WRITE_BOOL_FIELD(dependsOnRole);
WRITE_BOOL_FIELD(parallelModeOK);
WRITE_BOOL_FIELD(parallelModeNeeded);
+ WRITE_CHAR_FIELD(maxParallelHazard);
}
static void
static void create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel);
static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte);
-static bool function_rte_parallel_ok(RangeTblEntry *rte);
static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte);
static void set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel,
if (proparallel != PROPARALLEL_SAFE)
return;
- if (has_parallel_hazard((Node *) rte->tablesample->args,
- false))
+ if (!is_parallel_safe(root, (Node *) rte->tablesample->args))
return;
}
case RTE_FUNCTION:
/* Check for parallel-restricted functions. */
- if (!function_rte_parallel_ok(rte))
+ if (!is_parallel_safe(root, (Node *) rte->functions))
return;
break;
* outer join clauses work correctly. It would likely break equivalence
* classes, too.
*/
- if (has_parallel_hazard((Node *) rel->baserestrictinfo, false))
+ if (!is_parallel_safe(root, (Node *) rel->baserestrictinfo))
return;
/*
* Likewise, if the relation's outputs are not parallel-safe, give up.
* (Usually, they're just Vars, but sometimes they're not.)
*/
- if (has_parallel_hazard((Node *) rel->reltarget->exprs, false))
+ if (!is_parallel_safe(root, (Node *) rel->reltarget->exprs))
return;
/* We have a winner. */
rel->consider_parallel = true;
}
-/*
- * Check whether a function RTE is scanning something parallel-restricted.
- */
-static bool
-function_rte_parallel_ok(RangeTblEntry *rte)
-{
- ListCell *lc;
-
- foreach(lc, rte->functions)
- {
- RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
-
- Assert(IsA(rtfunc, RangeTblFunction));
- if (has_parallel_hazard(rtfunc->funcexpr, false))
- return false;
- }
-
- return true;
-}
-
/*
* set_plain_rel_pathlist
* Build access paths for a plain relation (no subquery, no inheritance)
/*
* If query allows parallelism in general, check whether the quals are
- * parallel-restricted. There's currently no real benefit to setting
- * this flag correctly because we can't yet reference subplans from
- * parallel workers. But that might change someday, so set this
- * correctly anyway.
+ * parallel-restricted. (We need not check final_rel->reltarget
+ * because it's empty at this point. Anything parallel-restricted in
+ * the query tlist will be dealt with later.)
*/
if (root->glob->parallelModeOK)
final_rel->consider_parallel =
- !has_parallel_hazard(parse->jointree->quals, false);
+ is_parallel_safe(root, parse->jointree->quals);
/* The only path for it is a trivial Result path */
add_path(final_rel, (Path *)
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/pg_constraint_fn.h"
+#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "executor/executor.h"
#include "executor/nodeAgg.h"
* time and execution time, so don't generate a parallel plan if we're in
* serializable mode.
*/
- glob->parallelModeOK = (cursorOptions & CURSOR_OPT_PARALLEL_OK) != 0 &&
- IsUnderPostmaster && dynamic_shared_memory_type != DSM_IMPL_NONE &&
- parse->commandType == CMD_SELECT && !parse->hasModifyingCTE &&
- parse->utilityStmt == NULL && max_parallel_workers_per_gather > 0 &&
- !IsParallelWorker() && !IsolationIsSerializable() &&
- !has_parallel_hazard((Node *) parse, true);
+ if ((cursorOptions & CURSOR_OPT_PARALLEL_OK) != 0 &&
+ IsUnderPostmaster &&
+ dynamic_shared_memory_type != DSM_IMPL_NONE &&
+ parse->commandType == CMD_SELECT &&
+ parse->utilityStmt == NULL &&
+ !parse->hasModifyingCTE &&
+ max_parallel_workers_per_gather > 0 &&
+ !IsParallelWorker() &&
+ !IsolationIsSerializable())
+ {
+ /* all the cheap tests pass, so scan the query tree */
+ glob->maxParallelHazard = max_parallel_hazard(parse);
+ glob->parallelModeOK = (glob->maxParallelHazard != PROPARALLEL_UNSAFE);
+ }
+ else
+ {
+ /* skip the query tree scan, just assume it's unsafe */
+ glob->maxParallelHazard = PROPARALLEL_UNSAFE;
+ glob->parallelModeOK = false;
+ }
/*
* glob->parallelModeNeeded should tell us whether it's necessary to
* computed by partial paths.
*/
if (current_rel->partial_pathlist &&
- !has_parallel_hazard((Node *) scanjoin_target->exprs, false))
+ is_parallel_safe(root, (Node *) scanjoin_target->exprs))
{
/* Apply the scan/join target to each partial path */
foreach(lc, current_rel->partial_pathlist)
* query.
*/
if (current_rel->consider_parallel &&
- !has_parallel_hazard(parse->limitOffset, false) &&
- !has_parallel_hazard(parse->limitCount, false))
+ is_parallel_safe(root, parse->limitOffset) &&
+ is_parallel_safe(root, parse->limitCount))
final_rel->consider_parallel = true;
/*
* target list and HAVING quals are parallel-safe.
*/
if (input_rel->consider_parallel &&
- !has_parallel_hazard((Node *) target->exprs, false) &&
- !has_parallel_hazard((Node *) parse->havingQual, false))
+ is_parallel_safe(root, (Node *) target->exprs) &&
+ is_parallel_safe(root, (Node *) parse->havingQual))
grouped_rel->consider_parallel = true;
/*
* target list and active windows for non-parallel-safe constructs.
*/
if (input_rel->consider_parallel &&
- !has_parallel_hazard((Node *) output_target->exprs, false) &&
- !has_parallel_hazard((Node *) activeWindows, false))
+ is_parallel_safe(root, (Node *) output_target->exprs) &&
+ is_parallel_safe(root, (Node *) activeWindows))
window_rel->consider_parallel = true;
/*
* target list is parallel-safe.
*/
if (input_rel->consider_parallel &&
- !has_parallel_hazard((Node *) target->exprs, false))
+ is_parallel_safe(root, (Node *) target->exprs))
ordered_rel->consider_parallel = true;
/*
typedef struct
{
- bool allow_restricted;
-} has_parallel_hazard_arg;
+ char max_hazard; /* worst proparallel hazard found so far */
+ char max_interesting; /* worst proparallel hazard of interest */
+} max_parallel_hazard_context;
static bool contain_agg_clause_walker(Node *node, void *context);
static bool get_agg_clause_costs_walker(Node *node,
static bool contain_mutable_functions_walker(Node *node, void *context);
static bool contain_volatile_functions_walker(Node *node, void *context);
static bool contain_volatile_functions_not_nextval_walker(Node *node, void *context);
-static bool has_parallel_hazard_walker(Node *node,
- has_parallel_hazard_arg *context);
+static bool max_parallel_hazard_walker(Node *node,
+ max_parallel_hazard_context *context);
static bool contain_nonstrict_functions_walker(Node *node, void *context);
static bool contain_context_dependent_node(Node *clause);
static bool contain_context_dependent_node_walker(Node *node, int *flags);
context);
}
+
/*****************************************************************************
* Check queries for parallel unsafe and/or restricted constructs
*****************************************************************************/
/*
- * Check whether a node tree contains parallel hazards. This is used both on
- * the entire query tree, to see whether the query can be parallelized at all
- * (with allow_restricted = true), and also to evaluate whether a particular
- * expression is safe to run within a parallel worker (with allow_restricted =
- * false). We could separate these concerns into two different functions, but
- * there's enough overlap that it doesn't seem worthwhile.
+ * max_parallel_hazard
+ * Find the worst parallel-hazard level in the given query
+ *
+ * Returns the worst function hazard property (the earliest in this list:
+ * PROPARALLEL_UNSAFE, PROPARALLEL_RESTRICTED, PROPARALLEL_SAFE) that can
+ * be found in the given parsetree. We use this to find out whether the query
+ * can be parallelized at all. The caller will also save the result in
+ * PlannerGlobal so as to short-circuit checks of portions of the querytree
+ * later, in the common case where everything is SAFE.
+ */
+char
+max_parallel_hazard(Query *parse)
+{
+ max_parallel_hazard_context context;
+
+ context.max_hazard = PROPARALLEL_SAFE;
+ context.max_interesting = PROPARALLEL_UNSAFE;
+ (void) max_parallel_hazard_walker((Node *) parse, &context);
+ return context.max_hazard;
+}
+
+/*
+ * is_parallel_safe
+ * Detect whether the given expr contains only parallel-safe functions
+ *
+ * root->glob->maxParallelHazard must previously have been set to the
+ * result of max_parallel_hazard() on the whole query.
*/
bool
-has_parallel_hazard(Node *node, bool allow_restricted)
+is_parallel_safe(PlannerInfo *root, Node *node)
{
- has_parallel_hazard_arg context;
+ max_parallel_hazard_context context;
- context.allow_restricted = allow_restricted;
- return has_parallel_hazard_walker(node, &context);
+ /* If max_parallel_hazard found nothing unsafe, we don't need to look */
+ if (root->glob->maxParallelHazard == PROPARALLEL_SAFE)
+ return true;
+ /* Else use max_parallel_hazard's search logic, but stop on RESTRICTED */
+ context.max_hazard = PROPARALLEL_SAFE;
+ context.max_interesting = PROPARALLEL_RESTRICTED;
+ return !max_parallel_hazard_walker(node, &context);
}
+/* core logic for all parallel-hazard checks */
static bool
-has_parallel_hazard_checker(Oid func_id, void *context)
+max_parallel_hazard_test(char proparallel, max_parallel_hazard_context *context)
{
- char proparallel = func_parallel(func_id);
+ switch (proparallel)
+ {
+ case PROPARALLEL_SAFE:
+ /* nothing to see here, move along */
+ break;
+ case PROPARALLEL_RESTRICTED:
+ /* increase max_hazard to RESTRICTED */
+ Assert(context->max_hazard != PROPARALLEL_UNSAFE);
+ context->max_hazard = proparallel;
+ /* done if we are not expecting any unsafe functions */
+ if (context->max_interesting == proparallel)
+ return true;
+ break;
+ case PROPARALLEL_UNSAFE:
+ context->max_hazard = proparallel;
+ /* we're always done at the first unsafe construct */
+ return true;
+ default:
+ elog(ERROR, "unrecognized proparallel value \"%c\"", proparallel);
+ break;
+ }
+ return false;
+}
- if (((has_parallel_hazard_arg *) context)->allow_restricted)
- return (proparallel == PROPARALLEL_UNSAFE);
- else
- return (proparallel != PROPARALLEL_SAFE);
+/* check_functions_in_node callback */
+static bool
+max_parallel_hazard_checker(Oid func_id, void *context)
+{
+ return max_parallel_hazard_test(func_parallel(func_id),
+ (max_parallel_hazard_context *) context);
}
static bool
-has_parallel_hazard_walker(Node *node, has_parallel_hazard_arg *context)
+max_parallel_hazard_walker(Node *node, max_parallel_hazard_context *context)
{
if (node == NULL)
return false;
/* Check for hazardous functions in node itself */
- if (check_functions_in_node(node, has_parallel_hazard_checker,
+ if (check_functions_in_node(node, max_parallel_hazard_checker,
context))
return true;
*/
if (IsA(node, CoerceToDomain))
{
- if (!context->allow_restricted)
+ if (max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
return true;
}
{
RestrictInfo *rinfo = (RestrictInfo *) node;
- return has_parallel_hazard_walker((Node *) rinfo->clause, context);
+ return max_parallel_hazard_walker((Node *) rinfo->clause, context);
}
/*
* not worry about examining their contents; if they are unsafe, we would
* have found that out while examining the whole tree before reduction of
* sublinks to subplans. (Really we should not see SubLink during a
- * not-allow_restricted scan, but if we do, return true.)
+ * max_interesting == restricted scan, but if we do, return true.)
*/
else if (IsA(node, SubLink) ||
IsA(node, SubPlan) ||
IsA(node, AlternativeSubPlan))
{
- if (!context->allow_restricted)
+ if (max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
return true;
}
*/
else if (IsA(node, Param))
{
- if (!context->allow_restricted)
+ if (max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
return true;
}
/* SELECT FOR UPDATE/SHARE must be treated as unsafe */
if (query->rowMarks != NULL)
+ {
+ context->max_hazard = PROPARALLEL_UNSAFE;
return true;
+ }
/* Recurse into subselects */
return query_tree_walker(query,
- has_parallel_hazard_walker,
+ max_parallel_hazard_walker,
context, 0);
}
/* Recurse to check arguments */
return expression_tree_walker(node,
- has_parallel_hazard_walker,
+ max_parallel_hazard_walker,
context);
}
+
/*****************************************************************************
* Check clauses for nonstrict functions
*****************************************************************************/
pathnode->path.parallel_aware = false;
pathnode->path.parallel_safe = rel->consider_parallel &&
subpath->parallel_safe &&
- !has_parallel_hazard((Node *) target->exprs, false);
+ is_parallel_safe(root, (Node *) target->exprs);
pathnode->path.parallel_workers = subpath->parallel_workers;
/* Projection does not change the sort order */
pathnode->path.pathkeys = subpath->pathkeys;
* target expressions, then we can't.
*/
if (IsA(path, GatherPath) &&
- !has_parallel_hazard((Node *) target->exprs, false))
+ is_parallel_safe(root, (Node *) target->exprs))
{
GatherPath *gpath = (GatherPath *) path;
target);
}
else if (path->parallel_safe &&
- has_parallel_hazard((Node *) target->exprs, false))
+ !is_parallel_safe(root, (Node *) target->exprs))
{
/*
* We're inserting a parallel-restricted target list into a path
* here.
*/
if (inner_rel->consider_parallel && outer_rel->consider_parallel &&
- !has_parallel_hazard((Node *) restrictlist, false) &&
- !has_parallel_hazard((Node *) joinrel->reltarget->exprs, false))
+ is_parallel_safe(root, (Node *) restrictlist) &&
+ is_parallel_safe(root, (Node *) joinrel->reltarget->exprs))
joinrel->consider_parallel = true;
/*
bool parallelModeOK; /* parallel mode potentially OK? */
bool parallelModeNeeded; /* parallel mode actually required? */
+
+ char maxParallelHazard; /* worst PROPARALLEL hazard level */
} PlannerGlobal;
/* macro for fetching the Plan associated with a SubPlan node */
extern bool contain_mutable_functions(Node *clause);
extern bool contain_volatile_functions(Node *clause);
extern bool contain_volatile_functions_not_nextval(Node *clause);
-extern bool has_parallel_hazard(Node *node, bool allow_restricted);
+extern char max_parallel_hazard(Query *parse);
+extern bool is_parallel_safe(PlannerInfo *root, Node *node);
extern bool contain_nonstrict_functions(Node *clause);
extern bool contain_leaked_vars(Node *clause);
projects / users / c2main / postgres.git / commitdiff