Move lsn_to_bytes and bytes_to_lsn into Postgresql class

and make their behavior version specific

helpers/postgresql.py

@@ -4,14 +4,10 @@ import psycopg2
 import shlex
 import shutil
 import subprocess
-import six
 
 from helpers.utils import sleep
 from six.moves.urllib_parse import urlparse
 
-if six.PY3:
-    long = int
-
 logger = logging.getLogger(__name__)
 
 ACTION_ON_START = "on_start"
@@ -39,6 +35,7 @@ def parseurl(url):
 
 
 class Postgresql:
+    _SERVER_VERSION = 90400
 
     def __init__(self, config):
         self.config = config
@@ -85,6 +82,7 @@ class Postgresql:
             r = parseurl('postgres://{}/postgres'.format(self.local_address))
             self._connection = psycopg2.connect(**r)
             self._connection.autocommit = True
+        self._SERVER_VERSION = self._connection.server_version
         return self._connection
 
     def _cursor(self):
@@ -394,3 +392,30 @@ recovery_target_timeline = 'latest'
 
     def last_operation(self):
         return str(self.xlog_position())
+
+    @staticmethod
+    def lsn_to_bytes(value):
+        """
+        >>> Postgresql.lsn_to_bytes('1/66000060')
+        6006243424
+        >>> Postgresql.lsn_to_bytes('j/66000060')
+        0
+        """
+        try:
+            multiplier = 0xFF000000 if Postgresql._SERVER_VERSION < 90300 else 0x100000000
+            e = value.split('/')
+            if len(e) == 2 and len(e[0]) > 0 and len(e[1]) > 0:
+                return int(e[0], 16) * multiplier + int(e[1], 16)
+        except ValueError:
+            return 0
+
+    @staticmethod
+    def bytes_to_lsn(value):
+        """
+        >>> Postgresql.bytes_to_lsn(6006243424)
+        '1/66000060'
+        """
+        divider = 0xFF000000 if Postgresql._SERVER_VERSION < 90300 else 0x100000000
+        segment = value / divider
+        offset = value % divider
+        return '%X/%X' % (segment, offset)

helpers/utils.py

@@ -42,32 +42,6 @@ def calculate_ttl(expiration):
     return int((expiration - now).total_seconds())
 
 
-def lsn_to_bytes(value):
-    """
-    >>> lsn_to_bytes('1/66000060')
-    6006243424
-    >>> lsn_to_bytes('j/66000060')
-    0
-    """
-    try:
-        e = value.split('/')
-        if len(e) == 2 and len(e[0]) > 0 and len(e[1]) > 0:
-            return (int(e[0], 16) << 32) | int(e[1], 16)
-    except ValueError:
-        pass
-    return 0
-
-
-def bytes_to_lsn(value):
-    """
-    >>> bytes_to_lsn(6006243424)
-    '1/66000060'
-    """
-    id = value >> 32
-    off = value & 0xffffffff
-    return '%x/%x' % (id, off)
-
-
 def sigterm_handler(signo, stack_frame):
     sys.exit()
 

tests/test_postgresql.py

@@ -79,6 +79,7 @@ class MockConnect:
     def __init__(self):
         self.autocommit = False
         self.closed = 0
+        self.server_version = 90400
 
     def cursor(self):
         return MockCursor()