var.c File Reference

#include "postgres.h"
#include "access/sysattr.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "optimizer/placeholder.h"
#include "optimizer/prep.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"

Include dependency graph for var.c:

Go to the source code of this file.

Data Structures
struct	pull_varnos_context
struct	pull_varattnos_context
struct	pull_vars_context
struct	locate_var_of_level_context
struct	pull_var_clause_context
struct	flatten_join_alias_vars_context

Functions
static bool	pull_varnos_walker (Node *node, pull_varnos_context *context)
static bool	pull_varattnos_walker (Node *node, pull_varattnos_context *context)
static bool	pull_vars_walker (Node *node, pull_vars_context *context)
static bool	contain_var_clause_walker (Node *node, void *context)
static bool	contain_vars_of_level_walker (Node *node, int *sublevels_up)
static bool	locate_var_of_level_walker (Node *node, locate_var_of_level_context *context)
static bool	pull_var_clause_walker (Node *node, pull_var_clause_context *context)
static Node *	flatten_join_alias_vars_mutator (Node *node, flatten_join_alias_vars_context *context)
static Relids	alias_relid_set (Query *query, Relids relids)
Relids	pull_varnos (PlannerInfo *root, Node *node)
Relids	pull_varnos_of_level (PlannerInfo *root, Node *node, int levelsup)
void	pull_varattnos (Node *node, Index varno, Bitmapset **varattnos)
List *	pull_vars_of_level (Node *node, int levelsup)
bool	contain_var_clause (Node *node)
bool	contain_vars_of_level (Node *node, int levelsup)
int	locate_var_of_level (Node *node, int levelsup)
List *	pull_var_clause (Node *node, int flags)
Node *	flatten_join_alias_vars (Query *query, Node *node)

Function Documentation

alias_relid_set()

static Relids alias_relid_set ( Query *  query, Relids  relids  )

static

Definition at line 888 of file var.c.

{
    Relids      result = NULL;
    int         rtindex;
 
    rtindex = -1;
    while ((rtindex = bms_next_member(relids, rtindex)) >= 0)
    {
        RangeTblEntry *rte = rt_fetch(rtindex, query->rtable);
 
        if (rte->rtekind == RTE_JOIN)
            result = bms_join(result, get_relids_for_join(query, rtindex));
        else
            result = bms_add_member(result, rtindex);
    }
    return result;
}

References bms_add_member(), bms_join(), bms_next_member(), get_relids_for_join(), rt_fetch, Query::rtable, RTE_JOIN, and RangeTblEntry::rtekind.

Referenced by flatten_join_alias_vars_mutator().

contain_var_clause()

bool contain_var_clause

(

Node *

node

)

Definition at line 393 of file var.c.

{
    return contain_var_clause_walker(node, NULL);
}

References contain_var_clause_walker().

Referenced by contain_leaked_vars_walker(), cookDefault(), domainAddConstraint(), interpret_function_parameter_list(), is_pseudo_constant_clause(), match_clause_to_ordering_op(), match_clause_to_partition_key(), test_opexpr_is_hashable(), and transformPartitionBoundValue().

contain_var_clause_walker()

static bool contain_var_clause_walker ( Node *  node, void *  context  )

static

Definition at line 399 of file var.c.

{
    if (node == NULL)
        return false;
    if (IsA(node, Var))
    {
        if (((Var *) node)->varlevelsup == 0)
            return true;        /* abort the tree traversal and return true */
        return false;
    }
    if (IsA(node, CurrentOfExpr))
        return true;
    if (IsA(node, PlaceHolderVar))
    {
        if (((PlaceHolderVar *) node)->phlevelsup == 0)
            return true;        /* abort the tree traversal and return true */
        /* else fall through to check the contained expr */
    }
    return expression_tree_walker(node, contain_var_clause_walker, context);
}

References expression_tree_walker(), and IsA.

Referenced by contain_var_clause().

contain_vars_of_level()

bool contain_vars_of_level	(	Node *	node,
		int	levelsup
	)

Definition at line 431 of file var.c.

{
    int         sublevels_up = levelsup;
 
    return query_or_expression_tree_walker(node,
                                           contain_vars_of_level_walker,
                                           (void *) &sublevels_up,
                                           0);
}

References contain_vars_of_level_walker(), and query_or_expression_tree_walker().

Referenced by apply_child_basequals(), checkExprIsVarFree(), convert_ANY_sublink_to_join(), convert_EXISTS_sublink_to_join(), convert_EXISTS_to_ANY(), pull_up_simple_values(), pullup_replace_vars_callback(), transformAExprIn(), transformRangeFunction(), transformRangeTableFunc(), transformSetOperationTree(), and transformValuesClause().

contain_vars_of_level_walker()

static bool contain_vars_of_level_walker ( Node *  node, int *  sublevels_up  )

static

Definition at line 442 of file var.c.

{
    if (node == NULL)
        return false;
    if (IsA(node, Var))
    {
        if (((Var *) node)->varlevelsup == *sublevels_up)
            return true;        /* abort tree traversal and return true */
        return false;
    }
    if (IsA(node, CurrentOfExpr))
    {
        if (*sublevels_up == 0)
            return true;
        return false;
    }
    if (IsA(node, PlaceHolderVar))
    {
        if (((PlaceHolderVar *) node)->phlevelsup == *sublevels_up)
            return true;        /* abort the tree traversal and return true */
        /* else fall through to check the contained expr */
    }
    if (IsA(node, Query))
    {
        /* Recurse into subselects */
        bool        result;
 
        (*sublevels_up)++;
        result = query_tree_walker((Query *) node,
                                   contain_vars_of_level_walker,
                                   (void *) sublevels_up,
                                   0);
        (*sublevels_up)--;
        return result;
    }
    return expression_tree_walker(node,
                                  contain_vars_of_level_walker,
                                  (void *) sublevels_up);
}

References expression_tree_walker(), IsA, and query_tree_walker().

Referenced by contain_vars_of_level().

flatten_join_alias_vars()

Node* flatten_join_alias_vars	(	Query *	query,
		Node *	node
	)

Definition at line 732 of file var.c.

{
    flatten_join_alias_vars_context context;
 
    context.query = query;
    context.sublevels_up = 0;
    /* flag whether join aliases could possibly contain SubLinks */
    context.possible_sublink = query->hasSubLinks;
    /* if hasSubLinks is already true, no need to work hard */
    context.inserted_sublink = query->hasSubLinks;
 
    return flatten_join_alias_vars_mutator(node, &context);
}

References flatten_join_alias_vars_mutator(), Query::hasSubLinks, flatten_join_alias_vars_context::inserted_sublink, flatten_join_alias_vars_context::possible_sublink, flatten_join_alias_vars_context::query, and flatten_join_alias_vars_context::sublevels_up.

Referenced by finalize_grouping_exprs_walker(), parseCheckAggregates(), preprocess_expression(), pull_up_simple_subquery(), and subquery_planner().

flatten_join_alias_vars_mutator()

static Node * flatten_join_alias_vars_mutator ( Node *  node, flatten_join_alias_vars_context *  context  )

static

Definition at line 747 of file var.c.

{
    if (node == NULL)
        return NULL;
    if (IsA(node, Var))
    {
        Var        *var = (Var *) node;
        RangeTblEntry *rte;
        Node       *newvar;
 
        /* No change unless Var belongs to a JOIN of the target level */
        if (var->varlevelsup != context->sublevels_up)
            return node;        /* no need to copy, really */
        rte = rt_fetch(var->varno, context->query->rtable);
        if (rte->rtekind != RTE_JOIN)
            return node;
        if (var->varattno == InvalidAttrNumber)
        {
            /* Must expand whole-row reference */
            RowExpr    *rowexpr;
            List       *fields = NIL;
            List       *colnames = NIL;
            AttrNumber  attnum;
            ListCell   *lv;
            ListCell   *ln;
 
            attnum = 0;
            Assert(list_length(rte->joinaliasvars) == list_length(rte->eref->colnames));
            forboth(lv, rte->joinaliasvars, ln, rte->eref->colnames)
            {
                newvar = (Node *) lfirst(lv);
                attnum++;
                /* Ignore dropped columns */
                if (newvar == NULL)
                    continue;
                newvar = copyObject(newvar);
 
                /*
                 * If we are expanding an alias carried down from an upper
                 * query, must adjust its varlevelsup fields.
                 */
                if (context->sublevels_up != 0)
                    IncrementVarSublevelsUp(newvar, context->sublevels_up, 0);
                /* Preserve original Var's location, if possible */
                if (IsA(newvar, Var))
                    ((Var *) newvar)->location = var->location;
                /* Recurse in case join input is itself a join */
                /* (also takes care of setting inserted_sublink if needed) */
                newvar = flatten_join_alias_vars_mutator(newvar, context);
                fields = lappend(fields, newvar);
                /* We need the names of non-dropped columns, too */
                colnames = lappend(colnames, copyObject((Node *) lfirst(ln)));
            }
            rowexpr = makeNode(RowExpr);
            rowexpr->args = fields;
            rowexpr->row_typeid = var->vartype;
            rowexpr->row_format = COERCE_IMPLICIT_CAST;
            rowexpr->colnames = colnames;
            rowexpr->location = var->location;
 
            return (Node *) rowexpr;
        }
 
        /* Expand join alias reference */
        Assert(var->varattno > 0);
        newvar = (Node *) list_nth(rte->joinaliasvars, var->varattno - 1);
        Assert(newvar != NULL);
        newvar = copyObject(newvar);
 
        /*
         * If we are expanding an alias carried down from an upper query, must
         * adjust its varlevelsup fields.
         */
        if (context->sublevels_up != 0)
            IncrementVarSublevelsUp(newvar, context->sublevels_up, 0);
 
        /* Preserve original Var's location, if possible */
        if (IsA(newvar, Var))
            ((Var *) newvar)->location = var->location;
 
        /* Recurse in case join input is itself a join */
        newvar = flatten_join_alias_vars_mutator(newvar, context);
 
        /* Detect if we are adding a sublink to query */
        if (context->possible_sublink && !context->inserted_sublink)
            context->inserted_sublink = checkExprHasSubLink(newvar);
 
        return newvar;
    }
    if (IsA(node, PlaceHolderVar))
    {
        /* Copy the PlaceHolderVar node with correct mutation of subnodes */
        PlaceHolderVar *phv;
 
        phv = (PlaceHolderVar *) expression_tree_mutator(node,
                                                         flatten_join_alias_vars_mutator,
                                                         (void *) context);
        /* now fix PlaceHolderVar's relid sets */
        if (phv->phlevelsup == context->sublevels_up)
        {
            phv->phrels = alias_relid_set(context->query,
                                          phv->phrels);
        }
        return (Node *) phv;
    }
 
    if (IsA(node, Query))
    {
        /* Recurse into RTE subquery or not-yet-planned sublink subquery */
        Query      *newnode;
        bool        save_inserted_sublink;
 
        context->sublevels_up++;
        save_inserted_sublink = context->inserted_sublink;
        context->inserted_sublink = ((Query *) node)->hasSubLinks;
        newnode = query_tree_mutator((Query *) node,
                                     flatten_join_alias_vars_mutator,
                                     (void *) context,
                                     QTW_IGNORE_JOINALIASES);
        newnode->hasSubLinks |= context->inserted_sublink;
        context->inserted_sublink = save_inserted_sublink;
        context->sublevels_up--;
        return (Node *) newnode;
    }
    /* Already-planned tree not supported */
    Assert(!IsA(node, SubPlan));
    /* Shouldn't need to handle these planner auxiliary nodes here */
    Assert(!IsA(node, SpecialJoinInfo));
    Assert(!IsA(node, PlaceHolderInfo));
    Assert(!IsA(node, MinMaxAggInfo));
 
    return expression_tree_mutator(node, flatten_join_alias_vars_mutator,
                                   (void *) context);
}

References alias_relid_set(), RowExpr::args, Assert(), attnum, checkExprHasSubLink(), COERCE_IMPLICIT_CAST, Alias::colnames, RowExpr::colnames, copyObject, RangeTblEntry::eref, expression_tree_mutator(), forboth, Query::hasSubLinks, IncrementVarSublevelsUp(), flatten_join_alias_vars_context::inserted_sublink, InvalidAttrNumber, IsA, RangeTblEntry::joinaliasvars, lappend(), lfirst, list_length(), list_nth(), Var::location, RowExpr::location, makeNode, NIL, PlaceHolderVar::phlevelsup, PlaceHolderVar::phrels, flatten_join_alias_vars_context::possible_sublink, QTW_IGNORE_JOINALIASES, flatten_join_alias_vars_context::query, query_tree_mutator(), RowExpr::row_format, RowExpr::row_typeid, rt_fetch, Query::rtable, RTE_JOIN, RangeTblEntry::rtekind, flatten_join_alias_vars_context::sublevels_up, Var::varattno, Var::varlevelsup, Var::varno, and Var::vartype.

Referenced by flatten_join_alias_vars().

locate_var_of_level()

int locate_var_of_level	(	Node *	node,
		int	levelsup
	)

Definition at line 499 of file var.c.

{
    locate_var_of_level_context context;
 
    context.var_location = -1;  /* in case we find nothing */
    context.sublevels_up = levelsup;
 
    (void) query_or_expression_tree_walker(node,
                                           locate_var_of_level_walker,
                                           (void *) &context,
                                           0);
 
    return context.var_location;
}

References locate_var_of_level_walker(), query_or_expression_tree_walker(), locate_var_of_level_context::sublevels_up, and locate_var_of_level_context::var_location.

Referenced by check_agg_arguments(), checkExprIsVarFree(), and transformSetOperationTree().

locate_var_of_level_walker()

static bool locate_var_of_level_walker ( Node *  node, locate_var_of_level_context *  context  )

static

Definition at line 515 of file var.c.

{
    if (node == NULL)
        return false;
    if (IsA(node, Var))
    {
        Var        *var = (Var *) node;
 
        if (var->varlevelsup == context->sublevels_up &&
            var->location >= 0)
        {
            context->var_location = var->location;
            return true;        /* abort tree traversal and return true */
        }
        return false;
    }
    if (IsA(node, CurrentOfExpr))
    {
        /* since CurrentOfExpr doesn't carry location, nothing we can do */
        return false;
    }
    /* No extra code needed for PlaceHolderVar; just look in contained expr */
    if (IsA(node, Query))
    {
        /* Recurse into subselects */
        bool        result;
 
        context->sublevels_up++;
        result = query_tree_walker((Query *) node,
                                   locate_var_of_level_walker,
                                   (void *) context,
                                   0);
        context->sublevels_up--;
        return result;
    }
    return expression_tree_walker(node,
                                  locate_var_of_level_walker,
                                  (void *) context);
}

References expression_tree_walker(), IsA, Var::location, query_tree_walker(), locate_var_of_level_context::sublevels_up, locate_var_of_level_context::var_location, and Var::varlevelsup.

Referenced by locate_var_of_level().

pull_var_clause()

List* pull_var_clause	(	Node *	node,
		int	flags
	)

Definition at line 597 of file var.c.

{
    pull_var_clause_context context;
 
    /* Assert that caller has not specified inconsistent flags */
    Assert((flags & (PVC_INCLUDE_AGGREGATES | PVC_RECURSE_AGGREGATES))
           != (PVC_INCLUDE_AGGREGATES | PVC_RECURSE_AGGREGATES));
    Assert((flags & (PVC_INCLUDE_WINDOWFUNCS | PVC_RECURSE_WINDOWFUNCS))
           != (PVC_INCLUDE_WINDOWFUNCS | PVC_RECURSE_WINDOWFUNCS));
    Assert((flags & (PVC_INCLUDE_PLACEHOLDERS | PVC_RECURSE_PLACEHOLDERS))
           != (PVC_INCLUDE_PLACEHOLDERS | PVC_RECURSE_PLACEHOLDERS));
 
    context.varlist = NIL;
    context.flags = flags;
 
    pull_var_clause_walker(node, &context);
    return context.varlist;
}

References Assert(), pull_var_clause_context::flags, NIL, pull_var_clause_walker(), PVC_INCLUDE_AGGREGATES, PVC_INCLUDE_PLACEHOLDERS, PVC_INCLUDE_WINDOWFUNCS, PVC_RECURSE_AGGREGATES, PVC_RECURSE_PLACEHOLDERS, PVC_RECURSE_WINDOWFUNCS, and pull_var_clause_context::varlist.

Referenced by AddRelationNewConstraints(), build_base_rel_tlists(), build_remote_returning(), build_tlist_to_deparse(), CreateTriggerFiringOn(), dependency_is_compatible_expression(), distribute_qual_to_rels(), estimate_num_groups(), find_computable_ec_member(), find_placeholders_in_expr(), fix_placeholder_input_needed_levels(), foreign_grouping_ok(), generate_base_implied_equalities_no_const(), make_group_input_target(), make_partial_grouping_target(), make_sort_input_target(), make_window_input_target(), preprocess_targetlist(), process_implied_equality(), qual_is_pushdown_safe(), and StoreRelCheck().

pull_var_clause_walker()

static bool pull_var_clause_walker ( Node *  node, pull_var_clause_context *  context  )

static

Definition at line 617 of file var.c.

{
    if (node == NULL)
        return false;
    if (IsA(node, Var))
    {
        if (((Var *) node)->varlevelsup != 0)
            elog(ERROR, "Upper-level Var found where not expected");
        context->varlist = lappend(context->varlist, node);
        return false;
    }
    else if (IsA(node, Aggref))
    {
        if (((Aggref *) node)->agglevelsup != 0)
            elog(ERROR, "Upper-level Aggref found where not expected");
        if (context->flags & PVC_INCLUDE_AGGREGATES)
        {
            context->varlist = lappend(context->varlist, node);
            /* we do NOT descend into the contained expression */
            return false;
        }
        else if (context->flags & PVC_RECURSE_AGGREGATES)
        {
            /* fall through to recurse into the aggregate's arguments */
        }
        else
            elog(ERROR, "Aggref found where not expected");
    }
    else if (IsA(node, GroupingFunc))
    {
        if (((GroupingFunc *) node)->agglevelsup != 0)
            elog(ERROR, "Upper-level GROUPING found where not expected");
        if (context->flags & PVC_INCLUDE_AGGREGATES)
        {
            context->varlist = lappend(context->varlist, node);
            /* we do NOT descend into the contained expression */
            return false;
        }
        else if (context->flags & PVC_RECURSE_AGGREGATES)
        {
            /*
             * We do NOT descend into the contained expression, even if the
             * caller asked for it, because we never actually evaluate it -
             * the result is driven entirely off the associated GROUP BY
             * clause, so we never need to extract the actual Vars here.
             */
            return false;
        }
        else
            elog(ERROR, "GROUPING found where not expected");
    }
    else if (IsA(node, WindowFunc))
    {
        /* WindowFuncs have no levelsup field to check ... */
        if (context->flags & PVC_INCLUDE_WINDOWFUNCS)
        {
            context->varlist = lappend(context->varlist, node);
            /* we do NOT descend into the contained expressions */
            return false;
        }
        else if (context->flags & PVC_RECURSE_WINDOWFUNCS)
        {
            /* fall through to recurse into the windowfunc's arguments */
        }
        else
            elog(ERROR, "WindowFunc found where not expected");
    }
    else if (IsA(node, PlaceHolderVar))
    {
        if (((PlaceHolderVar *) node)->phlevelsup != 0)
            elog(ERROR, "Upper-level PlaceHolderVar found where not expected");
        if (context->flags & PVC_INCLUDE_PLACEHOLDERS)
        {
            context->varlist = lappend(context->varlist, node);
            /* we do NOT descend into the contained expression */
            return false;
        }
        else if (context->flags & PVC_RECURSE_PLACEHOLDERS)
        {
            /* fall through to recurse into the placeholder's expression */
        }
        else
            elog(ERROR, "PlaceHolderVar found where not expected");
    }
    return expression_tree_walker(node, pull_var_clause_walker,
                                  (void *) context);
}

References elog, ERROR, expression_tree_walker(), pull_var_clause_context::flags, IsA, lappend(), PVC_INCLUDE_AGGREGATES, PVC_INCLUDE_PLACEHOLDERS, PVC_INCLUDE_WINDOWFUNCS, PVC_RECURSE_AGGREGATES, PVC_RECURSE_PLACEHOLDERS, PVC_RECURSE_WINDOWFUNCS, and pull_var_clause_context::varlist.

Referenced by pull_var_clause().

pull_varattnos()

void pull_varattnos	(	Node *	node,
		Index	varno,
		Bitmapset **	varattnos
	)

Definition at line 281 of file var.c.

{
    pull_varattnos_context context;
 
    context.varattnos = *varattnos;
    context.varno = varno;
 
    (void) pull_varattnos_walker(node, &context);
 
    *varattnos = context.varattnos;
}

References pull_varattnos_walker(), pull_varattnos_context::varattnos, and pull_varattnos_context::varno.

Referenced by check_index_only(), check_selective_binary_conversion(), ComputePartitionAttrs(), create_foreignscan_plan(), CreateStatistics(), DefineIndex(), deparseReturningList(), fill_extraUpdatedCols(), has_partition_attrs(), postgresGetForeignRelSize(), RelationGetIndexAttrBitmap(), remove_unused_subquery_outputs(), and statext_is_compatible_clause().

pull_varattnos_walker()

static bool pull_varattnos_walker ( Node *  node, pull_varattnos_context *  context  )

static

Definition at line 294 of file var.c.

{
    if (node == NULL)
        return false;
    if (IsA(node, Var))
    {
        Var        *var = (Var *) node;
 
        if (var->varno == context->varno && var->varlevelsup == 0)
            context->varattnos =
                bms_add_member(context->varattnos,
                               var->varattno - FirstLowInvalidHeapAttributeNumber);
        return false;
    }
 
    /* Should not find an unplanned subquery */
    Assert(!IsA(node, Query));
 
    return expression_tree_walker(node, pull_varattnos_walker,
                                  (void *) context);
}

References Assert(), bms_add_member(), expression_tree_walker(), FirstLowInvalidHeapAttributeNumber, IsA, Var::varattno, pull_varattnos_context::varattnos, Var::varlevelsup, pull_varattnos_context::varno, and Var::varno.

Referenced by pull_varattnos().

pull_varnos()

Relids pull_varnos	(	PlannerInfo *	root,
		Node *	node
	)

Definition at line 97 of file var.c.

{
    pull_varnos_context context;
 
    context.varnos = NULL;
    context.root = root;
    context.sublevels_up = 0;
 
    /*
     * Must be prepared to start with a Query or a bare expression tree; if
     * it's a Query, we don't want to increment sublevels_up.
     */
    query_or_expression_tree_walker(node,
                                    pull_varnos_walker,
                                    (void *) &context,
                                    0);
 
    return context.varnos;
}

References pull_varnos_walker(), query_or_expression_tree_walker(), pull_varnos_context::root, pull_varnos_context::sublevels_up, and pull_varnos_context::varnos.

Referenced by compute_semijoin_info(), convert_ANY_sublink_to_join(), convert_EXISTS_sublink_to_join(), cost_incremental_sort(), distribute_qual_to_rels(), examine_variable(), expand_indexqual_rowcompare(), find_placeholder_info(), get_eclass_for_sort_expr(), is_pseudo_constant_for_index(), IsTidEqualAnyClause(), join_is_removable(), make_outerjoininfo(), make_restrictinfo_internal(), match_rowcompare_to_indexcol(), match_saopclause_to_indexcol(), NumRelids(), process_implied_equality(), pullup_replace_vars_callback(), and reduce_outer_joins_pass2().

pull_varnos_of_level()

Relids pull_varnos_of_level	(	PlannerInfo *	root,
		Node *	node,
		int	levelsup
	)

Definition at line 123 of file var.c.

{
    pull_varnos_context context;
 
    context.varnos = NULL;
    context.root = root;
    context.sublevels_up = levelsup;
 
    /*
     * Must be prepared to start with a Query or a bare expression tree; if
     * it's a Query, we don't want to increment sublevels_up.
     */
    query_or_expression_tree_walker(node,
                                    pull_varnos_walker,
                                    (void *) &context,
                                    0);
 
    return context.varnos;
}

References pull_varnos_walker(), query_or_expression_tree_walker(), pull_varnos_context::root, pull_varnos_context::sublevels_up, and pull_varnos_context::varnos.

Referenced by is_simple_subquery(), and jointree_contains_lateral_outer_refs().

pull_varnos_walker()

static bool pull_varnos_walker ( Node *  node, pull_varnos_context *  context  )

static

Definition at line 144 of file var.c.

{
    if (node == NULL)
        return false;
    if (IsA(node, Var))
    {
        Var        *var = (Var *) node;
 
        if (var->varlevelsup == context->sublevels_up)
            context->varnos = bms_add_member(context->varnos, var->varno);
        return false;
    }
    if (IsA(node, CurrentOfExpr))
    {
        CurrentOfExpr *cexpr = (CurrentOfExpr *) node;
 
        if (context->sublevels_up == 0)
            context->varnos = bms_add_member(context->varnos, cexpr->cvarno);
        return false;
    }
    if (IsA(node, PlaceHolderVar))
    {
        PlaceHolderVar *phv = (PlaceHolderVar *) node;
 
        /*
         * If a PlaceHolderVar is not of the target query level, ignore it,
         * instead recursing into its expression to see if it contains any
         * vars that are of the target level.
         */
        if (phv->phlevelsup == context->sublevels_up)
        {
            /*
             * Ideally, the PHV's contribution to context->varnos is its
             * ph_eval_at set.  However, this code can be invoked before
             * that's been computed.  If we cannot find a PlaceHolderInfo,
             * fall back to the conservative assumption that the PHV will be
             * evaluated at its syntactic level (phv->phrels).
             *
             * There is a second hazard: this code is also used to examine
             * qual clauses during deconstruct_jointree, when we may have a
             * PlaceHolderInfo but its ph_eval_at value is not yet final, so
             * that theoretically we could obtain a relid set that's smaller
             * than we'd see later on.  That should never happen though,
             * because we deconstruct the jointree working upwards.  Any outer
             * join that forces delay of evaluation of a given qual clause
             * will be processed before we examine that clause here, so the
             * ph_eval_at value should have been updated to include it.
             *
             * Another problem is that a PlaceHolderVar can appear in quals or
             * tlists that have been translated for use in a child appendrel.
             * Typically such a PHV is a parameter expression sourced by some
             * other relation, so that the translation from parent appendrel
             * to child doesn't change its phrels, and we should still take
             * ph_eval_at at face value.  But in corner cases, the PHV's
             * original phrels can include the parent appendrel itself, in
             * which case the translated PHV will have the child appendrel in
             * phrels, and we must translate ph_eval_at to match.
             */
            PlaceHolderInfo *phinfo = NULL;
 
            if (phv->phlevelsup == 0)
            {
                ListCell   *lc;
 
                foreach(lc, context->root->placeholder_list)
                {
                    phinfo = (PlaceHolderInfo *) lfirst(lc);
                    if (phinfo->phid == phv->phid)
                        break;
                    phinfo = NULL;
                }
            }
            if (phinfo == NULL)
            {
                /* No PlaceHolderInfo yet, use phrels */
                context->varnos = bms_add_members(context->varnos,
                                                  phv->phrels);
            }
            else if (bms_equal(phv->phrels, phinfo->ph_var->phrels))
            {
                /* Normal case: use ph_eval_at */
                context->varnos = bms_add_members(context->varnos,
                                                  phinfo->ph_eval_at);
            }
            else
            {
                /* Translated PlaceHolderVar: translate ph_eval_at to match */
                Relids      newevalat,
                            delta;
 
                /* remove what was removed from phv->phrels ... */
                delta = bms_difference(phinfo->ph_var->phrels, phv->phrels);
                newevalat = bms_difference(phinfo->ph_eval_at, delta);
                /* ... then if that was in fact part of ph_eval_at ... */
                if (!bms_equal(newevalat, phinfo->ph_eval_at))
                {
                    /* ... add what was added */
                    delta = bms_difference(phv->phrels, phinfo->ph_var->phrels);
                    newevalat = bms_join(newevalat, delta);
                }
                context->varnos = bms_join(context->varnos,
                                           newevalat);
            }
            return false;       /* don't recurse into expression */
        }
    }
    else if (IsA(node, Query))
    {
        /* Recurse into RTE subquery or not-yet-planned sublink subquery */
        bool        result;
 
        context->sublevels_up++;
        result = query_tree_walker((Query *) node, pull_varnos_walker,
                                   (void *) context, 0);
        context->sublevels_up--;
        return result;
    }
    return expression_tree_walker(node, pull_varnos_walker,
                                  (void *) context);
}

References bms_add_member(), bms_add_members(), bms_difference(), bms_equal(), bms_join(), CurrentOfExpr::cvarno, expression_tree_walker(), IsA, lfirst, PlaceHolderInfo::ph_eval_at, PlaceHolderInfo::ph_var, PlaceHolderVar::phid, PlaceHolderInfo::phid, PlaceHolderVar::phlevelsup, PlaceHolderVar::phrels, PlannerInfo::placeholder_list, query_tree_walker(), pull_varnos_context::root, pull_varnos_context::sublevels_up, Var::varlevelsup, Var::varno, and pull_varnos_context::varnos.

Referenced by pull_varnos(), and pull_varnos_of_level().

pull_vars_of_level()

List* pull_vars_of_level	(	Node *	node,
		int	levelsup
	)

Definition at line 325 of file var.c.

{
    pull_vars_context context;
 
    context.vars = NIL;
    context.sublevels_up = levelsup;
 
    /*
     * Must be prepared to start with a Query or a bare expression tree; if
     * it's a Query, we don't want to increment sublevels_up.
     */
    query_or_expression_tree_walker(node,
                                    pull_vars_walker,
                                    (void *) &context,
                                    0);
 
    return context.vars;
}

References NIL, pull_vars_walker(), query_or_expression_tree_walker(), pull_vars_context::sublevels_up, and pull_vars_context::vars.

Referenced by extract_lateral_references().

pull_vars_walker()

static bool pull_vars_walker ( Node *  node, pull_vars_context *  context  )

static

Definition at line 345 of file var.c.

{
    if (node == NULL)
        return false;
    if (IsA(node, Var))
    {
        Var        *var = (Var *) node;
 
        if (var->varlevelsup == context->sublevels_up)
            context->vars = lappend(context->vars, var);
        return false;
    }
    if (IsA(node, PlaceHolderVar))
    {
        PlaceHolderVar *phv = (PlaceHolderVar *) node;
 
        if (phv->phlevelsup == context->sublevels_up)
            context->vars = lappend(context->vars, phv);
        /* we don't want to look into the contained expression */
        return false;
    }
    if (IsA(node, Query))
    {
        /* Recurse into RTE subquery or not-yet-planned sublink subquery */
        bool        result;
 
        context->sublevels_up++;
        result = query_tree_walker((Query *) node, pull_vars_walker,
                                   (void *) context, 0);
        context->sublevels_up--;
        return result;
    }
    return expression_tree_walker(node, pull_vars_walker,
                                  (void *) context);
}

References expression_tree_walker(), IsA, lappend(), PlaceHolderVar::phlevelsup, query_tree_walker(), pull_vars_context::sublevels_up, Var::varlevelsup, and pull_vars_context::vars.

Referenced by pull_vars_of_level().