diff --git a/parquet/parquet_cursor.cc b/parquet/parquet_cursor.cc
index 0e79ba7..b6bbf53 100644
--- a/parquet/parquet_cursor.cc
+++ b/parquet/parquet_cursor.cc
@@ -6,8 +6,35 @@ ParquetCursor::ParquetCursor(ParquetTable* table) {
   reset(std::vector<Constraint>());
 }
 
+// Return true if it is _possible_ that the current
+// rowgroup satisfies the constraints. Only return false
+// if it definitely does not.
+//
+// This avoids opening rowgroups that can't return useful
+// data, which provides substantial performance benefits.
+bool ParquetCursor::currentRowGroupSatisfiesFilter() {
+  for(unsigned int i = 0; i < constraints.size(); i++) {
+    int column = constraints[i].getColumn();
+    int op = constraints[i].getOperator();
+    bool rv = true;
+
+//    printf("column = %d\n", column);
+//    std::unique_ptr<parquet::ColumnChunkMetaData> md = rowGroupMetadata->ColumnChunk(column);
+
+    if(op == IsNull) {
+    } else if(op == IsNotNull) {
+    }
+
+    if(!rv)
+      return false;
+  }
+
+  return true;
+}
+
+
 bool ParquetCursor::nextRowGroup() {
-  // TODO: skip row groups that cannot satisfy the constraints
+start:
   if((rowGroupId + 1) >= numRowGroups)
     return false;
 
@@ -36,23 +63,34 @@ bool ParquetCursor::nextRowGroup() {
     colRows[i] = rowId;
   }
 
+  if(!currentRowGroupSatisfiesFilter())
+    goto start;
+
   return true;
 }
 
 // Return true if it is _possible_ that the current
 // row satisfies the constraints. Only return false
 // if it definitely does not.
+//
+// This avoids pointless transitions between the SQLite VM
+// and the extension, which can add up on a dataset of tens
+// of millions of rows.
 bool ParquetCursor::currentRowSatisfiesFilter() {
   for(unsigned int i = 0; i < constraints.size(); i++) {
+    bool rv = true;
     int column = constraints[i].getColumn();
     ensureColumn(column);
     int op = constraints[i].getOperator();
 
     if(op == IsNull) {
-      return isNull(column);
+      rv = isNull(column);
     } else if(op == IsNotNull) {
-      return !isNull(column);
+      rv = !isNull(column);
     }
+
+    if(!rv)
+      return false;
   }
   return true;
 }
diff --git a/parquet/parquet_cursor.h b/parquet/parquet_cursor.h
index 80bc64a..2ab51a6 100644
--- a/parquet/parquet_cursor.h
+++ b/parquet/parquet_cursor.h
@@ -36,6 +36,7 @@ public:
   ParquetCursor(ParquetTable* table);
   int getRowId();
   bool currentRowSatisfiesFilter();
+  bool currentRowGroupSatisfiesFilter();
   void next();
   void close();
   void reset(std::vector<Constraint> constraints);
diff --git a/tests/queries/050-rowid-gt-none.sql b/tests/queries/050-rowid-gt-none.sql
new file mode 100644
index 0000000..6ebb920
--- /dev/null
+++ b/tests/queries/050-rowid-gt-none.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid > 100
+0
diff --git a/tests/queries/051-rowid-gte-none.sql b/tests/queries/051-rowid-gte-none.sql
new file mode 100644
index 0000000..00b2eef
--- /dev/null
+++ b/tests/queries/051-rowid-gte-none.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid >= 100
+0
diff --git a/tests/queries/052-rowid-lt-none.sql b/tests/queries/052-rowid-lt-none.sql
new file mode 100644
index 0000000..0c28165
--- /dev/null
+++ b/tests/queries/052-rowid-lt-none.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid < 0
+0
diff --git a/tests/queries/053-rowid-lte-none.sql b/tests/queries/053-rowid-lte-none.sql
new file mode 100644
index 0000000..2545b46
--- /dev/null
+++ b/tests/queries/053-rowid-lte-none.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid < -1
+0
diff --git a/tests/queries/054-rowid-lte-one.sql b/tests/queries/054-rowid-lte-one.sql
new file mode 100644
index 0000000..ba6fc8b
--- /dev/null
+++ b/tests/queries/054-rowid-lte-one.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid <= 0
+1
diff --git a/tests/queries/055-rowid-lt-one.sql b/tests/queries/055-rowid-lt-one.sql
new file mode 100644
index 0000000..e52480d
--- /dev/null
+++ b/tests/queries/055-rowid-lt-one.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid < 1
+1
diff --git a/tests/queries/056-rowid-ne-some.sql b/tests/queries/056-rowid-ne-some.sql
new file mode 100644
index 0000000..fecfaad
--- /dev/null
+++ b/tests/queries/056-rowid-ne-some.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid <> 1
+98
diff --git a/tests/queries/057-rowid-is-null.sql b/tests/queries/057-rowid-is-null.sql
new file mode 100644
index 0000000..19d15af
--- /dev/null
+++ b/tests/queries/057-rowid-is-null.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid is null
+0
diff --git a/tests/queries/058-rowid-is-not-null.sql b/tests/queries/058-rowid-is-not-null.sql
new file mode 100644
index 0000000..ad1478c
--- /dev/null
+++ b/tests/queries/058-rowid-is-not-null.sql
@@ -0,0 +1,2 @@
+select count(*) from no_nulls1 where rowid is not null
+99