Re: [Tracker] Some Questions

[Jamie McCracken <jamiemcc blueyonder co uk>]

Gergan Penkov wrote:
> Hi, 
> first thanks for this wonderful application, it really
> shows great promises.
> I'm trying to build it on a gentoo-system, using the
> portage, in fact I'm having it running but I had few
> problems and worked around some of them.
> First it seems that on gentoo I need to add the
> openssl-libraries in order for it to compile&link, it
> could be because I use the --as-needed linker flag,
> and mysql_config does not provide the openssl-flags:
> mysql_config --libmysqld-libs
> -Wl,-O1 -Wl,--as-needed -L/usr/lib/mysql -lmysqld -lz
> -lpthread -lcrypt -lnsl -lm -lpthread -lrt

first off - what version of mysql are you using?

SSL should not be needed cause tracker uses the embedded mysql (it does 
not use the daemon mysqld at all)

It might be a bug with the build for gentoo or for mysql?

> now I've patched the configure.in in this probably not
> overly correct way:
> @@ -66,10 +66,16 @@
>  if test $? != 0 ; then
>      AC_MSG_ERROR(Could not find the MySQL
> Embedded-server libraries.)
>  fi
> +
> +PKG_CHECK_MODULES(SSL, [ openssl >= 0.9.6 ])
> +AC_SUBST(SSL_CFLAGS)
> +AC_SUBST(SSL_LIBS)
> +
>  MYSQL_CFLAGS=`$MYSQL_CONFIG --cflags`
>  MYSQL_CFLAGS=`eval echo $MYSQL_CFLAGS`
>  MYSQL_LIBS=`eval echo $MYSQL_LIBS`
> -
> +MYSQL_CFLAGS="$MYSQL_CFLAGS $SSL_CFLAGS"
> +MYSQL_LIBS="$MYSQL_LIBS $SSL_LIBS"
>  # Now test that we can actually build with MySQL
>  save_CPPFLAGS="$CPPFLAGS"
>  CPPFLAGS="$CPPFLAGS $MYSQL_CFLAGS"
>
> And it compiles and installs just fine.
> The next problem is again with mysql, now I haven't
> looked very thouroughly at the implementation, but
> every user is supposed to run its own instance of the
> tracker with its own db?

Yes thats right - no daemon of mysql is needed nor is any used.

libmysqld.a is an embbeded in process library that gets statically 
linked into tracker. There is no *runtime* dependency on any mysql stuff.


> or the idea is to have a single tracker with a single
> db?
> I suppose it is the first one as I do not see anything
> user related in the db.
> Now the problems in the moment, on which I have
> stumbled, could be probably gentoo-specific, are:
> out of the box it could not run, because I have mysql
> installed and running (which I need) and it tries to
> get the same lock and use the system db.

Thats not right at all! I have the client/server running as well and 
they do not conflict (in fact they cannot!).

libmysqld.a does not use a socket as its in-process (embedded mysql is 
the same as sqlite in that sense)

> now I've tried to make some changes to the main my.cnf
> file (and to the source) and to move the default db
> for tracker_client and tracker_server to some other
> place (not /var/lib/mysql/) , but again as the only
> tracker-db on the system, which again was not
> successful.
> Now with some changes to the main my.cnf and the
> source I'm able to run it for one of my users and it
> creates the db in ~/.Tracker as the other files. If
> this is the idea, it probably should install a
> my.cnf-file in the ~/.Tracker directory and load the
> settings in the db_connect-function, in this way it
> will not conflict with the system mysql-deamons.

There should be no conflict. Tracker is not designed for use with the 
server version (daemon) of mysql ATM (I will accept patches for it if 
you want to provide them). It should not interfere at all with the 
server mysql unless you are trying to tell the server to use 
~/.Tracker/data (which is a bad idea!)

As the Db is stored in $Home/.Tracker/data you really dont want two 
processes (trackerd and mysql daemon) accessing the DB file simultaneously.

we dont use a my.cnf at all - all the options are hardcoded in the 
source (see trackerd.c line 1456).

Tracker is designed to just work out of the box (which is why it uses 
the embedded libmysqld and not the client/server mysql daemon)

If you are using a source distro then you are at a disadvantage cause 
you will need all the mysql junk in order to build it (the binaries of 
tracker do not require any mysql stuff at all to run!)

Hopefully that helps...

--
Mr Jamie McCracken
http://jamiemcc.livejournal.com/