Make sure automatic re-balancing of semaphores only happens for pipelines that...

Make sure automatic re-balancing of semaphores only happens for pipelines that have specifically asked for it.

modules/Bio/EnsEMBL/Hive/DBSQL/DBAdaptor.pm

@@ -154,7 +154,7 @@ sub hive_use_triggers {  # getter only, not setter
 
     unless( defined($self->{'_hive_use_triggers'}) ) {
         my $hive_use_triggers = $self->get_MetaAdaptor->get_value_by_key( 'hive_use_triggers' );
-        $self->{'_hive_use_triggers'} = $hive_use_triggers || 0;
+        $self->{'_hive_use_triggers'} = $hive_use_triggers // 0;
     } 
     return $self->{'_hive_use_triggers'};
 }
@@ -165,12 +165,23 @@ sub hive_use_param_stack {  # getter only, not setter
 
     unless( defined($self->{'_hive_use_param_stack'}) ) {
         my $hive_use_param_stack = $self->get_MetaAdaptor->get_value_by_key( 'hive_use_param_stack' );
-        $self->{'_hive_use_param_stack'} = $hive_use_param_stack || 0;
+        $self->{'_hive_use_param_stack'} = $hive_use_param_stack // 0;
     } 
     return $self->{'_hive_use_param_stack'};
 }
 
 
+sub hive_auto_rebalance_semaphores {  # getter only, not setter
+    my $self = shift @_;
+
+    unless( defined($self->{'_hive_auto_rebalance_semaphores'}) ) {
+        my $hive_auto_rebalance_semaphores = $self->get_MetaAdaptor->get_value_by_key( 'hive_auto_rebalance_semaphores' );
+        $self->{'_hive_auto_rebalance_semaphores'} = $hive_auto_rebalance_semaphores // 0;
+    } 
+    return $self->{'_hive_auto_rebalance_semaphores'};
+}
+
+
 our %adaptor_type_2_package_name = (
     'Accumulator'           => 'Bio::EnsEMBL::Hive::DBSQL::AccumulatorAdaptor',
     'Analysis'              => 'Bio::EnsEMBL::Hive::DBSQL::AnalysisAdaptor',

modules/Bio/EnsEMBL/Hive/PipeConfig/HiveGeneric_conf.pm

@@ -104,10 +104,11 @@ sub default_options {
         'dbowner'               => $ENV{'EHIVE_USER'} || $ENV{'USER'} || $self->o('dbowner'),   # although it is very unlikely $ENV{USER} is not set
         'pipeline_name'         => $self->pipeline_name(),
 
-        'hive_use_triggers'     => 0,                   # there have been a few cases of big pipelines misbehaving with triggers on, let's keep the default off.
-        'hive_use_param_stack'  => 0,                   # do not reconstruct the calling stack of parameters by default (yet)
-        'hive_force_init'       => 0,                   # setting it to 1 will drop the database prior to creation (use with care!)
-        'hive_no_init'          => 0,                   # setting it to 1 will skip pipeline_create_commands (useful for topping up)
+        'hive_use_triggers'                 => 0,       # there have been a few cases of big pipelines misbehaving with triggers on, let's keep the default off.
+        'hive_use_param_stack'              => 0,       # do not reconstruct the calling stack of parameters by default (yet)
+        'hive_auto_rebalance_semaphores'    => 0,       # do not attempt to rebalance semaphores periodically by default
+        'hive_force_init'                   => 0,       # setting it to 1 will drop the database prior to creation (use with care!)
+        'hive_no_init'                      => 0,       # setting it to 1 will skip pipeline_create_commands (useful for topping up)
 
         'pipeline_db'   => {
             -driver => $self->o('hive_driver'),
@@ -226,9 +227,10 @@ sub hive_meta_table {
     my ($self) = @_;
 
     return {
-        'hive_sql_schema_version'   => Bio::EnsEMBL::Hive::DBSQL::SqlSchemaAdaptor->get_code_sql_schema_version(),
-        'hive_pipeline_name'        => $self->o('pipeline_name'),
-        'hive_use_param_stack'      => $self->o('hive_use_param_stack'),
+        'hive_sql_schema_version'           => Bio::EnsEMBL::Hive::DBSQL::SqlSchemaAdaptor->get_code_sql_schema_version(),
+        'hive_pipeline_name'                => $self->o('pipeline_name'),
+        'hive_use_param_stack'              => $self->o('hive_use_param_stack'),
+        'hive_auto_rebalance_semaphores'    => $self->o('hive_auto_rebalance_semaphores'),
     };
 }
 

modules/Bio/EnsEMBL/Hive/Scheduler.pm

@@ -66,8 +66,14 @@ sub schedule_workers_resync_if_necessary {
             print "Scheduler: mismatch between DB's active Roles and Valley's running Workers detected, checking for dead workers...\n";
             $queen->check_for_dead_workers($valley, 1);
         }
-        print "Scheduler: re-balancing of semaphore_counts...\n";
-        $queen->db->get_AnalysisJobAdaptor->balance_semaphores($filter_analysis && $filter_analysis->dbID);
+
+        if($queen->db->hive_auto_rebalance_semaphores) {    # make sure rebalancing only ever happens for the pipelines that asked for it
+            print "Scheduler: re-balancing of semaphore_counts...\n";
+            $queen->db->get_AnalysisJobAdaptor->balance_semaphores($filter_analysis && $filter_analysis->dbID);
+        } else {
+            print "Scheduler: automatic re-balancing of semaphore_counts is off by default. If you think your pipeline might benefit from it, set hive_auto_rebalance_semaphores => 1 in the PipeConfig's hive_meta_table.\n";
+        }
+
         print "Scheduler: re-synchronizing the Hive...\n";
         $queen->synchronize_hive($filter_analysis);