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, 15 insertions, 8 deletions

diff --git a/OpenSim/Data/MySQL/MySQLAuthenticationData.cs b/OpenSim/Data/MySQL/MySQLAuthenticationData.cs
index 8d82f61..664ce84 100644
--- a/OpenSim/Data/MySQL/MySQLAuthenticationData.cs
+++ b/OpenSim/Data/MySQL/MySQLAuthenticationData.cs
@@ -79,14 +79,7 @@ namespace OpenSim.Data.MySQL
                 {
                     ret.PrincipalID = principalID;
 
-                    if (m_ColumnNames == null)
-                    {
-                        m_ColumnNames = new List<string>();
-
-                        DataTable schemaTable = result.GetSchemaTable();
-                        foreach (DataRow row in schemaTable.Rows)
-                            m_ColumnNames.Add(row["ColumnName"].ToString());
-                    }
+                    CheckColumnNames(result);
 
                     foreach (string s in m_ColumnNames)
                     {
@@ -105,6 +98,20 @@ namespace OpenSim.Data.MySQL
             }
         }
 
+        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)
+                columnNames.Add(row["ColumnName"].ToString());
+
+            m_ColumnNames = columnNames;
+        }
+
         public bool Store(AuthenticationData data)
         {
             if (data.Data.ContainsKey("UUID"))