Minor improvement: Index.isFirstColumn

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

@@ -377,6 +377,11 @@ public abstract class BaseIndex extends SchemaObjectBase implements Index {
         return -1;
     }
 
+    @Override
+    public boolean isFirstColumn(Column column) {
+        return column.equals(columns[0]);
+    }
+
     /**
      * Get the list of columns as a string.
      *

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

@@ -190,6 +190,14 @@ public interface Index extends SchemaObject {
      */
     int getColumnIndex(Column col);
 
+    /**
+     * Check if the given column is the first for this index
+     *
+     * @param column the column
+     * @return true if the given columns is the first
+     */
+    boolean isFirstColumn(Column column);
+
     /**
      * Get the indexed columns as index columns (with ordering information).
      *

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

@@ -82,6 +82,14 @@ public class MetaIndex extends BaseIndex {
         return super.getColumnIndex(col);
     }
 
+    @Override
+    public boolean isFirstColumn(Column column) {
+        if (scan) {
+            return false;
+        }
+        return super.isFirstColumn(column);
+    }
+
     @Override
     public void checkRename() {
         throw DbException.getUnsupportedException("META");

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

@@ -230,6 +230,11 @@ public class MultiVersionIndex implements Index {
         return base.getColumnIndex(col);
     }
 
+    @Override
+    public boolean isFirstColumn(Column column) {
+        return base.isFirstColumn(column);
+    }
+
     @Override
     public Column[] getColumns() {
         return base.getColumns();

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

@@ -464,6 +464,11 @@ public class PageDataIndex extends PageIndex {
         return -1;
     }
 
+    @Override
+    public boolean isFirstColumn(Column column) {
+        return false;
+    }
+
     @Override
     public void close(Session session) {
         if (trace.isDebugEnabled()) {

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

@@ -96,6 +96,11 @@ public class PageDelegateIndex extends PageIndex {
         return -1;
     }
 
+    @Override
+    public boolean isFirstColumn(Column column) {
+        return getColumnIndex(column) == 0;
+    }
+
     @Override
     public double getCost(Session session, int[] masks,
             TableFilter[] filters, int filter, SortOrder sortOrder,

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

@@ -222,6 +222,11 @@ public class ScanIndex extends BaseIndex {
         return -1;
     }
 
+    @Override
+    public boolean isFirstColumn(Column column) {
+        return false;
+    }
+
     @Override
     public void checkRename() {
         throw DbException.getUnsupportedException("SCAN");

h2/src/main/org/h2/mvstore/db/MVDelegateIndex.java

@@ -88,6 +88,11 @@ public class MVDelegateIndex extends BaseIndex implements MVIndex {
         return -1;
     }
 
+    @Override
+    public boolean isFirstColumn(Column column) {
+        return getColumnIndex(column) == 0;
+    }
+
     @Override
     public double getCost(Session session, int[] masks,
             TableFilter[] filters, int filter, SortOrder sortOrder,

h2/src/main/org/h2/mvstore/db/MVPrimaryIndex.java

@@ -242,6 +242,11 @@ public class MVPrimaryIndex extends BaseIndex {
         return -1;
     }
 
+    @Override
+    public boolean isFirstColumn(Column column) {
+        return false;
+    }
+
     @Override
     public void remove(Session session) {
         TransactionMap<Value, Value> map = getMap(session);

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

@@ -1069,10 +1069,9 @@ public abstract class Table extends SchemaObjectBase {
                 if (needFindNext && !index.canFindNext()) {
                     continue;
                 }
-                int idx = index.getColumnIndex(column);
                 // choose the minimal covering index with the needed first column
                 // to work consistently with execution plan from Optimizer
-                if (idx == 0 && (result == null ||
+                if (index.isFirstColumn(column) && (result == null ||
                         result.getColumns().length > index.getColumns().length)) {
                     result = index;
                 }