joininfo.h File Reference

#include "nodes/pathnodes.h"

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Functions
bool	have_relevant_joinclause (PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
void	add_join_clause_to_rels (PlannerInfo *root, RestrictInfo *restrictinfo, Relids join_relids)
void	remove_join_clause_from_rels (PlannerInfo *root, RestrictInfo *restrictinfo, Relids join_relids)

Function Documentation

add_join_clause_to_rels()

void add_join_clause_to_rels ( PlannerInfo *  root, RestrictInfo *  restrictinfo, Relids  join_relids  )

extern

Definition at line 98 of file joininfo.c.

{
    int         cur_relid;
 
    /* Don't add the clause if it is always true */
    if (restriction_is_always_true(root, restrictinfo))
        return;
 
    /*
     * Substitute the origin qual with constant-FALSE if it is provably always
     * false.
     *
     * Note that we need to keep the same rinfo_serial, since it is in
     * practice the same condition.  We also need to reset the
     * last_rinfo_serial counter, which is essential to ensure that the
     * RestrictInfos for the "same" qual condition get identical serial
     * numbers (see deconstruct_distribute_oj_quals).
     */
    if (restriction_is_always_false(root, restrictinfo))
    {
        int         save_rinfo_serial = restrictinfo->rinfo_serial;
        int         save_last_rinfo_serial = root->last_rinfo_serial;
 
        restrictinfo = make_restrictinfo(root,
                                         (Expr *) makeBoolConst(false, false),
                                         restrictinfo->is_pushed_down,
                                         restrictinfo->has_clone,
                                         restrictinfo->is_clone,
                                         restrictinfo->pseudoconstant,
                                         0, /* security_level */
                                         restrictinfo->required_relids,
                                         restrictinfo->incompatible_relids,
                                         restrictinfo->outer_relids);
        restrictinfo->rinfo_serial = save_rinfo_serial;
        root->last_rinfo_serial = save_last_rinfo_serial;
    }
 
    cur_relid = -1;
    while ((cur_relid = bms_next_member(join_relids, cur_relid)) >= 0)
    {
        RelOptInfo *rel = find_base_rel_ignore_join(root, cur_relid);
 
        /* We only need to add the clause to baserels */
        if (rel == NULL)
            continue;
        rel->joininfo = lappend(rel->joininfo, restrictinfo);
    }
}

References bms_next_member(), fb(), find_base_rel_ignore_join(), RelOptInfo::joininfo, lappend(), make_restrictinfo(), makeBoolConst(), restriction_is_always_false(), restriction_is_always_true(), and root.

Referenced by distribute_restrictinfo_to_rels().

have_relevant_joinclause()

bool have_relevant_joinclause ( PlannerInfo *  root, RelOptInfo *  rel1, RelOptInfo *  rel2  )

extern

Definition at line 39 of file joininfo.c.

{
    bool        result = false;
    List       *joininfo;
    Relids      other_relids;
    ListCell   *l;
 
    /*
     * We could scan either relation's joininfo list; may as well use the
     * shorter one.
     */
    if (list_length(rel1->joininfo) <= list_length(rel2->joininfo))
    {
        joininfo = rel1->joininfo;
        other_relids = rel2->relids;
    }
    else
    {
        joininfo = rel2->joininfo;
        other_relids = rel1->relids;
    }
 
    foreach(l, joininfo)
    {
        RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
 
        if (bms_overlap(other_relids, rinfo->required_relids))
        {
            result = true;
            break;
        }
    }
 
    /*
     * We also need to check the EquivalenceClass data structure, which might
     * contain relationships not emitted into the joininfo lists.
     */
    if (!result && rel1->has_eclass_joins && rel2->has_eclass_joins)
        result = have_relevant_eclass_joinclause(root, rel1, rel2);
 
    return result;
}

References bms_overlap(), fb(), have_relevant_eclass_joinclause(), lfirst, list_length(), RestrictInfo::required_relids, and root.

Referenced by desirable_join(), has_legal_joinclause(), join_search_one_level(), and make_rels_by_clause_joins().

remove_join_clause_from_rels()

void remove_join_clause_from_rels ( PlannerInfo *  root, RestrictInfo *  restrictinfo, Relids  join_relids  )

extern

Definition at line 161 of file joininfo.c.

{
    int         cur_relid;
 
    cur_relid = -1;
    while ((cur_relid = bms_next_member(join_relids, cur_relid)) >= 0)
    {
        RelOptInfo *rel = find_base_rel_ignore_join(root, cur_relid);
 
        /* We would only have added the clause to baserels */
        if (rel == NULL)
            continue;
 
        /*
         * Remove the restrictinfo from the list.  Pointer comparison is
         * sufficient.
         */
        Assert(list_member_ptr(rel->joininfo, restrictinfo));
        rel->joininfo = list_delete_ptr(rel->joininfo, restrictinfo);
    }
}

References Assert, bms_next_member(), fb(), find_base_rel_ignore_join(), RelOptInfo::joininfo, list_delete_ptr(), list_member_ptr(), and root.

Referenced by remove_leftjoinrel_from_query(), and remove_self_join_rel().