diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index fc95399b396ff410d8de9f8b4ee695f04a93a214..c1e1651c7989afce8ad7ac0242cf87bc8570cbdb 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -54,7 +54,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.189 2007/11/15 22:25:15 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.190 2007/12/08 21:05:11 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1372,12 +1372,16 @@ cost_mergejoin(MergePath *path, PlannerInfo *root)
double outer_path_rows = PATH_ROWS(outer_path);
double inner_path_rows = PATH_ROWS(inner_path);
double outer_rows,
- inner_rows;
+ inner_rows,
+ outer_skip_rows,
+ inner_skip_rows;
double mergejointuples,
rescannedtuples;
double rescanratio;
- Selectivity outerscansel,
- innerscansel;
+ Selectivity outerstartsel,
+ outerendsel,
+ innerstartsel,
+ innerendsel;
Selectivity joininfactor;
Path sort_path; /* dummy for result of cost_sort */
@@ -1444,10 +1448,12 @@ cost_mergejoin(MergePath *path, PlannerInfo *root)
* A merge join will stop as soon as it exhausts either input stream
* (unless it's an outer join, in which case the outer side has to be
* scanned all the way anyway). Estimate fraction of the left and right
- * inputs that will actually need to be scanned. We use only the first
- * (most significant) merge clause for this purpose. Since
- * mergejoinscansel() is a fairly expensive computation, we cache the
- * results in the merge clause RestrictInfo.
+ * inputs that will actually need to be scanned. Likewise, we can
+ * estimate the number of rows that will be skipped before the first
+ * join pair is found, which should be factored into startup cost.
+ * We use only the first (most significant) merge clause for this purpose.
+ * Since mergejoinscansel() is a fairly expensive computation, we cache
+ * the results in the merge clause RestrictInfo.
*/
if (mergeclauses && path->jpath.jointype != JOIN_FULL)
{
@@ -1478,37 +1484,61 @@ cost_mergejoin(MergePath *path, PlannerInfo *root)
outer_path->parent->relids))
{
/* left side of clause is outer */
- outerscansel = cache->leftscansel;
- innerscansel = cache->rightscansel;
+ outerstartsel = cache->leftstartsel;
+ outerendsel = cache->leftendsel;
+ innerstartsel = cache->rightstartsel;
+ innerendsel = cache->rightendsel;
}
else
{
/* left side of clause is inner */
- outerscansel = cache->rightscansel;
- innerscansel = cache->leftscansel;
+ outerstartsel = cache->rightstartsel;
+ outerendsel = cache->rightendsel;
+ innerstartsel = cache->leftstartsel;
+ innerendsel = cache->leftendsel;
}
if (path->jpath.jointype == JOIN_LEFT)
- outerscansel = 1.0;
+ {
+ outerstartsel = 0.0;
+ outerendsel = 1.0;
+ }
else if (path->jpath.jointype == JOIN_RIGHT)
- innerscansel = 1.0;
+ {
+ innerstartsel = 0.0;
+ innerendsel = 1.0;
+ }
}
else
{
/* cope with clauseless or full mergejoin */
- outerscansel = innerscansel = 1.0;
+ outerstartsel = innerstartsel = 0.0;
+ outerendsel = innerendsel = 1.0;
}
- /* convert selectivity to row count; must scan at least one row */
- outer_rows = clamp_row_est(outer_path_rows * outerscansel);
- inner_rows = clamp_row_est(inner_path_rows * innerscansel);
+ /*
+ * Convert selectivities to row counts. We force outer_rows and
+ * inner_rows to be at least 1, but the skip_rows estimates can be zero.
+ */
+ outer_skip_rows = rint(outer_path_rows * outerstartsel);
+ inner_skip_rows = rint(inner_path_rows * innerstartsel);
+ outer_rows = clamp_row_est(outer_path_rows * outerendsel);
+ inner_rows = clamp_row_est(inner_path_rows * innerendsel);
+
+ Assert(outer_skip_rows <= outer_rows);
+ Assert(inner_skip_rows <= inner_rows);
/*
* Readjust scan selectivities to account for above rounding. This is
* normally an insignificant effect, but when there are only a few rows in
* the inputs, failing to do this makes for a large percentage error.
*/
- outerscansel = outer_rows / outer_path_rows;
- innerscansel = inner_rows / inner_path_rows;
+ outerstartsel = outer_skip_rows / outer_path_rows;
+ innerstartsel = inner_skip_rows / inner_path_rows;
+ outerendsel = outer_rows / outer_path_rows;
+ innerendsel = inner_rows / inner_path_rows;
+
+ Assert(outerstartsel <= outerendsel);
+ Assert(innerstartsel <= innerendsel);
/* cost of source data */
@@ -1522,14 +1552,18 @@ cost_mergejoin(MergePath *path, PlannerInfo *root)
outer_path->parent->width,
-1.0);
startup_cost += sort_path.startup_cost;
+ startup_cost += (sort_path.total_cost - sort_path.startup_cost)
+ * outerstartsel;
run_cost += (sort_path.total_cost - sort_path.startup_cost)
- * outerscansel;
+ * (outerendsel - outerstartsel);
}
else
{
startup_cost += outer_path->startup_cost;
+ startup_cost += (outer_path->total_cost - outer_path->startup_cost)
+ * outerstartsel;
run_cost += (outer_path->total_cost - outer_path->startup_cost)
- * outerscansel;
+ * (outerendsel - outerstartsel);
}
if (innersortkeys) /* do we need to sort inner? */
@@ -1542,14 +1576,18 @@ cost_mergejoin(MergePath *path, PlannerInfo *root)
inner_path->parent->width,
-1.0);
startup_cost += sort_path.startup_cost;
+ startup_cost += (sort_path.total_cost - sort_path.startup_cost)
+ * innerstartsel * rescanratio;
run_cost += (sort_path.total_cost - sort_path.startup_cost)
- * innerscansel * rescanratio;
+ * (innerendsel - innerstartsel) * rescanratio;
}
else
{
startup_cost += inner_path->startup_cost;
+ startup_cost += (inner_path->total_cost - inner_path->startup_cost)
+ * innerstartsel * rescanratio;
run_cost += (inner_path->total_cost - inner_path->startup_cost)
- * innerscansel * rescanratio;
+ * (innerendsel - innerstartsel) * rescanratio;
}
/* CPU costs */
@@ -1571,8 +1609,11 @@ cost_mergejoin(MergePath *path, PlannerInfo *root)
* joininfactor.
*/
startup_cost += merge_qual_cost.startup;
+ startup_cost += merge_qual_cost.per_tuple *
+ (outer_skip_rows + inner_skip_rows * rescanratio);
run_cost += merge_qual_cost.per_tuple *
- (outer_rows + inner_rows * rescanratio);
+ ((outer_rows - outer_skip_rows) +
+ (inner_rows - inner_skip_rows) * rescanratio);
/*
* For each tuple that gets through the mergejoin proper, we charge
@@ -1597,8 +1638,10 @@ cached_scansel(PlannerInfo *root, RestrictInfo *rinfo, PathKey *pathkey)
{
MergeScanSelCache *cache;
ListCell *lc;
- Selectivity leftscansel,
- rightscansel;
+ Selectivity leftstartsel,
+ leftendsel,
+ rightstartsel,
+ rightendsel;
MemoryContext oldcontext;
/* Do we have this result already? */
@@ -1617,8 +1660,10 @@ cached_scansel(PlannerInfo *root, RestrictInfo *rinfo, PathKey *pathkey)
pathkey->pk_opfamily,
pathkey->pk_strategy,
pathkey->pk_nulls_first,
- &leftscansel,
- &rightscansel);
+ &leftstartsel,
+ &leftendsel,
+ &rightstartsel,
+ &rightendsel);
/* Cache the result in suitably long-lived workspace */
oldcontext = MemoryContextSwitchTo(root->planner_cxt);
@@ -1627,8 +1672,10 @@ cached_scansel(PlannerInfo *root, RestrictInfo *rinfo, PathKey *pathkey)
cache->opfamily = pathkey->pk_opfamily;
cache->strategy = pathkey->pk_strategy;
cache->nulls_first = pathkey->pk_nulls_first;
- cache->leftscansel = leftscansel;
- cache->rightscansel = rightscansel;
+ cache->leftstartsel = leftstartsel;
+ cache->leftendsel = leftendsel;
+ cache->rightstartsel = rightstartsel;
+ cache->rightendsel = rightendsel;
rinfo->scansel_cache = lappend(rinfo->scansel_cache, cache);
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 103f4dc9d7620b8cd3ca62d712e0829ccf4ffb52..0b0d992a3b19d2133c07a747bc5df46304ce17e4 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -15,7 +15,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.241 2007/11/15 22:25:16 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.242 2007/12/08 21:05:11 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -128,8 +128,8 @@ static double convert_one_bytea_to_scalar(unsigned char *value, int valuelen,
int rangelo, int rangehi);
static char *convert_string_datum(Datum value, Oid typid);
static double convert_timevalue_to_scalar(Datum value, Oid typid);
-static bool get_variable_maximum(PlannerInfo *root, VariableStatData *vardata,
- Oid sortop, Datum *max);
+static bool get_variable_range(PlannerInfo *root, VariableStatData *vardata,
+ Oid sortop, Datum *min, Datum *max);
static Selectivity prefix_selectivity(VariableStatData *vardata,
Oid vartype, Oid opfamily, Const *prefixcon);
static Selectivity pattern_selectivity(Const *patt, Pattern_Type ptype);
@@ -2172,18 +2172,24 @@ icnlikejoinsel(PG_FUNCTION_ARGS)
* we can estimate how much of the input will actually be read. This
* can have a considerable impact on the cost when using indexscans.
*
+ * Also, we can estimate how much of each input has to be read before the
+ * first join pair is found, which will affect the join's startup time.
+ *
* clause should be a clause already known to be mergejoinable. opfamily,
* strategy, and nulls_first specify the sort ordering being used.
*
- * *leftscan is set to the fraction of the left-hand variable expected
- * to be scanned (0 to 1), and similarly *rightscan for the right-hand
- * variable.
+ * The outputs are:
+ * *leftstart is set to the fraction of the left-hand variable expected
+ * to be scanned before the first join pair is found (0 to 1).
+ * *leftend is set to the fraction of the left-hand variable expected
+ * to be scanned before the join terminates (0 to 1).
+ * *rightstart, *rightend similarly for the right-hand variable.
*/
void
mergejoinscansel(PlannerInfo *root, Node *clause,
Oid opfamily, int strategy, bool nulls_first,
- Selectivity *leftscan,
- Selectivity *rightscan)
+ Selectivity *leftstart, Selectivity *leftend,
+ Selectivity *rightstart, Selectivity *rightend)
{
Node *left,
*right;
@@ -2196,14 +2202,23 @@ mergejoinscansel(PlannerInfo *root, Node *clause,
Oid opno,
lsortop,
rsortop,
+ lstatop,
+ rstatop,
+ ltop,
leop,
+ revltop,
revleop;
- Datum leftmax,
+ bool isgt;
+ Datum leftmin,
+ leftmax,
+ rightmin,
rightmax;
double selec;
/* Set default results if we can't figure anything out. */
- *leftscan = *rightscan = 1.0;
+ /* XXX should default "start" fraction be a bit more than 0? */
+ *leftstart = *rightstart = 0.0;
+ *leftend = *rightend = 1.0;
/* Deconstruct the merge clause */
if (!is_opclause(clause))
@@ -2229,30 +2244,103 @@ mergejoinscansel(PlannerInfo *root, Node *clause,
/*
* Look up the various operators we need. If we don't find them all, it
- * probably means the opfamily is broken, but we cope anyway.
+ * probably means the opfamily is broken, but we just fail silently.
+ *
+ * Note: we expect that pg_statistic histograms will be sorted by the
+ * '<' operator, regardless of which sort direction we are considering.
*/
switch (strategy)
{
case BTLessStrategyNumber:
- lsortop = get_opfamily_member(opfamily, op_lefttype, op_lefttype,
- BTLessStrategyNumber);
- rsortop = get_opfamily_member(opfamily, op_righttype, op_righttype,
- BTLessStrategyNumber);
- leop = get_opfamily_member(opfamily, op_lefttype, op_righttype,
- BTLessEqualStrategyNumber);
- revleop = get_opfamily_member(opfamily, op_righttype, op_lefttype,
- BTLessEqualStrategyNumber);
+ isgt = false;
+ if (op_lefttype == op_righttype)
+ {
+ /* easy case */
+ ltop = get_opfamily_member(opfamily,
+ op_lefttype, op_righttype,
+ BTLessStrategyNumber);
+ leop = get_opfamily_member(opfamily,
+ op_lefttype, op_righttype,
+ BTLessEqualStrategyNumber);
+ lsortop = ltop;
+ rsortop = ltop;
+ lstatop = lsortop;
+ rstatop = rsortop;
+ revltop = ltop;
+ revleop = leop;
+ }
+ else
+ {
+ ltop = get_opfamily_member(opfamily,
+ op_lefttype, op_righttype,
+ BTLessStrategyNumber);
+ leop = get_opfamily_member(opfamily,
+ op_lefttype, op_righttype,
+ BTLessEqualStrategyNumber);
+ lsortop = get_opfamily_member(opfamily,
+ op_lefttype, op_lefttype,
+ BTLessStrategyNumber);
+ rsortop = get_opfamily_member(opfamily,
+ op_righttype, op_righttype,
+ BTLessStrategyNumber);
+ lstatop = lsortop;
+ rstatop = rsortop;
+ revltop = get_opfamily_member(opfamily,
+ op_righttype, op_lefttype,
+ BTLessStrategyNumber);
+ revleop = get_opfamily_member(opfamily,
+ op_righttype, op_lefttype,
+ BTLessEqualStrategyNumber);
+ }
break;
case BTGreaterStrategyNumber:
/* descending-order case */
- lsortop = get_opfamily_member(opfamily, op_lefttype, op_lefttype,
- BTGreaterStrategyNumber);
- rsortop = get_opfamily_member(opfamily, op_righttype, op_righttype,
- BTGreaterStrategyNumber);
- leop = get_opfamily_member(opfamily, op_lefttype, op_righttype,
- BTGreaterEqualStrategyNumber);
- revleop = get_opfamily_member(opfamily, op_righttype, op_lefttype,
- BTGreaterEqualStrategyNumber);
+ isgt = true;
+ if (op_lefttype == op_righttype)
+ {
+ /* easy case */
+ ltop = get_opfamily_member(opfamily,
+ op_lefttype, op_righttype,
+ BTGreaterStrategyNumber);
+ leop = get_opfamily_member(opfamily,
+ op_lefttype, op_righttype,
+ BTGreaterEqualStrategyNumber);
+ lsortop = ltop;
+ rsortop = ltop;
+ lstatop = get_opfamily_member(opfamily,
+ op_lefttype, op_lefttype,
+ BTLessStrategyNumber);
+ rstatop = lstatop;
+ revltop = ltop;
+ revleop = leop;
+ }
+ else
+ {
+ ltop = get_opfamily_member(opfamily,
+ op_lefttype, op_righttype,
+ BTGreaterStrategyNumber);
+ leop = get_opfamily_member(opfamily,
+ op_lefttype, op_righttype,
+ BTGreaterEqualStrategyNumber);
+ lsortop = get_opfamily_member(opfamily,
+ op_lefttype, op_lefttype,
+ BTGreaterStrategyNumber);
+ rsortop = get_opfamily_member(opfamily,
+ op_righttype, op_righttype,
+ BTGreaterStrategyNumber);
+ lstatop = get_opfamily_member(opfamily,
+ op_lefttype, op_lefttype,
+ BTLessStrategyNumber);
+ rstatop = get_opfamily_member(opfamily,
+ op_righttype, op_righttype,
+ BTLessStrategyNumber);
+ revltop = get_opfamily_member(opfamily,
+ op_righttype, op_lefttype,
+ BTGreaterStrategyNumber);
+ revleop = get_opfamily_member(opfamily,
+ op_righttype, op_lefttype,
+ BTGreaterEqualStrategyNumber);
+ }
break;
default:
goto fail; /* shouldn't get here */
@@ -2260,66 +2348,133 @@ mergejoinscansel(PlannerInfo *root, Node *clause,
if (!OidIsValid(lsortop) ||
!OidIsValid(rsortop) ||
+ !OidIsValid(lstatop) ||
+ !OidIsValid(rstatop) ||
+ !OidIsValid(ltop) ||
!OidIsValid(leop) ||
+ !OidIsValid(revltop) ||
!OidIsValid(revleop))
goto fail; /* insufficient info in catalogs */
- /* Try to get maximum values of both inputs */
- if (!get_variable_maximum(root, &leftvar, lsortop, &leftmax))
- goto fail; /* no max available from stats */
-
- if (!get_variable_maximum(root, &rightvar, rsortop, &rightmax))
- goto fail; /* no max available from stats */
+ /* Try to get ranges of both inputs */
+ if (!isgt)
+ {
+ if (!get_variable_range(root, &leftvar, lstatop,
+ &leftmin, &leftmax))
+ goto fail; /* no range available from stats */
+ if (!get_variable_range(root, &rightvar, rstatop,
+ &rightmin, &rightmax))
+ goto fail; /* no range available from stats */
+ }
+ else
+ {
+ /* need to swap the max and min */
+ if (!get_variable_range(root, &leftvar, lstatop,
+ &leftmax, &leftmin))
+ goto fail; /* no range available from stats */
+ if (!get_variable_range(root, &rightvar, rstatop,
+ &rightmax, &rightmin))
+ goto fail; /* no range available from stats */
+ }
/*
* Now, the fraction of the left variable that will be scanned is the
* fraction that's <= the right-side maximum value. But only believe
- * non-default estimates, else stick with our 1.0. Also, if the sort
- * order is nulls-first, we're going to have to read over any nulls too.
+ * non-default estimates, else stick with our 1.0.
*/
- selec = scalarineqsel(root, leop, false, &leftvar,
+ selec = scalarineqsel(root, leop, isgt, &leftvar,
rightmax, op_righttype);
if (selec != DEFAULT_INEQ_SEL)
- {
- if (nulls_first && HeapTupleIsValid(leftvar.statsTuple))
- {
- Form_pg_statistic stats;
-
- stats = (Form_pg_statistic) GETSTRUCT(leftvar.statsTuple);
- selec += stats->stanullfrac;
- CLAMP_PROBABILITY(selec);
- }
- *leftscan = selec;
- }
+ *leftend = selec;
/* And similarly for the right variable. */
- selec = scalarineqsel(root, revleop, false, &rightvar,
+ selec = scalarineqsel(root, revleop, isgt, &rightvar,
leftmax, op_lefttype);
if (selec != DEFAULT_INEQ_SEL)
+ *rightend = selec;
+
+ /*
+ * Only one of the two "end" fractions can really be less than 1.0;
+ * believe the smaller estimate and reset the other one to exactly 1.0.
+ * If we get exactly equal estimates (as can easily happen with
+ * self-joins), believe neither.
+ */
+ if (*leftend > *rightend)
+ *leftend = 1.0;
+ else if (*leftend < *rightend)
+ *rightend = 1.0;
+ else
+ *leftend = *rightend = 1.0;
+
+ /*
+ * Also, the fraction of the left variable that will be scanned before
+ * the first join pair is found is the fraction that's < the right-side
+ * minimum value. But only believe non-default estimates, else stick with
+ * our own default.
+ */
+ selec = scalarineqsel(root, ltop, isgt, &leftvar,
+ rightmin, op_righttype);
+ if (selec != DEFAULT_INEQ_SEL)
+ *leftstart = selec;
+
+ /* And similarly for the right variable. */
+ selec = scalarineqsel(root, revltop, isgt, &rightvar,
+ leftmin, op_lefttype);
+ if (selec != DEFAULT_INEQ_SEL)
+ *rightstart = selec;
+
+ /*
+ * Only one of the two "start" fractions can really be more than zero;
+ * believe the larger estimate and reset the other one to exactly 0.0.
+ * If we get exactly equal estimates (as can easily happen with
+ * self-joins), believe neither.
+ */
+ if (*leftstart < *rightstart)
+ *leftstart = 0.0;
+ else if (*leftstart > *rightstart)
+ *rightstart = 0.0;
+ else
+ *leftstart = *rightstart = 0.0;
+
+ /*
+ * If the sort order is nulls-first, we're going to have to skip over any
+ * nulls too. These would not have been counted by scalarineqsel, and
+ * we can safely add in this fraction regardless of whether we believe
+ * scalarineqsel's results or not. But be sure to clamp the sum to 1.0!
+ */
+ if (nulls_first)
{
- if (nulls_first && HeapTupleIsValid(rightvar.statsTuple))
- {
- Form_pg_statistic stats;
+ Form_pg_statistic stats;
+ if (HeapTupleIsValid(leftvar.statsTuple))
+ {
+ stats = (Form_pg_statistic) GETSTRUCT(leftvar.statsTuple);
+ *leftstart += stats->stanullfrac;
+ CLAMP_PROBABILITY(*leftstart);
+ *leftend += stats->stanullfrac;
+ CLAMP_PROBABILITY(*leftend);
+ }
+ if (HeapTupleIsValid(rightvar.statsTuple))
+ {
stats = (Form_pg_statistic) GETSTRUCT(rightvar.statsTuple);
- selec += stats->stanullfrac;
- CLAMP_PROBABILITY(selec);
+ *rightstart += stats->stanullfrac;
+ CLAMP_PROBABILITY(*rightstart);
+ *rightend += stats->stanullfrac;
+ CLAMP_PROBABILITY(*rightend);
}
- *rightscan = selec;
}
- /*
- * Only one of the two fractions can really be less than 1.0; believe the
- * smaller estimate and reset the other one to exactly 1.0. If we get
- * exactly equal estimates (as can easily happen with self-joins), believe
- * neither.
- */
- if (*leftscan > *rightscan)
- *leftscan = 1.0;
- else if (*leftscan < *rightscan)
- *rightscan = 1.0;
- else
- *leftscan = *rightscan = 1.0;
+ /* Disbelieve start >= end, just in case that can happen */
+ if (*leftstart >= *leftend)
+ {
+ *leftstart = 0.0;
+ *leftend = 1.0;
+ }
+ if (*rightstart >= *rightend)
+ {
+ *rightstart = 0.0;
+ *rightend = 1.0;
+ }
fail:
ReleaseVariableStats(leftvar);
@@ -3778,20 +3933,21 @@ get_variable_numdistinct(VariableStatData *vardata)
}
/*
- * get_variable_maximum
- * Estimate the maximum value of the specified variable.
- * If successful, store value in *max and return TRUE.
+ * get_variable_range
+ * Estimate the minimum and maximum value of the specified variable.
+ * If successful, store values in *min and *max, and return TRUE.
* If no data available, return FALSE.
*
- * sortop is the "<" comparison operator to use. (To extract the
- * minimum instead of the maximum, just pass the ">" operator instead.)
+ * sortop is the "<" comparison operator to use. This should generally
+ * be "<" not ">", as only the former is likely to be found in pg_statistic.
*/
static bool
-get_variable_maximum(PlannerInfo *root, VariableStatData *vardata,
- Oid sortop, Datum *max)
+get_variable_range(PlannerInfo *root, VariableStatData *vardata, Oid sortop,
+ Datum *min, Datum *max)
{
+ Datum tmin = 0;
Datum tmax = 0;
- bool have_max = false;
+ bool have_data = false;
Form_pg_statistic stats;
int16 typLen;
bool typByVal;
@@ -3809,7 +3965,7 @@ get_variable_maximum(PlannerInfo *root, VariableStatData *vardata,
get_typlenbyval(vardata->atttype, &typLen, &typByVal);
/*
- * If there is a histogram, grab the last or first value as appropriate.
+ * If there is a histogram, grab the first and last values.
*
* If there is a histogram that is sorted with some other operator than
* the one we want, fail --- this suggests that there is data we can't
@@ -3823,42 +3979,24 @@ get_variable_maximum(PlannerInfo *root, VariableStatData *vardata,
{
if (nvalues > 0)
{
+ tmin = datumCopy(values[0], typByVal, typLen);
tmax = datumCopy(values[nvalues - 1], typByVal, typLen);
- have_max = true;
+ have_data = true;
}
free_attstatsslot(vardata->atttype, values, nvalues, NULL, 0);
}
- else
+ else if (get_attstatsslot(vardata->statsTuple,
+ vardata->atttype, vardata->atttypmod,
+ STATISTIC_KIND_HISTOGRAM, InvalidOid,
+ &values, &nvalues,
+ NULL, NULL))
{
- Oid rsortop = get_commutator(sortop);
-
- if (OidIsValid(rsortop) &&
- get_attstatsslot(vardata->statsTuple,
- vardata->atttype, vardata->atttypmod,
- STATISTIC_KIND_HISTOGRAM, rsortop,
- &values, &nvalues,
- NULL, NULL))
- {
- if (nvalues > 0)
- {
- tmax = datumCopy(values[0], typByVal, typLen);
- have_max = true;
- }
- free_attstatsslot(vardata->atttype, values, nvalues, NULL, 0);
- }
- else if (get_attstatsslot(vardata->statsTuple,
- vardata->atttype, vardata->atttypmod,
- STATISTIC_KIND_HISTOGRAM, InvalidOid,
- &values, &nvalues,
- NULL, NULL))
- {
- free_attstatsslot(vardata->atttype, values, nvalues, NULL, 0);
- return false;
- }
+ free_attstatsslot(vardata->atttype, values, nvalues, NULL, 0);
+ return false;
}
/*
- * If we have most-common-values info, look for a large MCV. This is
+ * If we have most-common-values info, look for extreme MCVs. This is
* needed even if we also have a histogram, since the histogram excludes
* the MCVs. However, usually the MCVs will not be the extreme values, so
* avoid unnecessary data copying.
@@ -3869,31 +4007,41 @@ get_variable_maximum(PlannerInfo *root, VariableStatData *vardata,
&values, &nvalues,
NULL, NULL))
{
- bool large_mcv = false;
+ bool tmin_is_mcv = false;
+ bool tmax_is_mcv = false;
FmgrInfo opproc;
fmgr_info(get_opcode(sortop), &opproc);
for (i = 0; i < nvalues; i++)
{
- if (!have_max)
+ if (!have_data)
{
- tmax = values[i];
- large_mcv = have_max = true;
+ tmin = tmax = values[i];
+ tmin_is_mcv = tmax_is_mcv = have_data = true;
+ continue;
+ }
+ if (DatumGetBool(FunctionCall2(&opproc, values[i], tmin)))
+ {
+ tmin = values[i];
+ tmin_is_mcv = true;
}
- else if (DatumGetBool(FunctionCall2(&opproc, tmax, values[i])))
+ if (DatumGetBool(FunctionCall2(&opproc, tmax, values[i])))
{
tmax = values[i];
- large_mcv = true;
+ tmax_is_mcv = true;
}
}
- if (large_mcv)
+ if (tmin_is_mcv)
+ tmin = datumCopy(tmin, typByVal, typLen);
+ if (tmax_is_mcv)
tmax = datumCopy(tmax, typByVal, typLen);
free_attstatsslot(vardata->atttype, values, nvalues, NULL, 0);
}
+ *min = tmin;
*max = tmax;
- return have_max;
+ return have_data;
}
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 2dce223d3a7a2b162fa64c488d6bfdd79d5bc9e4..e82b00cdd46649a7cde81663b9abdb305d00d32e 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.150 2007/11/15 22:25:17 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.151 2007/12/08 21:05:11 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -993,8 +993,10 @@ typedef struct MergeScanSelCache
int strategy; /* sort direction (ASC or DESC) */
bool nulls_first; /* do NULLs come before normal values? */
/* Results */
- Selectivity leftscansel; /* scan fraction for clause left side */
- Selectivity rightscansel; /* scan fraction for clause right side */
+ Selectivity leftstartsel; /* first-join fraction for clause left side */
+ Selectivity leftendsel; /* last-join fraction for clause left side */
+ Selectivity rightstartsel; /* first-join fraction for clause right side */
+ Selectivity rightendsel; /* last-join fraction for clause right side */
} MergeScanSelCache;
/*
diff --git a/src/include/utils/selfuncs.h b/src/include/utils/selfuncs.h
index f92bb16d07981fab39ffd5477af6284da122657f..ededfdf3c6293455db92ad5c4d23d89b3f81393f 100644
--- a/src/include/utils/selfuncs.h
+++ b/src/include/utils/selfuncs.h
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.41 2007/11/07 22:37:24 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.42 2007/12/08 21:05:11 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -161,8 +161,8 @@ extern Selectivity rowcomparesel(PlannerInfo *root,
extern void mergejoinscansel(PlannerInfo *root, Node *clause,
Oid opfamily, int strategy, bool nulls_first,
- Selectivity *leftscan,
- Selectivity *rightscan);
+ Selectivity *leftstart, Selectivity *leftend,
+ Selectivity *rightstart, Selectivity *rightend);
extern double estimate_num_groups(PlannerInfo *root, List *groupExprs,
double input_rows);