[GRASS-dev] native WinGRASS and attribute data deadlock, next try

[Moritz Lennert]

On Mon, September 3, 2007 17:38, Moritz Lennert wrote:
> Benjamin wrote:
>
>  >> So, how are we going to go ahead?
>  >
>
> Glynn answered:
>
>  > Figure out how to debug the processes. If you can't get gdb to work, I
>  > can only suggest logging every significant event at the lowest level,
>  > i.e. log every read/write operation: the arguments, the return code,
>  > and the complete data (i.e. the buffer contents before read and after
>  > write). This is all done in the RPC/XDR library, in xdr_stdio.c. It
>  > will probably help to also log the beginning/end of each procedure
>  > call (i.e. lib/db/dbmi_base/xdrprocedure.c).
>
> I would really like this to be solved, so I am willing to try to find
> some time to do the logging effort. Benjamin, have you advanced on this ?
>
> I will need some time understanding the xdr logic and code, but hope to
> be able to help with this.
>

Ok, very first simple debugging effort seems to confirm timin issue.
Here's what I did:

diff -u dbmi_base dbmi_base_debug/
Common subdirectories: dbmi_base/CVS and dbmi_base_debug/CVS
Only in dbmi_base_debug/: OBJ.i686-pc-mingw32
diff -u dbmi_base/xdrint.c dbmi_base_debug/xdrint.c
--- dbmi_base/xdrint.c  Thu Oct  5 06:13:28 2006
+++ dbmi_base_debug/xdrint.c    Mon Sep  3 20:17:35 2007
@@ -10,10 +10,12 @@

     stat = DB_OK;

+    G_debug(1, "xdrint.c: Begin send");
     xdr_begin_send (&xdrs);
     if(!xdr_int (&xdrs, &n))
        stat = DB_PROTOCOL_ERR;
     xdr_end_send (&xdrs);
+    G_debug(1, "xdrint.c: End send");

     if (stat == DB_PROTOCOL_ERR)
        db_protocol_error();
diff -u dbmi_base/xdrprocedure.c dbmi_base_debug/xdrprocedure.c
--- dbmi_base/xdrprocedure.c    Thu Oct  5 06:13:28 2006
+++ dbmi_base_debug/xdrprocedure.c      Mon Sep  3 20:17:35 2007
@@ -40,10 +40,12 @@

     stat = DB_OK;

+    G_debug(1, "xdrprocedure.c: Begin receive");
     xdr_begin_recv (&xdrs);
     if(!xdr_int (&xdrs, n))
        stat = DB_EOF;
     xdr_end_recv (&xdrs);
+    G_debug(1, "xdrprocedure.c: End receive");

     return stat;
 }

and now, after setting 'g.gisenv set=DEBUG=1', I cannot reproduce the
deadlock anymore, using Benjamin's test data, except when I do other
things on the machine (open other windows, type an email, etc). When I
just run the command and stare at the screen I get no deadlock. With
DEBUG=0 I get the same irregular deadlock.

I'll dig into xdrstdio.c now.

Moritz