Update of /cvsroot/monetdb/pathfinder/runtime
In directory sc8-pr-cvs16:/tmp/cvs-serv1709/runtime
Modified Files:
ll_staircasejoin.mx
Log Message:
Fixing BUG #1611545 "XQ: wrong path step result (duplicates)"
loop-lifted child implementation did not properly cope with the case
that the same item (context node) occurs more than once for the same iter,
i.e., in case [iter,item] ([iter,ctx]) is not a set (i.e., contains duplicates).
Fix: avoid producing duplicates in such cases in ll_child result generation.
ToDo:
Can we do this more efficiently, e.g.,
by upfront ensuring that [iter,item] ([iter,ctx])
is a set, i.e., duplicate free??
Added tests in
benchmarks/XBench/TC/SD/Tests/q02alg.*
benchmarks/XBench/TC/MD/Tests/q17alg.*
Index: ll_staircasejoin.mx
===================================================================
RCS file: /cvsroot/monetdb/pathfinder/runtime/ll_staircasejoin.mx,v
retrieving revision 1.53
retrieving revision 1.54
diff -u -d -r1.53 -r1.54
--- ll_staircasejoin.mx 23 Feb 2007 12:51:42 -0000 1.53
+++ ll_staircasejoin.mx 6 May 2007 12:51:10 -0000 1.54
@@ -562,6 +562,7 @@
size_t grow = ((stack[stack_top-1].last - stack[stack_top-1].first) /
iter_bunsize) + 1;
BUN dst = NULL;
int bunsize = BUNsize(res);
+ oid prev_iter = oid_nil;
/* check, if result buffer is big enough; otherwise extend it */
PFll_check_BAT_capacity(res, grow);
@@ -572,9 +573,22 @@
for (cur_bun = stack[stack_top-1].first;
cur_bun <= stack[stack_top-1].last;
cur_bun += iter_bunsize) {
- *(oid*)dst = *(oid*)BUNtail(iter_bat,cur_bun);
- *(oid*)(dst+SIZEOF_OID) = pre;
- dst += bunsize;
+ oid next_iter = *(oid*)BUNtail(iter_bat,cur_bun);
+ if (next_iter != prev_iter) {
+ /* (Even) if the same context node (item)
+ * occurs multiple times per iter,
+ * we must not produce duplicate results;
+ * let's hope, the iters are ordered per item (context node).
+ * ToDo:
+ * Can we do this more efficiently, e.g.,
+ * by upfront ensuring that [iter,item] ([iter,ctx])
+ * is a set, i.e., duplicate free??
+ */
+ *(oid*)dst = next_iter;
+ *(oid*)(dst+SIZEOF_OID) = pre;
+ dst += bunsize;
+ prev_iter = next_iter;
+ }
}
res->batBuns->free = dst - res->batBuns->base;
BATsetcount(res,
(res->batBuns->free+Bunbase(res)-BUNfirst(res))/bunsize);
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