Fixed problem with MySQL: it was possible for one thread to use an incomplete list of column names if another thread was creating the list at the same time. Now this is thread-safe.

1 files changed, 18 insertions, 11 deletions

diff --git a/OpenSim/Data/MySQL/MySQLRegionData.cs b/OpenSim/Data/MySQL/MySQLRegionData.cs
index 948cdf3..d1f1932 100644
--- a/OpenSim/Data/MySQL/MySQLRegionData.cs
+++ b/OpenSim/Data/MySQL/MySQLRegionData.cs
@@ -162,17 +162,7 @@ namespace OpenSim.Data.MySQL
                         ret.sizeX = Convert.ToInt32(result["sizeX"]);
                         ret.sizeY = Convert.ToInt32(result["sizeY"]);
 
-                        if (m_ColumnNames == null)
-                        {
-                            m_ColumnNames = new List<string>();
-
-                            DataTable schemaTable = result.GetSchemaTable();
-                            foreach (DataRow row in schemaTable.Rows)
-                            {
-                                if (row["ColumnName"] != null)
-                                    m_ColumnNames.Add(row["ColumnName"].ToString());
-                            }
-                        }
+                        CheckColumnNames(result);
 
                         foreach (string s in m_ColumnNames)
                         {
@@ -202,6 +192,23 @@ namespace OpenSim.Data.MySQL
             return retList;
         }
 
+        private void CheckColumnNames(IDataReader result)
+        {
+            if (m_ColumnNames != null)
+                return;
+
+            List<string> columnNames = new List<string>();
+
+            DataTable schemaTable = result.GetSchemaTable();
+            foreach (DataRow row in schemaTable.Rows)
+            {
+                if (row["ColumnName"] != null)
+                    columnNames.Add(row["ColumnName"].ToString());
+            }
+
+            m_ColumnNames = columnNames;
+        }
+
         public bool Store(RegionData data)
         {
             if (data.Data.ContainsKey("uuid"))