Changeset: bcf0331174bc for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=bcf0331174bc
Modified Files:
monetdb5/optimizer/opt_projectionpath.c
Branch: default
Log Message:
Minor additions
diffs (107 lines):
diff --git a/monetdb5/optimizer/opt_projectionpath.c
b/monetdb5/optimizer/opt_projectionpath.c
--- a/monetdb5/optimizer/opt_projectionpath.c
+++ b/monetdb5/optimizer/opt_projectionpath.c
@@ -8,7 +8,6 @@
/* author: M Kersten
* Post-optimization of projection lists.
- * The algorithm is quadratic in the number of paths considered.
*/
#include "monetdb_config.h"
#include "opt_deadcode.h"
@@ -17,12 +16,18 @@
//#undef OPTDEBUGprojectionpath
//#define OPTDEBUGprojectionpath if(1)
+#define ELIMCOMMONPREFIX
+
#define LOOKAHEAD 500 /* limit the lookahead for candidates */
-/* locate common prefixes in projection lists */
+
+/* locate common prefixes in projection lists
+ * The algorithm is quadratic in the number of paths considered. */
+
+#ifdef ELIMCOMMONPREFIX
static int
OPTprojectionPrefix(Client cntxt, MalBlkPtr mb, int prefixlength)
{
- int i, j, k, match, actions=0;
+ int i, j, k, match, actions=0;
InstrPtr p,q,r,*old;
int limit, slimit;
@@ -72,6 +77,8 @@ OPTprojectionPrefix(Client cntxt, MalBlk
r->argc = prefixlength;
getArg(r,0) = newTmpVariable(mb, newBatType( TYPE_oid,
getColumnType(getArgType(mb,r,r->argc-1))));
setVarUDFtype(mb, getArg(r,0));
+ if( r->argc == 3)
+ setFunctionId(r,projectionRef);
pushInstruction(mb,r);
OPTDEBUGprojectionpath {
mnstr_printf(cntxt->fdout,"#projectionpath
prefix instruction\n");
@@ -99,6 +106,8 @@ OPTprojectionPrefix(Client cntxt, MalBlk
getArg(q,q->retc) = getArg(r,0);
for( k= q->retc +1 ; k <
prefixlength; k++)
delArgument(q, q->retc
+ 1);
+ if( q->argc == 3)
+
setFunctionId(q,projectionRef);
}
OPTDEBUGprojectionpath {
mnstr_printf(cntxt->fdout,"#projectionpath after :");
@@ -115,22 +124,9 @@ OPTprojectionPrefix(Client cntxt, MalBlk
getArg(p,p->retc) = getArg(r,0);
for( k= p->retc + 1; k < prefixlength; k++)
delArgument(p, p->retc + 1);
+ if( p->argc == 3)
+ setFunctionId(p,projectionRef);
}
- /* Finally check if we already have this prefix
operation then an alias is sufficient
- for( jj= i-1; jj > 0 && jj > i - LOOKAHEAD; jj--) {
- q= old[jj];
- if ( getFunctionId(q) != getFunctionId(r) ||
q->argc != r->argc)
- continue;
- for( match =0, k = q->retc; k < q->argc; k++)
- match += getArg(q,k) == getArg(r,k);
- if ( match && match == q->argc - q->retc){
- clrFunction(r);
- r->argc = r->retc +1;
- getArg(r,r->retc) = getArg(q,0);
- break;
- }
- }
- */
OPTDEBUGprojectionpath
printInstruction(cntxt->fdout,mb, 0, p,
LIST_MAL_ALL);
@@ -150,6 +146,7 @@ OPTprojectionPrefix(Client cntxt, MalBlk
actions += OPTdeadcodeImplementation(cntxt, mb, 0, 0);
return actions;
}
+#endif
int
OPTprojectionpathImplementation(Client cntxt, MalBlkPtr mb, MalStkPtr stk,
InstrPtr p)
@@ -288,14 +285,22 @@ OPTprojectionpathImplementation(Client c
/* All complete projection paths have been constructed.
* There may be cases where there is a common prefix used multiple
times.
- * There are located and removed in a few scans over the plan
+ * They are located and removed in a few scans over the plan
+ *
+ * The prefix path mostly consist of smaller columns,
+ * which make the benefit not large. In SF100 roughly 100 out of
+ * 4500 projection operations were removed.
+ * On medium scale databases it may save cpu cycles.
+ * Turning this feature into a compile time option.
*/
+#ifdef ELIMCOMMONPREFIX
if( maxprefixlength > 3){
/* Before searching the prefix, we should remove all non-used
instructions. */
actions += OPTdeadcodeImplementation(cntxt, mb, 0, 0);
for( ; maxprefixlength > 2; maxprefixlength--)
actions += OPTprojectionPrefix(cntxt, mb,
maxprefixlength);
}
+#endif
OPTDEBUGprojectionpath {
mnstr_printf(cntxt->fdout,"#projectionpath optimizer result
\n");
printFunction(cntxt->fdout,mb, 0, LIST_MAL_ALL);
_______________________________________________
checkin-list mailing list
checkin-list@monetdb.org
https://www.monetdb.org/mailman/listinfo/checkin-list
