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pgindent run.
This commit is contained in:
@@ -49,7 +49,7 @@
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.111 2003/07/25 00:01:06 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.112 2003/08/04 00:43:20 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@@ -102,10 +102,10 @@ bool enable_hashjoin = true;
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static Selectivity estimate_hash_bucketsize(Query *root, Var *var,
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int nbuckets);
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static bool cost_qual_eval_walker(Node *node, QualCost *total);
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int nbuckets);
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static bool cost_qual_eval_walker(Node *node, QualCost * total);
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static Selectivity approx_selectivity(Query *root, List *quals,
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JoinType jointype);
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JoinType jointype);
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static void set_rel_width(Query *root, RelOptInfo *rel);
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static double relation_byte_size(double tuples, int width);
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static double page_size(double tuples, int width);
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@@ -358,13 +358,13 @@ cost_index(Path *path, Query *root,
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* Normally the indexquals will be removed from the list of restriction
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* clauses that we have to evaluate as qpquals, so we should subtract
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* their costs from baserestrictcost. But if we are doing a join then
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* some of the indexquals are join clauses and shouldn't be subtracted.
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* Rather than work out exactly how much to subtract, we don't subtract
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* anything.
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* some of the indexquals are join clauses and shouldn't be
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* subtracted. Rather than work out exactly how much to subtract, we
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* don't subtract anything.
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*
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* XXX For a lossy index, not all the quals will be removed and so we
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* really shouldn't subtract their costs; but detecting that seems more
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* expensive than it's worth.
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* really shouldn't subtract their costs; but detecting that seems
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* more expensive than it's worth.
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*/
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startup_cost += baserel->baserestrictcost.startup;
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cpu_per_tuple = cpu_tuple_cost + baserel->baserestrictcost.per_tuple;
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@@ -433,8 +433,8 @@ cost_subqueryscan(Path *path, RelOptInfo *baserel)
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/*
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* Cost of path is cost of evaluating the subplan, plus cost of
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* evaluating any restriction clauses that will be attached to the
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* SubqueryScan node, plus cpu_tuple_cost to account for selection
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* and projection overhead.
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* SubqueryScan node, plus cpu_tuple_cost to account for selection and
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* projection overhead.
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*/
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path->startup_cost = baserel->subplan->startup_cost;
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path->total_cost = baserel->subplan->total_cost;
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@@ -597,8 +597,9 @@ cost_material(Path *path,
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}
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/*
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* Also charge a small amount per extracted tuple. We use cpu_tuple_cost
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* so that it doesn't appear worthwhile to materialize a bare seqscan.
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* Also charge a small amount per extracted tuple. We use
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* cpu_tuple_cost so that it doesn't appear worthwhile to materialize
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* a bare seqscan.
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*/
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run_cost += cpu_tuple_cost * tuples;
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@@ -631,17 +632,17 @@ cost_agg(Path *path, Query *root,
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* additional cpu_operator_cost per grouping column per input tuple
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* for grouping comparisons.
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*
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* We will produce a single output tuple if not grouping,
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* and a tuple per group otherwise.
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* We will produce a single output tuple if not grouping, and a tuple per
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* group otherwise.
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*
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* Note: in this cost model, AGG_SORTED and AGG_HASHED have exactly the
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* same total CPU cost, but AGG_SORTED has lower startup cost. If the
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* same total CPU cost, but AGG_SORTED has lower startup cost. If the
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* input path is already sorted appropriately, AGG_SORTED should be
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* preferred (since it has no risk of memory overflow). This will happen
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* as long as the computed total costs are indeed exactly equal --- but
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* if there's roundoff error we might do the wrong thing. So be sure
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* that the computations below form the same intermediate values in the
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* same order.
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* preferred (since it has no risk of memory overflow). This will
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* happen as long as the computed total costs are indeed exactly equal
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* --- but if there's roundoff error we might do the wrong thing. So
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* be sure that the computations below form the same intermediate
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* values in the same order.
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*/
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if (aggstrategy == AGG_PLAIN)
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{
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@@ -724,26 +725,26 @@ cost_nestloop(NestPath *path, Query *root)
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double outer_path_rows = PATH_ROWS(outer_path);
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double inner_path_rows = PATH_ROWS(inner_path);
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double ntuples;
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Selectivity joininfactor;
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Selectivity joininfactor;
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if (!enable_nestloop)
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startup_cost += disable_cost;
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/*
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* If we're doing JOIN_IN then we will stop scanning inner tuples for an
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* outer tuple as soon as we have one match. Account for the effects of
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* this by scaling down the cost estimates in proportion to the expected
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* output size. (This assumes that all the quals attached to the join are
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* IN quals, which should be true.)
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* If we're doing JOIN_IN then we will stop scanning inner tuples for
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* an outer tuple as soon as we have one match. Account for the
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* effects of this by scaling down the cost estimates in proportion to
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* the expected output size. (This assumes that all the quals
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* attached to the join are IN quals, which should be true.)
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*
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* Note: it's probably bogus to use the normal selectivity calculation
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* here when either the outer or inner path is a UniquePath.
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*/
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if (path->jointype == JOIN_IN)
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{
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Selectivity qual_selec = approx_selectivity(root, restrictlist,
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Selectivity qual_selec = approx_selectivity(root, restrictlist,
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path->jointype);
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double qptuples;
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double qptuples;
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qptuples = ceil(qual_selec * outer_path_rows * inner_path_rows);
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if (qptuples > path->path.parent->rows)
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@@ -761,8 +762,8 @@ cost_nestloop(NestPath *path, Query *root)
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* before we can start returning tuples, so the join's startup cost is
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* their sum. What's not so clear is whether the inner path's
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* startup_cost must be paid again on each rescan of the inner path.
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* This is not true if the inner path is materialized or is a hashjoin,
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* but probably is true otherwise.
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* This is not true if the inner path is materialized or is a
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* hashjoin, but probably is true otherwise.
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*/
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startup_cost += outer_path->startup_cost + inner_path->startup_cost;
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run_cost += outer_path->total_cost - outer_path->startup_cost;
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@@ -783,14 +784,15 @@ cost_nestloop(NestPath *path, Query *root)
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(inner_path->total_cost - inner_path->startup_cost) * joininfactor;
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/*
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* Compute number of tuples processed (not number emitted!).
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* If inner path is an indexscan, be sure to use its estimated output row
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* count, which may be lower than the restriction-clause-only row count of
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* its parent. (We don't include this case in the PATH_ROWS macro because
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* it applies *only* to a nestloop's inner relation.) Note: it is correct
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* to use the unadjusted inner_path_rows in the above calculation for
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* joininfactor, since otherwise we'd be double-counting the selectivity
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* of the join clause being used for the index.
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* Compute number of tuples processed (not number emitted!). If inner
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* path is an indexscan, be sure to use its estimated output row
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* count, which may be lower than the restriction-clause-only row
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* count of its parent. (We don't include this case in the PATH_ROWS
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* macro because it applies *only* to a nestloop's inner relation.)
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* Note: it is correct to use the unadjusted inner_path_rows in the
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* above calculation for joininfactor, since otherwise we'd be
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* double-counting the selectivity of the join clause being used for
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* the index.
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*/
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if (IsA(inner_path, IndexPath))
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inner_path_rows = ((IndexPath *) inner_path)->rows;
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@@ -831,8 +833,8 @@ cost_mergejoin(MergePath *path, Query *root)
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Cost startup_cost = 0;
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Cost run_cost = 0;
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Cost cpu_per_tuple;
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Selectivity merge_selec;
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Selectivity qp_selec;
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Selectivity merge_selec;
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Selectivity qp_selec;
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QualCost merge_qual_cost;
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QualCost qp_qual_cost;
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RestrictInfo *firstclause;
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@@ -847,7 +849,7 @@ cost_mergejoin(MergePath *path, Query *root)
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double rescanratio;
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Selectivity outerscansel,
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innerscansel;
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Selectivity joininfactor;
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Selectivity joininfactor;
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Path sort_path; /* dummy for result of cost_sort */
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if (!enable_mergejoin)
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@@ -856,7 +858,8 @@ cost_mergejoin(MergePath *path, Query *root)
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/*
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* Compute cost and selectivity of the mergequals and qpquals (other
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* restriction clauses) separately. We use approx_selectivity here
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* for speed --- in most cases, any errors won't affect the result much.
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* for speed --- in most cases, any errors won't affect the result
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* much.
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*
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* Note: it's probably bogus to use the normal selectivity calculation
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* here when either the outer or inner path is a UniquePath.
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@@ -876,29 +879,30 @@ cost_mergejoin(MergePath *path, Query *root)
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qptuples = ceil(mergejointuples * qp_selec);
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/*
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* When there are equal merge keys in the outer relation, the mergejoin
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* must rescan any matching tuples in the inner relation. This means
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* re-fetching inner tuples. Our cost model for this is that a re-fetch
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* costs the same as an original fetch, which is probably an overestimate;
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* but on the other hand we ignore the bookkeeping costs of mark/restore.
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* Not clear if it's worth developing a more refined model.
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* When there are equal merge keys in the outer relation, the
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* mergejoin must rescan any matching tuples in the inner relation.
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* This means re-fetching inner tuples. Our cost model for this is
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* that a re-fetch costs the same as an original fetch, which is
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* probably an overestimate; but on the other hand we ignore the
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* bookkeeping costs of mark/restore. Not clear if it's worth
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* developing a more refined model.
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*
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* The number of re-fetches can be estimated approximately as size of
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* merge join output minus size of inner relation. Assume that the
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* distinct key values are 1, 2, ..., and denote the number of values of
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* each key in the outer relation as m1, m2, ...; in the inner relation,
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* n1, n2, ... Then we have
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* merge join output minus size of inner relation. Assume that the
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* distinct key values are 1, 2, ..., and denote the number of values
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* of each key in the outer relation as m1, m2, ...; in the inner
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* relation, n1, n2, ... Then we have
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*
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* size of join = m1 * n1 + m2 * n2 + ...
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* size of join = m1 * n1 + m2 * n2 + ...
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*
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* number of rescanned tuples = (m1 - 1) * n1 + (m2 - 1) * n2 + ...
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* = m1 * n1 + m2 * n2 + ... - (n1 + n2 + ...)
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* = size of join - size of inner relation
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* number of rescanned tuples = (m1 - 1) * n1 + (m2 - 1) * n2 + ... = m1 *
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* n1 + m2 * n2 + ... - (n1 + n2 + ...) = size of join - size of inner
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* relation
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*
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* This equation works correctly for outer tuples having no inner match
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* (nk = 0), but not for inner tuples having no outer match (mk = 0);
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* we are effectively subtracting those from the number of rescanned
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* tuples, when we should not. Can we do better without expensive
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* tuples, when we should not. Can we do better without expensive
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* selectivity computations?
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*/
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if (IsA(outer_path, UniquePath))
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@@ -953,8 +957,9 @@ cost_mergejoin(MergePath *path, Query *root)
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/*
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* Readjust scan selectivities to account for above rounding. This is
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* normally an insignificant effect, but when there are only a few rows
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* in the inputs, failing to do this makes for a large percentage error.
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* normally an insignificant effect, but when there are only a few
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* rows in the inputs, failing to do this makes for a large percentage
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* error.
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*/
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outerscansel = outer_rows / outer_path_rows;
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innerscansel = inner_rows / inner_path_rows;
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@@ -1002,11 +1007,11 @@ cost_mergejoin(MergePath *path, Query *root)
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/* CPU costs */
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/*
|
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* If we're doing JOIN_IN then we will stop outputting inner
|
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* tuples for an outer tuple as soon as we have one match. Account for
|
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* the effects of this by scaling down the cost estimates in proportion
|
||||
* to the expected output size. (This assumes that all the quals attached
|
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* to the join are IN quals, which should be true.)
|
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* If we're doing JOIN_IN then we will stop outputting inner tuples
|
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* for an outer tuple as soon as we have one match. Account for the
|
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* effects of this by scaling down the cost estimates in proportion to
|
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* the expected output size. (This assumes that all the quals
|
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* attached to the join are IN quals, which should be true.)
|
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*/
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if (path->jpath.jointype == JOIN_IN &&
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qptuples > path->jpath.path.parent->rows)
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@@ -1017,9 +1022,9 @@ cost_mergejoin(MergePath *path, Query *root)
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/*
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* The number of tuple comparisons needed is approximately number of
|
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* outer rows plus number of inner rows plus number of rescanned
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* tuples (can we refine this?). At each one, we need to evaluate
|
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* the mergejoin quals. NOTE: JOIN_IN mode does not save any work
|
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* here, so do NOT include joininfactor.
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* tuples (can we refine this?). At each one, we need to evaluate the
|
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* mergejoin quals. NOTE: JOIN_IN mode does not save any work here,
|
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* so do NOT include joininfactor.
|
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*/
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startup_cost += merge_qual_cost.startup;
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run_cost += merge_qual_cost.per_tuple *
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@@ -1028,7 +1033,7 @@ cost_mergejoin(MergePath *path, Query *root)
|
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/*
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* For each tuple that gets through the mergejoin proper, we charge
|
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* cpu_tuple_cost plus the cost of evaluating additional restriction
|
||||
* clauses that are to be applied at the join. (This is pessimistic
|
||||
* clauses that are to be applied at the join. (This is pessimistic
|
||||
* since not all of the quals may get evaluated at each tuple.) This
|
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* work is skipped in JOIN_IN mode, so apply the factor.
|
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*/
|
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@@ -1059,8 +1064,8 @@ cost_hashjoin(HashPath *path, Query *root)
|
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Cost startup_cost = 0;
|
||||
Cost run_cost = 0;
|
||||
Cost cpu_per_tuple;
|
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Selectivity hash_selec;
|
||||
Selectivity qp_selec;
|
||||
Selectivity hash_selec;
|
||||
Selectivity qp_selec;
|
||||
QualCost hash_qual_cost;
|
||||
QualCost qp_qual_cost;
|
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double hashjointuples;
|
||||
@@ -1076,7 +1081,7 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
int physicalbuckets;
|
||||
int numbatches;
|
||||
Selectivity innerbucketsize;
|
||||
Selectivity joininfactor;
|
||||
Selectivity joininfactor;
|
||||
List *hcl;
|
||||
List *qpquals;
|
||||
|
||||
@@ -1086,7 +1091,8 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
/*
|
||||
* Compute cost and selectivity of the hashquals and qpquals (other
|
||||
* restriction clauses) separately. We use approx_selectivity here
|
||||
* for speed --- in most cases, any errors won't affect the result much.
|
||||
* for speed --- in most cases, any errors won't affect the result
|
||||
* much.
|
||||
*
|
||||
* Note: it's probably bogus to use the normal selectivity calculation
|
||||
* here when either the outer or inner path is a UniquePath.
|
||||
@@ -1114,9 +1120,9 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
* Cost of computing hash function: must do it once per input tuple.
|
||||
* We charge one cpu_operator_cost for each column's hash function.
|
||||
*
|
||||
* XXX when a hashclause is more complex than a single operator,
|
||||
* we really should charge the extra eval costs of the left or right
|
||||
* side, as appropriate, here. This seems more work than it's worth
|
||||
* XXX when a hashclause is more complex than a single operator, we
|
||||
* really should charge the extra eval costs of the left or right
|
||||
* side, as appropriate, here. This seems more work than it's worth
|
||||
* at the moment.
|
||||
*/
|
||||
startup_cost += cpu_operator_cost * num_hashclauses * inner_path_rows;
|
||||
@@ -1131,13 +1137,13 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
|
||||
/*
|
||||
* Determine bucketsize fraction for inner relation. We use the
|
||||
* smallest bucketsize estimated for any individual hashclause;
|
||||
* this is undoubtedly conservative.
|
||||
* smallest bucketsize estimated for any individual hashclause; this
|
||||
* is undoubtedly conservative.
|
||||
*
|
||||
* BUT: if inner relation has been unique-ified, we can assume it's
|
||||
* good for hashing. This is important both because it's the right
|
||||
* answer, and because we avoid contaminating the cache with a value
|
||||
* that's wrong for non-unique-ified paths.
|
||||
* BUT: if inner relation has been unique-ified, we can assume it's good
|
||||
* for hashing. This is important both because it's the right answer,
|
||||
* and because we avoid contaminating the cache with a value that's
|
||||
* wrong for non-unique-ified paths.
|
||||
*/
|
||||
if (IsA(inner_path, UniquePath))
|
||||
innerbucketsize = 1.0 / virtualbuckets;
|
||||
@@ -1152,12 +1158,13 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
Assert(IsA(restrictinfo, RestrictInfo));
|
||||
|
||||
/*
|
||||
* First we have to figure out which side of the hashjoin clause
|
||||
* is the inner side.
|
||||
* First we have to figure out which side of the hashjoin
|
||||
* clause is the inner side.
|
||||
*
|
||||
* Since we tend to visit the same clauses over and over when
|
||||
* planning a large query, we cache the bucketsize estimate in the
|
||||
* RestrictInfo node to avoid repeated lookups of statistics.
|
||||
* planning a large query, we cache the bucketsize estimate in
|
||||
* the RestrictInfo node to avoid repeated lookups of
|
||||
* statistics.
|
||||
*/
|
||||
if (bms_is_subset(restrictinfo->right_relids,
|
||||
inner_path->parent->relids))
|
||||
@@ -1169,7 +1176,7 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
/* not cached yet */
|
||||
thisbucketsize =
|
||||
estimate_hash_bucketsize(root,
|
||||
(Var *) get_rightop(restrictinfo->clause),
|
||||
(Var *) get_rightop(restrictinfo->clause),
|
||||
virtualbuckets);
|
||||
restrictinfo->right_bucketsize = thisbucketsize;
|
||||
}
|
||||
@@ -1185,7 +1192,7 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
/* not cached yet */
|
||||
thisbucketsize =
|
||||
estimate_hash_bucketsize(root,
|
||||
(Var *) get_leftop(restrictinfo->clause),
|
||||
(Var *) get_leftop(restrictinfo->clause),
|
||||
virtualbuckets);
|
||||
restrictinfo->left_bucketsize = thisbucketsize;
|
||||
}
|
||||
@@ -1217,11 +1224,11 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
/* CPU costs */
|
||||
|
||||
/*
|
||||
* If we're doing JOIN_IN then we will stop comparing inner
|
||||
* tuples to an outer tuple as soon as we have one match. Account for
|
||||
* the effects of this by scaling down the cost estimates in proportion
|
||||
* to the expected output size. (This assumes that all the quals attached
|
||||
* to the join are IN quals, which should be true.)
|
||||
* If we're doing JOIN_IN then we will stop comparing inner tuples to
|
||||
* an outer tuple as soon as we have one match. Account for the
|
||||
* effects of this by scaling down the cost estimates in proportion to
|
||||
* the expected output size. (This assumes that all the quals
|
||||
* attached to the join are IN quals, which should be true.)
|
||||
*/
|
||||
if (path->jpath.jointype == JOIN_IN &&
|
||||
qptuples > path->jpath.path.parent->rows)
|
||||
@@ -1243,7 +1250,7 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
/*
|
||||
* For each tuple that gets through the hashjoin proper, we charge
|
||||
* cpu_tuple_cost plus the cost of evaluating additional restriction
|
||||
* clauses that are to be applied at the join. (This is pessimistic
|
||||
* clauses that are to be applied at the join. (This is pessimistic
|
||||
* since not all of the quals may get evaluated at each tuple.)
|
||||
*/
|
||||
startup_cost += qp_qual_cost.startup;
|
||||
@@ -1254,14 +1261,14 @@ cost_hashjoin(HashPath *path, Query *root)
|
||||
* Bias against putting larger relation on inside. We don't want an
|
||||
* absolute prohibition, though, since larger relation might have
|
||||
* better bucketsize --- and we can't trust the size estimates
|
||||
* unreservedly, anyway. Instead, inflate the run cost by the
|
||||
* square root of the size ratio. (Why square root? No real good
|
||||
* reason, but it seems reasonable...)
|
||||
* unreservedly, anyway. Instead, inflate the run cost by the square
|
||||
* root of the size ratio. (Why square root? No real good reason,
|
||||
* but it seems reasonable...)
|
||||
*
|
||||
* Note: before 7.4 we implemented this by inflating startup cost;
|
||||
* but if there's a disable_cost component in the input paths'
|
||||
* startup cost, that unfairly penalizes the hash. Probably it'd
|
||||
* be better to keep track of disable penalty separately from cost.
|
||||
* Note: before 7.4 we implemented this by inflating startup cost; but if
|
||||
* there's a disable_cost component in the input paths' startup cost,
|
||||
* that unfairly penalizes the hash. Probably it'd be better to keep
|
||||
* track of disable penalty separately from cost.
|
||||
*/
|
||||
if (innerbytes > outerbytes && outerbytes > 0)
|
||||
run_cost *= sqrt(innerbytes / outerbytes);
|
||||
@@ -1442,7 +1449,7 @@ estimate_hash_bucketsize(Query *root, Var *var, int nbuckets)
|
||||
* and a per-evaluation component.
|
||||
*/
|
||||
void
|
||||
cost_qual_eval(QualCost *cost, List *quals)
|
||||
cost_qual_eval(QualCost * cost, List *quals)
|
||||
{
|
||||
List *l;
|
||||
|
||||
@@ -1484,7 +1491,7 @@ cost_qual_eval(QualCost *cost, List *quals)
|
||||
}
|
||||
|
||||
static bool
|
||||
cost_qual_eval_walker(Node *node, QualCost *total)
|
||||
cost_qual_eval_walker(Node *node, QualCost * total)
|
||||
{
|
||||
if (node == NULL)
|
||||
return false;
|
||||
@@ -1502,9 +1509,7 @@ cost_qual_eval_walker(Node *node, QualCost *total)
|
||||
IsA(node, OpExpr) ||
|
||||
IsA(node, DistinctExpr) ||
|
||||
IsA(node, NullIfExpr))
|
||||
{
|
||||
total->per_tuple += cpu_operator_cost;
|
||||
}
|
||||
else if (IsA(node, ScalarArrayOpExpr))
|
||||
{
|
||||
/* should charge more than 1 op cost, but how many? */
|
||||
@@ -1519,47 +1524,48 @@ cost_qual_eval_walker(Node *node, QualCost *total)
|
||||
{
|
||||
/*
|
||||
* A subplan node in an expression typically indicates that the
|
||||
* subplan will be executed on each evaluation, so charge accordingly.
|
||||
* (Sub-selects that can be executed as InitPlans have already been
|
||||
* removed from the expression.)
|
||||
* subplan will be executed on each evaluation, so charge
|
||||
* accordingly. (Sub-selects that can be executed as InitPlans
|
||||
* have already been removed from the expression.)
|
||||
*
|
||||
* An exception occurs when we have decided we can implement the
|
||||
* subplan by hashing.
|
||||
*
|
||||
*/
|
||||
SubPlan *subplan = (SubPlan *) node;
|
||||
SubPlan *subplan = (SubPlan *) node;
|
||||
Plan *plan = subplan->plan;
|
||||
|
||||
if (subplan->useHashTable)
|
||||
{
|
||||
/*
|
||||
* If we are using a hash table for the subquery outputs, then
|
||||
* the cost of evaluating the query is a one-time cost.
|
||||
* We charge one cpu_operator_cost per tuple for the work of
|
||||
* the cost of evaluating the query is a one-time cost. We
|
||||
* charge one cpu_operator_cost per tuple for the work of
|
||||
* loading the hashtable, too.
|
||||
*/
|
||||
total->startup += plan->total_cost +
|
||||
cpu_operator_cost * plan->plan_rows;
|
||||
|
||||
/*
|
||||
* The per-tuple costs include the cost of evaluating the
|
||||
* lefthand expressions, plus the cost of probing the hashtable.
|
||||
* Recursion into the exprs list will handle the lefthand
|
||||
* expressions properly, and will count one cpu_operator_cost
|
||||
* for each comparison operator. That is probably too low for
|
||||
* the probing cost, but it's hard to make a better estimate,
|
||||
* so live with it for now.
|
||||
* lefthand expressions, plus the cost of probing the
|
||||
* hashtable. Recursion into the exprs list will handle the
|
||||
* lefthand expressions properly, and will count one
|
||||
* cpu_operator_cost for each comparison operator. That is
|
||||
* probably too low for the probing cost, but it's hard to
|
||||
* make a better estimate, so live with it for now.
|
||||
*/
|
||||
}
|
||||
else
|
||||
{
|
||||
/*
|
||||
* Otherwise we will be rescanning the subplan output on each
|
||||
* evaluation. We need to estimate how much of the output
|
||||
* we will actually need to scan. NOTE: this logic should
|
||||
* agree with the estimates used by make_subplan() in
|
||||
* evaluation. We need to estimate how much of the output we
|
||||
* will actually need to scan. NOTE: this logic should agree
|
||||
* with the estimates used by make_subplan() in
|
||||
* plan/subselect.c.
|
||||
*/
|
||||
Cost plan_run_cost = plan->total_cost - plan->startup_cost;
|
||||
Cost plan_run_cost = plan->total_cost - plan->startup_cost;
|
||||
|
||||
if (subplan->subLinkType == EXISTS_SUBLINK)
|
||||
{
|
||||
@@ -1579,23 +1585,20 @@ cost_qual_eval_walker(Node *node, QualCost *total)
|
||||
/* assume we need all tuples */
|
||||
total->per_tuple += plan_run_cost;
|
||||
}
|
||||
|
||||
/*
|
||||
* Also account for subplan's startup cost.
|
||||
* If the subplan is uncorrelated or undirect correlated,
|
||||
* AND its topmost node is a Sort or Material node, assume
|
||||
* that we'll only need to pay its startup cost once;
|
||||
* otherwise assume we pay the startup cost every time.
|
||||
* Also account for subplan's startup cost. If the subplan is
|
||||
* uncorrelated or undirect correlated, AND its topmost node
|
||||
* is a Sort or Material node, assume that we'll only need to
|
||||
* pay its startup cost once; otherwise assume we pay the
|
||||
* startup cost every time.
|
||||
*/
|
||||
if (subplan->parParam == NIL &&
|
||||
(IsA(plan, Sort) ||
|
||||
IsA(plan, Material)))
|
||||
{
|
||||
total->startup += plan->startup_cost;
|
||||
}
|
||||
else
|
||||
{
|
||||
total->per_tuple += plan->startup_cost;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
@@ -1745,7 +1748,7 @@ set_joinrel_size_estimates(Query *root, RelOptInfo *rel,
|
||||
UniquePath *upath;
|
||||
|
||||
/*
|
||||
* Compute joinclause selectivity. Note that we are only considering
|
||||
* Compute joinclause selectivity. Note that we are only considering
|
||||
* clauses that become restriction clauses at this join level; we are
|
||||
* not double-counting them because they were not considered in
|
||||
* estimating the sizes of the component rels.
|
||||
@@ -1758,8 +1761,8 @@ set_joinrel_size_estimates(Query *root, RelOptInfo *rel,
|
||||
/*
|
||||
* Basically, we multiply size of Cartesian product by selectivity.
|
||||
*
|
||||
* If we are doing an outer join, take that into account: the output
|
||||
* must be at least as large as the non-nullable input. (Is there any
|
||||
* If we are doing an outer join, take that into account: the output must
|
||||
* be at least as large as the non-nullable input. (Is there any
|
||||
* chance of being even smarter?)
|
||||
*
|
||||
* For JOIN_IN and variants, the Cartesian product is figured with
|
||||
@@ -1823,8 +1826,8 @@ set_joinrel_size_estimates(Query *root, RelOptInfo *rel,
|
||||
rel->rows = temp;
|
||||
|
||||
/*
|
||||
* We need not compute the output width here, because build_joinrel_tlist
|
||||
* already did.
|
||||
* We need not compute the output width here, because
|
||||
* build_joinrel_tlist already did.
|
||||
*/
|
||||
}
|
||||
|
||||
@@ -1911,11 +1914,14 @@ set_rel_width(Query *root, RelOptInfo *rel)
|
||||
|
||||
Assert(IsA(var, Var));
|
||||
|
||||
/* The width probably hasn't been cached yet, but may as well check */
|
||||
/*
|
||||
* The width probably hasn't been cached yet, but may as well
|
||||
* check
|
||||
*/
|
||||
if (rel->attr_widths[ndx] > 0)
|
||||
{
|
||||
tuple_width += rel->attr_widths[ndx];
|
||||
continue;
|
||||
tuple_width += rel->attr_widths[ndx];
|
||||
continue;
|
||||
}
|
||||
|
||||
relid = getrelid(var->varno, root->rtable);
|
||||
@@ -1931,8 +1937,8 @@ set_rel_width(Query *root, RelOptInfo *rel)
|
||||
}
|
||||
|
||||
/*
|
||||
* Not a plain relation, or can't find statistics for it.
|
||||
* Estimate using just the type info.
|
||||
* Not a plain relation, or can't find statistics for it. Estimate
|
||||
* using just the type info.
|
||||
*/
|
||||
item_width = get_typavgwidth(var->vartype, var->vartypmod);
|
||||
Assert(item_width > 0);
|
||||
|
||||
Reference in New Issue
Block a user