Changeset: b27a4f95a033 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/b27a4f95a033
Modified Files:
monetdb5/optimizer/opt_projectionpath.c
Branch: Jun2023
Log Message:
Remove experimental and commented out code.
diffs (159 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
@@ -15,132 +15,6 @@
#include "opt_deadcode.h"
#include "opt_projectionpath.h"
-
-// Common prefix reduction was not effective it is retained for
-// future experiments.
-//#define ELIMCOMMONPREFIX
-
-#ifdef ELIMCOMMONPREFIX
-static int
-OPTprojectionPrefix(Client cntxt, MalBlkPtr mb)
-{
- int i, j, k, maxmatch, actions=0;
- InstrPtr p,q,*old = NULL;
- int limit, slimit;
- InstrPtr *paths = NULL;
- int *alias = NULL;
-
- (void) cntxt;
- limit = mb->stop;
- slimit= mb->ssize;
-
- paths = (InstrPtr *) GDKzalloc(mb->vsize * sizeof(InstrPtr));
- if (paths == NULL)
- return 0;
- alias = (int*) GDKzalloc(mb->vsize * sizeof(int));
- if( alias == NULL){
- GDKfree(paths);
- return 0;
- }
-
- maxmatch = 0; // to collect maximum common paths
- old = mb->stmt;
- /* Collect the projection paths achored at the same start */
- for( i=0; i< limit; i++){
- p = old[i];
- if ( getFunctionId(p) == projectionpathRef && p->argc > 3){
- k = getArg(p,1);
- if( paths[k] == 0)
- paths[k] = p;
- q = paths[k];
- // Calculate the number of almost identical paths
- if( q->argc == p->argc){
- for(j = q->retc; j<q->argc - 1; j++)
- if( getArg(p,j) != getArg(q,j))
- break;
- if( j == q->argc -1 ){
- alias[k] = alias[k] -1;
- if (alias[k] < maxmatch)
- maxmatch = alias[k];
- }
- }
- }
- }
- if (maxmatch == -1){
- GDKfree(alias);
- GDKfree(paths);
- return 0;
- }
-
- if (newMalBlkStmt(mb,mb->ssize) < 0){
- GDKfree(paths);
- GDKfree(alias);
- return 0;
- }
-
-
- for( i = 0; i < limit; i++){
- p = old[i];
- if ( getFunctionId(p) != projectionpathRef ){
- pushInstruction(mb,p);
- continue;
- }
- if( p->argc < 3){
- pushInstruction(mb,p);
- continue;
- }
-
- actions++;
- // the first one should be split if there is interest
- k = getArg(p,1);
- q = paths[k];
- if( alias[k] < 0){
- // inject the join prefix calculation
- q= copyInstruction(q);
- q->argc = q->argc -1;
- getArg(q,0) = newTmpVariable(mb, getArgType(mb,q,
q->argc -1));
- pushInstruction(mb, q);
- alias[k] = getArg(q,0);
- q = copyInstruction(p);
- getArg(q,1) = alias[k];
- getArg(q,2) = getArg(q, q->argc -1);
- q->argc = 3;
- pushInstruction(mb,q);
- continue;
- }
- // check if we can replace the projectionpath with an alias
- k = getArg(p,1);
- q = paths[k];
- if( alias[k] > 0 && q->argc == p->argc){
- for(j = q->retc; j<q->argc - 1; j++)
- if( getArg(p,j) != getArg(q,j))
- break;
- if( j == q->argc - 1){
- // we found a common prefix, and it is the
first one?
- getArg(p,1) = alias[k];
- getArg(p,2) = getArg(p, p->argc -1);
- p->argc = 3;
- pushInstruction(mb,p);
- }
- } else {
- pushInstruction(mb,p);
- continue;
- }
-
- }
-
- for(; i<slimit; i++)
- if(old[i])
- freeInstruction(old[i]);
- GDKfree(old);
- GDKfree(paths);
- GDKfree(alias);
- //if(actions)
- //printFunction(cntxt->fdout, mb, 0, LIST_MAL_ALL);
- return actions;
-}
-#endif
-
str
OPTprojectionpathImplementation(Client cntxt, MalBlkPtr mb, MalStkPtr stk,
InstrPtr pci)
{
@@ -280,19 +154,9 @@ OPTprojectionpathImplementation(Client c
if(old[i])
pushInstruction(mb, old[i]);
-#ifdef ELIMCOMMONPREFIX
- /* All complete projection paths have been constructed.
- * There may be cases where there is a common prefix used multiple
times.
- * Especially in wide table projections and lengthy paths
- * They can be located and replaced in the plan by factoring the common
part out
- * First experiments on tpch SF10- Q7, showed significant decrease in
performance
- * Also a run against SF-100 did not show improvement in Q7
- * Also there are collateral damages in the testweb.
- */
- if( OPTdeadcodeImplementation(cntxt, mb, 0, 0) == MAL_SUCCEED){
- actions += OPTprojectionPrefix(cntxt, mb);
- }
-#endif
+ /* At this location there used to be commented out experimental code
+ * to reuse common prefixes, but this was counter productive. This
+ * comment is all that is left. */
/* Defense line against incorrect plans */
if( actions > 0){
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