From 06aa3e5fdf230bff112c1c3361073051120e968e Mon Sep 17 00:00:00 2001
From: Andrew Yates <ayates@ebi.ac.uk>
Date: Mon, 13 Sep 2010 10:20:45 +0000
Subject: [PATCH] Changing the code and now we issue a begin_work() call and
eval the call.
---
modules/Bio/EnsEMBL/Utils/SqlHelper.pm | 36 ++++++++++++++------------
1 file changed, 20 insertions(+), 16 deletions(-)
diff --git a/modules/Bio/EnsEMBL/Utils/SqlHelper.pm b/modules/Bio/EnsEMBL/Utils/SqlHelper.pm
index 62357577be..4c5052ec5a 100644
--- a/modules/Bio/EnsEMBL/Utils/SqlHelper.pm
+++ b/modules/Bio/EnsEMBL/Utils/SqlHelper.pm
@@ -468,11 +468,13 @@ previous setting. If your DBI/DBD driver does not support manual commits
then this code will break. The code will turn off the
C<disconnect_when_idle()> method to allow transactions to work as expected.
-If the connection given already had AutoCommit off we will issue a rollback
-before handing the connection into the closure. This ensures the connection
-contains as fresh information from the database as possible. An effect of
-using REPEATABLE READ transaction isolation (InnoDB's default) is that
-your data is as fresh as when you started your current transaction. To
+All connections are issued a C<begin_work()> call on the DBI handle which
+informs the target engine we are starting a transaction. Giving this method
+a connection already in a transaction will cause an error to be raised and
+the abortion of the running transaction.
+
+An effect of using REPEATABLE READ transaction isolation (InnoDB's default)
+is that your data is as fresh as when you started your current transaction. To
ensure the freshest data use C<SELECT ... from ... LOCK IN SHARE MODE>
or C<SELECT ... from ... LOCK FOR UPDATE> if you are going to issue
updates.
@@ -496,6 +498,9 @@ sub transaction {
my $original_dwi;
my $ac;
+ my $error;
+ my $result;
+
#If we were already in a transaction then we do not do any management of the
#session & wait for the parent transaction(s) to finish
my $perform_transaction = $self->_perform_transaction_code();
@@ -503,19 +508,18 @@ sub transaction {
$original_dwi = $dbc->disconnect_when_inactive();
$ac = $dbc->db_handle()->{'AutoCommit'};
$dbc->db_handle()->{'AutoCommit'} = 0;
- #Issue a rollback as a signal for a fresh transaction if AutoCommit was off
- $dbc->db_handle()->rollback() if(! $ac);
- $self->_enable_transaction();
+ eval { $dbc->db_handle()->begin_work() };
+ $error = $@ if $@;
+ $self->_enable_transaction() unless $error;
}
- my $error;
- my $result;
-
- eval {
- $result = $callback->($dbc);
- $dbc->db_handle()->commit() if $perform_transaction;
- };
- $error = $@;
+ if(!$error) {
+ eval {
+ $result = $callback->($dbc);
+ $dbc->db_handle()->commit() if $perform_transaction;
+ };
+ $error = $@;
+ }
if($perform_transaction) {
if($error) {
--
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