var.c File Reference

#include "postgres.h"
#include "access/sysattr.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.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	contain_vars_returning_old_or_new_walker (Node *node, void *context)
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 Node *	flatten_group_exprs_mutator (Node *node, flatten_join_alias_vars_context *context)
static Node *	mark_nullable_by_grouping (PlannerInfo *root, Node *newnode, Var *oldvar)
static Node *	add_nullingrels_if_needed (PlannerInfo *root, Node *newnode, Var *oldvar)
static bool	is_standard_join_alias_expression (Node *newnode, Var *oldvar)
static void	adjust_standard_join_alias_expression (Node *newnode, Var *oldvar)
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)
bool	contain_vars_returning_old_or_new (Node *node)
int	locate_var_of_level (Node *node, int levelsup)
List *	pull_var_clause (Node *node, int flags)
Node *	flatten_join_alias_vars (PlannerInfo *root, Query *query, Node *node)
Node *	flatten_group_exprs (PlannerInfo *root, Query *query, Node *node)

Function Documentation

add_nullingrels_if_needed()

static Node * add_nullingrels_if_needed ( PlannerInfo *  root, Node *  newnode, Var *  oldvar  )

static

Definition at line 1177 of file var.c.

{
    if (oldvar->varnullingrels == NULL)
        return newnode;         /* nothing to do */
    /* If possible, do it by adding to existing nullingrel fields */
    if (is_standard_join_alias_expression(newnode, oldvar))
        adjust_standard_join_alias_expression(newnode, oldvar);
    else if (root)
    {
        /*
         * We can insert a PlaceHolderVar to carry the nullingrels.  However,
         * deciding where to evaluate the PHV is slightly tricky.  We first
         * try to evaluate it at the natural semantic level of the new
         * expression; but if that expression is variable-free, fall back to
         * evaluating it at the join that the oldvar is an alias Var for.
         */
        PlaceHolderVar *newphv;
        Index       levelsup = oldvar->varlevelsup;
        Relids      phrels = pull_varnos_of_level(root, newnode, levelsup);
 
        if (bms_is_empty(phrels))   /* variable-free? */
        {
            if (levelsup != 0)  /* this won't work otherwise */
                elog(ERROR, "unsupported join alias expression");
            phrels = get_relids_for_join(root->parse, oldvar->varno);
            /* If it's an outer join, eval below not above the join */
            phrels = bms_del_member(phrels, oldvar->varno);
            Assert(!bms_is_empty(phrels));
        }
        newphv = make_placeholder_expr(root, (Expr *) newnode, phrels);
        /* newphv has zero phlevelsup and NULL phnullingrels; fix it */
        newphv->phlevelsup = levelsup;
        newphv->phnullingrels = bms_copy(oldvar->varnullingrels);
        newnode = (Node *) newphv;
    }
    else
    {
        /* ooops, we're missing support for something the parser can make */
        elog(ERROR, "unsupported join alias expression");
    }
    return newnode;
}

References adjust_standard_join_alias_expression(), Assert, bms_copy(), bms_del_member(), bms_is_empty, elog, ERROR, fb(), get_relids_for_join(), is_standard_join_alias_expression(), make_placeholder_expr(), pull_varnos_of_level(), and root.

Referenced by flatten_join_alias_vars_mutator().

adjust_standard_join_alias_expression()

static void adjust_standard_join_alias_expression ( Node *  newnode, Var *  oldvar  )

static

Definition at line 1303 of file var.c.

{
    if (IsA(newnode, Var) &&
        ((Var *) newnode)->varlevelsup == oldvar->varlevelsup)
    {
        Var        *newvar = (Var *) newnode;
 
        newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
                                                 oldvar->varnullingrels);
    }
    else if (IsA(newnode, PlaceHolderVar) &&
             ((PlaceHolderVar *) newnode)->phlevelsup == oldvar->varlevelsup)
    {
        PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
 
        newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
                                                oldvar->varnullingrels);
    }
    else if (IsA(newnode, FuncExpr))
    {
        FuncExpr   *fexpr = (FuncExpr *) newnode;
 
        adjust_standard_join_alias_expression(linitial(fexpr->args), oldvar);
    }
    else if (IsA(newnode, RelabelType))
    {
        RelabelType *relabel = (RelabelType *) newnode;
 
        adjust_standard_join_alias_expression((Node *) relabel->arg, oldvar);
    }
    else if (IsA(newnode, CoerceViaIO))
    {
        CoerceViaIO *iocoerce = (CoerceViaIO *) newnode;
 
        adjust_standard_join_alias_expression((Node *) iocoerce->arg, oldvar);
    }
    else if (IsA(newnode, ArrayCoerceExpr))
    {
        ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) newnode;
 
        adjust_standard_join_alias_expression((Node *) acoerce->arg, oldvar);
    }
    else if (IsA(newnode, CoalesceExpr))
    {
        CoalesceExpr *cexpr = (CoalesceExpr *) newnode;
        ListCell   *lc;
 
        Assert(cexpr->args != NIL);
        foreach(lc, cexpr->args)
        {
            adjust_standard_join_alias_expression(lfirst(lc), oldvar);
        }
    }
    else
        Assert(false);
}

References adjust_standard_join_alias_expression(), CoerceViaIO::arg, CoalesceExpr::args, Assert, bms_add_members(), fb(), IsA, lfirst, linitial, NIL, and PlaceHolderVar::phnullingrels.

Referenced by add_nullingrels_if_needed(), and adjust_standard_join_alias_expression().

alias_relid_set()

static Relids alias_relid_set ( Query *  query, Relids  relids  )

static

Definition at line 1365 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(), fb(), get_relids_for_join(), rt_fetch, Query::rtable, and RTE_JOIN.

Referenced by flatten_join_alias_vars_mutator().

contain_var_clause()

bool contain_var_clause

(

Node *

node

)

Definition at line 406 of file var.c.

{
    return contain_var_clause_walker(node, NULL);
}

References contain_var_clause_walker(), and fb().

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

contain_var_clause_walker()

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

static

Definition at line 412 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 contain_var_clause_walker(), expression_tree_walker, fb(), and IsA.

Referenced by contain_var_clause(), and contain_var_clause_walker().

contain_vars_of_level()

bool contain_vars_of_level	(	Node *	node,
		int	levelsup
	)

Definition at line 444 of file var.c.

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

References contain_vars_of_level_walker(), and query_or_expression_tree_walker.

Referenced by apply_child_basequals(), checkExprIsVarFree(), convert_EXISTS_sublink_to_join(), convert_EXISTS_to_ANY(), pull_up_simple_values(), pullup_replace_vars_callback(), rewriteRuleAction(), transformAExprIn(), transformInsertStmt(), transformJsonTable(), 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 455 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,
                                   sublevels_up,
                                   0);
        (*sublevels_up)--;
        return result;
    }
    return expression_tree_walker(node,
                                  contain_vars_of_level_walker,
                                  sublevels_up);
}

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

Referenced by contain_vars_of_level(), and contain_vars_of_level_walker().

contain_vars_returning_old_or_new()

bool contain_vars_returning_old_or_new

(

Node *

node

)

Definition at line 511 of file var.c.

{
    return contain_vars_returning_old_or_new_walker(node, NULL);
}

References contain_vars_returning_old_or_new_walker(), and fb().

Referenced by make_modifytable().

contain_vars_returning_old_or_new_walker()

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

static

Definition at line 517 of file var.c.

{
    if (node == NULL)
        return false;
    if (IsA(node, Var))
    {
        if (((Var *) node)->varlevelsup == 0 &&
            ((Var *) node)->varreturningtype != VAR_RETURNING_DEFAULT)
            return true;        /* abort the tree traversal and return true */
        return false;
    }
    if (IsA(node, ReturningExpr))
    {
        if (((ReturningExpr *) node)->retlevelsup == 0)
            return true;        /* abort the tree traversal and return true */
        return false;
    }
    return expression_tree_walker(node, contain_vars_returning_old_or_new_walker,
                                  context);
}

References contain_vars_returning_old_or_new_walker(), expression_tree_walker, fb(), IsA, and VAR_RETURNING_DEFAULT.

Referenced by contain_vars_returning_old_or_new(), and contain_vars_returning_old_or_new_walker().

flatten_group_exprs()

Node * flatten_group_exprs	(	PlannerInfo *	root,
		Query *	query,
		Node *	node
	)

Definition at line 972 of file var.c.

{
    flatten_join_alias_vars_context context;
 
    /*
     * We do not expect this to be applied to the whole Query, only to
     * expressions or LATERAL subqueries.  Hence, if the top node is a Query,
     * it's okay to immediately increment sublevels_up.
     */
    Assert(node != (Node *) query);
 
    context.root = root;
    context.query = query;
    context.sublevels_up = 0;
    /* flag whether grouping expressions 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_group_exprs_mutator(node, &context);
}

References Assert, flatten_group_exprs_mutator(), flatten_join_alias_vars_context::inserted_sublink, flatten_join_alias_vars_context::possible_sublink, flatten_join_alias_vars_context::query, flatten_join_alias_vars_context::root, root, and flatten_join_alias_vars_context::sublevels_up.

Referenced by check_output_expressions(), get_query_def(), and subquery_planner().

flatten_group_exprs_mutator()

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

static

Definition at line 995 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 the GROUP 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_GROUP)
            return node;
 
        /* Expand group exprs reference */
        Assert(var->varattno > 0);
        newvar = (Node *) list_nth(rte->groupexprs, var->varattno - 1);
        Assert(newvar != NULL);
        newvar = copyObject(newvar);
 
        /*
         * If we are expanding an expr 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;
 
        /* Detect if we are adding a sublink to query */
        if (context->possible_sublink && !context->inserted_sublink)
            context->inserted_sublink = checkExprHasSubLink(newvar);
 
        /* Lastly, add any varnullingrels to the replacement expression */
        return mark_nullable_by_grouping(context->root, newvar, var);
    }
 
    if (IsA(node, Aggref))
    {
        Aggref     *agg = (Aggref *) node;
 
        if ((int) agg->agglevelsup == context->sublevels_up)
        {
            /*
             * If we find an aggregate call of the original level, do not
             * recurse into its normal arguments, ORDER BY arguments, or
             * filter; there are no grouped vars there.  But we should check
             * direct arguments as though they weren't in an aggregate.
             */
            agg = copyObject(agg);
            agg->aggdirectargs = (List *)
                flatten_group_exprs_mutator((Node *) agg->aggdirectargs, context);
 
            return (Node *) agg;
        }
 
        /*
         * We can skip recursing into aggregates of higher levels altogether,
         * since they could not possibly contain Vars of concern to us (see
         * transformAggregateCall).  We do need to look at aggregates of lower
         * levels, however.
         */
        if ((int) agg->agglevelsup > context->sublevels_up)
            return node;
    }
 
    if (IsA(node, GroupingFunc))
    {
        GroupingFunc *grp = (GroupingFunc *) node;
 
        /*
         * If we find a GroupingFunc node of the original or higher level, do
         * not recurse into its arguments; there are no grouped vars there.
         */
        if ((int) grp->agglevelsup >= context->sublevels_up)
            return node;
    }
 
    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_group_exprs_mutator,
                                     context,
                                     QTW_IGNORE_GROUPEXPRS);
        newnode->hasSubLinks |= context->inserted_sublink;
        context->inserted_sublink = save_inserted_sublink;
        context->sublevels_up--;
        return (Node *) newnode;
    }
 
    return expression_tree_mutator(node, flatten_group_exprs_mutator,
                                   context);
}

References Assert, checkExprHasSubLink(), copyObject, expression_tree_mutator, fb(), flatten_group_exprs_mutator(), IncrementVarSublevelsUp(), flatten_join_alias_vars_context::inserted_sublink, IsA, list_nth(), Var::location, mark_nullable_by_grouping(), flatten_join_alias_vars_context::possible_sublink, QTW_IGNORE_GROUPEXPRS, flatten_join_alias_vars_context::query, query_tree_mutator, flatten_join_alias_vars_context::root, rt_fetch, Query::rtable, RTE_GROUP, flatten_join_alias_vars_context::sublevels_up, Var::varattno, Var::varlevelsup, and Var::varno.

Referenced by flatten_group_exprs(), and flatten_group_exprs_mutator().

flatten_join_alias_vars()

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

Definition at line 789 of file var.c.

{
    flatten_join_alias_vars_context context;
 
    /*
     * We do not expect this to be applied to the whole Query, only to
     * expressions or LATERAL subqueries.  Hence, if the top node is a Query,
     * it's okay to immediately increment sublevels_up.
     */
    Assert(node != (Node *) query);
 
    context.root = root;
    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 Assert, flatten_join_alias_vars_mutator(), flatten_join_alias_vars_context::inserted_sublink, flatten_join_alias_vars_context::possible_sublink, flatten_join_alias_vars_context::query, flatten_join_alias_vars_context::root, root, 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 812 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;
            ListCell   *lv;
            ListCell   *ln;
 
            Assert(list_length(rte->joinaliasvars) == list_length(rte->eref->colnames));
            forboth(lv, rte->joinaliasvars, ln, rte->eref->colnames)
            {
                newvar = (Node *) lfirst(lv);
                /* 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;
            /* vartype will always be RECORDOID, so we always need colnames */
            rowexpr->colnames = colnames;
            rowexpr->location = var->location;
 
            /* Lastly, add any varnullingrels to the replacement expression */
            return add_nullingrels_if_needed(context->root, (Node *) rowexpr,
                                             var);
        }
 
        /* 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);
 
        /* Lastly, add any varnullingrels to the replacement expression */
        return add_nullingrels_if_needed(context->root, newvar, var);
    }
    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,
                                                         context);
        /* now fix PlaceHolderVar's relid sets */
        if (phv->phlevelsup == context->sublevels_up)
        {
            phv->phrels = alias_relid_set(context->query,
                                          phv->phrels);
            /* we *don't* change phnullingrels */
        }
        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,
                                     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));
    Assert(!IsA(node, AlternativeSubPlan));
    /* 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, context);
}

References add_nullingrels_if_needed(), alias_relid_set(), RowExpr::args, Assert, checkExprHasSubLink(), COERCE_IMPLICIT_CAST, copyObject, expression_tree_mutator, fb(), flatten_join_alias_vars_mutator(), forboth, IncrementVarSublevelsUp(), flatten_join_alias_vars_context::inserted_sublink, InvalidAttrNumber, IsA, lappend(), lfirst, list_length(), list_nth(), Var::location, RowExpr::location, makeNode, NIL, flatten_join_alias_vars_context::possible_sublink, QTW_IGNORE_JOINALIASES, flatten_join_alias_vars_context::query, query_tree_mutator, flatten_join_alias_vars_context::root, rt_fetch, Query::rtable, RTE_JOIN, flatten_join_alias_vars_context::sublevels_up, Var::varattno, Var::varlevelsup, and Var::varno.

Referenced by flatten_join_alias_vars(), and flatten_join_alias_vars_mutator().

is_standard_join_alias_expression()

static bool is_standard_join_alias_expression ( Node *  newnode, Var *  oldvar  )

static

Definition at line 1229 of file var.c.

{
    if (newnode == NULL)
        return false;
    if (IsA(newnode, Var) &&
        ((Var *) newnode)->varlevelsup == oldvar->varlevelsup)
        return true;
    else if (IsA(newnode, PlaceHolderVar) &&
             ((PlaceHolderVar *) newnode)->phlevelsup == oldvar->varlevelsup)
        return true;
    else if (IsA(newnode, FuncExpr))
    {
        FuncExpr   *fexpr = (FuncExpr *) newnode;
 
        /*
         * We need to assume that the function wouldn't produce non-NULL from
         * NULL, which is reasonable for implicit coercions but otherwise not
         * so much.  (Looking at its strictness is likely overkill, and anyway
         * it would cause us to fail if someone forgot to mark an implicit
         * coercion as strict.)
         */
        if (fexpr->funcformat != COERCE_IMPLICIT_CAST ||
            fexpr->args == NIL)
            return false;
 
        /*
         * Examine only the first argument --- coercions might have additional
         * arguments that are constants.
         */
        return is_standard_join_alias_expression(linitial(fexpr->args), oldvar);
    }
    else if (IsA(newnode, RelabelType))
    {
        RelabelType *relabel = (RelabelType *) newnode;
 
        /* This definitely won't produce non-NULL from NULL */
        return is_standard_join_alias_expression((Node *) relabel->arg, oldvar);
    }
    else if (IsA(newnode, CoerceViaIO))
    {
        CoerceViaIO *iocoerce = (CoerceViaIO *) newnode;
 
        /* This definitely won't produce non-NULL from NULL */
        return is_standard_join_alias_expression((Node *) iocoerce->arg, oldvar);
    }
    else if (IsA(newnode, ArrayCoerceExpr))
    {
        ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) newnode;
 
        /* This definitely won't produce non-NULL from NULL (at array level) */
        return is_standard_join_alias_expression((Node *) acoerce->arg, oldvar);
    }
    else if (IsA(newnode, CoalesceExpr))
    {
        CoalesceExpr *cexpr = (CoalesceExpr *) newnode;
        ListCell   *lc;
 
        Assert(cexpr->args != NIL);
        foreach(lc, cexpr->args)
        {
            if (!is_standard_join_alias_expression(lfirst(lc), oldvar))
                return false;
        }
        return true;
    }
    else
        return false;
}

References CoerceViaIO::arg, CoalesceExpr::args, Assert, COERCE_IMPLICIT_CAST, fb(), is_standard_join_alias_expression(), IsA, lfirst, linitial, and NIL.

Referenced by add_nullingrels_if_needed(), and is_standard_join_alias_expression().

locate_var_of_level()

int locate_var_of_level	(	Node *	node,
		int	levelsup
	)

Definition at line 555 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,
                                           &context,
                                           0);
 
    return context.var_location;
}

References fb(), 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 571 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,
                                   context,
                                   0);
        context->sublevels_up--;
        return result;
    }
    return expression_tree_walker(node,
                                  locate_var_of_level_walker,
                                  context);
}

References expression_tree_walker, fb(), IsA, locate_var_of_level_walker(), 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(), and locate_var_of_level_walker().

mark_nullable_by_grouping()

static Node * mark_nullable_by_grouping ( PlannerInfo *  root, Node *  newnode, Var *  oldvar  )

static

Definition at line 1107 of file var.c.

{
    Relids      relids;
 
    if (root == NULL)
        return newnode;
    if (oldvar->varnullingrels == NULL)
        return newnode;         /* nothing to do */
 
    Assert(bms_equal(oldvar->varnullingrels,
                     bms_make_singleton(root->group_rtindex)));
 
    relids = pull_varnos_of_level(root, newnode, oldvar->varlevelsup);
 
    if (!bms_is_empty(relids))
    {
        /*
         * If the newnode is not variable-free, we set the nullingrels of Vars
         * or PHVs that are contained in the expression.  This is not really
         * 'correct' in theory, because it is the whole expression that can be
         * nullable by grouping sets, not its individual vars.  But it works
         * in practice, because what we need is that the expression can be
         * somehow distinguished from the same expression in ECs, and marking
         * its vars is sufficient for this purpose.
         */
        newnode = add_nulling_relids(newnode,
                                     relids,
                                     oldvar->varnullingrels);
    }
    else                        /* variable-free? */
    {
        /*
         * If the newnode is variable-free and does not contain volatile
         * functions or set-returning functions, it can be treated as a member
         * of EC that is redundant.  So wrap it in a new PlaceHolderVar to
         * carry the nullingrels.  Otherwise we do not bother to make any
         * changes.
         *
         * Aggregate functions and window functions are not allowed in
         * grouping expressions.
         */
        Assert(!contain_agg_clause(newnode));
        Assert(!contain_window_function(newnode));
 
        if (!contain_volatile_functions(newnode) &&
            !expression_returns_set(newnode))
        {
            PlaceHolderVar *newphv;
            Relids      phrels;
 
            phrels = get_relids_in_jointree((Node *) root->parse->jointree,
                                            true, false);
            Assert(!bms_is_empty(phrels));
 
            newphv = make_placeholder_expr(root, (Expr *) newnode, phrels);
            /* newphv has zero phlevelsup and NULL phnullingrels; fix it */
            newphv->phlevelsup = oldvar->varlevelsup;
            newphv->phnullingrels = bms_copy(oldvar->varnullingrels);
            newnode = (Node *) newphv;
        }
    }
 
    return newnode;
}

References add_nulling_relids(), Assert, bms_copy(), bms_equal(), bms_is_empty, bms_make_singleton(), contain_agg_clause(), contain_volatile_functions(), contain_window_function(), expression_returns_set(), fb(), get_relids_in_jointree(), make_placeholder_expr(), pull_varnos_of_level(), and root.

Referenced by flatten_group_exprs_mutator().

pull_var_clause()

List * pull_var_clause	(	Node *	node,
		int	flags
	)

Definition at line 653 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 add_paths_with_pathkeys_for_rel(), AddRelationNewConstraints(), build_base_rel_tlists(), build_remote_returning(), build_tlist_to_deparse(), create_agg_clause_infos(), CreateTriggerFiringOn(), 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(), is_var_in_aggref_only(), 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(), rebuild_eclass_attr_needed(), rebuild_joinclause_attr_needed(), rebuild_placeholder_attr_needed(), semijoin_target_ok(), and StoreRelCheck().

pull_var_clause_walker()

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

static

Definition at line 673 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)
        {
            /* fall through to recurse into the GroupingFunc's arguments */
        }
        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, context);
}

References elog, ERROR, expression_tree_walker, fb(), pull_var_clause_context::flags, IsA, lappend(), 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 pull_var_clause(), and pull_var_clause_walker().

pull_varattnos()

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

Definition at line 296 of file var.c.

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

References fb(), 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(), createTableConstraints(), DefineIndex(), deparseReturningList(), DoCopy(), ExecInitGenerated(), get_dependent_generated_columns(), 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 309 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, context);
}

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

Referenced by pull_varattnos(), and pull_varattnos_walker().

pull_varnos()

Relids pull_varnos	(	PlannerInfo *	root,
		Node *	node
	)

Definition at line 114 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,
                                    &context,
                                    0);
 
    return context.varnos;
}

References fb(), pull_varnos_walker(), query_or_expression_tree_walker, pull_varnos_context::root, 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(), create_agg_clause_infos(), distribute_qual_to_rels(), examine_variable(), expand_indexqual_rowcompare(), extract_lateral_vars_from_PHVs(), find_placeholder_info(), get_eclass_for_sort_expr(), is_pseudo_constant_for_index(), IsTidEqualAnyClause(), join_is_removable(), make_outerjoininfo(), make_plain_restrictinfo(), match_rowcompare_to_indexcol(), match_saopclause_to_indexcol(), NumRelids(), pg_get_expr_worker(), process_implied_equality(), pullup_replace_vars_callback(), remove_leftjoinrel_from_query(), and subquery_planner().

pull_varnos_of_level()

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

Definition at line 140 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,
                                    &context,
                                    0);
 
    return context.varnos;
}

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

Referenced by add_nullingrels_if_needed(), convert_ANY_sublink_to_join(), is_simple_subquery(), jointree_contains_lateral_outer_refs(), and mark_nullable_by_grouping().

pull_varnos_walker()

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

static

Definition at line 161 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);
            context->varnos = bms_add_members(context->varnos,
                                              var->varnullingrels);
        }
        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.  We'll also do that when the
         * caller doesn't pass a "root" pointer.  (We probably shouldn't see
         * PlaceHolderVars at all in such cases, but if we do, this is a
         * reasonable behavior.)
         */
        if (phv->phlevelsup == context->sublevels_up &&
            context->root != NULL)
        {
            /*
             * 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).
             *
             * 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)
            {
                if (phv->phid < context->root->placeholder_array_size)
                    phinfo = context->root->placeholder_array[phv->phid];
            }
            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);
            }
 
            /*
             * In all three cases, include phnullingrels in the result.  We
             * don't worry about possibly needing to translate it, because
             * appendrels only translate varnos of baserels, not outer joins.
             */
            context->varnos = bms_add_members(context->varnos,
                                              phv->phnullingrels);
            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,
                                   context, 0);
        context->sublevels_up--;
        return result;
    }
    return expression_tree_walker(node, pull_varnos_walker, context);
}

References bms_add_member(), bms_add_members(), bms_difference(), bms_equal(), bms_join(), CurrentOfExpr::cvarno, expression_tree_walker, fb(), IsA, pull_varnos_walker(), 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(), pull_varnos_of_level(), and pull_varnos_walker().

pull_vars_of_level()

List * pull_vars_of_level	(	Node *	node,
		int	levelsup
	)

Definition at line 339 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,
                                    &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(), and extract_lateral_vars_from_PHVs().

pull_vars_walker()

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

static

Definition at line 359 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,
                                   context, 0);
        context->sublevels_up--;
        return result;
    }
    return expression_tree_walker(node, pull_vars_walker, context);
}

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

Referenced by pull_vars_of_level(), and pull_vars_walker().