From c6cc7338f57aea0a03ff5e79d3848092969619d5 Mon Sep 17 00:00:00 2001
From: Giorgi <giorgi@giorgi.dev>
Date: Fri, 14 Jun 2024 10:54:35 +0400
Subject: [PATCH] Initialize writers only once

---
 DuckDB.NET.Data/DuckDBAppender.cs             | 20 ++++++++-----------
 DuckDB.NET.Test/DuckDBManagedAppenderTests.cs |  2 +-
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/DuckDB.NET.Data/DuckDBAppender.cs b/DuckDB.NET.Data/DuckDBAppender.cs
index ae1fb5c..5174279 100644
--- a/DuckDB.NET.Data/DuckDBAppender.cs
+++ b/DuckDB.NET.Data/DuckDBAppender.cs
@@ -39,6 +39,13 @@ internal unsafe DuckDBAppender(Native.DuckDBAppender appender, string qualifiedT
         }
 
         dataChunk = NativeMethods.DataChunks.DuckDBCreateDataChunk(logicalTypeHandles, columnCount);
+
+        for (long index = 0; index < vectorWriters.LongLength; index++)
+        {
+            var vector = NativeMethods.DataChunks.DuckDBDataChunkGetVector(dataChunk, index);
+
+            vectorWriters[index] = VectorDataWriterFactory.CreateWriter(vector, logicalTypes[index]);
+        }
     }
 
     public DuckDBAppenderRow CreateRow()
@@ -48,11 +55,10 @@ public DuckDBAppenderRow CreateRow()
             throw new InvalidOperationException("Appender is already closed");
         }
 
-        if (rowCount % DuckDBVectorSize == 0)
+        if (rowCount == DuckDBVectorSize)
         {
             AppendDataChunk();
 
-            InitVectorWriters();
             rowCount = 0;
         }
 
@@ -95,16 +101,6 @@ public void Dispose()
         }
     }
 
-    private unsafe void InitVectorWriters()
-    {
-        for (long index = 0; index < vectorWriters.LongLength; index++)
-        {
-            var vector = NativeMethods.DataChunks.DuckDBDataChunkGetVector(dataChunk, index);
-
-            vectorWriters[index] = VectorDataWriterFactory.CreateWriter(vector, logicalTypes[index]);
-        }
-    }
-
     private void AppendDataChunk()
     {
         NativeMethods.DataChunks.DuckDBDataChunkSetSize(dataChunk, rowCount);
diff --git a/DuckDB.NET.Test/DuckDBManagedAppenderTests.cs b/DuckDB.NET.Test/DuckDBManagedAppenderTests.cs
index ec2bf60..ac788a3 100644
--- a/DuckDB.NET.Test/DuckDBManagedAppenderTests.cs
+++ b/DuckDB.NET.Test/DuckDBManagedAppenderTests.cs
@@ -197,7 +197,7 @@ public void GuidValues()
         Command.CommandText = "CREATE TABLE managedAppenderGuids(a UUID);";
         Command.ExecuteNonQuery();
 
-        var guids = GetRandomList<Guid?>(faker => faker.Random.Guid());
+        var guids = GetRandomList<Guid?>(faker => faker.Random.Guid(), 5000);
         guids.Add(null);
 
         using (var appender = Connection.CreateAppender("managedAppenderGuids"))