def _get_memory_usage(self, pid):
""" calculate usage of private memory per process """
# compute process's own non-shared memory.
# See http://www.depesz.com/2012/06/09/how-much-ram-is-postgresql-using/ for the explanation of how
# to measure PostgreSQL process memory usage and the stackexchange answer for details on the unshared counts:
# http://unix.stackexchange.com/questions/33381/getting-information-about-a-process-memory-usage-from-proc-pid-smaps
# there is also a good discussion here:
# http://rhaas.blogspot.de/2012/01/linux-memory-reporting.html
# we use statm instead of /proc/smaps because of performance considerations. statm is much faster,
# while providing slightly outdated results.
uss = 0
statm = None
fp = None
try:
fp = open(self.STATM_FILENAME.format(pid), 'r')
statm = fp.read().strip().split()
logger.info("calculating memory for process {0}".format(pid))
except IOError as e:
logger.warning(
'Unable to read {0}: {1}, process memory information will be unavailable'
.format(self.format(pid), e))
finally:
fp and fp.close()
if statm and len(statm) >= 3:
uss = (long(statm[1]) - long(statm[2])) * MEM_PAGE_SIZE
return uss
def _get_memory_usage(self, pid):
""" calculate usage of private memory per process """
# compute process's own non-shared memory.
# See http://www.depesz.com/2012/06/09/how-much-ram-is-postgresql-using/ for the explanation of how
# to measure PostgreSQL process memory usage and the stackexchange answer for details on the unshared counts:
# http://unix.stackexchange.com/questions/33381/getting-information-about-a-process-memory-usage-from-proc-pid-smaps
# there is also a good discussion here:
# http://rhaas.blogspot.de/2012/01/linux-memory-reporting.html
# we use statm instead of /proc/smaps because of performance considerations. statm is much faster,
# while providing slightly outdated results.
uss = 0
statm = None
fp = None
try:
fp = open(self.STATM_FILENAME.format(pid), 'r')
statm = fp.read().strip().split()
logger.info("calculating memory for process {0}".format(pid))
except IOError as e:
logger.warning(
'Unable to read {0}: {1}, process memory information will be unavailable'.format(
self.STATM_FILENAME.format(pid), e))
finally:
fp and fp.close()
if statm and len(statm) >= 3:
uss = (long(statm[1]) - long(statm[2])) * MEM_PAGE_SIZE
return uss
def get_subprocesses_pid(self):
ppid = self.postmaster_pid
result = self.exec_command_with_output('ps -o pid --ppid {0} --noheaders'.format(ppid))
if result[0] != 0:
logger.info("Couldn't determine the pid of subprocesses for {0}".format(ppid))
self.pids = []
self.pids = [int(x) for x in result[1].split()]
def get_subprocesses_pid(self):
ppid = self.postmaster_pid
result = self.exec_command_with_output('ps -o pid --ppid {0} --noheaders'.format(ppid))
if result[0] != 0:
logger.info("Couldn't determine the pid of subprocesses for {0}".format(ppid))
self.pids = []
self.pids = [int(x) for x in result[1].split()]
def exec_command_with_output(cmdline):
""" Execute comand (including shell ones), return a tuple with error code (1 element) and output (rest) """
proc = subprocess.Popen(cmdline, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
ret = proc.wait()
if ret != 0:
logger.info('The command {cmd} returned a non-zero exit code'.format(cmd=cmdline))
return ret, proc.stdout.read().strip()
def exec_command_with_output(cmdline):
""" Execute comand (including shell ones), return a tuple with error code (1 element) and output (rest) """
proc = subprocess.Popen(cmdline,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
shell=True)
ret = proc.wait()
if ret != 0:
logger.info(
'The command {cmd} returned a non-zero exit code'.format(
cmd=cmdline))
return ret, proc.stdout.read().strip()
def refresh(self):
""" Reads data from /proc and PostgreSQL stats """
result = []
# fetch up-to-date list of subprocess PIDs
self.get_subprocesses_pid()
try:
if not self.pgcon:
# if we've lost the connection, try to reconnect and
# re-initialize all connection invariants
self.pgcon, self.postmaster_pid = self.reconnect()
self.connection_pid = self.pgcon.get_backend_pid()
self.max_connections = self._get_max_connections()
self.dbver = dbversion_as_float(self.pgcon)
self.server_version = self.pgcon.get_parameter_status(
'server_version')
stat_data = self._read_pg_stat_activity()
except psycopg2.OperationalError as e:
logger.info("failed to query the server: {}".format(e))
if self.pgcon and not self.pgcon.closed:
self.pgcon.close()
self.pgcon = None
self._do_refresh([])
return
logger.info("new refresh round")
for pid in self.pids:
if pid == self.connection_pid:
continue
is_backend = pid in stat_data
is_active = is_backend and (stat_data[pid]['query'] != 'idle'
or pid in self.always_track_pids)
result_row = {}
# for each pid, get hash row from /proc/
proc_data = self._read_proc(pid, is_backend, is_active)
if proc_data:
result_row.update(proc_data)
if stat_data and pid in stat_data:
# ditto for the pg_stat_activity
result_row.update(stat_data[pid])
# result is not empty - add it to the list of current rows
if result_row:
result.append(result_row)
# and refresh the rows with this data
self._do_refresh(result)
def refresh(self):
""" Reads data from /proc and PostgreSQL stats """
result = []
# fetch up-to-date list of subprocess PIDs
self.get_subprocesses_pid()
try:
if not self.pgcon:
# if we've lost the connection, try to reconnect and
# re-initialize all connection invariants
self.pgcon, self.postmaster_pid = self.reconnect()
self.connection_pid = self.pgcon.get_backend_pid()
self.max_connections = self._get_max_connections()
self.dbver = dbversion_as_float(self.pgcon)
self.server_version = self.pgcon.get_parameter_status('server_version')
stat_data = self._read_pg_stat_activity()
except psycopg2.OperationalError as e:
logger.info("failed to query the server: {}".format(e))
if self.pgcon and not self.pgcon.closed:
self.pgcon.close()
self.pgcon = None
self._do_refresh([])
return
logger.info("new refresh round")
for pid in self.pids:
if pid == self.connection_pid:
continue
is_backend = pid in stat_data
is_active = is_backend and (stat_data[pid]['query'] != 'idle' or pid in self.always_track_pids)
result_row = {}
# for each pid, get hash row from /proc/
proc_data = self._read_proc(pid, is_backend, is_active)
if proc_data:
result_row.update(proc_data)
if stat_data and pid in stat_data:
# ditto for the pg_stat_activity
result_row.update(stat_data[pid])
# result is not empty - add it to the list of current rows
if result_row:
result.append(result_row)
# and refresh the rows with this data
self._do_refresh(result)