From d0b4399d81f39decccb23fa38f772b71b51bf96a Mon Sep 17 00:00:00 2001 From: Neil Conway Date: Wed, 26 May 2004 04:41:50 +0000 Subject: Reimplement the linked list data structure used throughout the backend. In the past, we used a 'Lispy' linked list implementation: a "list" was merely a pointer to the head node of the list. The problem with that design is that it makes lappend() and length() linear time. This patch fixes that problem (and others) by maintaining a count of the list length and a pointer to the tail node along with each head node pointer. A "list" is now a pointer to a structure containing some meta-data about the list; the head and tail pointers in that structure refer to ListCell structures that maintain the actual linked list of nodes. The function names of the list API have also been changed to, I hope, be more logically consistent. By default, the old function names are still available; they will be disabled-by-default once the rest of the tree has been updated to use the new API names. --- src/backend/optimizer/path/allpaths.c | 51 ++++++++++++++++++----------------- 1 file changed, 26 insertions(+), 25 deletions(-) (limited to 'src/backend/optimizer/path/allpaths.c') diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index 217f06a6b2b..a4bc92b1c3b 100644 --- a/src/backend/optimizer/path/allpaths.c +++ b/src/backend/optimizer/path/allpaths.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.114 2004/05/10 22:44:44 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.115 2004/05/26 04:41:21 neilc Exp $ * *------------------------------------------------------------------------- */ @@ -102,11 +102,11 @@ make_one_rel(Query *root) static void set_base_rel_pathlists(Query *root) { - List *rellist; + ListCell *l; - foreach(rellist, root->base_rel_list) + foreach(l, root->base_rel_list) { - RelOptInfo *rel = (RelOptInfo *) lfirst(rellist); + RelOptInfo *rel = (RelOptInfo *) lfirst(l); Index rti = rel->relid; RangeTblEntry *rte; List *inheritlist; @@ -212,7 +212,7 @@ set_inherited_rel_pathlist(Query *root, RelOptInfo *rel, int parentRTindex = rti; Oid parentOID = rte->relid; List *subpaths = NIL; - List *il; + ListCell *il; /* * XXX for now, can't handle inherited expansion of FOR UPDATE; can we @@ -247,8 +247,8 @@ set_inherited_rel_pathlist(Query *root, RelOptInfo *rel, Oid childOID; RelOptInfo *childrel; List *reltlist; - List *parentvars; - List *childvars; + ListCell *parentvars; + ListCell *childvars; childrte = rt_fetch(childRTindex, root->rtable); childOID = childrte->relid; @@ -300,7 +300,7 @@ set_inherited_rel_pathlist(Query *root, RelOptInfo *rel, if (childrel->width > rel->width) rel->width = childrel->width; - childvars = FastListValue(&childrel->reltargetlist); + childvars = list_head(FastListValue(&childrel->reltargetlist)); foreach(parentvars, FastListValue(&rel->reltargetlist)) { Var *parentvar = (Var *) lfirst(parentvars); @@ -366,11 +366,11 @@ set_subquery_pathlist(Query *root, RelOptInfo *rel, { /* OK to consider pushing down individual quals */ List *upperrestrictlist = NIL; - List *lst; + ListCell *l; - foreach(lst, rel->baserestrictinfo) + foreach(l, rel->baserestrictinfo) { - RestrictInfo *rinfo = (RestrictInfo *) lfirst(lst); + RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); Node *clause = (Node *) rinfo->clause; if (qual_is_pushdown_safe(subquery, rti, clause, differentTypes)) @@ -434,7 +434,7 @@ make_fromexpr_rel(Query *root, FromExpr *from) { int levels_needed; List *initial_rels = NIL; - List *jt; + ListCell *jt; /* * Count the number of child jointree nodes. This is the depth of the @@ -464,7 +464,7 @@ make_fromexpr_rel(Query *root, FromExpr *from) /* * Single jointree node, so we're done. */ - return (RelOptInfo *) lfirst(initial_rels); + return (RelOptInfo *) linitial(initial_rels); } else { @@ -516,7 +516,7 @@ make_one_rel_by_joins(Query *root, int levels_needed, List *initial_rels) for (lev = 2; lev <= levels_needed; lev++) { - List *x; + ListCell *x; /* * Determine all possible pairs of relations to be joined at this @@ -548,7 +548,7 @@ make_one_rel_by_joins(Query *root, int levels_needed, List *initial_rels) elog(ERROR, "failed to build any %d-way joins", levels_needed); Assert(length(joinitems[levels_needed]) == 1); - rel = (RelOptInfo *) lfirst(joinitems[levels_needed]); + rel = (RelOptInfo *) linitial(joinitems[levels_needed]); return rel; } @@ -660,21 +660,22 @@ static void compare_tlist_datatypes(List *tlist, List *colTypes, bool *differentTypes) { - List *i; + ListCell *l; + ListCell *colType = list_head(colTypes); - foreach(i, tlist) + foreach(l, tlist) { - TargetEntry *tle = (TargetEntry *) lfirst(i); + TargetEntry *tle = (TargetEntry *) lfirst(l); if (tle->resdom->resjunk) continue; /* ignore resjunk columns */ - if (colTypes == NIL) + if (colType == NULL) elog(ERROR, "wrong number of tlist entries"); - if (tle->resdom->restype != lfirsto(colTypes)) + if (tle->resdom->restype != lfirst_oid(colType)) differentTypes[tle->resdom->resno] = true; - colTypes = lnext(colTypes); + colType = lnext(colType); } - if (colTypes != NIL) + if (colType != NULL) elog(ERROR, "wrong number of tlist entries"); } @@ -712,7 +713,7 @@ qual_is_pushdown_safe(Query *subquery, Index rti, Node *qual, { bool safe = true; List *vars; - List *vl; + ListCell *vl; Bitmapset *tested = NULL; /* Refuse subselects (point 1) */ @@ -869,7 +870,7 @@ print_relids(Relids relids) static void print_restrictclauses(Query *root, List *clauses) { - List *l; + ListCell *l; foreach(l, clauses) { @@ -987,7 +988,7 @@ print_path(Query *root, Path *path, int indent) void debug_print_rel(Query *root, RelOptInfo *rel) { - List *l; + ListCell *l; printf("RELOPTINFO ("); print_relids(rel->relids); -- cgit v1.2.3