From c54f509b0e802b2c79b4f63a82b80e465910023e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=90=D0=BB=D0=B5=D0=BA=D1=81=D0=B5=D0=B9?=
 <tselofan@gmail.com>
Date: Wed, 29 Jan 2020 15:06:57 +0300
Subject: [PATCH] changing string concatenation with stringbuilder.append in
 Helper.ReplaceAll

With the previous implementation, large queries took a very long time to compile.
---
 QueryBuilder/Helper.cs | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/QueryBuilder/Helper.cs b/QueryBuilder/Helper.cs
index 23b77eb6..8e6b2384 100644
--- a/QueryBuilder/Helper.cs
+++ b/QueryBuilder/Helper.cs
@@ -2,6 +2,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 using System.Text.RegularExpressions;
 
 namespace SqlKata
@@ -10,7 +11,7 @@ public static class Helper
     {
         public static bool IsArray(object value)
         {
-            if(value is string)
+            if (value is string)
             {
                 return false;
             }
@@ -88,8 +89,9 @@ public static string ReplaceAll(string subject, string match, Func<int, string>
             );
 
             return splitted.Skip(1)
-                .Select((item, index) => callback(index) + item)
-                .Aggregate(splitted.First(), (left, right) => left + right);
+              .Select((item, index) => callback(index) + item)
+              .Aggregate(new StringBuilder(splitted.First()), (prev, right) => prev.Append(right))
+              .ToString();
         }
 
         public static string JoinArray(string glue, IEnumerable array)
@@ -158,13 +160,13 @@ public static IEnumerable<string> Repeat(this string str, int count)
         {
             return Enumerable.Repeat(str, count);
         }
-        
+
         public static string ReplaceIdentifierUnlessEscaped(this string input, string escapeCharacter, string identifier, string newIdentifier)
         {
             //Replace standard, non-escaped identifiers first
             var nonEscapedRegex = new Regex($@"(?<!{Regex.Escape(escapeCharacter)}){Regex.Escape(identifier)}");
             var nonEscapedReplace = nonEscapedRegex.Replace(input, newIdentifier);
-            
+
             //Then replace escaped identifiers, by just removing the escape character
             var escapedRegex = new Regex($@"{Regex.Escape(escapeCharacter)}{Regex.Escape(identifier)}");
             return escapedRegex.Replace(nonEscapedReplace, identifier);