clauses.h File Reference

#include "access/htup.h"
#include "nodes/pathnodes.h"

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Data Structures
struct	WindowFuncLists

Functions
bool	contain_agg_clause (Node *clause)
void	get_agg_clause_costs (PlannerInfo *root, Node *clause, AggSplit aggsplit, AggClauseCosts *costs)
bool	contain_window_function (Node *clause)
WindowFuncLists *	find_window_functions (Node *clause, Index maxWinRef)
double	expression_returns_set_rows (PlannerInfo *root, Node *clause)
bool	contain_subplans (Node *clause)
char	max_parallel_hazard (Query *parse)
bool	is_parallel_safe (PlannerInfo *root, Node *node)
bool	contain_nonstrict_functions (Node *clause)
bool	contain_leaked_vars (Node *clause)
Relids	find_nonnullable_rels (Node *clause)
List *	find_nonnullable_vars (Node *clause)
List *	find_forced_null_vars (Node *clause)
Var *	find_forced_null_var (Node *clause)
bool	is_pseudo_constant_clause (Node *clause)
bool	is_pseudo_constant_clause_relids (Node *clause, Relids relids)
int	NumRelids (Node *clause)
void	CommuteOpExpr (OpExpr *clause)
Query *	inline_set_returning_function (PlannerInfo *root, RangeTblEntry *rte)

Function Documentation

CommuteOpExpr()

void CommuteOpExpr

(

OpExpr *

clause

)

Definition at line 2145 of file clauses.c.

References OpExpr::args, elog, ERROR, get_commutator(), InvalidOid, is_opclause(), linitial, list_length(), lsecond, OidIsValid, OpExpr::opfuncid, and OpExpr::opno.

Referenced by get_switched_clauses().

{
    Oid         opoid;
    Node       *temp;

    /* Sanity checks: caller is at fault if these fail */
    if (!is_opclause(clause) ||
        list_length(clause->args) != 2)
        elog(ERROR, "cannot commute non-binary-operator clause");

    opoid = get_commutator(clause->opno);

    if (!OidIsValid(opoid))
        elog(ERROR, "could not find commutator for operator %u",
             clause->opno);

    /*
     * modify the clause in-place!
     */
    clause->opno = opoid;
    clause->opfuncid = InvalidOid;
    /* opresulttype, opretset, opcollid, inputcollid need not change */

    temp = linitial(clause->args);
    linitial(clause->args) = lsecond(clause->args);
    lsecond(clause->args) = temp;
}

contain_agg_clause()

bool contain_agg_clause

(

Node *

clause

)

Definition at line 178 of file clauses.c.

References contain_agg_clause_walker().

Referenced by get_eclass_for_sort_expr(), and subquery_planner().

{
    return contain_agg_clause_walker(clause, NULL);
}

contain_leaked_vars()

bool contain_leaked_vars

(

Node *

clause

)

Definition at line 1326 of file clauses.c.

References contain_leaked_vars_walker().

Referenced by make_restrictinfo_internal(), and qual_is_pushdown_safe().

{
    return contain_leaked_vars_walker(clause, NULL);
}

contain_nonstrict_functions()

bool contain_nonstrict_functions

(

Node *

clause

)

Definition at line 1093 of file clauses.c.

References contain_nonstrict_functions_walker().

Referenced by inline_function(), process_equivalence(), and pullup_replace_vars_callback().

{
    return contain_nonstrict_functions_walker(clause, NULL);
}

contain_subplans()

bool contain_subplans

(

Node *

clause

)

Definition at line 609 of file clauses.c.

References contain_subplans_walker().

Referenced by convert_EXISTS_to_ANY(), ExecInitValuesScan(), inline_function(), inline_set_returning_function(), qual_is_pushdown_safe(), and subquery_planner().

{
    return contain_subplans_walker(clause, NULL);
}

contain_window_function()

bool contain_window_function

(

Node *

clause

)

Definition at line 493 of file clauses.c.

References contain_windowfuncs().

Referenced by get_eclass_for_sort_expr(), and qual_is_pushdown_safe().

{
    return contain_windowfuncs(clause);
}

expression_returns_set_rows()

double expression_returns_set_rows	(	PlannerInfo *	root,
		Node *	clause
	)

Definition at line 568 of file clauses.c.

References clamp_row_est(), FuncExpr::funcid, FuncExpr::funcretset, get_function_rows(), IsA, OpExpr::opfuncid, OpExpr::opretset, and set_opfuncid().

Referenced by create_set_projection_path(), estimate_num_groups(), and set_function_size_estimates().

{
    if (clause == NULL)
        return 1.0;
    if (IsA(clause, FuncExpr))
    {
        FuncExpr   *expr = (FuncExpr *) clause;

        if (expr->funcretset)
            return clamp_row_est(get_function_rows(root, expr->funcid, clause));
    }
    if (IsA(clause, OpExpr))
    {
        OpExpr     *expr = (OpExpr *) clause;

        if (expr->opretset)
        {
            set_opfuncid(expr);
            return clamp_row_est(get_function_rows(root, expr->opfuncid, clause));
        }
    }
    return 1.0;
}

find_forced_null_var()

Var* find_forced_null_var

(

Node *

clause

)

Definition at line 1977 of file clauses.c.

References NullTest::arg, BooleanTest::arg, NullTest::argisrow, BooleanTest::booltesttype, IS_NULL, IS_UNKNOWN, IsA, NullTest::nulltesttype, and Var::varlevelsup.

Referenced by check_redundant_nullability_qual(), and find_forced_null_vars().

{
    if (node == NULL)
        return NULL;
    if (IsA(node, NullTest))
    {
        /* check for var IS NULL */
        NullTest   *expr = (NullTest *) node;

        if (expr->nulltesttype == IS_NULL && !expr->argisrow)
        {
            Var        *var = (Var *) expr->arg;

            if (var && IsA(var, Var) &&
                var->varlevelsup == 0)
                return var;
        }
    }
    else if (IsA(node, BooleanTest))
    {
        /* var IS UNKNOWN is equivalent to var IS NULL */
        BooleanTest *expr = (BooleanTest *) node;

        if (expr->booltesttype == IS_UNKNOWN)
        {
            Var        *var = (Var *) expr->arg;

            if (var && IsA(var, Var) &&
                var->varlevelsup == 0)
                return var;
        }
    }
    return NULL;
}

find_forced_null_vars()

List* find_forced_null_vars

(

Node *

clause

)

Definition at line 1918 of file clauses.c.

References AND_EXPR, BoolExpr::args, BoolExpr::boolop, find_forced_null_var(), find_forced_null_vars(), IsA, lfirst, list_concat(), list_make1, and NIL.

Referenced by find_forced_null_vars(), and reduce_outer_joins_pass2().

{
    List       *result = NIL;
    Var        *var;
    ListCell   *l;

    if (node == NULL)
        return NIL;
    /* Check single-clause cases using subroutine */
    var = find_forced_null_var(node);
    if (var)
    {
        result = list_make1(var);
    }
    /* Otherwise, handle AND-conditions */
    else if (IsA(node, List))
    {
        /*
         * At top level, we are examining an implicit-AND list: if any of the
         * arms produces FALSE-or-NULL then the result is FALSE-or-NULL.
         */
        foreach(l, (List *) node)
        {
            result = list_concat(result,
                                 find_forced_null_vars(lfirst(l)));
        }
    }
    else if (IsA(node, BoolExpr))
    {
        BoolExpr   *expr = (BoolExpr *) node;

        /*
         * We don't bother considering the OR case, because it's fairly
         * unlikely anyone would write "v1 IS NULL OR v1 IS NULL". Likewise,
         * the NOT case isn't worth expending code on.
         */
        if (expr->boolop == AND_EXPR)
        {
            /* At top level we can just recurse (to the List case) */
            result = find_forced_null_vars((Node *) expr->args);
        }
    }
    return result;
}

find_nonnullable_rels()

Relids find_nonnullable_rels

(

Node *

clause

)

Definition at line 1500 of file clauses.c.

References find_nonnullable_rels_walker().

Referenced by make_outerjoininfo(), and reduce_outer_joins_pass2().

{
    return find_nonnullable_rels_walker(clause, true);
}

find_nonnullable_vars()

List* find_nonnullable_vars

(

Node *

clause

)

Definition at line 1725 of file clauses.c.

References find_nonnullable_vars_walker().

Referenced by reduce_outer_joins_pass2().

{
    return find_nonnullable_vars_walker(clause, true);
}

find_window_functions()

WindowFuncLists* find_window_functions	(	Node *	clause,
		Index	maxWinRef
	)

Definition at line 506 of file clauses.c.

References find_window_functions_walker(), WindowFuncLists::maxWinRef, WindowFuncLists::numWindowFuncs, palloc(), palloc0(), and WindowFuncLists::windowFuncs.

Referenced by grouping_planner().

{
    WindowFuncLists *lists = palloc(sizeof(WindowFuncLists));

    lists->numWindowFuncs = 0;
    lists->maxWinRef = maxWinRef;
    lists->windowFuncs = (List **) palloc0((maxWinRef + 1) * sizeof(List *));
    (void) find_window_functions_walker(clause, lists);
    return lists;
}

get_agg_clause_costs()

void get_agg_clause_costs	(	PlannerInfo *	root,
		Node *	clause,
		AggSplit	aggsplit,
		AggClauseCosts *	costs
	)

Definition at line 228 of file clauses.c.

References get_agg_clause_costs_context::aggsplit, get_agg_clause_costs_context::costs, get_agg_clause_costs_walker(), and get_agg_clause_costs_context::root.

Referenced by create_partial_grouping_paths(), estimate_path_cost_size(), and grouping_planner().

{
    get_agg_clause_costs_context context;

    context.root = root;
    context.aggsplit = aggsplit;
    context.costs = costs;
    (void) get_agg_clause_costs_walker(clause, &context);
}

inline_set_returning_function()

Query* inline_set_returning_function	(	PlannerInfo *	root,
		RangeTblEntry *	rte
	)

Definition at line 4880 of file clauses.c.

References ACL_EXECUTE, ACLCHECK_OK, ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, ErrorContextCallback::arg, FuncExpr::args, Assert, BuildDescFromLists(), ErrorContextCallback::callback, check_sql_fn_retval(), check_stack_depth(), CMD_SELECT, Query::commandType, contain_subplans(), contain_volatile_functions(), copyObject, CurrentMemoryContext, elog, ERROR, error_context_stack, FmgrHookIsNeeded, RangeTblFunction::funccolcollations, RangeTblFunction::funccolnames, RangeTblFunction::funccoltypes, RangeTblFunction::funccoltypmods, RangeTblFunction::funcexpr, FuncExpr::funcid, RangeTblEntry::funcordinality, FuncExpr::funcretset, RangeTblEntry::functions, get_expr_result_type(), GETSTRUCT, GetUserId(), heap_attisnull(), HeapTupleIsValid, IsA, linitial, list_length(), MemoryContextDelete(), MemoryContextSwitchTo(), NameStr, ObjectIdGetDatum, pg_analyze_and_rewrite_params(), pg_parse_query(), pg_proc_aclcheck(), prepare_sql_fn_parse_info(), ErrorContextCallback::previous, PROCOID, inline_error_callback_arg::proname, inline_error_callback_arg::prosrc, querytree(), record_plan_function_dependency(), ReleaseSysCache(), RTE_FUNCTION, RangeTblEntry::rtekind, SearchSysCache1(), sql_fn_parser_setup(), sql_inline_error_callback(), substitute_actual_srf_parameters(), SysCacheGetAttr(), TextDatumGetCString, TYPEFUNC_COMPOSITE, TYPEFUNC_COMPOSITE_DOMAIN, and TYPEFUNC_RECORD.

Referenced by preprocess_function_rtes().

{
    RangeTblFunction *rtfunc;
    FuncExpr   *fexpr;
    Oid         func_oid;
    HeapTuple   func_tuple;
    Form_pg_proc funcform;
    char       *src;
    Datum       tmp;
    bool        isNull;
    MemoryContext oldcxt;
    MemoryContext mycxt;
    inline_error_callback_arg callback_arg;
    ErrorContextCallback sqlerrcontext;
    SQLFunctionParseInfoPtr pinfo;
    TypeFuncClass functypclass;
    TupleDesc   rettupdesc;
    List       *raw_parsetree_list;
    List       *querytree_list;
    Query      *querytree;

    Assert(rte->rtekind == RTE_FUNCTION);

    /*
     * It doesn't make a lot of sense for a SQL SRF to refer to itself in its
     * own FROM clause, since that must cause infinite recursion at runtime.
     * It will cause this code to recurse too, so check for stack overflow.
     * (There's no need to do more.)
     */
    check_stack_depth();

    /* Fail if the RTE has ORDINALITY - we don't implement that here. */
    if (rte->funcordinality)
        return NULL;

    /* Fail if RTE isn't a single, simple FuncExpr */
    if (list_length(rte->functions) != 1)
        return NULL;
    rtfunc = (RangeTblFunction *) linitial(rte->functions);

    if (!IsA(rtfunc->funcexpr, FuncExpr))
        return NULL;
    fexpr = (FuncExpr *) rtfunc->funcexpr;

    func_oid = fexpr->funcid;

    /*
     * The function must be declared to return a set, else inlining would
     * change the results if the contained SELECT didn't return exactly one
     * row.
     */
    if (!fexpr->funcretset)
        return NULL;

    /*
     * Refuse to inline if the arguments contain any volatile functions or
     * sub-selects.  Volatile functions are rejected because inlining may
     * result in the arguments being evaluated multiple times, risking a
     * change in behavior.  Sub-selects are rejected partly for implementation
     * reasons (pushing them down another level might change their behavior)
     * and partly because they're likely to be expensive and so multiple
     * evaluation would be bad.
     */
    if (contain_volatile_functions((Node *) fexpr->args) ||
        contain_subplans((Node *) fexpr->args))
        return NULL;

    /* Check permission to call function (fail later, if not) */
    if (pg_proc_aclcheck(func_oid, GetUserId(), ACL_EXECUTE) != ACLCHECK_OK)
        return NULL;

    /* Check whether a plugin wants to hook function entry/exit */
    if (FmgrHookIsNeeded(func_oid))
        return NULL;

    /*
     * OK, let's take a look at the function's pg_proc entry.
     */
    func_tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(func_oid));
    if (!HeapTupleIsValid(func_tuple))
        elog(ERROR, "cache lookup failed for function %u", func_oid);
    funcform = (Form_pg_proc) GETSTRUCT(func_tuple);

    /*
     * Forget it if the function is not SQL-language or has other showstopper
     * properties.  In particular it mustn't be declared STRICT, since we
     * couldn't enforce that.  It also mustn't be VOLATILE, because that is
     * supposed to cause it to be executed with its own snapshot, rather than
     * sharing the snapshot of the calling query.  We also disallow returning
     * SETOF VOID, because inlining would result in exposing the actual result
     * of the function's last SELECT, which should not happen in that case.
     * (Rechecking prokind, proretset, and pronargs is just paranoia.)
     */
    if (funcform->prolang != SQLlanguageId ||
        funcform->prokind != PROKIND_FUNCTION ||
        funcform->proisstrict ||
        funcform->provolatile == PROVOLATILE_VOLATILE ||
        funcform->prorettype == VOIDOID ||
        funcform->prosecdef ||
        !funcform->proretset ||
        list_length(fexpr->args) != funcform->pronargs ||
        !heap_attisnull(func_tuple, Anum_pg_proc_proconfig, NULL))
    {
        ReleaseSysCache(func_tuple);
        return NULL;
    }

    /*
     * Make a temporary memory context, so that we don't leak all the stuff
     * that parsing might create.
     */
    mycxt = AllocSetContextCreate(CurrentMemoryContext,
                                  "inline_set_returning_function",
                                  ALLOCSET_DEFAULT_SIZES);
    oldcxt = MemoryContextSwitchTo(mycxt);

    /* Fetch the function body */
    tmp = SysCacheGetAttr(PROCOID,
                          func_tuple,
                          Anum_pg_proc_prosrc,
                          &isNull);
    if (isNull)
        elog(ERROR, "null prosrc for function %u", func_oid);
    src = TextDatumGetCString(tmp);

    /*
     * Setup error traceback support for ereport().  This is so that we can
     * finger the function that bad information came from.
     */
    callback_arg.proname = NameStr(funcform->proname);
    callback_arg.prosrc = src;

    sqlerrcontext.callback = sql_inline_error_callback;
    sqlerrcontext.arg = (void *) &callback_arg;
    sqlerrcontext.previous = error_context_stack;
    error_context_stack = &sqlerrcontext;

    /*
     * Set up to handle parameters while parsing the function body.  We can
     * use the FuncExpr just created as the input for
     * prepare_sql_fn_parse_info.
     */
    pinfo = prepare_sql_fn_parse_info(func_tuple,
                                      (Node *) fexpr,
                                      fexpr->inputcollid);

    /*
     * Also resolve the actual function result tupdesc, if composite.  If the
     * function is just declared to return RECORD, dig the info out of the AS
     * clause.
     */
    functypclass = get_expr_result_type((Node *) fexpr, NULL, &rettupdesc);
    if (functypclass == TYPEFUNC_RECORD)
        rettupdesc = BuildDescFromLists(rtfunc->funccolnames,
                                        rtfunc->funccoltypes,
                                        rtfunc->funccoltypmods,
                                        rtfunc->funccolcollations);

    /*
     * Parse, analyze, and rewrite (unlike inline_function(), we can't skip
     * rewriting here).  We can fail as soon as we find more than one query,
     * though.
     */
    raw_parsetree_list = pg_parse_query(src);
    if (list_length(raw_parsetree_list) != 1)
        goto fail;

    querytree_list = pg_analyze_and_rewrite_params(linitial(raw_parsetree_list),
                                                   src,
                                                   (ParserSetupHook) sql_fn_parser_setup,
                                                   pinfo, NULL);
    if (list_length(querytree_list) != 1)
        goto fail;
    querytree = linitial(querytree_list);

    /*
     * The single command must be a plain SELECT.
     */
    if (!IsA(querytree, Query) ||
        querytree->commandType != CMD_SELECT)
        goto fail;

    /*
     * Make sure the function (still) returns what it's declared to.  This
     * will raise an error if wrong, but that's okay since the function would
     * fail at runtime anyway.  Note that check_sql_fn_retval will also insert
     * coercions if needed to make the tlist expression(s) match the declared
     * type of the function.  We also ask it to insert dummy NULL columns for
     * any dropped columns in rettupdesc, so that the elements of the modified
     * tlist match up to the attribute numbers.
     *
     * If the function returns a composite type, don't inline unless the check
     * shows it's returning a whole tuple result; otherwise what it's
     * returning is a single composite column which is not what we need.
     */
    if (!check_sql_fn_retval(querytree_list,
                             fexpr->funcresulttype, rettupdesc,
                             true, NULL) &&
        (functypclass == TYPEFUNC_COMPOSITE ||
         functypclass == TYPEFUNC_COMPOSITE_DOMAIN ||
         functypclass == TYPEFUNC_RECORD))
        goto fail;              /* reject not-whole-tuple-result cases */

    /*
     * check_sql_fn_retval might've inserted a projection step, but that's
     * fine; just make sure we use the upper Query.
     */
    querytree = linitial(querytree_list);

    /*
     * Looks good --- substitute parameters into the query.
     */
    querytree = substitute_actual_srf_parameters(querytree,
                                                 funcform->pronargs,
                                                 fexpr->args);

    /*
     * Copy the modified query out of the temporary memory context, and clean
     * up.
     */
    MemoryContextSwitchTo(oldcxt);

    querytree = copyObject(querytree);

    MemoryContextDelete(mycxt);
    error_context_stack = sqlerrcontext.previous;
    ReleaseSysCache(func_tuple);

    /*
     * We don't have to fix collations here because the upper query is already
     * parsed, ie, the collations in the RTE are what count.
     */

    /*
     * Since there is now no trace of the function in the plan tree, we must
     * explicitly record the plan's dependency on the function.
     */
    record_plan_function_dependency(root, func_oid);

    return querytree;

    /* Here if func is not inlinable: release temp memory and return NULL */
fail:
    MemoryContextSwitchTo(oldcxt);
    MemoryContextDelete(mycxt);
    error_context_stack = sqlerrcontext.previous;
    ReleaseSysCache(func_tuple);

    return NULL;
}

is_parallel_safe()

bool is_parallel_safe	(	PlannerInfo *	root,
		Node *	node
	)

Definition at line 853 of file clauses.c.

References PlannerInfo::glob, PlannerInfo::init_plans, lfirst, list_concat(), max_parallel_hazard_context::max_hazard, max_parallel_hazard_context::max_interesting, max_parallel_hazard_walker(), PlannerGlobal::maxParallelHazard, NIL, PlannerGlobal::paramExecTypes, PlannerInfo::parent_root, max_parallel_hazard_context::safe_param_ids, and SubPlan::setParam.

Referenced by apply_projection_to_path(), build_join_rel(), create_projection_path(), create_set_projection_path(), create_window_paths(), grouping_planner(), make_grouping_rel(), plan_create_index_workers(), query_planner(), and set_rel_consider_parallel().

{
    max_parallel_hazard_context context;
    PlannerInfo *proot;
    ListCell   *l;

    /*
     * Even if the original querytree contained nothing unsafe, we need to
     * search the expression if we have generated any PARAM_EXEC Params while
     * planning, because those are parallel-restricted and there might be one
     * in this expression.  But otherwise we don't need to look.
     */
    if (root->glob->maxParallelHazard == PROPARALLEL_SAFE &&
        root->glob->paramExecTypes == NIL)
        return true;
    /* Else use max_parallel_hazard's search logic, but stop on RESTRICTED */
    context.max_hazard = PROPARALLEL_SAFE;
    context.max_interesting = PROPARALLEL_RESTRICTED;
    context.safe_param_ids = NIL;

    /*
     * The params that refer to the same or parent query level are considered
     * parallel-safe.  The idea is that we compute such params at Gather or
     * Gather Merge node and pass their value to workers.
     */
    for (proot = root; proot != NULL; proot = proot->parent_root)
    {
        foreach(l, proot->init_plans)
        {
            SubPlan    *initsubplan = (SubPlan *) lfirst(l);

            context.safe_param_ids = list_concat(context.safe_param_ids,
                                                 initsubplan->setParam);
        }
    }

    return !max_parallel_hazard_walker(node, &context);
}

is_pseudo_constant_clause()

bool is_pseudo_constant_clause

(

Node *

clause

)

Definition at line 2088 of file clauses.c.

References contain_var_clause(), and contain_volatile_functions().

Referenced by clauselist_selectivity_simple(), and dependency_is_compatible_clause().

{
    /*
     * We could implement this check in one recursive scan.  But since the
     * check for volatile functions is both moderately expensive and unlikely
     * to fail, it seems better to look for Vars first and only check for
     * volatile functions if we find no Vars.
     */
    if (!contain_var_clause(clause) &&
        !contain_volatile_functions(clause))
        return true;
    return false;
}

is_pseudo_constant_clause_relids()

bool is_pseudo_constant_clause_relids	(	Node *	clause,
		Relids	relids
	)

Definition at line 2108 of file clauses.c.

References bms_is_empty(), and contain_volatile_functions().

Referenced by clauselist_selectivity_simple().

{
    if (bms_is_empty(relids) &&
        !contain_volatile_functions(clause))
        return true;
    return false;
}

max_parallel_hazard()

char max_parallel_hazard

(

Query *

parse

)

Definition at line 834 of file clauses.c.

References max_parallel_hazard_context::max_hazard, max_parallel_hazard_context::max_interesting, max_parallel_hazard_walker(), NIL, parse(), and max_parallel_hazard_context::safe_param_ids.

Referenced by standard_planner().

{
    max_parallel_hazard_context context;

    context.max_hazard = PROPARALLEL_SAFE;
    context.max_interesting = PROPARALLEL_UNSAFE;
    context.safe_param_ids = NIL;
    (void) max_parallel_hazard_walker((Node *) parse, &context);
    return context.max_hazard;
}

NumRelids()

int NumRelids

(

Node *

clause

)

Definition at line 2130 of file clauses.c.

References bms_free(), bms_num_members(), and pull_varnos().

Referenced by clauselist_selectivity_simple(), rowcomparesel(), and treat_as_join_clause().

{
    Relids      varnos = pull_varnos(clause);
    int         result = bms_num_members(varnos);

    bms_free(varnos);
    return result;
}