Nagayasu-san,
> Could you find something in your PostgreSQL server log?
I attached log files that collected under the below situation.
> 1) [NG] MADLib 1.10(Compiling From Source) + PG 9.6 (+ Ubuntu 16.04)
> : Failed. Same result with before.
> As an additional information,
> madlib install-check was failed on this environment.
> It looks similar with the below.
> https://issues.apache.org/jira/browse/MADLIB-1068
log_install-check_fail.txt:
Log when madlib install check failed at check_elastic_net.
log_multinom_fail.txt:
Log when madlib.multinorm failed.
In both of them, I can see the following message.
> 2017-04-06 07:53:03 UTC [12162-4] LOG: server process (PID 12483) was
terminated by signal 11: Segmentation fault
> 2017-04-06 07:53:03 UTC [12162-6] LOG: terminating any other active server
processes
> 2017-04-06 07:53:03 UTC [12168-2] WARNING: terminating connection because
of crash of another server process
> 2017-04-06 07:53:03 UTC [12168-3] DETAIL: The postmaster has commanded
this server process to roll back the current transaction and exit, because
another server process exited abnormally and possibly corrupted shared memory.
> 2017-04-06 07:53:03 UTC [12168-4] HINT: In a moment you should be able to
reconnect to the database and repeat your command.
According to HINT in log message,
I confirmed that other server had already been stopped.
And then I reconnected. But the situation didn't get better.
$ pg_lsclusters
Ver Cluster Port Status Owner Data directory Log file
9.4 main 5434 down postgres /var/lib/postgresql/9.4/main
/var/log/postgresql/postgresql-9.4-main.log
9.5 main 5432 down postgres /var/lib/postgresql/9.5/main
/var/log/postgresql/postgresql-9.5-main.log
9.6 main 5433 online postgres /var/lib/postgresql/9.6/main
pg_log/postgresql-%Y-%m-%d_%H%M%S.log
> And how did you install your PostgreSQL 9.6 on Ubuntu?
> Built from the source by yourself, or used some packages?
I used packages that provided from PostgreSQL Apt Repository.
http://askubuntu.com/questions/831292/how-to-install-postgresql-9-6-on-any-ubuntu-version
Thank you,
Atsushi
-----Original Message-----
From: Satoshi Nagayasu [mailto:sn...@uptime.jp]
Sent: Thursday, April 6, 2017 2:57 PM
To: user@madlib.incubator.apache.org
Subject: Re: Multinomial Regression: Failed with a msg "Hessian or gradient is
not finite."
Hi Neki-san,
I have tried to reproduce the situation with PG9.6 and MADlib 1.10.0 on CentOS
6.
Unfortunately, I couldn't reproduce it (see below), and it looked working well
on my box.
Could you find something in your PostgreSQL server log?
And how did you install your PostgreSQL 9.6 on Ubuntu?
Built from the source by yourself, or used some packages?
Regards,
------------------------------------
testdb=# select version();
version
----------------------------------------------------------------------------------------------------------
PostgreSQL 9.6.0 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.4.7
20120313 (Red Hat 4.4.7-17), 64-bit
(1 row)
testdb=# select madlib.version();
version
----------------------------------------------------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------
MADlib version: 1.10.0, git revision: unknown, cmake configuration
time: 2017年 4月 6日 木曜日 05:36:25 UTC, build type: RelWithDebInfo, build system:
Linux-2.6.32-504.el6.x86_64, C compiler: gcc 4.4.7, C++ compiler: g++ 4.4.7
(1 row)
testdb=# create table mactbl_mini(
testdb(# ap1 integer,
testdb(# ap2 integer,
testdb(# ap3 integer,
testdb(# floor integer,
testdb(# id integer
testdb(# );
CREATE TABLE
testdb=# INSERT INTO mactbl_mini VALUES
testdb-# (-90,-86,0,601,1),
testdb-# (-84,0,0,601,2),
testdb-# (-83,0,0,601,3),
testdb-# (0,-72,-84,601,6),
testdb-# (0,0,-89,602,7),
testdb-# (0,0,0,602,8),
testdb-# (0,-85,0,603,43);
INSERT 0 7
testdb=# SELECT madlib.multinom('mactbl_mini',
testdb(# 'mactbl_output',
testdb(# 'floor',
testdb(# 'ARRAY[1,
testdb'# ap1,
testdb'# ap2,
testdb'# ap3]',
testdb(# '601',
testdb(# 'logit');
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
WARNING: Hessian or gradient is not finite.
multinom
----------
(1 row)
testdb=# \x
Expanded display is on.
testdb=# select * from mactbl_output;
-[ RECORD 1
]------+----------------------------------------------------------------------
category | 602
coef |
{98.501202727275,1.66424014822047,1.23992159121658,0.719054608268981}
log_likelihood | NaN
std_err | {NaN,NaN,NaN,NaN}
z_stats | {NaN,NaN,NaN,NaN}
p_values | {NaN,NaN,NaN,NaN}
num_rows_processed | 7
num_rows_skipped | 0
num_iterations | 100
-[ RECORD 2
]------+----------------------------------------------------------------------
category | 603
coef |
{6715539712038.1,-52386230744.054,-483412078248451,-563980757956539}
log_likelihood | NaN
std_err | {NaN,NaN,NaN,NaN}
z_stats | {NaN,NaN,NaN,NaN}
p_values | {NaN,NaN,NaN,NaN}
num_rows_processed | 7
num_rows_skipped | 0
num_iterations | 100
testdb=#
------------------------------------
2017-04-06 13:50 GMT+09:00 Neki, Atsushi <neki.atsu...@jp.fujitsu.com>:
> Frank,
>
> I tried again the following environments:
>
> 1) [NG] MADLib 1.10(Compiling From Source) + PG 9.6 (+ Ubuntu 16.04)
> : Failed. Same result with before.
> As an additional information,
> madlib install-check was failed on this environment.
> It looks similar with the below.
> https://issues.apache.org/jira/browse/MADLIB-1068
>
> 2) [OK] MADLib 1.9.1(Binary) + PG 9.5 (+ Ubuntu 16.04)
> : Successed.
> Still remain the msg 'WARNING: Hessian or gradient is not finite.'
>
> 3) [NT] MADLib 1.10(Compiling From Source) + PG 9.4 (+ Ubuntu 16.04)
> : MADLib Build error (so far, I will not report more about that in here)
> > [ 48%] Building CXX object
> src/ports/postgres/9.6/CMakeFiles/madlib_postgresql_9_6.dir/__/__/__/modules/linalg/matrix_decomp.cpp.o
> > g++: internal compiler error: Killed (program cc1plus)
>
> 4) [OK] MADLib 1.10(Compiling From Source) + PG 9.6 (+ CentOS 7)
> : Successed.
> Still remain the msg 'WARNING: Hessian or gradient is not finite.'
>
>
> I will move my workspace to the 4th environment (1.10 + PG9.6 + CentOS).
> Thank you very much for your quick response and advice.
>
>
> Does the msg 'WARNING: Hessian or gradient is not finite.' mean that
> something is wrong?
> Should I care something about it?
> In case I see the message, some NaN values are included in output.
> This model can predict category well.
>
>
> # select * from mactbl_output;
> -[ RECORD 1
> ]------+-----------------------------------------------------------------------
> category | 602
> coef |
> {104.464636547264,1.72398814787594,1.29895329386266,0.688758979636415}
> log_likelihood | NaN
> std_err | {NaN,NaN,NaN,NaN}
> z_stats | {NaN,NaN,NaN,NaN}
> p_values | {NaN,NaN,NaN,NaN}
> num_rows_processed | 7
> num_rows_skipped | 0
> num_iterations | 100
> -[ RECORD 2
> ]------+-----------------------------------------------------------------------
> category | 603
> coef |
> {-572252710812.094,4826990013.37584,41195201231745.7,48061068103698.5}
> log_likelihood | NaN
> std_err | {NaN,NaN,NaN,NaN}
> z_stats | {NaN,NaN,NaN,NaN}
> p_values | {NaN,NaN,NaN,NaN}
> num_rows_processed | 7
> num_rows_skipped | 0
> num_iterations | 100
>
>
>
> Thank you,
> Atsushi
>
>
>
> From: Frank McQuillan [mailto:fmcquil...@pivotal.io]
> Sent: Thursday, April 6, 2017 2:21 AM
> To: user@madlib.incubator.apache.org
> Subject: Re: Multinomial Regression: Failed with a msg "Hessian or gradient
> is not finite."
>
> Atsushi-san,
>
> The error that you see makes me think that you lost connection to the
> database in the middle of the query:
>
> "server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
> The connection to the server was lost. Attempting reset: Failed."
>
> I ran the same query with MADlib 1.10 on PG 9.4 and it seemed to work fine
> for me:
>
> madlib=# SELECT * FROM mactbl_mini;
> ap1 | ap2 | ap3 | floor | id
> -----+-----+-----+-------+----
> -90 | -86 | 0 | 601 | 1
> -84 | 0 | 0 | 601 | 2
> -83 | 0 | 0 | 601 | 3
> 0 | -72 | -84 | 601 | 6
> 0 | 0 | -89 | 602 | 7
> 0 | 0 | 0 | 602 | 8
> 0 | -85 | 0 | 603 | 43
> (7 rows)
>
>
> madlib=# SELECT madlib.multinom('mactbl_mini',
> madlib(# 'mactbl_output',
> madlib(# 'floor',
> madlib(# 'ARRAY[1,
> madlib'# ap1,
> madlib'# ap2,
> madlib'# ap3]',
> madlib(# '601',
> madlib(# 'logit');
> multinom
> ----------
>
> (1 row)
>
>
> madlib=# \x on
> Expanded display is on.
> madlib=# SELECT * FROM mactbl_output;
> -[ RECORD 1
> ]------+--------------------------------------------------------------------------------------
> category | 602
> coef |
> {112.327782768804,2.47679877229691,1.69069062458081,0.841889190837338}
> log_likelihood | NaN
> std_err |
> {5.81382676773028e+16,8.77427991785089e+17,1.06802178555571e+15,1.67358709762743e+15}
> z_stats |
> {1.93207997514273e-15,2.82279434379335e-18,1.58301136497989e-15,5.0304474265537e-16}
> p_values | {0.999999999999998,1,0.999999999999999,1}
> num_rows_processed | 7
> num_rows_skipped | 0
> num_iterations | 100
> -[ RECORD 2
> ]------+--------------------------------------------------------------------------------------
> category | 603
> coef |
> {32.633774536969,1.61185753977669,-0.177075877885652,1.8769521118073}
> log_likelihood | NaN
> std_err |
> {9.40692076915866e+16,5.45753786923624e+18,1.30468621462021e+15,1.1421554354824e+22}
> z_stats |
> {3.46912399262056e-16,2.95345186491992e-19,-1.35722962273498e-16,1.6433420999433e-22}
> p_values | {1,1,1,1}
> num_rows_processed | 7
> num_rows_skipped | 0
> num_iterations | 100
>
>
>
> So please try again.
>
> Frank
>
> On Tue, Apr 4, 2017 at 7:28 PM, Neki, Atsushi <neki.atsu...@jp.fujitsu.com>
> wrote:
> Hello,
>
>
> I detected a failure of computation when using madlib.multinom function.
> Is there anything wrong with my procedure?
>
> ====================================
>
> - Issue description
>
> madlib.multinom failed with the following message:
>
> > WARNING: Hessian or gradient is not finite.
> > server closed the connection unexpectedly
> > This probably means the server terminated abnormally
> > before or while processing the request.
> > The connection to the server was lost. Attempting reset: Failed.
>
>
> - Library
>
> This issue happens in the following environment:
> 1. madlib 1.9.1 + PostgreSQL 9.5
> 2. madlib 1.10 + PostgreSQL 9.6
>
>
> - Expectation
>
> The result should be:
>
> 1. Success computing the model
> 2. Success building a model that can predict output precisely.
> (Because this is quite simple use case)
>
>
> - Procedure to reproduce this issue
>
> 1. Prepare the following table:
>
> testdb=# select * from mactbl_mini;
> ap1 | ap2 | ap3 | floor | id
> -----+-----+-----+-------+----
> -90 | -86 | 0 | 601 | 1
> -84 | 0 | 0 | 601 | 2
> -83 | 0 | 0 | 601 | 3
> 0 | -72 | -84 | 601 | 6
> 0 | 0 | -89 | 602 | 7
> 0 | 0 | 0 | 602 | 8
> 0 | -85 | 0 | 603 | 43
> (7 rows)
>
>
> 2. Compute a model to predict floor with ap by using madlib.multinom
>
> testdb=# drop table mactbl_output;
> DROP TABLE
> testdb=# drop table mactbl_output_summary; DROP TABLE testdb=#
> testdb=# SELECT madlib.multinom('mactbl_mini',
> testdb(# 'mactbl_output',
> testdb(# 'floor',
> testdb(# 'ARRAY[1,
> testdb'# ap1,
> testdb'# ap2,
> testdb'# ap3]',
> testdb(# '601',
> testdb(# 'logit');
> WARNING: Hessian or gradient is not finite.
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
> The connection to the server was lost. Attempting reset: Failed.
> !>
>
>
> When I changed some parameter, it successed.
>
> - Set '602' or '603' to ref_category. [Success]
> - Change max_iter from 100(default) to 10. [Success]
>
> ====================================
>
>
> Thanks in advance.
>
> --
> Atsushi Neki
>
--
Satoshi Nagayasu <sn...@uptime.jp>
2017-04-06 07:52:48 UTC [12164-1] LOG: database system was shut down at
2017-04-06 07:52:46 UTC
2017-04-06 07:52:48 UTC [12164-2] LOG: MultiXact member wraparound protections
are now enabled
2017-04-06 07:52:48 UTC [12162-3] LOG: database system is ready to accept
connections
2017-04-06 07:52:48 UTC [12168-1] LOG: autovacuum launcher started
2017-04-06 07:52:48 UTC [12170-1] [unknown]@[unknown] LOG: incomplete startup
packet
2017-04-06 07:53:00 UTC [12244-1] postgres@docodoco ERROR: role
"madlib_1100_installcheck" cannot be dropped because some objects depend on it
2017-04-06 07:53:00 UTC [12244-2] postgres@docodoco DETAIL: owner of function
madlib_installcheck_elastic_net.check_elastic_net()
owner of table madlib_installcheck_elastic_net.housing_test
owner of sequence madlib_installcheck_elastic_net.housing_test_id_seq
owner of table madlib_installcheck_elastic_net.elastic_type_src
owner of table madlib_installcheck_elastic_net.lin_housing_wi
owner of sequence madlib_installcheck_elastic_net.lin_housing_wi_id_seq
privileges for schema madlib_installcheck_elastic_net
privileges for schema madlib
2017-04-06 07:53:00 UTC [12244-3] postgres@docodoco STATEMENT: DROP USER IF
EXISTS madlib_1100_installcheck;
2017-04-06 07:53:03 UTC [12162-4] LOG: server process (PID 12483) was
terminated by signal 11: Segmentation fault
2017-04-06 07:53:03 UTC [12162-5] DETAIL: Failed process was running: select
check_elastic_net();
2017-04-06 07:53:03 UTC [12162-6] LOG: terminating any other active server
processes
2017-04-06 07:53:03 UTC [12168-2] WARNING: terminating connection because of
crash of another server process
2017-04-06 07:53:03 UTC [12168-3] DETAIL: The postmaster has commanded this
server process to roll back the current transaction and exit, because another
server process exited abnormally and possibly corrupted shared memory.
2017-04-06 07:53:03 UTC [12168-4] HINT: In a moment you should be able to
reconnect to the database and repeat your command.
2017-04-06 07:53:03 UTC [12162-7] LOG: all server processes terminated;
reinitializing
2017-04-06 07:53:03 UTC [12487-1] LOG: database system was interrupted; last
known up at 2017-04-06 07:52:48 UTC
2017-04-06 07:53:03 UTC [12487-2] LOG: database system was not properly shut
down; automatic recovery in progress
2017-04-06 07:53:03 UTC [12487-3] LOG: redo starts at 0/5A7D20D0
2017-04-06 07:53:03 UTC [12495-1] postgres@docodoco FATAL: the database system
is in recovery mode
2017-04-06 07:53:03 UTC [12487-4] LOG: invalid record length at 0/5ABCF440:
wanted 24, got 0
2017-04-06 07:53:03 UTC [12487-5] LOG: redo done at 0/5ABCF418
2017-04-06 07:53:03 UTC [12487-6] LOG: last completed transaction was at log
time 2017-04-06 07:53:03.611503+00
2017-04-06 07:53:03 UTC [12487-7] LOG: MultiXact member wraparound protections
are now enabled
2017-04-06 07:53:03 UTC [12162-8] LOG: database system is ready to accept
connections
2017-04-06 07:53:03 UTC [12499-1] LOG: autovacuum launcher started
2017-04-06 07:54:28 UTC [12542-1] LOG: database system was shut down at
2017-04-06 07:54:26 UTC
2017-04-06 07:54:28 UTC [12542-2] LOG: MultiXact member wraparound protections
are now enabled
2017-04-06 07:54:28 UTC [12540-3] LOG: database system is ready to accept
connections
2017-04-06 07:54:28 UTC [12546-1] LOG: autovacuum launcher started
2017-04-06 07:54:28 UTC [12548-1] [unknown]@[unknown] LOG: incomplete startup
packet
2017-04-06 07:55:03 UTC [12569-1] postgres@docodoco FATAL: password
authentication failed for user "postgres"
2017-04-06 07:55:03 UTC [12569-2] postgres@docodoco DETAIL: Password does not
match for user "postgres".
Connection matched pg_hba.conf line 92: "host all all
127.0.0.1/32 md5"
2017-04-06 07:56:46 UTC [12578-1] postgres@docodoco WARNING: Hessian or
gradient is not finite.
2017-04-06 07:56:46 UTC [12578-2] postgres@docodoco CONTEXT: SQL statement "
SELECT
array_to_string(ARRAY[NULL], ',') AS
__madlib_temp_col_grp_key36319142_1491465406_3163502__,
NULL,
41 AS __madlib_temp_88866112_1491465406_37507131__,
(
madlib.__multinom_logit_agg(
(CASE WHEN (floor)::text = '601' THEN 0
WHEN (floor)::text = '602' THEN 1
WHEN (floor)::text = '603' THEN 2
END)::integer,
(ARRAY[1,
ap1,
ap2,
ap3])::double precision[],
__madlib_temp_29383832_1491465406_12737782__.__madlib_temp_49088132_1491465406_4267733__,
3::smallint)
) AS __madlib_temp_49088132_1491465406_4267733__
FROM (
SELECT *,
array_to_string(ARRAY[NULL], ',') AS
__madlib_temp_col_grp_key36319142_1491465406_3163502__
FROM mactbl_mini
) AS _src
JOIN ( SELECT unnest($1) AS
__madlib_temp_col_grp_key36319142_1491465406_3163502__, unnest($2) AS
__madlib_temp_49088132_1491465406_4267733__ ) AS
__madlib_temp_29383832_1491465406_12737782__
ON TRUE
JOIN ( SELECT unnest($3) AS
__madlib_temp_col_grp_key36319142_1491465406_3163502__, unnest($4) AS
__madlib_temp_23507793_1491465406_10807770__ ) AS _rel_n_tuples
ON TRUE
"
PL/Python function "multinom"
2017-04-06 07:56:46 UTC [12540-4] LOG: server process (PID 12578) was
terminated by signal 11: Segmentation fault
2017-04-06 07:56:46 UTC [12540-5] DETAIL: Failed process was running: SELECT
madlib.multinom('mactbl_mini',
'mactbl_output',
'floor',
'ARRAY[1,
ap1,
ap2,
ap3]',
'601',
'logit');
2017-04-06 07:56:46 UTC [12540-6] LOG: terminating any other active server
processes
2017-04-06 07:56:46 UTC [12586-1] postgres@docodoco FATAL: the database system
is in recovery mode
2017-04-06 07:56:46 UTC [12546-2] WARNING: terminating connection because of
crash of another server process
2017-04-06 07:56:46 UTC [12546-3] DETAIL: The postmaster has commanded this
server process to roll back the current transaction and exit, because another
server process exited abnormally and possibly corrupted shared memory.
2017-04-06 07:56:46 UTC [12546-4] HINT: In a moment you should be able to
reconnect to the database and repeat your command.
2017-04-06 07:56:46 UTC [12540-7] LOG: all server processes terminated;
reinitializing
2017-04-06 07:56:46 UTC [12587-1] LOG: database system was interrupted; last
known up at 2017-04-06 07:54:28 UTC
2017-04-06 07:56:46 UTC [12587-2] LOG: database system was not properly shut
down; automatic recovery in progress
2017-04-06 07:56:46 UTC [12587-3] LOG: redo starts at 0/5ABCF520
2017-04-06 07:56:46 UTC [12587-4] LOG: invalid record length at 0/5ABD0938:
wanted 24, got 0
2017-04-06 07:56:46 UTC [12587-5] LOG: redo done at 0/5ABCF520
2017-04-06 07:56:46 UTC [12587-6] LOG: MultiXact member wraparound protections
are now enabled
2017-04-06 07:56:46 UTC [12540-8] LOG: database system is ready to accept
connections
2017-04-06 07:56:46 UTC [12591-1] LOG: autovacuum launcher started
docodoco=# select version();
version
----------------------------------------------------------------------------------------------------------
PostgreSQL 9.6.2 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
5.3.1-14ubuntu2) 5.3.1 20160413, 64-bit
(1 row)
docodoco=# select madlib.version();
version
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
MADlib version: 1.10.0, git revision: unknown, cmake configuration time: Thu
Apr 6 07:10:12 UTC 2017, build type: RelWithDebInfo, build system:
Linux-4.4.0-72-generic, C compiler: gcc 5.4.0, C++ compiler: g++ 5.4.0
(1 row)
