From 9808ec3f8b11fa0ce92098a932c6be872b0e9148 Mon Sep 17 00:00:00 2001
From: Akira Sawada <akira@peatix.com>
Date: Sun, 17 Mar 2019 12:48:01 +0900
Subject: [PATCH 1/2] Attempt to make D:OD fork safe

This commit add these functions to D:OD, when forked;

 - Reset all transaction status in child process
 - Destroy and forget all cached DBI handles safely

notes:
 - Works only when POSIX::AtFork was found
 - Basic logic was taken from Cache::Memcached::Fast::Safe, and some are
 taken from Teng/DBIx::Skinny
---
 lib/Data/ObjectDriver/BaseObject.pm | 12 +++++++++++
 lib/Data/ObjectDriver/Driver/DBI.pm | 33 +++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/lib/Data/ObjectDriver/BaseObject.pm b/lib/Data/ObjectDriver/BaseObject.pm
index 2c69179..eb7606a 100644
--- a/lib/Data/ObjectDriver/BaseObject.pm
+++ b/lib/Data/ObjectDriver/BaseObject.pm
@@ -8,6 +8,10 @@ our $HasWeaken;
 eval q{ use Scalar::Util qw(weaken) }; ## no critic
 $HasWeaken = !$@;
 
+our $HasAtFork;
+eval q{ use POSIX::AtFork }; ## no critic
+$HasAtFork = !$@;
+
 use Carp ();
 
 use Class::Trigger qw( pre_save post_save post_load pre_search
@@ -668,6 +672,14 @@ sub has_partitions {
     });
 }
 
+# At fork, forget about parent's current transaction status.
+if ( $HasAtFork ) {
+    POSIX::AtFork->add_to_child(sub {
+        @WorkingDrivers = ();
+        $TransactionLevel = 0;
+    });
+}
+
 1;
 
 __END__
diff --git a/lib/Data/ObjectDriver/Driver/DBI.pm b/lib/Data/ObjectDriver/Driver/DBI.pm
index becdd0c..4e1d5c8 100644
--- a/lib/Data/ObjectDriver/Driver/DBI.pm
+++ b/lib/Data/ObjectDriver/Driver/DBI.pm
@@ -13,6 +13,14 @@ use Data::ObjectDriver::SQL;
 use Data::ObjectDriver::Driver::DBD;
 use Data::ObjectDriver::Iterator;
 
+our $HasWeaken;
+eval q{ use Scalar::Util qw(weaken) }; ## no critic
+$HasWeaken = !$@;
+
+our $HasAtFork;
+eval q{ use POSIX::AtFork }; ## no critic
+$HasAtFork = !$@;
+
 __PACKAGE__->mk_accessors(qw( dsn username password connect_options dbh get_dbh dbd prefix reuse_dbh force_no_prepared_cache));
 
 
@@ -36,6 +44,21 @@ sub init {
         }
         $driver->dbd(Data::ObjectDriver::Driver::DBD->new($type));
     }
+
+    if ( $HasWeaken && $HasAtFork ) {
+        # Purge Cached dbh, and reset transaction level
+        weaken(my $driver_weaken = $driver);
+        POSIX::AtFork->add_to_child(sub {
+            eval {
+                if ( my $dbh = $driver_weaken->dbh ) {
+                    $dbh->{InactiveDestroy} = 1;
+                    $driver_weaken->dbh(undef);
+                }
+                $driver->txn_active(0);
+            };
+        });
+    }
+
     $driver;
 }
 
@@ -752,4 +775,14 @@ sub last_error {
     return $driver->dbd->map_error_code($DBI::err, $DBI::errstr);
 }
 
+if ( $HasAtFork ) {
+    # Purge all reusable db handles
+    POSIX::AtFork->add_to_child(sub {
+        for my $handle ( values %Handles ) {
+            $handle->{InactiveDestroy} = 1;
+        }
+        %Handles = ();
+    });
+}
+
 1;

From 42e1f86653d34ea1e5792a6b2a3db4a4b6c0f80a Mon Sep 17 00:00:00 2001
From: Akira Sawada <akira@peatix.com>
Date: Fri, 12 Apr 2019 18:23:01 +0900
Subject: [PATCH 2/2] Typo

---
 lib/Data/ObjectDriver/Driver/DBI.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Data/ObjectDriver/Driver/DBI.pm b/lib/Data/ObjectDriver/Driver/DBI.pm
index 4e1d5c8..739866a 100644
--- a/lib/Data/ObjectDriver/Driver/DBI.pm
+++ b/lib/Data/ObjectDriver/Driver/DBI.pm
@@ -54,7 +54,7 @@ sub init {
                     $dbh->{InactiveDestroy} = 1;
                     $driver_weaken->dbh(undef);
                 }
-                $driver->txn_active(0);
+                $driver_weaken->txn_active(0);
             };
         });
     }