Mark Hedges schrieb:
Just curious, did you try eliminating every other module
that you might be loading (anywhere in any module loaded by
Apache)? i.e. did you try a simple setup that only tries
to open your database and does absolutely nothing else and
loads no other CPAN modules. With "use strict" and "use
warnings FATAL => 'all'" of course. --mark--
Time::HiRes was loaded in addition to the Apache2:: modules.
FATAL warnings weren't on, just plain warnings.
I changed the setup as follows:
use strict;
use warnings FATAL => 'all';
use Apache2::RequestRec ();
use Apache2::RequestIO ();
use Apache2::Const -compile => qw( OK );
use Apache2::RequestUtil ();
use Apache2::Util ();
use Apache2::Request ();
use Sleepycat::Db;
use Sleepycat::DbXml;
I dropped the query I was doing, which took about 0.7 seconds. So now
it's just opening the environment. Still seeing SEGVs.
I think the failure is related to how threads or processes are torn
down. What I'm getting is the following:
Database handles still open at environment close
Open database handle: tv.dbxml/structural_stats
Open database handle: tv.dbxml/secondary_document_statistics_decimal
Open database handle: tv.dbxml/secondary_document_index_decimal
Open database handle: tv.dbxml/secondary_document_statistics_date
Open database handle: tv.dbxml/secondary_document_index_date
Open database handle: tv.dbxml/secondary_document_statistics_string
Open database handle: tv.dbxml/secondary_document_index_string
Open database handle: tv.dbxml/secondary_document
Open database handle: tv.dbxml/content_document
Open database handle: tv.dbxml/secondary_dictionary
Open database handle: tv.dbxml/primary_dictionary
Open database handle: tv.dbxml/secondary_sequence
Open database handle: tv.dbxml/secondary_configuration
[Tue Jan 20 17:47:39 2009] [notice]
child pid 17142 exit signal Segmentation fault (11)
What does this mean? There is a file called tv.dbxml, which is the
Berkeley XML database (XmlContainer). The structural_stats etc are
named databases within that database files, as *file and *database
in open:
int
Db::open(DbTxn *txnid, const char *file,
const char *database, DBTYPE type, u_int32_t flags, int mode);
http://www.oracle.com/technology/documentation/berkeley-db/db/api_cxx/frame.html
I'm just realizing Google doesn't know about these database names yet.
The error message is pretty explicit about what's wrong here: "Database
handles still open at environment close". Indeed, I do not explicitly
close the handles. In a batch script, this doesn't pose any problem;
mod_perl, however, isn't exactly equivalent to a batch script.
The problem is: Where in threaded mod_perl do I get a chance to do fixup
work, like closing handles?
I tried PerlChildInitHandler/PerlChildExitHandler, only to notice
that I then run into the issues of nothing being global, unless using
threads::shared, which caused even more weird issues (remember the
PerlChildInitHandler seemingly *blocking* on $DbEnv->open).
So I went back to Mark's and Craig's initial recommendation of using
package level my-variables (which are local to the thread) to hold the
handles, initialize them lazily, and then using them as long as needed.
The issue *seems* to be (I could be wrong) that in order for Berkeley to
be happy, I'd have to be able to have some fixup code run the moment a
thread decides it has to leave the stage, so the handles stored in the
package-level my-variables can be closed in a controlled fashion.
Can I have code run at that instant?
Or any other ideas what's going on?
Michael Ludwig
