SID-01381: Error: Could not perform search

Status:	Answered	TWiki version:	5.1.0	Perl version:	v5.10.0
Category:	CategorySearch	Server OS:	Debian 5.0.9	Last update:	13 years ago

Searching in the TWiki web gives an error:

<pre> Could not perform search. Error was: /bin/grep -F -i -l -H -- %TOKEN|U% %FILES|F% Grep for 'big' returned error </pre>

This is using the URL /bin/view/TWiki/WebSearch?search=big&scope=all

The error indicates that grep returned an error, but I'm unable to find what the error is. The only clue is that setting TRACE to 1 in Sandbox.pm shows a very long command line, and I wonder if it's too long.

Any suggestions as to how I can diagnose this problem would be welcome.

-- KeithEdmunds - 2012-01-17

Discussion and Answer

Examine the apache error log, there might be more details.

I don't think the command line length is the issue, but if you you want to can test that: Reduce the value of $maxTopicsInSet in twiki/lib/TWiki/Store/SearchAlgorithms/Forking.pm to a low number, such as 20.

-- PeterThoeny - 2012-01-23

Thanks Peter. Reducing $maxTopicInSet to 20 did not fix this, so you're right about the command length not being a problem.

There's nothing logged to the Apache error log (once I had changed TRACE back to zero).

The error only occurs with the TWiki web; if I change the URL to end 'scope=Main', there is no error.

Appreciate your help: what more can I do to try to understand why this error is occurring?

Thanks -

-- KeithEdmunds - 2012-01-25

Wondering why grep would fail just in the TWiki web. May be a file that causes grep to show an error, such as a broken symlink? Run grep on the TWiki web from the shell, such as: grep testing data/TWiki/*txt

-- PeterThoeny - 2012-01-25

I've done a grep for 'big' of all files from our TWiki. No errors.

This is puzzling!

-- KeithEdmunds - 2012-01-27

All files below twiki/data and twiki/pub owned by webserver user?

-- PeterThoeny - 2012-01-27

Yes:

# pwd
/var/www
# find twiki ! -user www-data
# find twiki ! -group www-data
#

(there was one file owned root:root, which the above commands found, and which I've fixed. The problem persists even after restarting Apache).

-- KeithEdmunds - 2012-01-30

How can I execute the 'grep' command in the same context as TWiki does?

If I can do that, I can probably find the cause of (and thus resolve) this issue.

Thanks.

-- KeithEdmunds - 2012-02-01

Temporarily allow the shell for www-data user in /etc/passwd to /bin/bash, then do a su www-data. Don't forget to set set the shell back to /sbin/nologin.

-- PeterThoeny - 2012-02-01

No joy (no need to edit /etc/passwd as the -s switch can be used):

# su -s /bin/bash - www-data
$ cd /var/www/twiki
$ grep -lr big *
[file list omitted]
$ echo $?
0
$

So I don't understand why TWiki's grep is failing.

-- KeithEdmunds - 2012-02-02

Quick update: I just disabled all plugins on the TWiki in question, and the search still fails.

-- KeithEdmunds - 2012-02-02

Peter, I owe you an apology: sorry. There were some files that were not readable by www-data (finger trouble when testing). Thank you very much for your help - Keith.

-- KeithEdmunds - 2012-02-02

I am glad it worked out.

-- PeterThoeny - 2012-02-02

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