Update ExtensionMethods.cs

2016-02-18 19:33:08 +01:00
parent 2595737e58
commit 07ef6b754e
1 changed files with 21 additions and 1 deletions
@@ -147,7 +147,27 @@ namespace Duplicati.Library.Main.Database
            con.Transaction = transaction;
            return con;
        }
-            
+
+        /// <summary> Small helper method querying and returning a textual representation of the SQLite execution plan. </summary>
+        public static string GetSQLiteExecutionPlan(this System.Data.IDbCommand cmd)
+        {
+            var qpCmd = cmd.Connection.CreateCommand();
+            qpCmd.CommandText = "EXPLAIN QUERY PLAN " + cmd.CommandText;
+            qpCmd.Connection = cmd.Connection;
+            qpCmd.CommandType = cmd.CommandType;
+            qpCmd.Transaction = cmd.Transaction;
+
+            System.Data.DataTable dt = new System.Data.DataTable();
+            using (var rd = qpCmd.ExecuteReader())
+                dt.Load(rd);
+
+            string plan =
+                 String.Join("\t", dt.Columns.Cast<System.Data.DataColumn>().Select(c => c.ColumnName).ToArray()) + "\n"
+                + string.Join("\n", dt.Rows.Cast<System.Data.DataRow>().Select(r => String.Join("\t", r.ItemArray.Select(o => o == null ? "" : o.ToString()).ToArray())).ToArray());
+
+            return plan;
+        }
+        
        public static void DumpSQL(this System.Data.IDbConnection self, System.Data.IDbTransaction trans, string sql, params object[] parameters)
        {
            using (var c = self.CreateCommand())