Fix some planner performance problems with large WHERE clauses, by
authorTom Lane
Wed, 28 May 2003 22:32:50 +0000 (22:32 +0000)
committerTom Lane
Wed, 28 May 2003 22:32:50 +0000 (22:32 +0000)
introducing new 'FastList' list-construction subroutines to use in
hot spots.  This avoids the O(N^2) behavior of repeated lappend's
by keeping a tail pointer, while not changing behavior by reversing
list order as the lcons() method would do.

src/backend/executor/execQual.c
src/backend/nodes/list.c
src/backend/optimizer/path/indxpath.c
src/backend/optimizer/path/orindxpath.c
src/backend/optimizer/prep/prepqual.c
src/backend/optimizer/util/clauses.c
src/backend/optimizer/util/var.c
src/include/nodes/pg_list.h

index a2d0a8346f1d1e776372d5373310dec6236edf69..8dac4b2e44049a74eeddd1d2184fc87503b5164b 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.129 2003/05/02 20:54:33 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.130 2003/05/28 22:32:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2320,9 +2320,10 @@ ExecInitExpr(Expr *node, PlanState *parent)
            {
                CaseExpr   *caseexpr = (CaseExpr *) node;
                CaseExprState *cstate = makeNode(CaseExprState);
-               List       *outlist = NIL;
+               FastList    outlist;
                List       *inlist;
 
+               FastListInit(&outlist);
                foreach(inlist, caseexpr->args)
                {
                    CaseWhen   *when = (CaseWhen *) lfirst(inlist);
@@ -2332,9 +2333,9 @@ ExecInitExpr(Expr *node, PlanState *parent)
                    wstate->xprstate.expr = (Expr *) when;
                    wstate->expr = ExecInitExpr(when->expr, parent);
                    wstate->result = ExecInitExpr(when->result, parent);
-                   outlist = lappend(outlist, wstate);
+                   FastAppend(&outlist, wstate);
                }
-               cstate->args = outlist;
+               cstate->args = FastListValue(&outlist);
                /* caseexpr->arg should be null by now */
                Assert(caseexpr->arg == NULL);
                cstate->defresult = ExecInitExpr(caseexpr->defresult, parent);
@@ -2345,18 +2346,19 @@ ExecInitExpr(Expr *node, PlanState *parent)
            {
                ArrayExpr      *arrayexpr = (ArrayExpr *) node;
                ArrayExprState *astate = makeNode(ArrayExprState);
-               List           *outlist = NIL;
+               FastList        outlist;
                List           *inlist;
 
+               FastListInit(&outlist);
                foreach(inlist, arrayexpr->elements)
                {
                    Expr       *e = (Expr *) lfirst(inlist);
                    ExprState  *estate;
 
                    estate = ExecInitExpr(e, parent);
-                   outlist = lappend(outlist, estate);
+                   FastAppend(&outlist, estate);
                }
-               astate->elements = outlist;
+               astate->elements = FastListValue(&outlist);
                /* do one-time catalog lookup for type info */
                get_typlenbyvalalign(arrayexpr->element_typeid,
                                     &astate->elemlength,
@@ -2369,18 +2371,19 @@ ExecInitExpr(Expr *node, PlanState *parent)
            {
                CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;
                CoalesceExprState *cstate = makeNode(CoalesceExprState);
-               List       *outlist = NIL;
+               FastList    outlist;
                List       *inlist;
 
+               FastListInit(&outlist);
                foreach(inlist, coalesceexpr->args)
                {
                    Expr *e = (Expr *) lfirst(inlist);
                    ExprState *estate;
 
                    estate = ExecInitExpr(e, parent);
-                   outlist = lappend(outlist, estate);
+                   FastAppend(&outlist, estate);
                }
-               cstate->args = outlist;
+               cstate->args = FastListValue(&outlist);
                state = (ExprState *) cstate;
            }
            break;
@@ -2434,17 +2437,18 @@ ExecInitExpr(Expr *node, PlanState *parent)
            break;
        case T_List:
            {
-               List       *outlist = NIL;
+               FastList    outlist;
                List       *inlist;
 
+               FastListInit(&outlist);
                foreach(inlist, (List *) node)
                {
-                   outlist = lappend(outlist,
-                                     ExecInitExpr((Expr *) lfirst(inlist),
-                                                  parent));
+                   FastAppend(&outlist,
+                              ExecInitExpr((Expr *) lfirst(inlist),
+                                           parent));
                }
                /* Don't fall through to the "common" code below */
-               return (ExprState *) outlist;
+               return (ExprState *) FastListValue(&outlist);
            }
        default:
            elog(ERROR, "ExecInitExpr: unknown expression type %d",
index 0a379a753b1a2d3058138f9df42be09e039a8127..207acea9472b05d57b9aa33f37d564d9e9045e94 100644 (file)
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/nodes/list.c,v 1.48 2003/02/09 06:56:27 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/nodes/list.c,v 1.49 2003/05/28 22:32:49 tgl Exp $
  *
  * NOTES
  *   XXX a few of the following functions are duplicated to handle
@@ -141,9 +141,9 @@ lconso(Oid datum, List *list)
  * MORE EXPENSIVE THAN lcons
  */
 List *
-lappend(List *list, void *obj)
+lappend(List *list, void *datum)
 {
-   return nconc(list, makeList1(obj));
+   return nconc(list, makeList1(datum));
 }
 
 /*
@@ -195,6 +195,120 @@ nconc(List *l1, List *l2)
    return l1;                  /* list1 is now list1+list2  */
 }
 
+/*
+ * FastAppend - append to a FastList.
+ *
+ * For long lists this is significantly faster than repeated lappend's,
+ * since we avoid having to chase down the list again each time.
+ */
+void
+FastAppend(FastList *fl, void *datum)
+{
+   List       *cell = makeList1(datum);
+
+   if (fl->tail)
+   {
+       lnext(fl->tail) = cell;
+       fl->tail = cell;
+   }
+   else
+   {
+       /* First cell of list */
+       Assert(fl->head == NIL);
+       fl->head = fl->tail = cell;
+   }
+}
+
+/*
+ * FastAppendi - same for integers
+ */
+void
+FastAppendi(FastList *fl, int datum)
+{
+   List       *cell = makeListi1(datum);
+
+   if (fl->tail)
+   {
+       lnext(fl->tail) = cell;
+       fl->tail = cell;
+   }
+   else
+   {
+       /* First cell of list */
+       Assert(fl->head == NIL);
+       fl->head = fl->tail = cell;
+   }
+}
+
+/*
+ * FastAppendo - same for Oids
+ */
+void
+FastAppendo(FastList *fl, Oid datum)
+{
+   List       *cell = makeListo1(datum);
+
+   if (fl->tail)
+   {
+       lnext(fl->tail) = cell;
+       fl->tail = cell;
+   }
+   else
+   {
+       /* First cell of list */
+       Assert(fl->head == NIL);
+       fl->head = fl->tail = cell;
+   }
+}
+
+/*
+ * FastConc - nconc() for FastList building
+ *
+ * Note that the cells of the second argument are absorbed into the FastList.
+ */
+void
+FastConc(FastList *fl, List *cells)
+{
+   if (cells == NIL)
+       return;                 /* nothing to do */
+   if (fl->tail)
+   {
+       lnext(fl->tail) = cells;
+   }
+   else
+   {
+       /* First cell of list */
+       Assert(fl->head == NIL);
+       fl->head = cells;
+   }
+   while (lnext(cells) != NIL)
+       cells = lnext(cells);
+   fl->tail = cells;
+}
+
+/*
+ * FastConcFast - nconc() for FastList building
+ *
+ * Note that the cells of the second argument are absorbed into the first.
+ */
+void
+FastConcFast(FastList *fl, FastList *fl2)
+{
+   if (fl2->head == NIL)
+       return;                 /* nothing to do */
+   if (fl->tail)
+   {
+       lnext(fl->tail) = fl2->head;
+   }
+   else
+   {
+       /* First cell of list */
+       Assert(fl->head == NIL);
+       fl->head = fl2->head;
+   }
+   fl->tail = fl2->tail;
+}
+
 /*
  * nth
  *
index 9319f8c147414b88376c22b6df2593cd28894e33..ace494ba20bad254c566dc177c09671599a5675d 100644 (file)
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.142 2003/05/28 16:03:56 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.143 2003/05/28 22:32:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -417,10 +417,11 @@ extract_or_indexqual_conditions(RelOptInfo *rel,
                                IndexOptInfo *index,
                                Expr *orsubclause)
 {
-   List       *quals = NIL;
+   FastList    quals;
    int         indexcol = 0;
    Oid        *classes = index->classlist;
 
+   FastListInit(&quals);
    /*
     * Extract relevant indexclauses in indexkey order.  This is
     * essentially just like group_clauses_by_indexkey() except that the
@@ -430,9 +431,10 @@ extract_or_indexqual_conditions(RelOptInfo *rel,
    do
    {
        Oid         curClass = classes[0];
-       List       *clausegroup = NIL;
+       FastList    clausegroup;
        List       *item;
 
+       FastListInit(&clausegroup);
        if (and_clause((Node *) orsubclause))
        {
            foreach(item, ((BoolExpr *) orsubclause)->args)
@@ -442,21 +444,23 @@ extract_or_indexqual_conditions(RelOptInfo *rel,
                if (match_clause_to_indexcol(rel, index,
                                             indexcol, curClass,
                                             subsubclause))
-                   clausegroup = nconc(clausegroup,
-                                       expand_indexqual_condition(subsubclause,
-                                                                  curClass));
+                   FastConc(&clausegroup,
+                            expand_indexqual_condition(subsubclause,
+                                                       curClass));
            }
        }
        else if (match_clause_to_indexcol(rel, index,
                                          indexcol, curClass,
                                          orsubclause))
-           clausegroup = expand_indexqual_condition(orsubclause, curClass);
+           FastConc(&clausegroup,
+                    expand_indexqual_condition(orsubclause,
+                                               curClass));
 
        /*
         * If we found no clauses for this indexkey in the OR subclause
         * itself, try looking in the rel's top-level restriction list.
         */
-       if (clausegroup == NIL)
+       if (FastListValue(&clausegroup) == NIL)
        {
            foreach(item, rel->baserestrictinfo)
            {
@@ -465,9 +469,9 @@ extract_or_indexqual_conditions(RelOptInfo *rel,
                if (match_clause_to_indexcol(rel, index,
                                             indexcol, curClass,
                                             rinfo->clause))
-                   clausegroup = nconc(clausegroup,
-                                       expand_indexqual_condition(rinfo->clause,
-                                                                  curClass));
+                   FastConc(&clausegroup,
+                            expand_indexqual_condition(rinfo->clause,
+                                                       curClass));
            }
        }
 
@@ -475,20 +479,20 @@ extract_or_indexqual_conditions(RelOptInfo *rel,
         * If still no clauses match this key, we're done; we don't want
         * to look at keys to its right.
         */
-       if (clausegroup == NIL)
+       if (FastListValue(&clausegroup) == NIL)
            break;
 
-       quals = nconc(quals, clausegroup);
+       FastConcFast(&quals, &clausegroup);
 
        indexcol++;
        classes++;
 
    } while (!DoneMatchingIndexKeys(classes));
 
-   if (quals == NIL)
+   if (FastListValue(&quals) == NIL)
        elog(ERROR, "extract_or_indexqual_conditions: no matching clause");
 
-   return quals;
+   return FastListValue(&quals);
 }
 
 
@@ -520,7 +524,7 @@ extract_or_indexqual_conditions(RelOptInfo *rel,
 static List *
 group_clauses_by_indexkey(RelOptInfo *rel, IndexOptInfo *index)
 {
-   List       *clausegroup_list = NIL;
+   FastList    clausegroup_list;
    List       *restrictinfo_list = rel->baserestrictinfo;
    int         indexcol = 0;
    Oid        *classes = index->classlist;
@@ -528,12 +532,14 @@ group_clauses_by_indexkey(RelOptInfo *rel, IndexOptInfo *index)
    if (restrictinfo_list == NIL)
        return NIL;
 
+   FastListInit(&clausegroup_list);
    do
    {
        Oid         curClass = classes[0];
-       List       *clausegroup = NIL;
+       FastList    clausegroup;
        List       *i;
 
+       FastListInit(&clausegroup);
        foreach(i, restrictinfo_list)
        {
            RestrictInfo *rinfo = (RestrictInfo *) lfirst(i);
@@ -543,24 +549,24 @@ group_clauses_by_indexkey(RelOptInfo *rel, IndexOptInfo *index)
                                         indexcol,
                                         curClass,
                                         rinfo->clause))
-               clausegroup = lappend(clausegroup, rinfo);
+               FastAppend(&clausegroup, rinfo);
        }
 
        /*
         * If no clauses match this key, we're done; we don't want to look
         * at keys to its right.
         */
-       if (clausegroup == NIL)
+       if (FastListValue(&clausegroup) == NIL)
            break;
 
-       clausegroup_list = lappend(clausegroup_list, clausegroup);
+       FastAppend(&clausegroup_list, FastListValue(&clausegroup));
 
        indexcol++;
        classes++;
 
    } while (!DoneMatchingIndexKeys(classes));
 
-   return clausegroup_list;
+   return FastListValue(&clausegroup_list);
 }
 
 /*
@@ -580,17 +586,20 @@ static List *
 group_clauses_by_indexkey_for_join(RelOptInfo *rel, IndexOptInfo *index,
                                   Relids outer_relids, bool isouterjoin)
 {
-   List       *clausegroup_list = NIL;
+   FastList    clausegroup_list;
    bool        jfound = false;
    int         indexcol = 0;
    Oid        *classes = index->classlist;
 
+   FastListInit(&clausegroup_list);
    do
    {
        Oid         curClass = classes[0];
-       List       *clausegroup = NIL;
+       FastList    clausegroup;
        List       *i;
 
+       FastListInit(&clausegroup);
+
        /* Look for joinclauses that are usable with given outer_relids */
        foreach(i, rel->joininfo)
        {
@@ -614,7 +623,7 @@ group_clauses_by_indexkey_for_join(RelOptInfo *rel, IndexOptInfo *index,
                                                  curClass,
                                                  rinfo->clause))
                {
-                   clausegroup = lappend(clausegroup, rinfo);
+                   FastAppend(&clausegroup, rinfo);
                    jfound = true;
                }
            }
@@ -634,17 +643,17 @@ group_clauses_by_indexkey_for_join(RelOptInfo *rel, IndexOptInfo *index,
                                         indexcol,
                                         curClass,
                                         rinfo->clause))
-               clausegroup = lappend(clausegroup, rinfo);
+               FastAppend(&clausegroup, rinfo);
        }
 
        /*
         * If no clauses match this key, we're done; we don't want to look
         * at keys to its right.
         */
-       if (clausegroup == NIL)
+       if (FastListValue(&clausegroup) == NIL)
            break;
 
-       clausegroup_list = lappend(clausegroup_list, clausegroup);
+       FastAppend(&clausegroup_list, FastListValue(&clausegroup));
 
        indexcol++;
        classes++;
@@ -653,12 +662,9 @@ group_clauses_by_indexkey_for_join(RelOptInfo *rel, IndexOptInfo *index,
 
    /* if no join clause was matched then forget it, per comments above */
    if (!jfound)
-   {
-       freeList(clausegroup_list);
        return NIL;
-   }
 
-   return clausegroup_list;
+   return FastListValue(&clausegroup_list);
 }
 
 
@@ -1870,12 +1876,13 @@ match_special_index_operator(Expr *clause, Oid opclass,
 List *
 expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups)
 {
-   List       *resultquals = NIL;
+   FastList    resultquals;
    Oid        *classes = index->classlist;
 
    if (clausegroups == NIL)
        return NIL;
 
+   FastListInit(&resultquals);
    do
    {
        Oid         curClass = classes[0];
@@ -1885,9 +1892,9 @@ expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups)
        {
            RestrictInfo *rinfo = (RestrictInfo *) lfirst(i);
 
-           resultquals = nconc(resultquals,
-                               expand_indexqual_condition(rinfo->clause,
-                                                          curClass));
+           FastConc(&resultquals,
+                    expand_indexqual_condition(rinfo->clause,
+                                               curClass));
        }
 
        clausegroups = lnext(clausegroups);
@@ -1898,7 +1905,7 @@ expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups)
 
    Assert(clausegroups == NIL); /* else more groups than indexkeys... */
 
-   return resultquals;
+   return FastListValue(&resultquals);
 }
 
 /*
index 101866867b9627a6f8c82fc572ce2adba277f435..10eb050f3a3193dba8da301b5a9b54c76c3d770a 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/orindxpath.c,v 1.49 2002/12/12 15:49:31 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/orindxpath.c,v 1.50 2003/05/28 22:32:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -149,10 +149,12 @@ best_or_subclause_indices(Query *root,
                          List *indices,
                          IndexPath *pathnode)
 {
+   FastList    infos;
+   FastList    quals;
    List       *slist;
 
-   pathnode->indexinfo = NIL;
-   pathnode->indexqual = NIL;
+   FastListInit(&infos);
+   FastListInit(&quals);
    pathnode->path.startup_cost = 0;
    pathnode->path.total_cost = 0;
 
@@ -170,14 +172,17 @@ best_or_subclause_indices(Query *root,
 
        Assert(best_indexinfo != NULL);
 
-       pathnode->indexinfo = lappend(pathnode->indexinfo, best_indexinfo);
-       pathnode->indexqual = lappend(pathnode->indexqual, best_indexqual);
+       FastAppend(&infos, best_indexinfo);
+       FastAppend(&quals, best_indexqual);
        if (slist == subclauses)    /* first scan? */
            pathnode->path.startup_cost = best_startup_cost;
        pathnode->path.total_cost += best_total_cost;
 
        indices = lnext(indices);
    }
+
+   pathnode->indexinfo = FastListValue(&infos);
+   pathnode->indexqual = FastListValue(&quals);
 }
 
 /*
index 4016ba476deafc55e542eb2c3024317861db9ee1..24ea1316e117c7cec527f8de3ad36629f85e4aa3 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepqual.c,v 1.34 2002/12/12 15:49:32 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepqual.c,v 1.35 2003/05/28 22:32:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include "utils/lsyscache.h"
 
 static Expr *flatten_andors(Expr *qual);
-static List *pull_ors(List *orlist);
+static void flatten_andors_and_walker(FastList *out_list, List *andlist);
+static void flatten_andors_or_walker(FastList *out_list, List *orlist);
 static List *pull_ands(List *andlist);
+static void pull_ands_walker(FastList *out_list, List *andlist);
+static List *pull_ors(List *orlist);
+static void pull_ors_walker(FastList *out_list, List *orlist);
 static Expr *find_nots(Expr *qual);
 static Expr *push_nots(Expr *qual);
 static Expr *find_ors(Expr *qual);
@@ -291,47 +295,19 @@ flatten_andors(Expr *qual)
 
    if (and_clause((Node *) qual))
    {
-       List       *out_list = NIL;
-       List       *arg;
+       FastList    out_list;
 
-       foreach(arg, ((BoolExpr *) qual)->args)
-       {
-           Expr       *subexpr = flatten_andors((Expr *) lfirst(arg));
-
-           /*
-            * Note: we can destructively nconc the subexpression's
-            * arglist because we know the recursive invocation of
-            * flatten_andors will have built a new arglist not shared
-            * with any other expr. Otherwise we'd need a listCopy here.
-            */
-           if (and_clause((Node *) subexpr))
-               out_list = nconc(out_list, ((BoolExpr *) subexpr)->args);
-           else
-               out_list = lappend(out_list, subexpr);
-       }
-       return make_andclause(out_list);
+       FastListInit(&out_list);
+       flatten_andors_and_walker(&out_list, ((BoolExpr *) qual)->args);
+       return make_andclause(FastListValue(&out_list));
    }
    else if (or_clause((Node *) qual))
    {
-       List       *out_list = NIL;
-       List       *arg;
+       FastList    out_list;
 
-       foreach(arg, ((BoolExpr *) qual)->args)
-       {
-           Expr       *subexpr = flatten_andors((Expr *) lfirst(arg));
-
-           /*
-            * Note: we can destructively nconc the subexpression's
-            * arglist because we know the recursive invocation of
-            * flatten_andors will have built a new arglist not shared
-            * with any other expr. Otherwise we'd need a listCopy here.
-            */
-           if (or_clause((Node *) subexpr))
-               out_list = nconc(out_list, ((BoolExpr *) subexpr)->args);
-           else
-               out_list = lappend(out_list, subexpr);
-       }
-       return make_orclause(out_list);
+       FastListInit(&out_list);
+       flatten_andors_or_walker(&out_list, ((BoolExpr *) qual)->args);
+       return make_orclause(FastListValue(&out_list));
    }
    else if (not_clause((Node *) qual))
        return make_notclause(flatten_andors(get_notclausearg(qual)));
@@ -351,69 +327,102 @@ flatten_andors(Expr *qual)
        return qual;
 }
 
-/*
- * pull_ors
- *   Pull the arguments of an 'or' clause nested within another 'or'
- *   clause up into the argument list of the parent.
- *
- * Input is the arglist of an OR clause.
- * Returns the rebuilt arglist (note original list structure is not touched).
- */
-static List *
-pull_ors(List *orlist)
+static void
+flatten_andors_and_walker(FastList *out_list, List *andlist)
+{
+   List       *arg;
+
+   foreach(arg, andlist)
+   {
+       Expr       *subexpr = (Expr *) lfirst(arg);
+
+       if (and_clause((Node *) subexpr))
+           flatten_andors_and_walker(out_list, ((BoolExpr *) subexpr)->args);
+       else
+           FastAppend(out_list, flatten_andors(subexpr));
+   }
+}
+
+static void
+flatten_andors_or_walker(FastList *out_list, List *orlist)
 {
-   List       *out_list = NIL;
    List       *arg;
 
    foreach(arg, orlist)
    {
        Expr       *subexpr = (Expr *) lfirst(arg);
 
-       /*
-        * Note: we can destructively nconc 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 listCopy here.
-        */
        if (or_clause((Node *) subexpr))
-           out_list = nconc(out_list,
-                            pull_ors(((BoolExpr *) subexpr)->args));
+           flatten_andors_or_walker(out_list, ((BoolExpr *) subexpr)->args);
        else
-           out_list = lappend(out_list, subexpr);
+           FastAppend(out_list, flatten_andors(subexpr));
    }
-   return out_list;
 }
 
 /*
  * pull_ands
- *   Pull the arguments of an 'and' clause nested within another 'and'
- *   clause up into the argument list of the parent.
+ *   Recursively flatten nested AND clauses into a single and-clause list.
  *
- * Returns the modified list.
+ * Input is the arglist of an AND clause.
+ * Returns the rebuilt arglist (note original list structure is not touched).
  */
 static List *
 pull_ands(List *andlist)
 {
-   List       *out_list = NIL;
+   FastList    out_list;
+
+   FastListInit(&out_list);
+   pull_ands_walker(&out_list, andlist);
+   return FastListValue(&out_list);
+}
+
+static void
+pull_ands_walker(FastList *out_list, List *andlist)
+{
    List       *arg;
 
    foreach(arg, andlist)
    {
        Expr       *subexpr = (Expr *) lfirst(arg);
 
-       /*
-        * Note: we can destructively nconc 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 listCopy here.
-        */
        if (and_clause((Node *) subexpr))
-           out_list = nconc(out_list,
-                            pull_ands(((BoolExpr *) subexpr)->args));
+           pull_ands_walker(out_list, ((BoolExpr *) subexpr)->args);
+       else
+           FastAppend(out_list, subexpr);
+   }
+}
+
+/*
+ * pull_ors
+ *   Recursively flatten nested OR clauses into a single or-clause list.
+ *
+ * Input is the arglist of an OR clause.
+ * Returns the rebuilt arglist (note original list structure is not touched).
+ */
+static List *
+pull_ors(List *orlist)
+{
+   FastList    out_list;
+
+   FastListInit(&out_list);
+   pull_ors_walker(&out_list, orlist);
+   return FastListValue(&out_list);
+}
+
+static void
+pull_ors_walker(FastList *out_list, List *orlist)
+{
+   List       *arg;
+
+   foreach(arg, orlist)
+   {
+       Expr       *subexpr = (Expr *) lfirst(arg);
+
+       if (or_clause((Node *) subexpr))
+           pull_ors_walker(out_list, ((BoolExpr *) subexpr)->args);
        else
-           out_list = lappend(out_list, subexpr);
+           FastAppend(out_list, subexpr);
    }
-   return out_list;
 }
 
 /*
@@ -447,21 +456,23 @@ find_nots(Expr *qual)
 #endif
    if (and_clause((Node *) qual))
    {
-       List       *t_list = NIL;
+       FastList    t_list;
        List       *temp;
 
+       FastListInit(&t_list);
        foreach(temp, ((BoolExpr *) qual)->args)
-           t_list = lappend(t_list, find_nots(lfirst(temp)));
-       return make_andclause(pull_ands(t_list));
+           FastAppend(&t_list, find_nots(lfirst(temp)));
+       return make_andclause(pull_ands(FastListValue(&t_list)));
    }
    else if (or_clause((Node *) qual))
    {
-       List       *t_list = NIL;
+       FastList    t_list;
        List       *temp;
 
+       FastListInit(&t_list);
        foreach(temp, ((BoolExpr *) qual)->args)
-           t_list = lappend(t_list, find_nots(lfirst(temp)));
-       return make_orclause(pull_ors(t_list));
+           FastAppend(&t_list, find_nots(lfirst(temp)));
+       return make_orclause(pull_ors(FastListValue(&t_list)));
    }
    else if (not_clause((Node *) qual))
        return push_nots(get_notclausearg(qual));
@@ -511,21 +522,23 @@ push_nots(Expr *qual)
         * i.e., swap AND for OR and negate all the subclauses.
         *--------------------
         */
-       List       *t_list = NIL;
+       FastList    t_list;
        List       *temp;
 
+       FastListInit(&t_list);
        foreach(temp, ((BoolExpr *) qual)->args)
-           t_list = lappend(t_list, push_nots(lfirst(temp)));
-       return make_orclause(pull_ors(t_list));
+           FastAppend(&t_list, push_nots(lfirst(temp)));
+       return make_orclause(pull_ors(FastListValue(&t_list)));
    }
    else if (or_clause((Node *) qual))
    {
-       List       *t_list = NIL;
+       FastList    t_list;
        List       *temp;
 
+       FastListInit(&t_list);
        foreach(temp, ((BoolExpr *) qual)->args)
-           t_list = lappend(t_list, push_nots(lfirst(temp)));
-       return make_andclause(pull_ands(t_list));
+           FastAppend(&t_list, push_nots(lfirst(temp)));
+       return make_andclause(pull_ands(FastListValue(&t_list)));
    }
    else if (not_clause((Node *) qual))
    {
index 4d51e7ffbc05b77603aa4036b864b9ab1f54a1c4..0c2e652c7950dbffc171ef47cab1e329c7e1cc99 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.137 2003/05/28 16:03:56 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.138 2003/05/28 22:32:49 tgl Exp $
  *
  * HISTORY
  *   AUTHOR            DATE            MAJOR EVENT
@@ -771,21 +771,24 @@ is_pseudo_constant_clause(Node *clause)
 List *
 pull_constant_clauses(List *quals, List **constantQual)
 {
-   List       *constqual = NIL;
-   List       *restqual = NIL;
+   FastList    constqual,
+               restqual;
    List       *q;
 
+   FastListInit(&constqual);
+   FastListInit(&restqual);
+
    foreach(q, quals)
    {
        Node       *qual = (Node *) lfirst(q);
 
        if (is_pseudo_constant_clause(qual))
-           constqual = lappend(constqual, qual);
+           FastAppend(&constqual, qual);
        else
-           restqual = lappend(restqual, qual);
+           FastAppend(&restqual, qual);
    }
-   *constantQual = constqual;
-   return restqual;
+   *constantQual = FastListValue(&constqual);
+   return FastListValue(&restqual);
 }
 
 
@@ -1187,16 +1190,17 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
                     * when no input is TRUE and at least one is NULL.
                     *----------
                     */
-                   List       *newargs = NIL;
+                   FastList    newargs;
                    List       *arg;
                    bool        haveNull = false;
                    bool        forceTrue = false;
 
+                   FastListInit(&newargs);
                    foreach(arg, args)
                    {
                        if (!IsA(lfirst(arg), Const))
                        {
-                           newargs = lappend(newargs, lfirst(arg));
+                           FastAppend(&newargs, lfirst(arg));
                            continue;
                        }
                        const_input = (Const *) lfirst(arg);
@@ -1217,15 +1221,15 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
                    if (forceTrue)
                        return MAKEBOOLCONST(true, false);
                    if (haveNull)
-                       newargs = lappend(newargs, MAKEBOOLCONST(false, true));
+                       FastAppend(&newargs, MAKEBOOLCONST(false, true));
                    /* If all the inputs are FALSE, result is FALSE */
-                   if (newargs == NIL)
+                   if (FastListValue(&newargs) == NIL)
                        return MAKEBOOLCONST(false, false);
                    /* If only one nonconst-or-NULL input, it's the result */
-                   if (lnext(newargs) == NIL)
-                       return (Node *) lfirst(newargs);
+                   if (lnext(FastListValue(&newargs)) == NIL)
+                       return (Node *) lfirst(FastListValue(&newargs));
                    /* Else we still need an OR node */
-                   return (Node *) make_orclause(newargs);
+                   return (Node *) make_orclause(FastListValue(&newargs));
                }
            case AND_EXPR:
                {
@@ -1239,16 +1243,17 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
                     * when no input is FALSE and at least one is NULL.
                     *----------
                     */
-                   List       *newargs = NIL;
+                   FastList    newargs;
                    List       *arg;
                    bool        haveNull = false;
                    bool        forceFalse = false;
 
+                   FastListInit(&newargs);
                    foreach(arg, args)
                    {
                        if (!IsA(lfirst(arg), Const))
                        {
-                           newargs = lappend(newargs, lfirst(arg));
+                           FastAppend(&newargs, lfirst(arg));
                            continue;
                        }
                        const_input = (Const *) lfirst(arg);
@@ -1269,15 +1274,15 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
                    if (forceFalse)
                        return MAKEBOOLCONST(false, false);
                    if (haveNull)
-                       newargs = lappend(newargs, MAKEBOOLCONST(false, true));
+                       FastAppend(&newargs, MAKEBOOLCONST(false, true));
                    /* If all the inputs are TRUE, result is TRUE */
-                   if (newargs == NIL)
+                   if (FastListValue(&newargs) == NIL)
                        return MAKEBOOLCONST(true, false);
                    /* If only one nonconst-or-NULL input, it's the result */
-                   if (lnext(newargs) == NIL)
-                       return (Node *) lfirst(newargs);
+                   if (lnext(FastListValue(&newargs)) == NIL)
+                       return (Node *) lfirst(FastListValue(&newargs));
                    /* Else we still need an AND node */
-                   return (Node *) make_andclause(newargs);
+                   return (Node *) make_andclause(FastListValue(&newargs));
                }
            case NOT_EXPR:
                Assert(length(args) == 1);
@@ -1370,11 +1375,12 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
         */
        CaseExpr   *caseexpr = (CaseExpr *) node;
        CaseExpr   *newcase;
-       List       *newargs = NIL;
+       FastList    newargs;
        Node       *defresult;
        Const      *const_input;
        List       *arg;
 
+       FastListInit(&newargs);
        foreach(arg, caseexpr->args)
        {
            /* Simplify this alternative's condition and result */
@@ -1387,7 +1393,7 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
            if (casewhen->expr == NULL ||
                !IsA(casewhen->expr, Const))
            {
-               newargs = lappend(newargs, casewhen);
+               FastAppend(&newargs, casewhen);
                continue;
            }
            const_input = (Const *) casewhen->expr;
@@ -1399,13 +1405,13 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
             * Found a TRUE condition.  If it's the first (un-dropped)
             * alternative, the CASE reduces to just this alternative.
             */
-           if (newargs == NIL)
+           if (FastListValue(&newargs) == NIL)
                return (Node *) casewhen->result;
 
            /*
             * Otherwise, add it to the list, and drop all the rest.
             */
-           newargs = lappend(newargs, casewhen);
+           FastAppend(&newargs, casewhen);
            break;
        }
 
@@ -1417,13 +1423,13 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
         * If no non-FALSE alternatives, CASE reduces to the default
         * result
         */
-       if (newargs == NIL)
+       if (FastListValue(&newargs) == NIL)
            return defresult;
        /* Otherwise we need a new CASE node */
        newcase = makeNode(CaseExpr);
        newcase->casetype = caseexpr->casetype;
        newcase->arg = NULL;
-       newcase->args = newargs;
+       newcase->args = FastListValue(&newargs);
        newcase->defresult = (Expr *) defresult;
        return (Node *) newcase;
    }
@@ -1432,9 +1438,10 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
        ArrayExpr *arrayexpr = (ArrayExpr *) node;
        ArrayExpr *newarray;
        bool all_const = true;
-       List *newelems = NIL;
+       FastList    newelems;
        List *element;
 
+       FastListInit(&newelems);
        foreach(element, arrayexpr->elements)
        {
            Node *e;
@@ -1443,13 +1450,13 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
                                               active_fns);
            if (!IsA(e, Const))
                all_const = false;
-           newelems = lappend(newelems, e);
+           FastAppend(&newelems, e);
        }
 
        newarray = makeNode(ArrayExpr);
        newarray->array_typeid = arrayexpr->array_typeid;
        newarray->element_typeid = arrayexpr->element_typeid;
-       newarray->elements = newelems;
+       newarray->elements = FastListValue(&newelems);
        newarray->ndims = arrayexpr->ndims;
 
        if (all_const)
@@ -1462,9 +1469,10 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
    {
        CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;
        CoalesceExpr *newcoalesce;
-       List *newargs = NIL;
+       FastList    newargs;
        List *arg;
 
+       FastListInit(&newargs);
        foreach(arg, coalesceexpr->args)
        {
            Node *e;
@@ -1480,15 +1488,15 @@ eval_const_expressions_mutator(Node *node, List *active_fns)
            {
                if (((Const *) e)->constisnull)
                    continue;   /* drop null constant */
-               if (newargs == NIL)
+               if (FastListValue(&newargs) == NIL)
                    return e;   /* first expr */
            }
-           newargs = lappend(newargs, e);
+           FastAppend(&newargs, e);
        }
 
        newcoalesce = makeNode(CoalesceExpr);
        newcoalesce->coalescetype = coalesceexpr->coalescetype;
-       newcoalesce->args = newargs;
+       newcoalesce->args = FastListValue(&newargs);
        return (Node *) newcoalesce;
    }
    if (IsA(node, FieldSelect))
@@ -2647,16 +2655,16 @@ expression_tree_mutator(Node *node,
                 * NOTE: this would fail badly on a list with integer
                 * elements!
                 */
-               List       *resultlist = NIL;
+               FastList    resultlist;
                List       *temp;
 
+               FastListInit(&resultlist);
                foreach(temp, (List *) node)
                {
-                   resultlist = lappend(resultlist,
-                                        mutator((Node *) lfirst(temp),
-                                                context));
+                   FastAppend(&resultlist,
+                              mutator((Node *) lfirst(temp), context));
                }
-               return (Node *) resultlist;
+               return (Node *) FastListValue(&resultlist);
            }
            break;
        case T_FromExpr:
@@ -2739,7 +2747,7 @@ query_tree_mutator(Query *query,
                   void *context,
                   int flags)
 {
-   List       *newrt = NIL;
+   FastList    newrt;
    List       *rt;
 
    Assert(query != NULL && IsA(query, Query));
@@ -2757,6 +2765,7 @@ query_tree_mutator(Query *query,
    MUTATE(query->setOperations, query->setOperations, Node *);
    MUTATE(query->havingQual, query->havingQual, Node *);
    MUTATE(query->in_info_list, query->in_info_list, List *);
+   FastListInit(&newrt);
    foreach(rt, query->rtable)
    {
        RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
@@ -2791,9 +2800,9 @@ query_tree_mutator(Query *query,
                rte = newrte;
                break;
        }
-       newrt = lappend(newrt, rte);
+       FastAppend(&newrt, rte);
    }
-   query->rtable = newrt;
+   query->rtable = FastListValue(&newrt);
    return query;
 }
 
index 929f5561dbc284bc18a95c141b49fb5929910f7c..a365b7b159ec4c680fd3dfc3e653253152790f27 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/util/var.c,v 1.49 2003/02/08 20:20:55 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/util/var.c,v 1.50 2003/05/28 22:32:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -37,7 +37,7 @@ typedef struct
 
 typedef struct
 {
-   List       *varlist;
+   FastList    varlist;
    bool        includeUpperVars;
 } pull_var_clause_context;
 
@@ -344,11 +344,11 @@ pull_var_clause(Node *node, bool includeUpperVars)
 {
    pull_var_clause_context context;
 
-   context.varlist = NIL;
+   FastListInit(&context.varlist);
    context.includeUpperVars = includeUpperVars;
 
    pull_var_clause_walker(node, &context);
-   return context.varlist;
+   return FastListValue(&context.varlist);
 }
 
 static bool
@@ -359,7 +359,7 @@ pull_var_clause_walker(Node *node, pull_var_clause_context *context)
    if (IsA(node, Var))
    {
        if (((Var *) node)->varlevelsup == 0 || context->includeUpperVars)
-           context->varlist = lappend(context->varlist, node);
+           FastAppend(&context->varlist, node);
        return false;
    }
    return expression_tree_walker(node, pull_var_clause_walker,
index b48fc02e8554ded06717f18c5d01121088df87f7..bc42917a355eea361a63b616c18f4b6771afd37b 100644 (file)
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_list.h,v 1.35 2003/02/09 06:56:28 tgl Exp $
+ * $Id: pg_list.h,v 1.36 2003/05/28 22:32:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -128,6 +128,21 @@ typedef struct List
 #define makeListo1(x1)             lconso(x1, NIL)
 #define makeListo2(x1,x2)          lconso(x1, makeListo1(x2))
 
+/*
+ * FastList is an optimization for building large lists.  The conventional
+ * way to build a list is repeated lappend() operations, but that is O(N^2)
+ * in the number of list items, which gets tedious for large lists.
+ */
+typedef struct FastList
+{
+   List       *head;
+   List       *tail;
+} FastList;
+
+#define FastListInit(fl)   ( (fl)->head = (fl)->tail = NIL )
+#define FastListValue(fl)  ( (fl)->head )
+
+
 /*
  * function prototypes in nodes/list.c
  */
@@ -143,6 +158,11 @@ extern List *lappend(List *list, void *datum);
 extern List *lappendi(List *list, int datum);
 extern List *lappendo(List *list, Oid datum);
 extern List *nconc(List *list1, List *list2);
+extern void FastAppend(FastList *fl, void *datum);
+extern void FastAppendi(FastList *fl, int datum);
+extern void FastAppendo(FastList *fl, Oid datum);
+extern void FastConc(FastList *fl, List *cells);
+extern void FastConcFast(FastList *fl, FastList *fl2);
 extern void *nth(int n, List *l);
 extern int length(List *list);
 extern void *llast(List *list);