Tapomay, thanks for the enlightment! Knowing what you are actually after helps us a lot to give you better advice how to approach your goal, than merely being able to answer individual specific questions without having/knowing the complete contexts. I cannot quickly answer your question right now, but I have one more general comment / advice. Not only is Mx to be phased out, but also the aggregation code structure in monetdb5/modules/kernel/aggr*.mx in the Oct2012 release branch is obsolete. For a complete re-implementation of aggregation functions using a largely simplified coding style in plain C (rather than Mx) is available in monetdb5/modules/kernel/aggr.{c,mal{.sh}} in the Feb2013 release candidate branch and the default development branch. You might also want to check that code for examples and inspiration. Best, Stefan 22:36:31 manegold@rome:/tmp $ cat /tmp/xyz Tapomay, thanks for the enlightment! Knowing what you are actually after helps us a lot to give you better advice how to approach your goal, than merely being able to answer individual specific questions without having/knowing the complete contexts. Having said that, the aggregation code structure in monetdb5/modules/kernel/aggr*.mx in the Oct2012 release branch is also obsolete. For a complete re-implementation of aggregations functions using a largely simplified coding style in plain C (rather than Mx) is available in monetdb5/modules/kernel/aggr.{c,mal{.sh}} in the Feb2013 release candidate branch and the default development branch. Please check this code ----- Original Message -----

Almost there. As suggested by Fabian in the following thread I gave up the MX file approach and implemented group_concat as UDF in C. http://sourceforge.net/mailarchive/forum.php?thread_name=mailman.243.1355328304.1624.developers-list%40monetdb.org&forum_name=monetdb-developers

When I try to conclude my function UDFBATgroup_concat_(BAT **ret, BAT *b, BAT *g, BAT *h, FILE* fp) //ignore fp as follows:

BATaccessBegin(h, USE_HEAD | USE_TAIL, MMAP_SEQUENTIAL); index = 0; BATloop(h, p, q) { ptr hhead = BUNhead(hi, p); fprintf(fp, "%d: hhead=%d", index, hhead); str dst = tailValArray[index]; fprintf(fp, "%d: dstStr=%s# ", index, dst);

BUNins(bn, hhead, dst, FALSE); fprintf(fp, "%d: Insert complete\n", index); index++; }

I get the following error on the client terminal [tapomay@tapomay-laptop monetdata]$ echo "select house, group_concat(name) from gs group by house;" | mclient -d tapomay GDKerror:!ERROR: BUNins: access denied to tmp_10162, aborting. BUNins: access denied to tmp_10162, aborting. BUNins: access denied to tmp_10162, aborting.

The groupings are ready in the tailVarArray.

NEED HELP. Thanks and Regards, Tapomay. _______________________________________________ developers-list mailing list developers-list@monetdb.org http://mail.monetdb.org/mailman/listinfo/developers-list

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