Index: src/backend/utils/adt/selfuncs.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v
retrieving revision 1.187
diff -r1.187 selfuncs.c
1309a1310,1433
>  *            contstatsel             - Selectivity of containment for any data types.
>  */
> Datum
> contstatsel(PG_FUNCTION_ARGS)
> {
>       PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);
>       Oid                     operator = PG_GETARG_OID(1);
>       List       *args = (List *) PG_GETARG_POINTER(2);
>       int                     varRelid = PG_GETARG_INT32(3);
>       VariableStatData vardata;
>       Node       *other;
>       bool            varonleft;
>       Datum      *values;
>       int                     nvalues;
>       double          selec = 0.0;
> 
>       /*
>        * If expression is not variable = something or something = variable,
>        * then punt and return a default estimate.
>        */
>       if (!get_restriction_variable(root, args, varRelid,
>                                                                 &vardata, &other, &varonleft))
>               PG_RETURN_FLOAT8(0.001);
> 
>       /*
>        * If the something is a NULL constant, assume operator is strict and
>        * return zero, ie, operator will never return TRUE.
>        */
>       if (IsA(other, Const) &&
>               ((Const *) other)->constisnull)
>       {
>               ReleaseVariableStats(vardata);
>               PG_RETURN_FLOAT8(0.0);
>       }
> 
>       if (HeapTupleIsValid(vardata.statsTuple))
>       {
>               Form_pg_statistic stats;
> 
>               stats = (Form_pg_statistic) GETSTRUCT(vardata.statsTuple);
> 
>               if (IsA(other, Const))
>               {
>                       /* Variable is being compared to a known non-null constant */
>                       Datum           constval = ((Const *) other)->constvalue;
>                       bool            match = false;
>                       int                     i;
> 
> elog(INFO, "Checking histogram");
> 
>                       /*
>                        * Is the constant "=" to any of the column's most common
>                        * values?      (Although the given operator may not really be
>                        * "=", we will assume that seeing whether it returns TRUE is
>                        * an appropriate test.  If you don't like this, maybe you
>                        * shouldn't be using eqsel for your operator...)
>                        */
>                       if (get_attstatsslot(vardata.statsTuple,
>                                                                vardata.atttype, vardata.atttypmod,
>                                                                STATISTIC_KIND_HISTOGRAM, InvalidOid,
>                                                                &values, &nvalues,
>                                                                NULL, NULL))
>                       {
>                               FmgrInfo        contproc;
> 
>                               fmgr_info(get_opcode(operator), &contproc);
> 
> elog(INFO, "Found %d values", nvalues);
> 
>                               for (i = 0; i < nvalues; i++)
>                               {
>                                       /* be careful to apply operator right way 'round */
>                                       if (varonleft)
>                                               match = DatumGetBool(FunctionCall2(&contproc,
>                                                                                                                  values[i],
>                                                                                                                  constval));
>                                       else
>                                               match = DatumGetBool(FunctionCall2(&contproc,
>                                                                                                                  constval,
>                                                                                                                  values[i]));
>                                       if (match)
>                                               selec++;
>                               }
> 
>                               if (selec > 0.0 && nvalues > 0)
>                               {
>                                       selec /= nvalues;
>                               }
> 
> elog(INFO, "Computed selectivity: %04.3f", selec);
> 
>                       }
>                       else
>                       {
> elog(INFO, "No histogram info");
> 
>                               /* no most-common-value info available */
>                               values = NULL;
>                               i = nvalues = 0;
>                       }
> 
>                       if (!selec)
>                               selec = 0.001;
> 
>                       free_attstatsslot(vardata.atttype, values, nvalues,
>                                                         NULL, 0);
>               }
>               else
>                       selec = 0.001;
>       }
>       else
>               selec = 0.001;
> 
>       ReleaseVariableStats(vardata);
> 
>       /* result should be in range, but make sure... */
>       CLAMP_PROBABILITY(selec);
> 
> elog(INFO, "Returned selectivity: %04.3f", selec);
> 
>       PG_RETURN_FLOAT8((float8) selec);
> }
> 
> /*
Index: src/include/catalog/pg_proc.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/catalog/pg_proc.h,v
retrieving revision 1.380
diff -r1.380 pg_proc.h
3752a3753,3755
> DATA(insert OID = 2600 (  contstatsel            PGNSP PGUID 12 f f t f s 4 701 "2281 26 2281 23" _null_ _null_ _null_        contstatsel - _null_ ));
> DESCR("enhanced restriction selectivity for containment comparison operators");
> 
Index: src/include/utils/selfuncs.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/utils/selfuncs.h,v
retrieving revision 1.23
diff -r1.23 selfuncs.h
97a98,99
> extern Datum contstatsel(PG_FUNCTION_ARGS);
>