FreeTDS Development Group

[Doug Morgan <doug AT surveymonkey.com>]

Hello FreeTDS community,

I work for SurveyMonkey and we just started to use pymssql as a 
connection to our MS SQL Server 2008 from our python stack. We are using
Ubuntu Server 10.04 LTS, FreeTDS 0.82, Python 2.6, PyMSSQL (v 1.0.2) +
SQLAlchemy and connecting using FreeTDS 8.0 in our freetds.conf file.

We started encountering some issues lately with intermittent connection
problems/failures on our python hosts connecting to the DB servers. The
following is a snippet from our Python logs (not sure how helpful that
will be but including anyway):


File "/xxxxxx/python2.6/site-packages/sqlalchemy/engine/ 
strategies.py", line 82, in connect 
    return dialect.connect(*cargs, **cparams) 
File "/xxxxxx/python2.6/site-packages/sqlalchemy/engine/default.py", 
line 249, in connect 
    return self.dbapi.connect(*cargs, **cparams) 
File "/usr/lib/pymodules/python2.6/pymssql.py", line 607, in connect 
    raise OperationalError, e[0] 
OperationalError: (OperationalError) DB-Lib error message 20004, 
severity 9: 
Read from the server failed 
Net-Lib error during Connection reset by peer Error 104 - Connection 
reset by peerDB-Lib error message 20002, severity 9: 
Adaptive Server connection failed 
 None None 


This not being very helpful, I turned on FreeTDS debugging (0x4FFF 
level) and I am seeing the following in our FreeTDS logs: 


net.c:210:Connecting to X.X.X.XX port 1433 (TDS version 8.0) 
net.c:266:tds_open_socket: connect(2) returned "Operation now in 
progress" 
net.c:307:tds_open_socket() succeeded 
util.c:162:Changed query state from DEAD to IDLE 
login.c:735:quietly sending TDS 7+ login packet 
token.c:312:tds_process_login_tokens() 
util.c:334:tdserror(0x246d3f0, 0x2a2d1a0, 20004, 104) 
dblib.c:7787:dbperror(0x2a3ef50, 20004, 104) 
dblib.c:7840:20004: "Read from the server failed" 
dblib.c:7861:"Read from the server failed", client returns 2 
(INT_CANCEL) 
util.c:368:tdserror: client library returned TDS_INT_CANCEL(2) 
util.c:389:tdserror: returning TDS_INT_CANCEL(2) 
util.c:162:Changed query state from IDLE to DEAD 
token.c:316:looking for login token, got  0() 
token.c:108:tds_process_default_tokens() marker is 0() 
token.c:111:leaving tds_process_default_tokens() connection dead 
util.c:334:tdserror(0x246d3f0, 0x2a2d1a0, 20002, 0) 
dblib.c:7787:dbperror(0x2a3ef50, 20002, 0) 
dblib.c:7840:20002: "Adaptive Server connection failed" 
dblib.c:7861:"Adaptive Server connection failed", client returns 2 
(INT_CANCEL) 
util.c:368:tdserror: client library returned TDS_INT_CANCEL(2) 
util.c:389:tdserror: returning TDS_INT_CANCEL(2) 
dblib.c:1372:dbclose(0x2a3ef50) 
dblib.c:256:dblib_del_connection(0x7fa1883f16c0, 0x2a2d1a0) 
mem.c:609:tds_free_all_results() 
dblib.c:303:dblib_release_tds_ctx(1) 
dblib.c:5731:dbfreebuf(0x2a3ef50) 
dblib.c:718:dbloginfree(0x29b8920) 
dblib.c:3093:dbcancel(0x31085b0) 
query.c:1894:tds_send_cancel: not in_cancel and idle 


However, this problem is intermittent, we will get a series of requests
that complete just fine with no problems but then we get a series of
these errors in a row. If anyone has an idea of what is going on / what
we need to do, I'd love some advice. 


Thanks, 
Doug