Remove local optimizations of empty Bitmapsets into null pointers.

These are all dead code now that it's done centrally.

Patch by me; thanks to Nathan Bossart and Richard Guo for review.

Discussion: https://postgr.es/m/1159933.1677621588@sss.pgh.pa.us

diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index c33a3c0bec7b2c08efa25b600a43d13f39672c06..cfa95a07e40f82f6a508e3d091aae6b09d35347e 100644 (file)
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -877,15 +877,7 @@ UpdateChangedParamSet(PlanState *node, Bitmapset *newchg)
     * include anything else into its chgParam set.
     */
    parmset = bms_intersect(node->plan->allParam, newchg);
-
-   /*
-    * Keep node->chgParam == NULL if there's not actually any members; this
-    * allows the simplest possible tests in executor node files.
-    */
-   if (!bms_is_empty(parmset))
-       node->chgParam = bms_join(node->chgParam, parmset);
-   else
-       bms_free(parmset);
+   node->chgParam = bms_join(node->chgParam, parmset);
 }
 
 /*

diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 011a0337dade5ca530c9edc6a218ef8c4addc8b2..9f4698f2a2807d0130235b462dce0b41d005e47c 100644 (file)
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -949,9 +949,6 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel,
 
    /* We do not want the index's rel itself listed in outer_relids */
    outer_relids = bms_del_member(outer_relids, rel->relid);
-   /* Enforce convention that outer_relids is exactly NULL if empty */
-   if (bms_is_empty(outer_relids))
-       outer_relids = NULL;
 
    /* Compute loop_count for cost estimation purposes */
    loop_count = get_loop_count(root, rel->relid, outer_relids);

diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 174c326cb940d33c237c9eda315db7e6f7440fc4..c6c21a73386cc694a52b5a26bb8b7c3db2905164 100644 (file)
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -679,16 +679,10 @@ create_lateral_join_info(PlannerInfo *root)
 
        /* Nothing to do at rels with no lateral refs */
        lateral_relids = brel->lateral_relids;
-       if (lateral_relids == NULL)
+       if (bms_is_empty(lateral_relids))
            continue;
 
-       /*
-        * We should not have broken the invariant that lateral_relids is
-        * exactly NULL if empty.
-        */
-       Assert(!bms_is_empty(lateral_relids));
-
-       /* Also, no rel should have a lateral dependency on itself */
+       /* No rel should have a lateral dependency on itself */
        Assert(!bms_is_member(rti, lateral_relids));
 
        /* Mark this rel's referencees */

diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index 22ffe4ca425af29d4afa9f404acdf9e5b7407a3c..052263aea6da7952d588e95d90e52fd0a1a9c91f 100644 (file)
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -2825,15 +2825,6 @@ finalize_plan(PlannerInfo *root, Plan *plan,
    /* but not any initplan setParams */
    plan->extParam = bms_del_members(plan->extParam, initSetParam);
 
-   /*
-    * For speed at execution time, make sure extParam/allParam are actually
-    * NULL if they are empty sets.
-    */
-   if (bms_is_empty(plan->extParam))
-       plan->extParam = NULL;
-   if (bms_is_empty(plan->allParam))
-       plan->allParam = NULL;
-
    return plan->allParam;
 }
 

diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index d749b5057853a9a09f160fa81aa384e5efcdeb2a..e8e06397a9c00888c5d225b75688ca6bae4c01d3 100644 (file)
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -2372,12 +2372,6 @@ calc_nestloop_required_outer(Relids outerrelids,
    /* ... and remove any mention of now-satisfied outer rels */
    required_outer = bms_del_members(required_outer,
                                     outerrelids);
-   /* maintain invariant that required_outer is exactly NULL if empty */
-   if (bms_is_empty(required_outer))
-   {
-       bms_free(required_outer);
-       required_outer = NULL;
-   }
    return required_outer;
 }
 

diff --git a/src/backend/optimizer/util/placeholder.c b/src/backend/optimizer/util/placeholder.c
index 9c6cb5eba7dfdb095fbf47e4f05cc3d1a1b46ce8..b1723578e6f9dbcc772f47c81f1775c735f329a1 100644 (file)
--- a/src/backend/optimizer/util/placeholder.c
+++ b/src/backend/optimizer/util/placeholder.c
@@ -125,8 +125,6 @@ find_placeholder_info(PlannerInfo *root, PlaceHolderVar *phv)
     */
    rels_used = pull_varnos(root, (Node *) phv->phexpr);
    phinfo->ph_lateral = bms_difference(rels_used, phv->phrels);
-   if (bms_is_empty(phinfo->ph_lateral))
-       phinfo->ph_lateral = NULL;  /* make it exactly NULL if empty */
    phinfo->ph_eval_at = bms_int_members(rels_used, phv->phrels);
    /* If no contained vars, force evaluation at syntactic location */
    if (bms_is_empty(phinfo->ph_eval_at))

diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index 9ad44a0508cc6e7fa9c03d01eca0e1827bd7e3a1..68fd03359522394169e8f254fbc52f482ded8f75 100644 (file)
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -772,8 +772,6 @@ build_join_rel(PlannerInfo *root,
     */
    joinrel->direct_lateral_relids =
        bms_del_members(joinrel->direct_lateral_relids, joinrel->relids);
-   if (bms_is_empty(joinrel->direct_lateral_relids))
-       joinrel->direct_lateral_relids = NULL;
 
    /*
     * Construct restrict and join clause lists for the new joinrel. (The
@@ -1024,11 +1022,6 @@ min_join_parameterization(PlannerInfo *root,
     */
    result = bms_union(outer_rel->lateral_relids, inner_rel->lateral_relids);
    result = bms_del_members(result, joinrelids);
-
-   /* Maintain invariant that result is exactly NULL if empty */
-   if (bms_is_empty(result))
-       result = NULL;
-
    return result;
 }
 

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 04718f66c0bc1810d9f94750f7020091ff0b8544..d28d0da62140ed56c3ad7dd78a6c51978f8a513e 100644 (file)
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1247,16 +1247,11 @@ remove_nulling_relids_mutator(Node *node,
            !bms_is_member(var->varno, context->except_relids) &&
            bms_overlap(var->varnullingrels, context->removable_relids))
        {
-           Relids      newnullingrels = bms_difference(var->varnullingrels,
-                                                       context->removable_relids);
-
-           /* Micro-optimization: ensure nullingrels is NULL if empty */
-           if (bms_is_empty(newnullingrels))
-               newnullingrels = NULL;
            /* Copy the Var ... */
            var = copyObject(var);
            /* ... and replace the copy's varnullingrels field */
-           var->varnullingrels = newnullingrels;
+           var->varnullingrels = bms_difference(var->varnullingrels,
+                                                context->removable_relids);
            return (Node *) var;
        }
        /* Otherwise fall through to copy the Var normally */
@@ -1268,26 +1263,20 @@ remove_nulling_relids_mutator(Node *node,
        if (phv->phlevelsup == context->sublevels_up &&
            !bms_overlap(phv->phrels, context->except_relids))
        {
-           Relids      newnullingrels = bms_difference(phv->phnullingrels,
-                                                       context->removable_relids);
-
            /*
-            * Micro-optimization: ensure nullingrels is NULL if empty.
-            *
             * Note: it might seem desirable to remove the PHV altogether if
             * phnullingrels goes to empty.  Currently we dare not do that
             * because we use PHVs in some cases to enforce separate identity
             * of subexpressions; see wrap_non_vars usages in prepjointree.c.
             */
-           if (bms_is_empty(newnullingrels))
-               newnullingrels = NULL;
            /* Copy the PlaceHolderVar and mutate what's below ... */
            phv = (PlaceHolderVar *)
                expression_tree_mutator(node,
                                        remove_nulling_relids_mutator,
                                        (void *) context);
            /* ... and replace the copy's phnullingrels field */
-           phv->phnullingrels = newnullingrels;
+           phv->phnullingrels = bms_difference(phv->phnullingrels,
+                                               context->removable_relids);
            /* We must also update phrels, if it contains a removable RTI */
            phv->phrels = bms_difference(phv->phrels,
                                         context->removable_relids);

diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index ffd6d2e3bc3b46de0cfa7929d58b503e27789ce3..b0a2cac2276e21cadbc33ea2a7191354ac42404e 100644 (file)
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -6240,12 +6240,9 @@ setup_param_list(PLpgSQL_execstate *estate, PLpgSQL_expr *expr)
    Assert(expr->plan != NULL);
 
    /*
-    * We only need a ParamListInfo if the expression has parameters.  In
-    * principle we should test with bms_is_empty(), but we use a not-null
-    * test because it's faster.  In current usage bits are never removed from
-    * expr->paramnos, only added, so this test is correct anyway.
+    * We only need a ParamListInfo if the expression has parameters.
     */
-   if (expr->paramnos)
+   if (!bms_is_empty(expr->paramnos))
    {
        /* Use the common ParamListInfo */
        paramLI = estate->paramLI;