From cfc9c1fa3cab07396b38d192da3d0b6bfa36d0f5 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Mon, 21 Feb 2011 10:42:13 +0200
Subject: Don't reuse failed connections

If MySQL API returns an error indicating the connection is no longer
usable, mark it as failed. In connection_pool_factory free failed
connections instead of returning them to the pool.
---
 odb/mysql/connection-factory.cxx |  7 ++++---
 odb/mysql/connection.cxx         |  1 +
 odb/mysql/connection.hxx         | 14 ++++++++++++++
 odb/mysql/error.cxx              | 11 ++++++++++-
 4 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/odb/mysql/connection-factory.cxx b/odb/mysql/connection-factory.cxx
index dce0f97..b9b3d19 100644
--- a/odb/mysql/connection-factory.cxx
+++ b/odb/mysql/connection-factory.cxx
@@ -230,9 +230,10 @@ namespace odb
 
       // Determine if we need to keep or free this connection.
       //
-      bool keep (waiters_ != 0 ||
-                 min_ == 0 ||
-                 (connections_.size () + in_use_ <= min_));
+      bool keep (!c->failed () &&
+                 (waiters_ != 0 ||
+                  min_ == 0 ||
+                  (connections_.size () + in_use_ <= min_)));
 
       in_use_--;
 
diff --git a/odb/mysql/connection.cxx b/odb/mysql/connection.cxx
index 1395592..7679e27 100644
--- a/odb/mysql/connection.cxx
+++ b/odb/mysql/connection.cxx
@@ -20,6 +20,7 @@ namespace odb
     connection::
     connection (database_type& db)
         : db_ (db),
+          failed_ (false),
           handle_ (&mysql_),
           active_ (0),
           statement_cache_ (new statement_cache_type (*this))
diff --git a/odb/mysql/connection.hxx b/odb/mysql/connection.hxx
index 0310ee6..6704f23 100644
--- a/odb/mysql/connection.hxx
+++ b/odb/mysql/connection.hxx
@@ -46,6 +46,19 @@ namespace odb
       }
 
     public:
+      bool
+      failed () const
+      {
+        return failed_;
+      }
+
+      void
+      mark_failed ()
+      {
+        failed_ = true;
+      }
+
+    public:
       MYSQL*
       handle ()
       {
@@ -91,6 +104,7 @@ namespace odb
 
     private:
       database_type& db_;
+      bool failed_;
 
       MYSQL mysql_;
       MYSQL* handle_;
diff --git a/odb/mysql/error.cxx b/odb/mysql/error.cxx
index 460816a..94a41b2 100644
--- a/odb/mysql/error.cxx
+++ b/odb/mysql/error.cxx
@@ -16,7 +16,7 @@ namespace odb
   namespace mysql
   {
     void
-    translate_error (connection&,
+    translate_error (connection& c,
                      unsigned int e,
                      const std::string& sqlstate,
                      const std::string& message)
@@ -31,6 +31,15 @@ namespace odb
         {
           throw deadlock ();
         }
+      case CR_SERVER_LOST:
+      case CR_SERVER_GONE_ERROR:
+      case CR_UNKNOWN_ERROR:
+        {
+          // This connection is no longer usable.
+          //
+          c.mark_failed ();
+          // Fall through.
+        }
       default:
         {
           throw database_exception (e, sqlstate, message);
-- 
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