A very strange freeze - Mailing list psycopg

<div>Hi there!</div><div> </div><div>I've faced with a very strange problem on my Linux-server (Linux [hostname]
3.0.4-2-lxcnax86_64 GNU/Linux).</div><div>Some of queries freezes. Even so simple like "select * from
reports".</div><div> </div><div>Atfirst I got the latest version of psycopg2 and build it in debug
mode.</div><div> </div><div>Hereis a piese of an output:</div><div> </div><div>[7321] psyco_connect: dsn =
'dbname=*****user=***** password=***** host=*****', async = 0<br />[7321] connection_setup: init connection object at
0xf53cd0,async 0, refcnt = 1<br />[7321] con_connect: connecting in SYNC mode<br />[7321] conn_connect: new postgresql
connectionat 0xf18300<br />[7321] conn_connect: server standard_conforming_strings parameter: off<br />[7321]
conn_connect:server requires E'' quotes: YES<br />[7321] conn_connect: using protocol 3<br />[7321] conn_connect:
clientencoding: UTF8<br />[7321] clear_encoding_name: UTF8 -> UTF8<br />[7321] conn_connect: DateStyle ISO, MDY<br
/>[7321]connection_setup: good connection object at 0xf53cd0, refcnt = 1<br />[7321] psyco_conn_cursor: new cursor for
connectionat 0xf53cd0<br />[7321] psyco_conn_cursor:     parameters: name = (null)<br />[7321] cursor_setup: init
cursorobject at 0x7f58cd6d4338<br />[7321] cursor_setup: parameters: name = (null), conn = 0xf53cd0<br />[7321]
cursor_setup:good cursor object at 0x7f58cd6d4338, refcnt = 1<br />[7321] psyco_conn_cursor: new cursor at
0x7f58cd6d4338:refcnt = 1<br />[7321] psyco_curs_execute: starting execution of new query<br />[7321] curs_execute: pg
connectionat 0xf18300 OK<br />[7321] pq_begin_locked: pgconn = 0xf18300, autocommit = 1, status = 1<br />[7321]
pq_begin_locked:transaction in progress<br />[7321] pq_execute: executing SYNC query: pgconn = 0xf18300<br />[7321]    
select* from reports</div><div> </div><div>[freeze]</div><div> </div><div>script is realy very
simple:</div><div> </div><div>importpsycopg2<br />connection = psycopg2.connect(database="*****", host="*****",
user="*****",password="******")<br />connection.autocommit = True<br />cursor = connection.cursor()<br />q = "select *
fromreports"<br />cursor.execute(q)<br />print cursor.fetchall()</div><div> </div><div>After a few minutes of
frustrationI started TCP-dump and executed the script again. Then compared it with tcpdump output of my 32-bit Ubuntu
desktopand something seemed to be strange.</div><div> </div><div>Here is output from my
hosting:</div><div> </div><div>$tcpdump -X -s0 -r
bad_query</div><div>[greetings]</div><div>[auth]</div><div>08:45:40.342613IP pg-server > frontend-server.49753:
Flags[P.], seq 15:339, ack 94, win 5, length 324<br />        0x0000:  4500 016c 2bf2 0000 4006 fb7d b29a f69c 
E..l+...@..}....<br/>        0x0010:  b29a f64a 1538 c259 3635 50c9 c9ab 13ff  ...J.8.Y65P.....<br />        0x0020: 
50180005 e1a3 0000 5200 0000 0800 0000  P.......R.......<br />        0x0030:  0053 0000 0016 6170 706c 6963 6174 696f 
.S....applicatio<br/>        0x0040:  6e5f 6e61 6d65 0000 5300 0000 1963 6c69  n_name..S....cli<br />        0x0050: 
656e745f 656e 636f 6469 6e67 0055 5446  ent_encoding.UTF<br />        0x0060:  3800 5300 0000 1744 6174 6553 7479 6c65 
8.S....DateStyle<br/>        0x0070:  0049 534f 2c20 4d44 5900 5300 0000 1969  .ISO,.MDY.S....i<br />        0x0080: 
6e746567 6572 5f64 6174 6574 696d 6573  nteger_datetimes<br />        0x0090:  006f 6e00 5300 0000 1b49 6e74 6572 7661 
.on.S....Interva<br/>        0x00a0:  6c53 7479 6c65 0070 6f73 7467 7265 7300  lStyle.postgres.<br />        0x00b0: 
53000000 1569 735f 7375 7065 7275 7365  S....is_superuse<br />        0x00c0:  7200 6f66 6600 5300 0000 1973 6572 7665 
r.off.S....serve<br/>        0x00d0:  725f 656e 636f 6469 6e67 0055 5446 3800  r_encoding.UTF8.<br />        0x00e0: 
53000000 1973 6572 7665 725f 7665 7273  S....server_vers<br />        0x00f0:  696f 6e00 392e 302e 3400 5300 0000 2673 
ion.9.0.4.S...&s<br/>        0x0100:  6573 7369 6f6e 5f61 7574 686f 7269 7a61  ession_authoriza<br />       
0x0110: 7469 6f6e 0062 7265 616b 7061 645f 7277  tion.breakpad_rw<br />        0x0120:  0053 0000 0024 7374 616e 6461
72645f63  .S...$standard_c<br />        0x0130:  6f6e 666f 726d 696e 675f 7374 7269 6e67  onforming_string<br />       
0x0140: 7300 6f66 6600 5300 0000 1254 696d 655a  s.off.S....TimeZ<br />        0x0150:  6f6e 6500 572d 5355 004b 0000
000c0000  one.W-SU.K......<br />        0x0160:  0c2d 4a8a aa52 5a00 0000 0549            .-J..RZ....I<br
/>08:45:40.342761IP frontend-server.49753 > pg-server.postgresql: Flags [P.], seq 94:105, ack 339, win 5, length
11<br/>        0x0000:  4500 0033 1445 0000 4006 1464 b29a f64a  E..3.E..@..d...J<br />        0x0010:  b29a f69c c259
1538c9ab 13ff 3635 520d  .....Y.8....65R.<br />        0x0020:  5018 0005 3649 0000 5100 0000 0a42 4547 
P...6I..Q....BEG<br/>        0x0030:  494e 00                                  IN.<br />08:45:40.343188 IP
pg-server.postgresql> frontend-server.49753: Flags [P.], seq 339:356, ack 105, win 5, length 17<br />       
0x0000: 4500 0039 2bf3 0000 4006 fcaf b29a f69c  E..9+...@.......<br />        0x0010:  b29a f64a 1538 c259 3635 520d
c9ab140a  ...J.8.Y65R.....<br />        0x0020:  5018 0005 efd8 0000 4300 0000 0a42 4547  P.......C....BEG<br />       
0x0030: 494e 005a 0000 0005 54                   IN.Z....T<br />08:45:40.343241 IP frontend-server.49753 >
pg-server.postgresql:Flags [P.], seq 105:132, ack 356, win 5, length 27<br />        0x0000:  4500 0043 1446 0000 4006
1453b29a f64a  E..C.F..@..S...J<br />        0x0010:  b29a f69c c259 1538 c9ab 140a 3635 521e  .....Y.8....65R.<br
/>       0x0020:  5018 0005 0bc9 0000 5100 0000 1a73 656c  P.......Q....sel<br />        0x0030:  6563 7420 2a20 6672
6f6d2072 6570 6f72  ect.*.from.repor<br />        0x0040:  7473 00                                  ts.<br
/>08:45:40.545206IP frontend-server.49753 > pg-server.postgresql: Flags [P.], seq 105:132, ack 356, win 5, length
27<br/>        0x0000:  4500 0043 1447 0000 4006 1452 b29a f64a  E..C.G..@..R...J<br />        0x0010:  b29a f69c c259
1538c9ab 140a 3635 521e  .....Y.8....65R.<br />        0x0020:  5018 0005 0bc9 0000 5100 0000 1a73 656c 
P.......Q....sel<br/>        0x0030:  6563 7420 2a20 6672 6f6d 2072 6570 6f72  ect.*.from.repor<br />        0x0040: 
747300                                  ts.<br />08:45:40.545563 IP pg-server.postgresql > frontend-server.49753:
Flags[.], ack 132, win 5, options [nop,nop,sack 1 {105:132}], length 0<br />        0x0000:  4500 0034 2bf5 0000 4006
fcb2b29a f69c  E..4+...@.......<br />        0x0010:  b29a f64a 1538 c259 3635 6d36 c9ab 1425  ...J.8.Y65m6...%<br
/>       0x0020:  8010 0005 1347 0000 0101 050a c9ab 140a  .....G..........<br />        0x0030:  c9ab
1425                               ...%<br />08:46:08.174098 IP frontend-server.49753 > pg-server.postgresql: Flags
[F.],seq 132, ack 356, win 5, length 0<br />        0x0000:  4500 0028 1448 0000 4006 146c b29a f64a 
E..(.H..@..l...J<br/>        0x0010:  b29a f69c c259 1538 c9ab 1425 3635 521e  .....Y.8...%65R.<br />        0x0020: 
50110005 5237 0000                      P...R7..<br />08:46:08.175583 IP pg-server.postgresql >
frontend-server.49753:Flags [F.], seq 7292, ack 133, win 5, length 0<br />        0x0000:  4500 0028 2bfd 0000 4006
fcb6b29a f69c  E..(+...@.......<br />        0x0010:  b29a f64a 1538 c259 3635 6d36 c9ab 1426  ...J.8.Y65m6...&<br
/>       0x0020:  5011 0005 04e3 0000                      P.......<br />08:46:08.175617 IP frontend-server.49753 >
pg-server.postgresql:Flags [R], seq 3383432230, win 0, length 0<br />        0x0000:  4500 0028 1449 0000 4006 146b
b29af64a  E..(.I..@..k...J<br />        0x0010:  b29a f69c c259 1538 c9ab 1426 0000 0000  .....Y.8...&....<br
/>       0x0020:  5004 0000 a860 0000                      P....`..</div><div> </div><div>Have a look at
08:45:40.343241</div><div>queryselect * from reports is sent twice!</div><div>(futhermore, output is the same for
psql).</div><div> </div><div>tcpdumpon my 32-bit desktop Ubuntu contains only one query, that is followed by response
fromserver.</div><div> </div><div>So, connection freezes because of the server error. On postgresql-server in
/var/log/postgres/error.logI found</div><div>> unexpected EOF on client connection</div><div> </div><div>Do you have
anyidea about reasons and solutions?</div><div>Thanks!</div><div> </div><div>-- </div><div>Yours
faithfully,</div><div>KonstantinNikitin,</div><div>Software Engeneer</div>