diff options
Diffstat (limited to 'src/backend/optimizer/path/prune.c')
| -rw-r--r-- | src/backend/optimizer/path/prune.c | 284 |
1 files changed, 151 insertions, 133 deletions
diff --git a/src/backend/optimizer/path/prune.c b/src/backend/optimizer/path/prune.c index 0b154e108fa..4f3ae2d15de 100644 --- a/src/backend/optimizer/path/prune.c +++ b/src/backend/optimizer/path/prune.c @@ -1,13 +1,13 @@ /*------------------------------------------------------------------------- * * prune.c-- - * Routines to prune redundant paths and relations + * Routines to prune redundant paths and relations * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/prune.c,v 1.3 1997/06/10 07:55:47 vadim Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/prune.c,v 1.4 1997/09/07 04:43:49 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -24,181 +24,199 @@ #include "utils/elog.h" -static List *prune_joinrel(Rel *rel, List *other_rels); +static List *prune_joinrel(Rel * rel, List * other_rels); -/* +/* * prune-joinrels-- - * Removes any redundant relation entries from a list of rel nodes - * 'rel-list'. - * - * Returns the resulting list. - * + * Removes any redundant relation entries from a list of rel nodes + * 'rel-list'. + * + * Returns the resulting list. + * */ -List *prune_joinrels(List *rel_list) +List * +prune_joinrels(List * rel_list) { - List *temp_list = NIL; - - if (rel_list != NIL) { - temp_list = lcons(lfirst(rel_list), - prune_joinrels(prune_joinrel((Rel*)lfirst(rel_list), - lnext(rel_list)))); - } - return(temp_list); + List *temp_list = NIL; + + if (rel_list != NIL) + { + temp_list = lcons(lfirst(rel_list), + prune_joinrels(prune_joinrel((Rel *) lfirst(rel_list), + lnext(rel_list)))); + } + return (temp_list); } -/* +/* * prune-joinrel-- - * Prunes those relations from 'other-rels' that are redundant with - * 'rel'. A relation is redundant if it is built up of the same - * relations as 'rel'. Paths for the redundant relation are merged into - * the pathlist of 'rel'. - * + * Prunes those relations from 'other-rels' that are redundant with + * 'rel'. A relation is redundant if it is built up of the same + * relations as 'rel'. Paths for the redundant relation are merged into + * the pathlist of 'rel'. + * * Returns a list of non-redundant relations, and sets the pathlist field * of 'rel' appropriately. - * + * */ -static List * -prune_joinrel(Rel *rel, List *other_rels) +static List * +prune_joinrel(Rel * rel, List * other_rels) { - List *i = NIL; - List *t_list = NIL; - List *temp_node = NIL; - Rel *other_rel = (Rel *)NULL; - - foreach(i, other_rels) { - other_rel = (Rel*)lfirst(i); - if(same(rel->relids, other_rel->relids)) { - rel->pathlist = add_pathlist(rel, - rel->pathlist, - other_rel->pathlist); - t_list = nconc(t_list, NIL); /* XXX is this right ? */ - } else { - temp_node = lcons(other_rel, NIL); - t_list = nconc(t_list,temp_node); - } - } - return(t_list); + List *i = NIL; + List *t_list = NIL; + List *temp_node = NIL; + Rel *other_rel = (Rel *) NULL; + + foreach(i, other_rels) + { + other_rel = (Rel *) lfirst(i); + if (same(rel->relids, other_rel->relids)) + { + rel->pathlist = add_pathlist(rel, + rel->pathlist, + other_rel->pathlist); + t_list = nconc(t_list, NIL); /* XXX is this right ? */ + } + else + { + temp_node = lcons(other_rel, NIL); + t_list = nconc(t_list, temp_node); + } + } + return (t_list); } -/* +/* * prune-rel-paths-- - * For each relation entry in 'rel-list' (which corresponds to a join - * relation), set pointers to the unordered path and cheapest paths - * (if the unordered path isn't the cheapest, it is pruned), and - * reset the relation's size field to reflect the join. - * + * For each relation entry in 'rel-list' (which corresponds to a join + * relation), set pointers to the unordered path and cheapest paths + * (if the unordered path isn't the cheapest, it is pruned), and + * reset the relation's size field to reflect the join. + * * Returns nothing of interest. - * + * */ void -prune_rel_paths(List *rel_list) +prune_rel_paths(List * rel_list) { - List *x = NIL; - List *y = NIL; - Path *path = NULL; - Rel *rel = (Rel*)NULL; - JoinPath *cheapest = (JoinPath*)NULL; - - foreach(x, rel_list) { - rel = (Rel*)lfirst(x); - rel->size = 0; - foreach(y, rel->pathlist) { - path = (Path*)lfirst(y); - - if(!path->p_ordering.ord.sortop) { - break; - } + List *x = NIL; + List *y = NIL; + Path *path = NULL; + Rel *rel = (Rel *) NULL; + JoinPath *cheapest = (JoinPath *) NULL; + + foreach(x, rel_list) + { + rel = (Rel *) lfirst(x); + rel->size = 0; + foreach(y, rel->pathlist) + { + path = (Path *) lfirst(y); + + if (!path->p_ordering.ord.sortop) + { + break; + } + } + cheapest = (JoinPath *) prune_rel_path(rel, path); + if (IsA_JoinPath(cheapest)) + { + rel->size = compute_joinrel_size(cheapest); + } + else + elog(WARN, "non JoinPath called"); } - cheapest = (JoinPath*)prune_rel_path(rel, path); - if (IsA_JoinPath(cheapest)) - { - rel->size = compute_joinrel_size(cheapest); - } - else - elog(WARN, "non JoinPath called"); - } } -/* +/* * prune-rel-path-- - * Compares the unordered path for a relation with the cheapest path. If - * the unordered path is not cheapest, it is pruned. - * - * Resets the pointers in 'rel' for unordered and cheapest paths. - * + * Compares the unordered path for a relation with the cheapest path. If + * the unordered path is not cheapest, it is pruned. + * + * Resets the pointers in 'rel' for unordered and cheapest paths. + * * Returns the cheapest path. - * + * */ -Path * -prune_rel_path(Rel *rel, Path *unorderedpath) +Path * +prune_rel_path(Rel * rel, Path * unorderedpath) { - Path *cheapest = set_cheapest(rel, rel->pathlist); - - /* don't prune if not pruneable -- JMH, 11/23/92 */ - if(unorderedpath != cheapest - && rel->pruneable) { - - rel->unorderedpath = (Path *)NULL; - rel->pathlist = lremove(unorderedpath, rel->pathlist); - } else { - rel->unorderedpath = (Path *)unorderedpath; - } - - return(cheapest); + Path *cheapest = set_cheapest(rel, rel->pathlist); + + /* don't prune if not pruneable -- JMH, 11/23/92 */ + if (unorderedpath != cheapest + && rel->pruneable) + { + + rel->unorderedpath = (Path *) NULL; + rel->pathlist = lremove(unorderedpath, rel->pathlist); + } + else + { + rel->unorderedpath = (Path *) unorderedpath; + } + + return (cheapest); } /* * merge-joinrels-- - * Given two lists of rel nodes that are already - * pruned, merge them into one pruned rel node list + * Given two lists of rel nodes that are already + * pruned, merge them into one pruned rel node list * * 'rel-list1' and * 'rel-list2' are the rel node lists * * Returns one pruned rel node list */ -List * -merge_joinrels(List *rel_list1, List *rel_list2) +List * +merge_joinrels(List * rel_list1, List * rel_list2) { - List *xrel = NIL; - - foreach(xrel,rel_list1) { - Rel *rel = (Rel*)lfirst(xrel); - rel_list2 = prune_joinrel(rel,rel_list2); - } - return(append(rel_list1, rel_list2)); + List *xrel = NIL; + + foreach(xrel, rel_list1) + { + Rel *rel = (Rel *) lfirst(xrel); + + rel_list2 = prune_joinrel(rel, rel_list2); + } + return (append(rel_list1, rel_list2)); } /* * prune_oldrels-- - * If all the joininfo's in a rel node are inactive, - * that means that this node has been joined into - * other nodes in all possible ways, therefore - * this node can be discarded. If not, it will cause - * extra complexity of the optimizer. + * If all the joininfo's in a rel node are inactive, + * that means that this node has been joined into + * other nodes in all possible ways, therefore + * this node can be discarded. If not, it will cause + * extra complexity of the optimizer. * * old_rels is a list of rel nodes - * + * * Returns a new list of rel nodes */ -List *prune_oldrels(List *old_rels) +List * +prune_oldrels(List * old_rels) { - Rel *rel; - List *joininfo_list, *xjoininfo; - - if(old_rels == NIL) - return(NIL); - - rel = (Rel*)lfirst(old_rels); - joininfo_list = rel->joininfo; - if(joininfo_list == NIL) - return (lcons(rel, prune_oldrels(lnext(old_rels)))); - - foreach(xjoininfo, joininfo_list) { - JInfo *joininfo = (JInfo*)lfirst(xjoininfo); - if(!joininfo->inactive) - return (lcons(rel, prune_oldrels(lnext(old_rels)))); - } - return(prune_oldrels(lnext(old_rels))); + Rel *rel; + List *joininfo_list, + *xjoininfo; + + if (old_rels == NIL) + return (NIL); + + rel = (Rel *) lfirst(old_rels); + joininfo_list = rel->joininfo; + if (joininfo_list == NIL) + return (lcons(rel, prune_oldrels(lnext(old_rels)))); + + foreach(xjoininfo, joininfo_list) + { + JInfo *joininfo = (JInfo *) lfirst(xjoininfo); + + if (!joininfo->inactive) + return (lcons(rel, prune_oldrels(lnext(old_rels)))); + } + return (prune_oldrels(lnext(old_rels))); } |