cachedResult;
+        }
         if (v == ValueNull.INSTANCE) {
             return new LocalResult();
         }
         ValueResultSet value = (ValueResultSet) v;
         ResultSet rs = value.getResultSet();
-        return LocalResult.read(session,  rs, 0);
+        LocalResult result = LocalResult.read(session,  rs, 0);
+        if (function.isDeterministic()) {
+            cachedResult = result;
+            cachedValue = v;
+        }
+        return result;
     }
 
     public long getMaxDataModificationId() {