Hi Peter,
I have two small comments to your changes:
1. Is there a reason for including monet_utils.h here? -- In my eyes it
introduces an unnecessary dependency to MonetDB (as we want the SQL code
generation to compile even without MonetDB).
Index: milprint_summer.c
===================================================================
RCS file: /cvsroot/monetdb/pathfinder/compiler/mil/milprint_summer.c,v
retrieving revision 1.404
retrieving revision 1.405
diff -u -d -r1.404 -r1.405
--- milprint_summer.c 5 Sep 2007 17:06:54 -0000 1.404
+++ milprint_summer.c 11 Sep 2007 22:15:29 -0000 1.405
@@ -56,6 +56,7 @@
#define USE_DEPRECATED_ACCESS_TO_TYPE_SYSTEM 1
#include "pathfinder.h"
+#include "monet_utils.h"
#include <stdio.h>
#include <assert.h>
2. I think you should use "#pf" (PFns_pf) as prefix for variables names
instead of "pf" (PFns_lib). Namespace PFns_lib can be used in the query
which allows a user to create pf:heur* variables that might conflict
lateron (whereas PFns_pf can only be created inside pathfinder).
--- NEW FILE: heuristic.c ---
...
static PFpnode_t*
var_(PFloc_t loc, int varnum)
{
PFpnode_t *r = p_leaf(p_varref, loc);
if (r) {
r->sem.qname_raw.prefix = "pf";
r->sem.qname_raw.loc = (char*) PFmalloc(8);
if (r->sem.qname_raw.loc)
snprintf(r->sem.qname_raw.loc, 8, "heur%03d", varnum);
}
return r;
}
On 09/12/2007 12:15 AM, Peter Boncz wrote with possible deletions:
> Update of /cvsroot/monetdb/pathfinder/compiler/semantics
> In directory
> sc8-pr-cvs16.sourceforge.net:/tmp/cvs-serv24884/compiler/semantics
>
> Modified Files:
> Makefile.ag xquery_fo.c
> Added Files:
> heuristic.c
> Log Message:
> The infamous push-selections-down heuristic rewrite
> ===================================================
>
> the good: equi comparisons on attributes, texts and elements in MXQ can now
> be done in sublinear time thanks to indices. This involves the
> "reversing"of multi-step XPath paths if required.
>
> the bad: it is a heuristic so no performance improvement assured, though much
> of the performance pitfalls are mitigated by a loop-lifted run-time
> decision whether to use the index plan or the original plan.
>
> the ugly: well, since I can't (or couldn't) stomach XQuery core plan, it is
> all
> implemeted on the absssyn level.
>
> there are quite a few comments/explanations in compiler/semantics/heuristic.c
>
> runtime/pathfinder.mx
> - major changes to the indexing scheme, supporting the pf:text/pf:attribute
> functions
> - added run-time behavior to vx_lookup: for those iterations where index
> lookup is
> not beneficial, it returns a bogus node ([EMAIL PROTECTED], recognizable as
> a docnode) so
> the original (non index-pushdown) plan is used for those iterations
>
> runtime/pf_support.mx
> - new xquery hash function, with less collisions and the ability to preserve
> equality
> semantics for any XQuery type (currently supported..).
> - added a new dbl(byte1,...byte8) constructor that allows a IEEE double to be
> constructed from its 8 binary bytes (per byte to avoid little/big endian
> issues)
> without any precision loss.
> - optimization for the ll_htordered_thetajoin in case we have constant join
> columns
>
> compiler/compile.c
> compiler/include/Makefile.ag
> compiler/semantics/Makefile.ag
> - add heuristic.[ch]
> - added heuristic index pushdown opt (currently only in mps, but alg/M4
> should follow)
>
> compiler/semantics/xquery_fo.c
> compiler/mil/milprint_summer.c
> - rewrote pf:atttribute and pf:text to give approximate answers
> - new pf:supernode function
> - pass parsed decimals/doubles using the new byte-wise MIL dbl() constructor
> (to avoid precision loss in the pf -> MonetDB transition)
> - bugfix in empty ipik opt for the for-rule
>
> compiler/debug/abssynprint.c
> - PFabssyn_stdout for debugging sanity
> compiler/debug/prettyp.c
> - margin=6 for better debug output readability
>
--
Jan Rittinger
Database Systems
Technische Universität München (Germany)
http://www-db.in.tum.de/~rittinge/
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