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Opened 13 years ago

Closed 13 years ago

#9829 closed defect (invalid)

'500 Internal Server Error' for timeline when logged in as a particular user

Reported by: david-sarah@… Owned by:
Priority: normal Milestone:
Component: timeline Version: 0.12dev
Severity: normal Keywords:
Cc: david-sarah@… Branch:
Release Notes:
API Changes:
Internal Changes:

Description

​http://tahoe-lafs.org/trac/tahoe-lafs is a Trac instance (running Trac 0.12.1dev-r9947) for the Tahoe-LAFS project. When logged in as a particular user account that has admin privileges, "davidsarah" (and apparently only then), the timeline page at ​http://tahoe-lafs.org/trac/tahoe-lafs/timeline always returns a '500 Internal Server Error'.

The bug ticket on the affected trac is ​http://tahoe-lafs.org/trac/tahoe-lafs/ticket/1250 . (Comments 2..4 about hard drive issues are a red herring.)

I will post the relevant server log entries when I have them.

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Change History (8)

comment:1 by david-sarah@…, 13 years ago

The full HTML returned is: 

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>500 Internal Server Error</title>
</head><body>
<h1>Internal Server Error</h1>
<p>The server encountered an internal error or
misconfiguration and was unable to complete
your request.</p>
<p>Please contact the server administrator,
 [no address given] and inform them of the time the error occurred,
and anything you might have done that may have
caused the error.</p>
<p>More information about this error may be available
in the server error log.</p>
<hr>
<address>Apache/2.2.14 (Ubuntu) Server at tahoe-lafs.org Port 80</address>
</body></html>

in reply to:  description comment:2 by Remy Blank, 13 years ago

Replying to david-sarah@…:

I will post the relevant server log entries when I have them.

The traceback from the log would be most helpful indeed.

comment:3 by david-sarah@…, 13 years ago

It appears there is no Trac log entry generated by this error.

I made another request to an invalid URL before and after, which did cause a log entry, so presumably I'm looking at the right logfile (log/trac.log in the Trac environment).

comment:4 by Remy Blank, 13 years ago

The weird thing is, the output from comment:1 is from Apache, not from Trac. When Trac generates a 500 internal error, it outputs a nice error page, or if that fails, a traceback as plain text.

Do you see anything related to the error in the Apache logs?

in reply to:  4 ; comment:5 by david-sarah@…, 13 years ago

Summary: '500 Internal Server Error' for timeline when logged in as a particular admin user → '500 Internal Server Error' for timeline when logged in as a particular user

Replying to rblank:

Do you see anything related to the error in the Apache logs?

The Apache error.log says (wrapped for readability): 

[Tue Nov 16 00:34:17 2010] [error] [client 90.217.140.169]
  FastCGI: comm with (dynamic) server "/usr/share/trac/cgi-bin/trac.fcgi"
  aborted: (first read) idle timeout (30 sec), referer:
  http://tahoe-lafs.org/trac/tahoe-lafs/timeline
[Tue Nov 16 00:34:17 2010] [error] [client 90.217.140.169]
  FastCGI: incomplete headers (0 bytes) received from server
  "/usr/share/trac/cgi-bin/trac.fcgi",
  referer: http://tahoe-lafs.org/trac/tahoe-lafs/timeline

The Apache access.log is probably not relevant, but anyway it says: 

90.217.140.169 - - [16/Nov/2010:00:32:41 +0000] "GET /trac/tahoe-lafs/timeline
  HTTP/1.1" 500 810 "http://tahoe-lafs.org/trac/tahoe-lafs/timeline"
  "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:1.9.2.12) Gecko/20101026
  Firefox/3.6.12 (.NET CLR 3.5.30729; .NET4.0C)"

The fact that the "davidsarah" user has TRAC_ADMIN privilege is probably not relevant; removing that privilege has no effect on the error, and another user with TRAC_ADMIN does not have the problem.

in reply to:  5 comment:6 by david-sarah@…, 13 years ago

Replying to david-sarah@…: 

>   aborted: (first read) idle timeout (30 sec),

I forgot to mention that the request takes about 38 seconds before failing, so that's consistent with a 30 second timeout.

comment:7 by Remy Blank, 13 years ago

So the FCGI server doesn't reply within 30 seconds, and Apache times out. It seems like Trac is choking on too much data for the timeline. Do you happen to remember setting a very high value for the "… days back" field in the timeline? This could explain the very long processing time, and the fact that it only happens to you and not other users.

Can you access the database directly? If yes, please post the output of: 

SELECT * FROM session_attribute WHERE sid='davidsarah' AND name LIKE 'timeline.%';

A very high value for timeline.daysback would explain the symptoms. You could set it to a small value with: 

UPDATE session_attribute SET value='1' WHERE sid='davidsarah' AND name='timeline.daysback';

To avoid such an issue in the future, you should set [timeline] max_daysback in trac.ini to a reasonable value.

comment:8 by Remy Blank, 13 years ago

Resolution: → invalid
Status: new → closed

Warner has confirmed on IRC that timeline.daysback was set to 512. Reducing the value fixed the issue, so I'm closing this as an InstallationIssue.

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