[Fedora-directory-users] Broken MMR - DB_BUFFER_SMALL: User memory too small for return value

[Richard Hesse]

Scenario: two FDS 1.1 servers in a multi-master setup. Working fine for
months without a hiccup (except to upgrade from 1.04) then replication
suddenly stops working. Checking the logs, I see this:

[03/Apr/2008:23:44:00 +0000] NSMMReplicationPlugin - changelog program -
agmt="cn=MM aa0-006-8.u.powerset.com" (aa0-006-8:636): Failed to retrieve
change with CSN 47f5710d000000010000; db error - -30999 DB_BUFFER_SMALL:
User memory too small for return value

How should I go about troubleshooting this? Searching for replication
conflicts didn't yield anything useful. I tried running template-cl-dump.pl
like the documentation suggested, but I couldn't find it anywhere in
/usr/share/dirsrv/script-templates (FC6 system).

Thanks.

-richard

[Rich Megginson]

Richard Hesse wrote:
>  Scenario: two FDS 1.1 servers in a multi-master setup. Working fine
> for
>  months without a hiccup (except to upgrade from 1.04) then replication
>  suddenly stops working. Checking the logs, I see this:
>
>  [03/Apr/2008:23:44:00 +0000] NSMMReplicationPlugin - changelog program -
>  agmt="cn=MM aa0-006-8.u.powerset.com" (aa0-006-8:636): Failed to retrieve
>  change with CSN 47f5710d000000010000; db error - -30999 DB_BUFFER_SMALL:
>  User memory too small for return value
>
>  How should I go about troubleshooting this? Searching for replication
>  conflicts didn't yield anything useful. 
It looks as though it's attempting
to read something from the changelog 
database, but it got the size wrong:
Errors

The DBcursor->get method may fail and return one of the following 
non-zero errors:

DB_BUFFER_SMALL
    The requested item could not be returned due to undersized buffer.

What version of db do you have on your system?  i.e. rpm -qi db4
32-bit or 64-bit?

I'm not sure, but it looks as though the code is perhaps expecting bdb 
to return ENOMEM in this case, and perhaps the bdb api has changed to 
return DB_BUFFER_SMALL instead for this case?

>  I tried running template-cl-dump.pl
>  like the documentation suggested, 
Which documentation?  That needs to be updated.
>  but I couldn't find it anywhere in
>  /usr/share/dirsrv/script-templates (FC6 system).
>     
/usr/bin/cl-dump
>  Thanks.
>
>  -richard
>
>
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>  Fedora-directory-users mailing list
>  Fedora-directory-users(a)redhat.com
>  https://www.redhat.com/mailman/listinfo/fedora-directory-users
>

[Richard Hesse]

Thanks for the reply Rich. It actually looks like we've got x86 and x64 builds of db4
on that server. I share this server with another team so I'll ask around who installed
what. I think the actual problem ended up being on-disk data corruption. There were a few
other signs of the disk heading south and things have cleared up since resolving them.

As for the documentation URL that references that script:

http://www.redhat.com/docs/manuals/dir-server/ag/8.0/Managing_Replication...

-richard

On 4/4/08 7:34 AM, "Rich Megginson" <rmeggins(a)redhat.com&gt; wrote:

Richard Hesse wrote:
>  Scenario: two FDS 1.1 servers in a multi-master setup. Working fine
> for
>  months without a hiccup (except to upgrade from 1.04) then replication
>  suddenly stops working. Checking the logs, I see this:
>
>  [03/Apr/2008:23:44:00 +0000] NSMMReplicationPlugin - changelog program -
>  agmt="cn=MM aa0-006-8.u.powerset.com" (aa0-006-8:636): Failed to retrieve
>  change with CSN 47f5710d000000010000; db error - -30999 DB_BUFFER_SMALL:
>  User memory too small for return value
>
>  How should I go about troubleshooting this? Searching for replication
>  conflicts didn't yield anything useful. 
It looks as though it's attempting
to read something from the changelog
database, but it got the size wrong:
Errors

The DBcursor->get method may fail and return one of the following
non-zero errors:

DB_BUFFER_SMALL
    The requested item could not be returned due to undersized buffer.

What version of db do you have on your system?  i.e. rpm -qi db4
32-bit or 64-bit?

I'm not sure, but it looks as though the code is perhaps expecting bdb
to return ENOMEM in this case, and perhaps the bdb api has changed to
return DB_BUFFER_SMALL instead for this case?

>  I tried running template-cl-dump.pl
>  like the documentation suggested, 
Which documentation?  That needs to be updated.
>  but I couldn't find it anywhere in
>  /usr/share/dirsrv/script-templates (FC6 system).
>  
/usr/bin/cl-dump
>  Thanks.
>
>  -richard
>
>
>  --
>  Fedora-directory-users mailing list
>  Fedora-directory-users(a)redhat.com
>  https://www.redhat.com/mailman/listinfo/fedora-directory-users
>