Rationalize use of list_concat + list_copy combinations.
authorTom Lane <tgl@sss.pgh.pa.us>
Mon, 12 Aug 2019 15:20:18 +0000 (11:20 -0400)
committerTom Lane <tgl@sss.pgh.pa.us>
Mon, 12 Aug 2019 15:20:18 +0000 (11:20 -0400)
In the wake of commit 1cff1b95a, the result of list_concat no longer
shares the ListCells of the second input.  Therefore, we can replace
"list_concat(x, list_copy(y))" with just "list_concat(x, y)".

To improve call sites that were list_copy'ing the first argument,
or both arguments, invent "list_concat_copy()" which produces a new
list sharing no ListCells with either input.  (This is a bit faster
than "list_concat(list_copy(x), y)" because it makes the result list
the right size to start with.)

In call sites that were not list_copy'ing the second argument, the new
semantics mean that we are usually leaking the second List's storage,
since typically there is no remaining pointer to it.  We considered
inventing another list_copy variant that would list_free the second
input, but concluded that for most call sites it isn't worth worrying
about, given the relative compactness of the new List representation.
(Note that in cases where such leakage would happen, the old code
already leaked the second List's header; so we're only discussing
the size of the leak not whether there is one.  I did adjust two or
three places that had been troubling to free that header so that
they manually free the whole second List.)

Patch by me; thanks to David Rowley for review.

Discussion: https://postgr.es/m/11587.1550975080@sss.pgh.pa.us

26 files changed:
contrib/postgres_fdw/deparse.c
contrib/postgres_fdw/postgres_fdw.c
src/backend/commands/indexcmds.c
src/backend/executor/functions.c
src/backend/nodes/list.c
src/backend/optimizer/path/allpaths.c
src/backend/optimizer/path/costsize.c
src/backend/optimizer/path/indxpath.c
src/backend/optimizer/plan/createplan.c
src/backend/optimizer/plan/initsplan.c
src/backend/optimizer/plan/planner.c
src/backend/optimizer/plan/setrefs.c
src/backend/optimizer/prep/prepjointree.c
src/backend/optimizer/prep/prepqual.c
src/backend/optimizer/util/clauses.c
src/backend/optimizer/util/orclauses.c
src/backend/optimizer/util/relnode.c
src/backend/optimizer/util/tlist.c
src/backend/parser/parse_agg.c
src/backend/parser/parse_clause.c
src/backend/partitioning/partprune.c
src/backend/replication/syncrep.c
src/backend/rewrite/rewriteHandler.c
src/backend/utils/adt/ruleutils.c
src/backend/utils/adt/selfuncs.c
src/include/nodes/pg_list.h

index 19f928ec598d55ee46975558844c6fcee9bfb8a3..431c34a424629d846e620eae8b571df9cf4e255a 100644 (file)
@@ -1497,7 +1497,7 @@ deparseFromExprForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
            if (fpinfo->jointype == JOIN_INNER)
            {
                *ignore_conds = list_concat(*ignore_conds,
-                                           list_copy(fpinfo->joinclauses));
+                                           fpinfo->joinclauses);
                fpinfo->joinclauses = NIL;
            }
 
index 06a205877d7c32e5f45efe502709bf4046c575f5..82d8140ba255eab61e2149601daa24fec1f645ce 100644 (file)
@@ -2667,7 +2667,7 @@ estimate_path_cost_size(PlannerInfo *root,
         * baserestrictinfo plus any extra join_conds relevant to this
         * particular path.
         */
-       remote_conds = list_concat(list_copy(remote_param_join_conds),
+       remote_conds = list_concat(remote_param_join_conds,
                                   fpinfo->remote_conds);
 
        /*
@@ -5102,23 +5102,23 @@ foreign_join_ok(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype,
    {
        case JOIN_INNER:
            fpinfo->remote_conds = list_concat(fpinfo->remote_conds,
-                                              list_copy(fpinfo_i->remote_conds));
+                                              fpinfo_i->remote_conds);
            fpinfo->remote_conds = list_concat(fpinfo->remote_conds,
-                                              list_copy(fpinfo_o->remote_conds));
+                                              fpinfo_o->remote_conds);
            break;
 
        case JOIN_LEFT:
            fpinfo->joinclauses = list_concat(fpinfo->joinclauses,
-                                             list_copy(fpinfo_i->remote_conds));
+                                             fpinfo_i->remote_conds);
            fpinfo->remote_conds = list_concat(fpinfo->remote_conds,
-                                              list_copy(fpinfo_o->remote_conds));
+                                              fpinfo_o->remote_conds);
            break;
 
        case JOIN_RIGHT:
            fpinfo->joinclauses = list_concat(fpinfo->joinclauses,
-                                             list_copy(fpinfo_o->remote_conds));
+                                             fpinfo_o->remote_conds);
            fpinfo->remote_conds = list_concat(fpinfo->remote_conds,
-                                              list_copy(fpinfo_i->remote_conds));
+                                              fpinfo_i->remote_conds);
            break;
 
        case JOIN_FULL:
index 8dc7a3987066f9d5d143f172e12df788887e0392..ef9539537119bf1a1d740dc776864b16a6ee05d2 100644 (file)
@@ -516,8 +516,8 @@ DefineIndex(Oid relationId,
     * is part of the key columns, and anything equal to and over is part of
     * the INCLUDE columns.
     */
-   allIndexParams = list_concat(list_copy(stmt->indexParams),
-                                list_copy(stmt->indexIncludingParams));
+   allIndexParams = list_concat_copy(stmt->indexParams,
+                                     stmt->indexIncludingParams);
    numberOfAttributes = list_length(allIndexParams);
 
    if (numberOfAttributes <= 0)
index 64a9e584627fc27d6eaefd1c4b2be9edf72314af..83337c2eed41380750d5fb2fd76eecf78c0001b2 100644 (file)
@@ -719,8 +719,7 @@ init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
                                                          fcache->pinfo,
                                                          NULL);
        queryTree_list = lappend(queryTree_list, queryTree_sublist);
-       flat_query_list = list_concat(flat_query_list,
-                                     list_copy(queryTree_sublist));
+       flat_query_list = list_concat(flat_query_list, queryTree_sublist);
    }
 
    check_sql_fn_statements(flat_query_list);
index 9163464de24dff9e128288ee74c74fcc97cc6e9f..6bf13ae0d4a24ef4a29b441c91b8611dfe28e0bf 100644 (file)
@@ -501,12 +501,15 @@ lcons_oid(Oid datum, List *list)
 }
 
 /*
- * Concatenate list2 to the end of list1, and return list1. list1 is
- * destructively changed, list2 is not. (However, in the case of pointer
- * lists, list1 and list2 will point to the same structures.) Callers
- * should be sure to use the return value as the new pointer to the
- * concatenated list: the 'list1' input pointer may or may not be the
- * same as the returned pointer.
+ * Concatenate list2 to the end of list1, and return list1.
+ *
+ * This is equivalent to lappend'ing each element of list2, in order, to list1.
+ * list1 is destructively changed, list2 is not.  (However, in the case of
+ * pointer lists, list1 and list2 will point to the same structures.)
+ *
+ * Callers should be sure to use the return value as the new pointer to the
+ * concatenated list: the 'list1' input pointer may or may not be the same
+ * as the returned pointer.
  */
 List *
 list_concat(List *list1, const List *list2)
@@ -534,6 +537,41 @@ list_concat(List *list1, const List *list2)
    return list1;
 }
 
+/*
+ * Form a new list by concatenating the elements of list1 and list2.
+ *
+ * Neither input list is modified.  (However, if they are pointer lists,
+ * the output list will point to the same structures.)
+ *
+ * This is equivalent to, but more efficient than,
+ * list_concat(list_copy(list1), list2).
+ * Note that some pre-v13 code might list_copy list2 as well, but that's
+ * pointless now.
+ */
+List *
+list_concat_copy(const List *list1, const List *list2)
+{
+   List       *result;
+   int         new_len;
+
+   if (list1 == NIL)
+       return list_copy(list2);
+   if (list2 == NIL)
+       return list_copy(list1);
+
+   Assert(list1->type == list2->type);
+
+   new_len = list1->length + list2->length;
+   result = new_list(list1->type, new_len);
+   memcpy(result->elements, list1->elements,
+          list1->length * sizeof(ListCell));
+   memcpy(result->elements + list1->length, list2->elements,
+          list2->length * sizeof(ListCell));
+
+   check_list_invariants(result);
+   return result;
+}
+
 /*
  * Truncate 'list' to contain no more than 'new_size' elements. This
  * modifies the list in-place! Despite this, callers should use the
index e9ee32b7f439d0e00d94dca353cb93eae05b925d..db3a68a51dd47e57930033d8f48791f79db94abc 100644 (file)
@@ -1266,7 +1266,7 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
        if (rel->part_scheme)
            rel->partitioned_child_rels =
                list_concat(rel->partitioned_child_rels,
-                           list_copy(childrel->partitioned_child_rels));
+                           childrel->partitioned_child_rels);
 
        /*
         * Child is live, so add it to the live_childrels list for use below.
@@ -1347,9 +1347,8 @@ add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
                component = root->simple_rel_array[relid];
                Assert(component->part_scheme != NULL);
                Assert(list_length(component->partitioned_child_rels) >= 1);
-               partrels =
-                   list_concat(partrels,
-                               list_copy(component->partitioned_child_rels));
+               partrels = list_concat(partrels,
+                                      component->partitioned_child_rels);
            }
 
            partitioned_rels = list_make1(partrels);
@@ -2048,8 +2047,7 @@ accumulate_append_subpath(Path *path, List **subpaths, List **special_subpaths)
 
        if (!apath->path.parallel_aware || apath->first_partial_path == 0)
        {
-           /* list_copy is important here to avoid sharing list substructure */
-           *subpaths = list_concat(*subpaths, list_copy(apath->subpaths));
+           *subpaths = list_concat(*subpaths, apath->subpaths);
            return;
        }
        else if (special_subpaths != NULL)
@@ -2072,8 +2070,7 @@ accumulate_append_subpath(Path *path, List **subpaths, List **special_subpaths)
    {
        MergeAppendPath *mpath = (MergeAppendPath *) path;
 
-       /* list_copy is important here to avoid sharing list substructure */
-       *subpaths = list_concat(*subpaths, list_copy(mpath->subpaths));
+       *subpaths = list_concat(*subpaths, mpath->subpaths);
        return;
    }
 
index 3a9a994733b42384ce56c2373b79c328343c5793..bc6bc9995738ed738643201438528c63e2fa0ca6 100644 (file)
@@ -4443,8 +4443,7 @@ get_parameterized_baserel_size(PlannerInfo *root, RelOptInfo *rel,
     * restriction clauses.  Note that we force the clauses to be treated as
     * non-join clauses during selectivity estimation.
     */
-   allclauses = list_concat(list_copy(param_clauses),
-                            rel->baserestrictinfo);
+   allclauses = list_concat_copy(param_clauses, rel->baserestrictinfo);
    nrows = rel->tuples *
        clauselist_selectivity(root,
                               allclauses,
index 5f339fdfde77e2df652c781c3b6919c5150e88f8..37b257cd0e91e7f64be9604da39f57c9422115b9 100644 (file)
@@ -656,7 +656,7 @@ get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
            }
        }
 
-       /* Add restriction clauses (this is nondestructive to rclauseset) */
+       /* Add restriction clauses */
        clauseset.indexclauses[indexcol] =
            list_concat(clauseset.indexclauses[indexcol],
                        rclauseset->indexclauses[indexcol]);
@@ -1204,8 +1204,7 @@ build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
            {
                /* Form all_clauses if not done already */
                if (all_clauses == NIL)
-                   all_clauses = list_concat(list_copy(clauses),
-                                             other_clauses);
+                   all_clauses = list_concat_copy(clauses, other_clauses);
 
                if (!predicate_implied_by(index->indpred, all_clauses, false))
                    continue;   /* can't use it at all */
@@ -1270,7 +1269,7 @@ generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
     * We can use both the current and other clauses as context for
     * build_paths_for_OR; no need to remove ORs from the lists.
     */
-   all_clauses = list_concat(list_copy(clauses), other_clauses);
+   all_clauses = list_concat_copy(clauses, other_clauses);
 
    foreach(lc, clauses)
    {
@@ -1506,8 +1505,7 @@ choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
        pathinfo = pathinfoarray[i];
        paths = list_make1(pathinfo->path);
        costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
-       qualsofar = list_concat(list_copy(pathinfo->quals),
-                               list_copy(pathinfo->preds));
+       qualsofar = list_concat_copy(pathinfo->quals, pathinfo->preds);
        clauseidsofar = bms_copy(pathinfo->clauseids);
 
        for (j = i + 1; j < npaths; j++)
@@ -1543,10 +1541,8 @@ choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
            {
                /* keep new path in paths, update subsidiary variables */
                costsofar = newcost;
-               qualsofar = list_concat(qualsofar,
-                                       list_copy(pathinfo->quals));
-               qualsofar = list_concat(qualsofar,
-                                       list_copy(pathinfo->preds));
+               qualsofar = list_concat(qualsofar, pathinfo->quals);
+               qualsofar = list_concat(qualsofar, pathinfo->preds);
                clauseidsofar = bms_add_members(clauseidsofar,
                                                pathinfo->clauseids);
            }
@@ -1849,7 +1845,7 @@ find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
 
            *quals = lappend(*quals, iclause->rinfo->clause);
        }
-       *preds = list_concat(*preds, list_copy(ipath->indexinfo->indpred));
+       *preds = list_concat(*preds, ipath->indexinfo->indpred);
    }
    else
        elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
index f2325694c53d2dd124585f091e5d2336b30e0c54..0c036209f09f6335cea2aae592a656eb9cf19235 100644 (file)
@@ -559,8 +559,8 @@ create_scan_plan(PlannerInfo *root, Path *best_path, int flags)
     * For paranoia's sake, don't modify the stored baserestrictinfo list.
     */
    if (best_path->param_info)
-       scan_clauses = list_concat(list_copy(scan_clauses),
-                                  best_path->param_info->ppi_clauses);
+       scan_clauses = list_concat_copy(scan_clauses,
+                                       best_path->param_info->ppi_clauses);
 
    /*
     * Detect whether we have any pseudoconstant quals to deal with.  Then, if
index 73da0c2d8e1d3e45fa080c26fad2b640b82a51f5..274fea076cb9c74005ee513f6d69a8f8fe6170a3 100644 (file)
@@ -973,7 +973,6 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
                *postponed_qual_list = lappend(*postponed_qual_list, pq);
            }
        }
-       /* list_concat is nondestructive of its second argument */
        my_quals = list_concat(my_quals, (List *) j->quals);
 
        /*
index 0f918dd358dcba37cada82b131c2135896e20df0..17c5f086fbf4479fa41270fb56f32d71523295b3 100644 (file)
@@ -3572,10 +3572,6 @@ reorder_grouping_sets(List *groupingsets, List *sortclause)
            }
        }
 
-       /*
-        * Safe to use list_concat (which shares cells of the second arg)
-        * because we know that new_elems does not share cells with anything.
-        */
        previous = list_concat(previous, new_elems);
 
        gs->set = list_copy(previous);
@@ -4287,8 +4283,8 @@ consider_groupingsets_paths(PlannerInfo *root,
             */
            if (!rollup->hashable)
                return;
-           else
-               sets_data = list_concat(sets_data, list_copy(rollup->gsets_data));
+
+           sets_data = list_concat(sets_data, rollup->gsets_data);
        }
        foreach(lc, sets_data)
        {
@@ -4473,7 +4469,7 @@ consider_groupingsets_paths(PlannerInfo *root,
                    {
                        if (bms_is_member(i, hash_items))
                            hash_sets = list_concat(hash_sets,
-                                                   list_copy(rollup->gsets_data));
+                                                   rollup->gsets_data);
                        else
                            rollups = lappend(rollups, rollup);
                        ++i;
@@ -5642,8 +5638,7 @@ make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc,
                 errdetail("Window ordering columns must be of sortable datatypes.")));
 
    /* Okay, make the combined pathkeys */
-   window_sortclauses = list_concat(list_copy(wc->partitionClause),
-                                    list_copy(wc->orderClause));
+   window_sortclauses = list_concat_copy(wc->partitionClause, wc->orderClause);
    window_pathkeys = make_pathkeys_for_sortclauses(root,
                                                    window_sortclauses,
                                                    tlist);
index 329ebd5f287e9fec12236b4120abbffec358514e..566ee96da8c65e235a1c36469cbb7dce67b958ef 100644 (file)
@@ -893,7 +893,7 @@ set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset)
                splan->resultRelIndex = list_length(root->glob->resultRelations);
                root->glob->resultRelations =
                    list_concat(root->glob->resultRelations,
-                               list_copy(splan->resultRelations));
+                               splan->resultRelations);
 
                /*
                 * If the main target relation is a partitioned table, also
index ccb32530ad2fddda083ff57979b3cd135cc3e7b1..d13cb5822725664e601502d60b0a7537b91a90a4 100644 (file)
@@ -2659,7 +2659,6 @@ reduce_outer_joins_pass2(Node *jtnode,
        pass_nonnullable_rels = find_nonnullable_rels(f->quals);
        pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels,
                                                nonnullable_rels);
-       /* NB: we rely on list_concat to not damage its second argument */
        pass_nonnullable_vars = find_nonnullable_vars(f->quals);
        pass_nonnullable_vars = list_concat(pass_nonnullable_vars,
                                            nonnullable_vars);
index e9a94976b73b34ade1109ed0e34f8e17510616b3..ee919575c528b19cc74c39dc38fdf2a5cfad7200 100644 (file)
@@ -328,12 +328,6 @@ pull_ands(List *andlist)
    {
        Node       *subexpr = (Node *) lfirst(arg);
 
-       /*
-        * Note: we can destructively concat the subexpression's arglist
-        * because we know the recursive invocation of pull_ands will have
-        * built a new arglist not shared with any other expr. Otherwise we'd
-        * need a list_copy here.
-        */
        if (is_andclause(subexpr))
            out_list = list_concat(out_list,
                                   pull_ands(((BoolExpr *) subexpr)->args));
@@ -360,12 +354,6 @@ pull_ors(List *orlist)
    {
        Node       *subexpr = (Node *) lfirst(arg);
 
-       /*
-        * Note: we can destructively concat the subexpression's arglist
-        * because we know the recursive invocation of pull_ors will have
-        * built a new arglist not shared with any other expr. Otherwise we'd
-        * need a list_copy here.
-        */
        if (is_orclause(subexpr))
            out_list = list_concat(out_list,
                                   pull_ors(((BoolExpr *) subexpr)->args));
index 7ad9d9ab79e7fc65626e527cf463de0ffaba8854..a04b62274d221ecf6d80f54259e5ab33443a4734 100644 (file)
@@ -1009,8 +1009,8 @@ max_parallel_hazard_walker(Node *node, max_parallel_hazard_context *context)
            max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
            return true;
        save_safe_param_ids = context->safe_param_ids;
-       context->safe_param_ids = list_concat(list_copy(subplan->paramIds),
-                                             context->safe_param_ids);
+       context->safe_param_ids = list_concat_copy(context->safe_param_ids,
+                                                  subplan->paramIds);
        if (max_parallel_hazard_walker(subplan->testexpr, context))
            return true;        /* no need to restore safe_param_ids */
        list_free(context->safe_param_ids);
@@ -3697,18 +3697,12 @@ simplify_or_arguments(List *args,
        /* flatten nested ORs as per above comment */
        if (is_orclause(arg))
        {
-           List       *subargs = list_copy(((BoolExpr *) arg)->args);
+           List       *subargs = ((BoolExpr *) arg)->args;
+           List       *oldlist = unprocessed_args;
 
-           /* overly tense code to avoid leaking unused list header */
-           if (!unprocessed_args)
-               unprocessed_args = subargs;
-           else
-           {
-               List       *oldhdr = unprocessed_args;
-
-               unprocessed_args = list_concat(subargs, unprocessed_args);
-               pfree(oldhdr);
-           }
+           unprocessed_args = list_concat_copy(subargs, unprocessed_args);
+           /* perhaps-overly-tense code to avoid leaking old lists */
+           list_free(oldlist);
            continue;
        }
 
@@ -3718,14 +3712,14 @@ simplify_or_arguments(List *args,
        /*
         * It is unlikely but not impossible for simplification of a non-OR
         * clause to produce an OR.  Recheck, but don't be too tense about it
-        * since it's not a mainstream case. In particular we don't worry
-        * about const-simplifying the input twice.
+        * since it's not a mainstream case.  In particular we don't worry
+        * about const-simplifying the input twice, nor about list leakage.
         */
        if (is_orclause(arg))
        {
-           List       *subargs = list_copy(((BoolExpr *) arg)->args);
+           List       *subargs = ((BoolExpr *) arg)->args;
 
-           unprocessed_args = list_concat(subargs, unprocessed_args);
+           unprocessed_args = list_concat_copy(subargs, unprocessed_args);
            continue;
        }
 
@@ -3799,18 +3793,12 @@ simplify_and_arguments(List *args,
        /* flatten nested ANDs as per above comment */
        if (is_andclause(arg))
        {
-           List       *subargs = list_copy(((BoolExpr *) arg)->args);
+           List       *subargs = ((BoolExpr *) arg)->args;
+           List       *oldlist = unprocessed_args;
 
-           /* overly tense code to avoid leaking unused list header */
-           if (!unprocessed_args)
-               unprocessed_args = subargs;
-           else
-           {
-               List       *oldhdr = unprocessed_args;
-
-               unprocessed_args = list_concat(subargs, unprocessed_args);
-               pfree(oldhdr);
-           }
+           unprocessed_args = list_concat_copy(subargs, unprocessed_args);
+           /* perhaps-overly-tense code to avoid leaking old lists */
+           list_free(oldlist);
            continue;
        }
 
@@ -3820,14 +3808,14 @@ simplify_and_arguments(List *args,
        /*
         * It is unlikely but not impossible for simplification of a non-AND
         * clause to produce an AND.  Recheck, but don't be too tense about it
-        * since it's not a mainstream case. In particular we don't worry
-        * about const-simplifying the input twice.
+        * since it's not a mainstream case.  In particular we don't worry
+        * about const-simplifying the input twice, nor about list leakage.
         */
        if (is_andclause(arg))
        {
-           List       *subargs = list_copy(((BoolExpr *) arg)->args);
+           List       *subargs = ((BoolExpr *) arg)->args;
 
-           unprocessed_args = list_concat(subargs, unprocessed_args);
+           unprocessed_args = list_concat_copy(subargs, unprocessed_args);
            continue;
        }
 
@@ -4188,7 +4176,7 @@ add_function_defaults(List *args, HeapTuple func_tuple)
        defaults = list_copy_tail(defaults, ndelete);
 
    /* And form the combined argument list, not modifying the input list */
-   return list_concat(list_copy(args), defaults);
+   return list_concat_copy(args, defaults);
 }
 
 /*
index 18ebc51bcac38e17ce2816b791b8d5ee7a46fca5..412a3964c30b1a4b4935aa220b618e45cadac8a9 100644 (file)
@@ -236,7 +236,7 @@ extract_or_clause(RestrictInfo *or_rinfo, RelOptInfo *rel)
        subclause = (Node *) make_ands_explicit(subclauses);
        if (is_orclause(subclause))
            clauselist = list_concat(clauselist,
-                                    list_copy(((BoolExpr *) subclause)->args));
+                                    ((BoolExpr *) subclause)->args);
        else
            clauselist = lappend(clauselist, subclause);
    }
index 582c5dd979be24a7d7a141c8ca6c8efd792cd7b0..19e5a449f7577e73507abe33b8a459c87c671983 100644 (file)
@@ -1718,43 +1718,39 @@ build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel,
     */
    for (cnt = 0; cnt < partnatts; cnt++)
    {
-       List       *outer_expr;
-       List       *outer_null_expr;
-       List       *inner_expr;
-       List       *inner_null_expr;
+       /* mark these const to enforce that we copy them properly */
+       const List *outer_expr = outer_rel->partexprs[cnt];
+       const List *outer_null_expr = outer_rel->nullable_partexprs[cnt];
+       const List *inner_expr = inner_rel->partexprs[cnt];
+       const List *inner_null_expr = inner_rel->nullable_partexprs[cnt];
        List       *partexpr = NIL;
        List       *nullable_partexpr = NIL;
 
-       outer_expr = list_copy(outer_rel->partexprs[cnt]);
-       outer_null_expr = list_copy(outer_rel->nullable_partexprs[cnt]);
-       inner_expr = list_copy(inner_rel->partexprs[cnt]);
-       inner_null_expr = list_copy(inner_rel->nullable_partexprs[cnt]);
-
        switch (jointype)
        {
            case JOIN_INNER:
-               partexpr = list_concat(outer_expr, inner_expr);
-               nullable_partexpr = list_concat(outer_null_expr,
-                                               inner_null_expr);
+               partexpr = list_concat_copy(outer_expr, inner_expr);
+               nullable_partexpr = list_concat_copy(outer_null_expr,
+                                                    inner_null_expr);
                break;
 
            case JOIN_SEMI:
            case JOIN_ANTI:
-               partexpr = outer_expr;
-               nullable_partexpr = outer_null_expr;
+               partexpr = list_copy(outer_expr);
+               nullable_partexpr = list_copy(outer_null_expr);
                break;
 
            case JOIN_LEFT:
-               partexpr = outer_expr;
-               nullable_partexpr = list_concat(inner_expr,
-                                               outer_null_expr);
+               partexpr = list_copy(outer_expr);
+               nullable_partexpr = list_concat_copy(inner_expr,
+                                                    outer_null_expr);
                nullable_partexpr = list_concat(nullable_partexpr,
                                                inner_null_expr);
                break;
 
            case JOIN_FULL:
-               nullable_partexpr = list_concat(outer_expr,
-                                               inner_expr);
+               nullable_partexpr = list_concat_copy(outer_expr,
+                                                    inner_expr);
                nullable_partexpr = list_concat(nullable_partexpr,
                                                outer_null_expr);
                nullable_partexpr = list_concat(nullable_partexpr,
index 7ccb10e4e1bcdc3d5daf22dca09b65ede47bcc30..d75796ac8b9859253947b01f8830f7a41be105a6 100644 (file)
@@ -665,9 +665,8 @@ make_tlist_from_pathtarget(PathTarget *target)
  * copy_pathtarget
  *   Copy a PathTarget.
  *
- * The new PathTarget has its own List cells, but shares the underlying
- * target expression trees with the old one.  We duplicate the List cells
- * so that items can be added to one target without damaging the other.
+ * The new PathTarget has its own exprs List, but shares the underlying
+ * target expression trees with the old one.
  */
 PathTarget *
 copy_pathtarget(PathTarget *src)
index 354030e549b76190fc3147fc4c475523afd2823d..f418c6154586198e3251bb51da1cec195fd53d64 100644 (file)
@@ -1649,9 +1649,8 @@ expand_groupingset_node(GroupingSet *gs)
 
                        Assert(gs_current->kind == GROUPING_SET_SIMPLE);
 
-                       current_result
-                           = list_concat(current_result,
-                                         list_copy(gs_current->content));
+                       current_result = list_concat(current_result,
+                                                    gs_current->content);
 
                        /* If we are done with making the current group, break */
                        if (--i == 0)
@@ -1691,11 +1690,8 @@ expand_groupingset_node(GroupingSet *gs)
                        Assert(gs_current->kind == GROUPING_SET_SIMPLE);
 
                        if (mask & i)
-                       {
-                           current_result
-                               = list_concat(current_result,
-                                             list_copy(gs_current->content));
-                       }
+                           current_result = list_concat(current_result,
+                                                        gs_current->content);
 
                        mask <<= 1;
                    }
index 2a6b2ff153bb3b784845b7d921ac06d5a0e85326..260ccd4d7fa42354d3139c2e5fb3eb36d392f1ef 100644 (file)
@@ -1214,9 +1214,6 @@ transformFromClauseItem(ParseState *pstate, Node *n,
         *
         * Notice that we don't require the merged namespace list to be
         * conflict-free.  See the comments for scanNameSpaceForRefname().
-        *
-        * NB: this coding relies on the fact that list_concat is not
-        * destructive to its second argument.
         */
        lateral_ok = (j->jointype == JOIN_INNER || j->jointype == JOIN_LEFT);
        setNamespaceLateralState(l_namespace, true, lateral_ok);
@@ -2116,9 +2113,7 @@ flatten_grouping_sets(Node *expr, bool toplevel, bool *hasGroupingSets)
 
                    if (IsA(n1, GroupingSet) &&
                        ((GroupingSet *) n1)->kind == GROUPING_SET_SETS)
-                   {
                        result_set = list_concat(result_set, (List *) n2);
-                   }
                    else
                        result_set = lappend(result_set, n2);
                }
index 2ee47b8c8a92555bf179f54e679e2f6ea6cbc90a..a1bd4efd0b049710ee89246a6625316d9ed65dd3 100644 (file)
@@ -642,8 +642,8 @@ gen_partprune_steps(RelOptInfo *rel, List *clauses, PartClauseTarget target,
        if (rel->relid != 1)
            ChangeVarNodes((Node *) partqual, 1, rel->relid, 0);
 
-       /* Use list_copy to avoid modifying the passed-in List */
-       clauses = list_concat(list_copy(clauses), partqual);
+       /* Make a copy to avoid modifying the passed-in List */
+       clauses = list_concat_copy(clauses, partqual);
    }
 
    /* Down into the rabbit-hole. */
@@ -1485,7 +1485,7 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
                                                          pc->keyno,
                                                          NULL,
                                                          prefix);
-                       opsteps = list_concat(opsteps, list_copy(pc_steps));
+                       opsteps = list_concat(opsteps, pc_steps);
                    }
                }
                break;
@@ -1556,7 +1556,7 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
                                                   pc->keyno,
                                                   nullkeys,
                                                   prefix);
-                       opsteps = list_concat(opsteps, list_copy(pc_steps));
+                       opsteps = list_concat(opsteps, pc_steps);
                    }
                }
                break;
index 79c7c13ada0989adeb63e5e1aed2b3eadc510a10..a21f7d334713cf796331ebe7dd07db599f0a9c43 100644 (file)
@@ -865,8 +865,6 @@ SyncRepGetSyncStandbysPriority(bool *am_sync)
     */
    if (list_length(result) + list_length(pending) <= SyncRepConfig->num_sync)
    {
-       bool        needfree = (result != NIL && pending != NIL);
-
        /*
         * Set *am_sync to true if this walsender is in the pending list
         * because all pending standbys are considered as sync.
@@ -875,8 +873,7 @@ SyncRepGetSyncStandbysPriority(bool *am_sync)
            *am_sync = am_in_pending;
 
        result = list_concat(result, pending);
-       if (needfree)
-           pfree(pending);
+       list_free(pending);
        return result;
    }
 
index c96ef8595affaa45cf17f3e9752019efac0fd7a7..3e38007643e617ba5477e5ca1ef874cf86c22b0b 100644 (file)
@@ -1041,11 +1041,11 @@ process_matched_tle(TargetEntry *src_tle,
            /* combine the two */
            memcpy(fstore, prior_expr, sizeof(FieldStore));
            fstore->newvals =
-               list_concat(list_copy(((FieldStore *) prior_expr)->newvals),
-                           list_copy(((FieldStore *) src_expr)->newvals));
+               list_concat_copy(((FieldStore *) prior_expr)->newvals,
+                                ((FieldStore *) src_expr)->newvals);
            fstore->fieldnums =
-               list_concat(list_copy(((FieldStore *) prior_expr)->fieldnums),
-                           list_copy(((FieldStore *) src_expr)->fieldnums));
+               list_concat_copy(((FieldStore *) prior_expr)->fieldnums,
+                                ((FieldStore *) src_expr)->fieldnums);
        }
        else
        {
index 13d5d542f94449f52ad2eb9cbe3a194bfc7468e8..3e64390d8198e0513f5b5801bd41cea74d96d972 100644 (file)
@@ -10097,7 +10097,7 @@ get_from_clause_item(Node *jtnode, Query *query, deparse_context *context)
                            RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
                            List       *args = ((FuncExpr *) rtfunc->funcexpr)->args;
 
-                           allargs = list_concat(allargs, list_copy(args));
+                           allargs = list_concat(allargs, args);
                        }
 
                        appendStringInfoString(buf, "UNNEST(");
index 7eba59eff324d165f06493af4b4249163abaccbc..17101298fb0200aa74a110e1778e1faafd5137dd 100644 (file)
@@ -5768,7 +5768,6 @@ add_predicate_to_index_quals(IndexOptInfo *index, List *indexQuals)
        if (!predicate_implied_by(oneQual, indexQuals, false))
            predExtraQuals = list_concat(predExtraQuals, oneQual);
    }
-   /* list_concat avoids modifying the passed-in indexQuals list */
    return list_concat(predExtraQuals, indexQuals);
 }
 
index 146340877c39f0106014453349bb412ce4811647..409d840e793b6957ef361c3e8f3241ef04819af6 100644 (file)
@@ -519,6 +519,8 @@ extern List *lcons_int(int datum, List *list);
 extern List *lcons_oid(Oid datum, List *list);
 
 extern List *list_concat(List *list1, const List *list2);
+extern List *list_concat_copy(const List *list1, const List *list2);
+
 extern List *list_truncate(List *list, int new_size);
 
 extern bool list_member(const List *list, const void *datum);