Hi Jan,

I just thought: how does your duplicate generating scjoins relate to the generalized scjoin I proposed in my TDM 2004-paper? http://db.cs.utwente.nl/Publications/PaperStore/db-utwente-0000003587.pdf

Maurice.

Jan Rittinger wrote:

Update of /cvsroot/monetdb/pathfinder/compiler/algebra/opt In directory sc8-pr-cvs7.sourceforge.net:/tmp/cvs-serv23019/algebra/opt

Modified Files: opt_set.c Log Message: -- Rewrite scjoin operators into duplicate generating ones as intermediate step. (This helps the join pushdown phase to push down more joins.)

Index: opt_set.c

RCS file: /cvsroot/monetdb/pathfinder/compiler/algebra/opt/opt_set.c,v retrieving revision 1.1 retrieving revision 1.2 diff -u -d -r1.1 -r1.2 --- opt_set.c 13 Nov 2006 17:10:59 -0000 1.1 +++ opt_set.c 17 Nov 2006 14:03:41 -0000 1.2 @@ -50,6 +50,11 @@ #define L(p) ((p)->child[0]) /** starting from p, make a step right */ #define R(p) ((p)->child[1]) +/** and so on ... */ +#define LL(p) (L(L(p))) +#define LR(p) (R(L(p))) +#define RL(p) (L(R(p))) +#define RR(p) (R(R(p)))

#define SEEN(p) ((p)->bit_dag)

@@ -71,6 +76,56 @@

 /* action code */
 switch (p->kind) {

•    case la_eqjoin:
  

•        /* Rewrite scjoin into duplicate generating scjoins
  

•           (underneath join operators). This hopefully allows
  

•           the above join to be pushed down in a later phase. */
  

•        if (PFprop_set (p->prop) &&
  

•            L(p)->kind == la_scjoin &&
  

•            PFprop_set (L(p)->prop)) {
  

•            PFalg_att_t item_res;
  

•            item_res = PFalg_ori_name (
  

•                           PFalg_unq_name (att_item, 0),
  

•                           ~(L(p)->sem.scjoin.item |
  

•                             L(p)->sem.scjoin.iter));
  

•            *L(p) = *PFla_project (
  

•                         PFla_dup_scjoin (
  

•                             LL(p),
  

•                             LR(p),
  

•                             L(p)->sem.scjoin.axis,
  

•                             L(p)->sem.scjoin.ty,
  

•                             L(p)->sem.scjoin.item,
  

•                             item_res),
  

•                         PFalg_proj (L(p)->sem.scjoin.iter,
  

•                                     L(p)->sem.scjoin.iter),
  

•                         PFalg_proj (L(p)->sem.scjoin.item,
  

•                                     item_res));
  

•            break;
  

•        }
  

•        if (PFprop_set (p->prop) &&
  

•            R(p)->kind == la_scjoin &&
  

•            PFprop_set (R(p)->prop)) {
  

•            PFalg_att_t item_res;
  

•            item_res = PFalg_ori_name (
  

•                           PFalg_unq_name (att_item, 0),
  

•                           ~(R(p)->sem.scjoin.item |
  

•                             R(p)->sem.scjoin.iter));
  

•            *R(p) = *PFla_project (
  

•                         PFla_dup_scjoin (
  

•                             RL(p),
  

•                             RR(p),
  

•                             R(p)->sem.scjoin.axis,
  

•                             R(p)->sem.scjoin.ty,
  

•                             R(p)->sem.scjoin.item,
  

•                             item_res),
  

•                         PFalg_proj (R(p)->sem.scjoin.iter,
  

•                                     R(p)->sem.scjoin.iter),
  

•                         PFalg_proj (R(p)->sem.scjoin.item,
  

•                                     item_res));
  

•            break;
  

•        }
  

•        break;
  

•        
     case la_distinct:
         if (PFprop_set (p->prop))
             *p = *PFla_dummy (L(p));
  
  
  

---

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