bundles/postgresql: add metadata keys for some performance related config options

bundles/postgresql/files/postgresql.conf

@@ -2,11 +2,7 @@ data_directory = '/var/lib/postgresql/${version}/main'
 hba_file = '/etc/postgresql/${version}/main/pg_hba.conf'
 ident_file = '/etc/postgresql/${version}/main/pg_ident.conf'
 external_pid_file = '/var/run/postgresql/${version}-main.pid'
-% if version == '9.1':
-unix_socket_directory = '/var/run/postgresql'
-% else:
 unix_socket_directories = '/var/run/postgresql'
-% endif
 port = 5432
 listen_addresses = 'localhost'
 max_connections = ${max_connections}
@@ -28,3 +24,9 @@ log_min_duration_statement = ${slow_query_log_sec*1000}
 % else:
 log_min_duration_statement = -1
 % endif
+effective_io_concurrency = ${effective_io_concurrency}
+max_worker_processes = ${max_worker_processes}
+% if version_list >= [10]:
+max_parallel_workers = ${max_parallel_workers}
+% endif
+max_parallel_workers_per_gather = ${max_parallel_workers_per_gather}

bundles/postgresql/items.py

@@ -43,7 +43,10 @@ files = {
     },
     "/etc/postgresql/{}/main/postgresql.conf".format(postgresql_version): {
         'content_type': 'mako',
-        'context': node.metadata['postgresql'],
+        'context': {
+            'version_list': [int(i) for i in node.metadata['postgresql']['version'].split('.')],
+            **node.metadata['postgresql'],
+        },
         'owner': 'postgres',
         'group': 'postgres',
         'needs': {

bundles/postgresql/metadata.py

@@ -77,3 +77,27 @@ def default_postgresql_version_for_debian(metadata):
             'version': version_to_be_installed,
         },
     }
+
+
+@metadata_reactor.provides(
+    'postgresql/effective_io_concurrency',
+    'postgresql/max_worker_processes',
+    'postgresql/max_parallel_workers',
+    'postgresql/max_parallel_workers_per_gather',
+)
+def worker_processes(metadata):
+    return {
+        'postgresql': {
+            # This is the amount of parallel I/O Operations the
+            # postgresql process is allowed to do on disk. We set
+            # this to max_connections by default.
+            'effective_io_concurrency': metadata.get('postgresql/max_connections'),
+
+            # Try to request one worker process per 10 configured
+            # connections. The default is 8 for both of these values.
+            'max_worker_processes': int(metadata.get('postgresql/max_connections')/10),
+            'max_parallel_workers': int(metadata.get('postgresql/max_connections')/10),
+            # default 2
+            'max_parallel_workers_per_gather': max(int(metadata.get('postgresql/max_connections')/100), 2),
+        },
+    }