PostgreSQL Source Code git master
subselect.h File Reference
#include "nodes/pathnodes.h"
#include "nodes/plannodes.h"
Include dependency graph for subselect.h:
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Functions

void SS_process_ctes (PlannerInfo *root)
 
JoinExprconvert_ANY_sublink_to_join (PlannerInfo *root, SubLink *sublink, Relids available_rels)
 
JoinExprconvert_EXISTS_sublink_to_join (PlannerInfo *root, SubLink *sublink, bool under_not, Relids available_rels)
 
NodeSS_replace_correlation_vars (PlannerInfo *root, Node *expr)
 
NodeSS_process_sublinks (PlannerInfo *root, Node *expr, bool isQual)
 
void SS_identify_outer_params (PlannerInfo *root)
 
void SS_charge_for_initplans (PlannerInfo *root, RelOptInfo *final_rel)
 
void SS_compute_initplan_cost (List *init_plans, Cost *initplan_cost_p, bool *unsafe_initplans_p)
 
void SS_attach_initplans (PlannerInfo *root, Plan *plan)
 
void SS_finalize_plan (PlannerInfo *root, Plan *plan)
 
ParamSS_make_initplan_output_param (PlannerInfo *root, Oid resulttype, int32 resulttypmod, Oid resultcollation)
 
void SS_make_initplan_from_plan (PlannerInfo *root, PlannerInfo *subroot, Plan *plan, Param *prm)
 

Function Documentation

◆ convert_ANY_sublink_to_join()

JoinExpr * convert_ANY_sublink_to_join ( PlannerInfo root,
SubLink sublink,
Relids  available_rels 
)

Definition at line 1253 of file subselect.c.

1255{
1256 JoinExpr *result;
1257 Query *parse = root->parse;
1258 Query *subselect = (Query *) sublink->subselect;
1259 Relids upper_varnos;
1260 int rtindex;
1261 ParseNamespaceItem *nsitem;
1262 RangeTblEntry *rte;
1263 RangeTblRef *rtr;
1264 List *subquery_vars;
1265 Node *quals;
1266 ParseState *pstate;
1267 Relids sub_ref_outer_relids;
1268 bool use_lateral;
1269
1270 Assert(sublink->subLinkType == ANY_SUBLINK);
1271
1272 /*
1273 * If the sub-select contains any Vars of the parent query, we treat it as
1274 * LATERAL. (Vars from higher levels don't matter here.)
1275 */
1276 sub_ref_outer_relids = pull_varnos_of_level(NULL, (Node *) subselect, 1);
1277 use_lateral = !bms_is_empty(sub_ref_outer_relids);
1278
1279 /*
1280 * Can't convert if the sub-select contains parent-level Vars of relations
1281 * not in available_rels.
1282 */
1283 if (!bms_is_subset(sub_ref_outer_relids, available_rels))
1284 return NULL;
1285
1286 /*
1287 * The test expression must contain some Vars of the parent query, else
1288 * it's not gonna be a join. (Note that it won't have Vars referring to
1289 * the subquery, rather Params.)
1290 */
1291 upper_varnos = pull_varnos(root, sublink->testexpr);
1292 if (bms_is_empty(upper_varnos))
1293 return NULL;
1294
1295 /*
1296 * However, it can't refer to anything outside available_rels.
1297 */
1298 if (!bms_is_subset(upper_varnos, available_rels))
1299 return NULL;
1300
1301 /*
1302 * The combining operators and left-hand expressions mustn't be volatile.
1303 */
1305 return NULL;
1306
1307 /* Create a dummy ParseState for addRangeTableEntryForSubquery */
1308 pstate = make_parsestate(NULL);
1309
1310 /*
1311 * Okay, pull up the sub-select into upper range table.
1312 *
1313 * We rely here on the assumption that the outer query has no references
1314 * to the inner (necessarily true, other than the Vars that we build
1315 * below). Therefore this is a lot easier than what pull_up_subqueries has
1316 * to go through.
1317 */
1318 nsitem = addRangeTableEntryForSubquery(pstate,
1319 subselect,
1320 makeAlias("ANY_subquery", NIL),
1321 use_lateral,
1322 false);
1323 rte = nsitem->p_rte;
1324 parse->rtable = lappend(parse->rtable, rte);
1325 rtindex = list_length(parse->rtable);
1326
1327 /*
1328 * Form a RangeTblRef for the pulled-up sub-select.
1329 */
1330 rtr = makeNode(RangeTblRef);
1331 rtr->rtindex = rtindex;
1332
1333 /*
1334 * Build a list of Vars representing the subselect outputs.
1335 */
1336 subquery_vars = generate_subquery_vars(root,
1337 subselect->targetList,
1338 rtindex);
1339
1340 /*
1341 * Build the new join's qual expression, replacing Params with these Vars.
1342 */
1343 quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
1344
1345 /*
1346 * And finally, build the JoinExpr node.
1347 */
1348 result = makeNode(JoinExpr);
1349 result->jointype = JOIN_SEMI;
1350 result->isNatural = false;
1351 result->larg = NULL; /* caller must fill this in */
1352 result->rarg = (Node *) rtr;
1353 result->usingClause = NIL;
1354 result->join_using_alias = NULL;
1355 result->quals = quals;
1356 result->alias = NULL;
1357 result->rtindex = 0; /* we don't need an RTE for it */
1358
1359 return result;
1360}
bool bms_is_subset(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:412
#define bms_is_empty(a)
Definition: bitmapset.h:118
bool contain_volatile_functions(Node *clause)
Definition: clauses.c:537
Assert(PointerIsAligned(start, uint64))
List * lappend(List *list, void *datum)
Definition: list.c:339
Alias * makeAlias(const char *aliasname, List *colnames)
Definition: makefuncs.c:438
#define makeNode(_type_)
Definition: nodes.h:157
@ JOIN_SEMI
Definition: nodes.h:309
ParseState * make_parsestate(ParseState *parentParseState)
Definition: parse_node.c:39
ParseNamespaceItem * addRangeTableEntryForSubquery(ParseState *pstate, Query *subquery, Alias *alias, bool lateral, bool inFromCl)
static int list_length(const List *l)
Definition: pg_list.h:152
#define NIL
Definition: pg_list.h:68
@ ANY_SUBLINK
Definition: primnodes.h:1016
tree ctl root
Definition: radixtree.h:1857
static struct subre * parse(struct vars *v, int stopper, int type, struct state *init, struct state *final)
Definition: regcomp.c:717
Node * quals
Definition: primnodes.h:2318
JoinType jointype
Definition: primnodes.h:2309
int rtindex
Definition: primnodes.h:2322
Node * larg
Definition: primnodes.h:2311
bool isNatural
Definition: primnodes.h:2310
Node * rarg
Definition: primnodes.h:2312
Definition: pg_list.h:54
Definition: nodes.h:131
List * targetList
Definition: parsenodes.h:193
static List * generate_subquery_vars(PlannerInfo *root, List *tlist, Index varno)
Definition: subselect.c:615
static Node * convert_testexpr(PlannerInfo *root, Node *testexpr, List *subst_nodes)
Definition: subselect.c:644
Relids pull_varnos_of_level(PlannerInfo *root, Node *node, int levelsup)
Definition: var.c:140
Relids pull_varnos(PlannerInfo *root, Node *node)
Definition: var.c:114

References addRangeTableEntryForSubquery(), ANY_SUBLINK, Assert(), bms_is_empty, bms_is_subset(), contain_volatile_functions(), convert_testexpr(), generate_subquery_vars(), JoinExpr::isNatural, JOIN_SEMI, JoinExpr::jointype, lappend(), JoinExpr::larg, list_length(), make_parsestate(), makeAlias(), makeNode, NIL, parse(), pull_varnos(), pull_varnos_of_level(), JoinExpr::quals, JoinExpr::rarg, root, JoinExpr::rtindex, SubLink::subLinkType, SubLink::subselect, Query::targetList, and SubLink::testexpr.

Referenced by pull_up_sublinks_qual_recurse().

◆ convert_EXISTS_sublink_to_join()

JoinExpr * convert_EXISTS_sublink_to_join ( PlannerInfo root,
SubLink sublink,
bool  under_not,
Relids  available_rels 
)

Definition at line 1370 of file subselect.c.

1372{
1373 JoinExpr *result;
1374 Query *parse = root->parse;
1375 Query *subselect = (Query *) sublink->subselect;
1376 Node *whereClause;
1377 int rtoffset;
1378 int varno;
1379 Relids clause_varnos;
1380 Relids upper_varnos;
1381
1382 Assert(sublink->subLinkType == EXISTS_SUBLINK);
1383
1384 /*
1385 * Can't flatten if it contains WITH. (We could arrange to pull up the
1386 * WITH into the parent query's cteList, but that risks changing the
1387 * semantics, since a WITH ought to be executed once per associated query
1388 * call.) Note that convert_ANY_sublink_to_join doesn't have to reject
1389 * this case, since it just produces a subquery RTE that doesn't have to
1390 * get flattened into the parent query.
1391 */
1392 if (subselect->cteList)
1393 return NULL;
1394
1395 /*
1396 * Copy the subquery so we can modify it safely (see comments in
1397 * make_subplan).
1398 */
1399 subselect = copyObject(subselect);
1400
1401 /*
1402 * See if the subquery can be simplified based on the knowledge that it's
1403 * being used in EXISTS(). If we aren't able to get rid of its
1404 * targetlist, we have to fail, because the pullup operation leaves us
1405 * with noplace to evaluate the targetlist.
1406 */
1407 if (!simplify_EXISTS_query(root, subselect))
1408 return NULL;
1409
1410 /*
1411 * Separate out the WHERE clause. (We could theoretically also remove
1412 * top-level plain JOIN/ON clauses, but it's probably not worth the
1413 * trouble.)
1414 */
1415 whereClause = subselect->jointree->quals;
1416 subselect->jointree->quals = NULL;
1417
1418 /*
1419 * The rest of the sub-select must not refer to any Vars of the parent
1420 * query. (Vars of higher levels should be okay, though.)
1421 */
1422 if (contain_vars_of_level((Node *) subselect, 1))
1423 return NULL;
1424
1425 /*
1426 * On the other hand, the WHERE clause must contain some Vars of the
1427 * parent query, else it's not gonna be a join.
1428 */
1429 if (!contain_vars_of_level(whereClause, 1))
1430 return NULL;
1431
1432 /*
1433 * We don't risk optimizing if the WHERE clause is volatile, either.
1434 */
1435 if (contain_volatile_functions(whereClause))
1436 return NULL;
1437
1438 /*
1439 * The subquery must have a nonempty jointree, but we can make it so.
1440 */
1441 replace_empty_jointree(subselect);
1442
1443 /*
1444 * Prepare to pull up the sub-select into top range table.
1445 *
1446 * We rely here on the assumption that the outer query has no references
1447 * to the inner (necessarily true). Therefore this is a lot easier than
1448 * what pull_up_subqueries has to go through.
1449 *
1450 * In fact, it's even easier than what convert_ANY_sublink_to_join has to
1451 * do. The machinations of simplify_EXISTS_query ensured that there is
1452 * nothing interesting in the subquery except an rtable and jointree, and
1453 * even the jointree FromExpr no longer has quals. So we can just append
1454 * the rtable to our own and use the FromExpr in our jointree. But first,
1455 * adjust all level-zero varnos in the subquery to account for the rtable
1456 * merger.
1457 */
1458 rtoffset = list_length(parse->rtable);
1459 OffsetVarNodes((Node *) subselect, rtoffset, 0);
1460 OffsetVarNodes(whereClause, rtoffset, 0);
1461
1462 /*
1463 * Upper-level vars in subquery will now be one level closer to their
1464 * parent than before; in particular, anything that had been level 1
1465 * becomes level zero.
1466 */
1467 IncrementVarSublevelsUp((Node *) subselect, -1, 1);
1468 IncrementVarSublevelsUp(whereClause, -1, 1);
1469
1470 /*
1471 * Now that the WHERE clause is adjusted to match the parent query
1472 * environment, we can easily identify all the level-zero rels it uses.
1473 * The ones <= rtoffset belong to the upper query; the ones > rtoffset do
1474 * not.
1475 */
1476 clause_varnos = pull_varnos(root, whereClause);
1477 upper_varnos = NULL;
1478 varno = -1;
1479 while ((varno = bms_next_member(clause_varnos, varno)) >= 0)
1480 {
1481 if (varno <= rtoffset)
1482 upper_varnos = bms_add_member(upper_varnos, varno);
1483 }
1484 bms_free(clause_varnos);
1485 Assert(!bms_is_empty(upper_varnos));
1486
1487 /*
1488 * Now that we've got the set of upper-level varnos, we can make the last
1489 * check: only available_rels can be referenced.
1490 */
1491 if (!bms_is_subset(upper_varnos, available_rels))
1492 return NULL;
1493
1494 /*
1495 * Now we can attach the modified subquery rtable to the parent. This also
1496 * adds subquery's RTEPermissionInfos into the upper query.
1497 */
1498 CombineRangeTables(&parse->rtable, &parse->rteperminfos,
1499 subselect->rtable, subselect->rteperminfos);
1500
1501 /*
1502 * And finally, build the JoinExpr node.
1503 */
1504 result = makeNode(JoinExpr);
1505 result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
1506 result->isNatural = false;
1507 result->larg = NULL; /* caller must fill this in */
1508 /* flatten out the FromExpr node if it's useless */
1509 if (list_length(subselect->jointree->fromlist) == 1)
1510 result->rarg = (Node *) linitial(subselect->jointree->fromlist);
1511 else
1512 result->rarg = (Node *) subselect->jointree;
1513 result->usingClause = NIL;
1514 result->join_using_alias = NULL;
1515 result->quals = whereClause;
1516 result->alias = NULL;
1517 result->rtindex = 0; /* we don't need an RTE for it */
1518
1519 return result;
1520}
int bms_next_member(const Bitmapset *a, int prevbit)
Definition: bitmapset.c:1306
void bms_free(Bitmapset *a)
Definition: bitmapset.c:239
Bitmapset * bms_add_member(Bitmapset *a, int x)
Definition: bitmapset.c:815
#define copyObject(obj)
Definition: nodes.h:226
@ JOIN_ANTI
Definition: nodes.h:310
#define linitial(l)
Definition: pg_list.h:178
void replace_empty_jointree(Query *parse)
Definition: prepjointree.c:410
@ EXISTS_SUBLINK
Definition: primnodes.h:1014
void OffsetVarNodes(Node *node, int offset, int sublevels_up)
Definition: rewriteManip.c:476
void CombineRangeTables(List **dst_rtable, List **dst_perminfos, List *src_rtable, List *src_perminfos)
Definition: rewriteManip.c:347
void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up, int min_sublevels_up)
Definition: rewriteManip.c:928
Node * quals
Definition: primnodes.h:2338
FromExpr * jointree
Definition: parsenodes.h:177
List * cteList
Definition: parsenodes.h:168
static bool simplify_EXISTS_query(PlannerInfo *root, Query *query)
Definition: subselect.c:1539
bool contain_vars_of_level(Node *node, int levelsup)
Definition: var.c:444

References Assert(), bms_add_member(), bms_free(), bms_is_empty, bms_is_subset(), bms_next_member(), CombineRangeTables(), contain_vars_of_level(), contain_volatile_functions(), copyObject, Query::cteList, EXISTS_SUBLINK, FromExpr::fromlist, IncrementVarSublevelsUp(), JoinExpr::isNatural, JOIN_ANTI, JOIN_SEMI, Query::jointree, JoinExpr::jointype, JoinExpr::larg, linitial, list_length(), makeNode, NIL, OffsetVarNodes(), parse(), pull_varnos(), JoinExpr::quals, FromExpr::quals, JoinExpr::rarg, replace_empty_jointree(), root, Query::rtable, JoinExpr::rtindex, simplify_EXISTS_query(), SubLink::subLinkType, and SubLink::subselect.

Referenced by pull_up_sublinks_qual_recurse().

◆ SS_attach_initplans()

void SS_attach_initplans ( PlannerInfo root,
Plan plan 
)

Definition at line 2273 of file subselect.c.

2274{
2275 plan->initPlan = root->init_plans;
2276}
#define plan(x)
Definition: pg_regress.c:161

References plan, and root.

Referenced by create_plan().

◆ SS_charge_for_initplans()

void SS_charge_for_initplans ( PlannerInfo root,
RelOptInfo final_rel 
)

Definition at line 2168 of file subselect.c.

2169{
2170 Cost initplan_cost;
2171 bool unsafe_initplans;
2172 ListCell *lc;
2173
2174 /* Nothing to do if no initPlans */
2175 if (root->init_plans == NIL)
2176 return;
2177
2178 /*
2179 * Compute the cost increment just once, since it will be the same for all
2180 * Paths. Also check for parallel-unsafe initPlans.
2181 */
2182 SS_compute_initplan_cost(root->init_plans,
2183 &initplan_cost, &unsafe_initplans);
2184
2185 /*
2186 * Now adjust the costs and parallel_safe flags.
2187 */
2188 foreach(lc, final_rel->pathlist)
2189 {
2190 Path *path = (Path *) lfirst(lc);
2191
2192 path->startup_cost += initplan_cost;
2193 path->total_cost += initplan_cost;
2194 if (unsafe_initplans)
2195 path->parallel_safe = false;
2196 }
2197
2198 /*
2199 * Adjust partial paths' costs too, or forget them entirely if we must
2200 * consider the rel parallel-unsafe.
2201 */
2202 if (unsafe_initplans)
2203 {
2204 final_rel->partial_pathlist = NIL;
2205 final_rel->consider_parallel = false;
2206 }
2207 else
2208 {
2209 foreach(lc, final_rel->partial_pathlist)
2210 {
2211 Path *path = (Path *) lfirst(lc);
2212
2213 path->startup_cost += initplan_cost;
2214 path->total_cost += initplan_cost;
2215 }
2216 }
2217
2218 /* We needn't do set_cheapest() here, caller will do it */
2219}
double Cost
Definition: nodes.h:253
#define lfirst(lc)
Definition: pg_list.h:172
Cost startup_cost
Definition: pathnodes.h:1700
Cost total_cost
Definition: pathnodes.h:1701
bool parallel_safe
Definition: pathnodes.h:1693
bool consider_parallel
Definition: pathnodes.h:914
List * pathlist
Definition: pathnodes.h:925
List * partial_pathlist
Definition: pathnodes.h:927
void SS_compute_initplan_cost(List *init_plans, Cost *initplan_cost_p, bool *unsafe_initplans_p)
Definition: subselect.c:2232

References RelOptInfo::consider_parallel, lfirst, NIL, Path::parallel_safe, RelOptInfo::partial_pathlist, RelOptInfo::pathlist, root, SS_compute_initplan_cost(), Path::startup_cost, and Path::total_cost.

Referenced by build_minmax_path(), and subquery_planner().

◆ SS_compute_initplan_cost()

void SS_compute_initplan_cost ( List init_plans,
Cost initplan_cost_p,
bool *  unsafe_initplans_p 
)

Definition at line 2232 of file subselect.c.

2235{
2236 Cost initplan_cost;
2237 bool unsafe_initplans;
2238 ListCell *lc;
2239
2240 /*
2241 * We assume each initPlan gets run once during top plan startup. This is
2242 * a conservative overestimate, since in fact an initPlan might be
2243 * executed later than plan startup, or even not at all.
2244 */
2245 initplan_cost = 0;
2246 unsafe_initplans = false;
2247 foreach(lc, init_plans)
2248 {
2249 SubPlan *initsubplan = lfirst_node(SubPlan, lc);
2250
2251 initplan_cost += initsubplan->startup_cost + initsubplan->per_call_cost;
2252 if (!initsubplan->parallel_safe)
2253 unsafe_initplans = true;
2254 }
2255 *initplan_cost_p = initplan_cost;
2256 *unsafe_initplans_p = unsafe_initplans;
2257}
#define lfirst_node(type, lc)
Definition: pg_list.h:176
bool parallel_safe
Definition: primnodes.h:1101
Cost startup_cost
Definition: primnodes.h:1110
Cost per_call_cost
Definition: primnodes.h:1111

References lfirst_node, SubPlan::parallel_safe, SubPlan::per_call_cost, and SubPlan::startup_cost.

Referenced by clean_up_removed_plan_level(), materialize_finished_plan(), SS_charge_for_initplans(), and standard_planner().

◆ SS_finalize_plan()

void SS_finalize_plan ( PlannerInfo root,
Plan plan 
)

Definition at line 2288 of file subselect.c.

2289{
2290 /* No setup needed, just recurse through plan tree. */
2291 (void) finalize_plan(root, plan, -1, root->outer_params, NULL);
2292}
static Bitmapset * finalize_plan(PlannerInfo *root, Plan *plan, int gather_param, Bitmapset *valid_params, Bitmapset *scan_params)
Definition: subselect.c:2326

References finalize_plan(), plan, and root.

Referenced by standard_planner().

◆ SS_identify_outer_params()

void SS_identify_outer_params ( PlannerInfo root)

Definition at line 2104 of file subselect.c.

2105{
2106 Bitmapset *outer_params;
2107 PlannerInfo *proot;
2108 ListCell *l;
2109
2110 /*
2111 * If no parameters have been assigned anywhere in the tree, we certainly
2112 * don't need to do anything here.
2113 */
2114 if (root->glob->paramExecTypes == NIL)
2115 return;
2116
2117 /*
2118 * Scan all query levels above this one to see which parameters are due to
2119 * be available from them, either because lower query levels have
2120 * requested them (via plan_params) or because they will be available from
2121 * initPlans of those levels.
2122 */
2123 outer_params = NULL;
2124 for (proot = root->parent_root; proot != NULL; proot = proot->parent_root)
2125 {
2126 /*
2127 * Include ordinary Var/PHV/Aggref/GroupingFunc/ReturningExpr params.
2128 */
2129 foreach(l, proot->plan_params)
2130 {
2132
2133 outer_params = bms_add_member(outer_params, pitem->paramId);
2134 }
2135 /* Include any outputs of outer-level initPlans */
2136 foreach(l, proot->init_plans)
2137 {
2138 SubPlan *initsubplan = (SubPlan *) lfirst(l);
2139 ListCell *l2;
2140
2141 foreach(l2, initsubplan->setParam)
2142 {
2143 outer_params = bms_add_member(outer_params, lfirst_int(l2));
2144 }
2145 }
2146 /* Include worktable ID, if a recursive query is being planned */
2147 if (proot->wt_param_id >= 0)
2148 outer_params = bms_add_member(outer_params, proot->wt_param_id);
2149 }
2150 root->outer_params = outer_params;
2151}
#define lfirst_int(lc)
Definition: pg_list.h:173
List * init_plans
Definition: pathnodes.h:323
int wt_param_id
Definition: pathnodes.h:560
List * plan_params
Definition: pathnodes.h:244
List * setParam
Definition: primnodes.h:1105

References bms_add_member(), PlannerInfo::init_plans, lfirst, lfirst_int, NIL, PlannerParamItem::paramId, PlannerInfo::plan_params, root, SubPlan::setParam, and PlannerInfo::wt_param_id.

Referenced by build_minmax_path(), and subquery_planner().

◆ SS_make_initplan_from_plan()

void SS_make_initplan_from_plan ( PlannerInfo root,
PlannerInfo subroot,
Plan plan,
Param prm 
)

Definition at line 3049 of file subselect.c.

3052{
3053 SubPlan *node;
3054
3055 /*
3056 * Add the subplan and its PlannerInfo, as well as a dummy path entry, to
3057 * the global lists. Ideally we'd save a real path, but right now our
3058 * sole caller doesn't build a path that exactly matches the plan. Since
3059 * we're not currently going to need the path for an initplan, it's not
3060 * worth requiring construction of such a path.
3061 */
3062 root->glob->subplans = lappend(root->glob->subplans, plan);
3063 root->glob->subpaths = lappend(root->glob->subpaths, NULL);
3064 root->glob->subroots = lappend(root->glob->subroots, subroot);
3065
3066 /*
3067 * Create a SubPlan node and add it to the outer list of InitPlans. Note
3068 * it has to appear after any other InitPlans it might depend on (see
3069 * comments in ExecReScan).
3070 */
3071 node = makeNode(SubPlan);
3072 node->subLinkType = EXPR_SUBLINK;
3073 node->plan_id = list_length(root->glob->subplans);
3074 node->plan_name = psprintf("InitPlan %d", node->plan_id);
3076 &node->firstColCollation);
3077 node->parallel_safe = plan->parallel_safe;
3078 node->setParam = list_make1_int(prm->paramid);
3079
3080 root->init_plans = lappend(root->init_plans, node);
3081
3082 /*
3083 * The node can't have any inputs (since it's an initplan), so the
3084 * parParam and args lists remain empty.
3085 */
3086
3087 /* Set costs of SubPlan using info from the plan tree */
3088 cost_subplan(subroot, node, plan);
3089}
void cost_subplan(PlannerInfo *root, SubPlan *subplan, Plan *plan)
Definition: costsize.c:4533
#define list_make1_int(x1)
Definition: pg_list.h:227
@ EXPR_SUBLINK
Definition: primnodes.h:1018
char * psprintf(const char *fmt,...)
Definition: psprintf.c:43
int paramid
Definition: primnodes.h:394
int plan_id
Definition: primnodes.h:1087
char * plan_name
Definition: primnodes.h:1089
int32 firstColTypmod
Definition: primnodes.h:1092
Oid firstColCollation
Definition: primnodes.h:1093
SubLinkType subLinkType
Definition: primnodes.h:1082
Oid firstColType
Definition: primnodes.h:1091
static void get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod, Oid *colcollation)
Definition: subselect.c:118

References cost_subplan(), EXPR_SUBLINK, SubPlan::firstColCollation, SubPlan::firstColType, SubPlan::firstColTypmod, get_first_col_type(), lappend(), list_length(), list_make1_int, makeNode, SubPlan::parallel_safe, Param::paramid, plan, SubPlan::plan_id, SubPlan::plan_name, psprintf(), root, SubPlan::setParam, and SubPlan::subLinkType.

Referenced by create_minmaxagg_plan().

◆ SS_make_initplan_output_param()

Param * SS_make_initplan_output_param ( PlannerInfo root,
Oid  resulttype,
int32  resulttypmod,
Oid  resultcollation 
)

Definition at line 3033 of file subselect.c.

3036{
3037 return generate_new_exec_param(root, resulttype,
3038 resulttypmod, resultcollation);
3039}
Param * generate_new_exec_param(PlannerInfo *root, Oid paramtype, int32 paramtypmod, Oid paramcollation)
Definition: paramassign.c:684

References generate_new_exec_param(), and root.

Referenced by preprocess_minmax_aggregates().

◆ SS_process_ctes()

void SS_process_ctes ( PlannerInfo root)

Definition at line 880 of file subselect.c.

881{
882 ListCell *lc;
883
884 Assert(root->cte_plan_ids == NIL);
885
886 foreach(lc, root->parse->cteList)
887 {
889 CmdType cmdType = ((Query *) cte->ctequery)->commandType;
890 Query *subquery;
891 PlannerInfo *subroot;
892 RelOptInfo *final_rel;
893 Path *best_path;
894 Plan *plan;
895 SubPlan *splan;
896 int paramid;
897
898 /*
899 * Ignore SELECT CTEs that are not actually referenced anywhere.
900 */
901 if (cte->cterefcount == 0 && cmdType == CMD_SELECT)
902 {
903 /* Make a dummy entry in cte_plan_ids */
904 root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
905 continue;
906 }
907
908 /*
909 * Consider inlining the CTE (creating RTE_SUBQUERY RTE(s)) instead of
910 * implementing it as a separately-planned CTE.
911 *
912 * We cannot inline if any of these conditions hold:
913 *
914 * 1. The user said not to (the CTEMaterializeAlways option).
915 *
916 * 2. The CTE is recursive.
917 *
918 * 3. The CTE has side-effects; this includes either not being a plain
919 * SELECT, or containing volatile functions. Inlining might change
920 * the side-effects, which would be bad.
921 *
922 * 4. The CTE is multiply-referenced and contains a self-reference to
923 * a recursive CTE outside itself. Inlining would result in multiple
924 * recursive self-references, which we don't support.
925 *
926 * Otherwise, we have an option whether to inline or not. That should
927 * always be a win if there's just a single reference, but if the CTE
928 * is multiply-referenced then it's unclear: inlining adds duplicate
929 * computations, but the ability to absorb restrictions from the outer
930 * query level could outweigh that. We do not have nearly enough
931 * information at this point to tell whether that's true, so we let
932 * the user express a preference. Our default behavior is to inline
933 * only singly-referenced CTEs, but a CTE marked CTEMaterializeNever
934 * will be inlined even if multiply referenced.
935 *
936 * Note: we check for volatile functions last, because that's more
937 * expensive than the other tests needed.
938 */
941 cte->cterefcount == 1)) &&
942 !cte->cterecursive &&
943 cmdType == CMD_SELECT &&
944 !contain_dml(cte->ctequery) &&
945 (cte->cterefcount <= 1 ||
948 {
949 inline_cte(root, cte);
950 /* Make a dummy entry in cte_plan_ids */
951 root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
952 continue;
953 }
954
955 /*
956 * Copy the source Query node. Probably not necessary, but let's keep
957 * this similar to make_subplan.
958 */
959 subquery = (Query *) copyObject(cte->ctequery);
960
961 /* plan_params should not be in use in current query level */
962 Assert(root->plan_params == NIL);
963
964 /*
965 * Generate Paths for the CTE query. Always plan for full retrieval
966 * --- we don't have enough info to predict otherwise.
967 */
968 subroot = subquery_planner(root->glob, subquery, root,
969 cte->cterecursive, 0.0, NULL);
970
971 /*
972 * Since the current query level doesn't yet contain any RTEs, it
973 * should not be possible for the CTE to have requested parameters of
974 * this level.
975 */
976 if (root->plan_params)
977 elog(ERROR, "unexpected outer reference in CTE query");
978
979 /*
980 * Select best Path and turn it into a Plan. At least for now, there
981 * seems no reason to postpone doing that.
982 */
983 final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
984 best_path = final_rel->cheapest_total_path;
985
986 plan = create_plan(subroot, best_path);
987
988 /*
989 * Make a SubPlan node for it. This is just enough unlike
990 * build_subplan that we can't share code.
991 *
992 * Note plan_id, plan_name, and cost fields are set further down.
993 */
995 splan->subLinkType = CTE_SUBLINK;
996 splan->testexpr = NULL;
997 splan->paramIds = NIL;
998 get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
999 &splan->firstColCollation);
1000 splan->useHashTable = false;
1001 splan->unknownEqFalse = false;
1002
1003 /*
1004 * CTE scans are not considered for parallelism (cf
1005 * set_rel_consider_parallel).
1006 */
1007 splan->parallel_safe = false;
1008 splan->setParam = NIL;
1009 splan->parParam = NIL;
1010 splan->args = NIL;
1011
1012 /*
1013 * The node can't have any inputs (since it's an initplan), so the
1014 * parParam and args lists remain empty. (It could contain references
1015 * to earlier CTEs' output param IDs, but CTE outputs are not
1016 * propagated via the args list.)
1017 */
1018
1019 /*
1020 * Assign a param ID to represent the CTE's output. No ordinary
1021 * "evaluation" of this param slot ever happens, but we use the param
1022 * ID for setParam/chgParam signaling just as if the CTE plan were
1023 * returning a simple scalar output. (Also, the executor abuses the
1024 * ParamExecData slot for this param ID for communication among
1025 * multiple CteScan nodes that might be scanning this CTE.)
1026 */
1028 splan->setParam = list_make1_int(paramid);
1029
1030 /*
1031 * Add the subplan, its path, and its PlannerInfo to the global lists.
1032 */
1033 root->glob->subplans = lappend(root->glob->subplans, plan);
1034 root->glob->subpaths = lappend(root->glob->subpaths, best_path);
1035 root->glob->subroots = lappend(root->glob->subroots, subroot);
1036 splan->plan_id = list_length(root->glob->subplans);
1037
1038 root->init_plans = lappend(root->init_plans, splan);
1039
1040 root->cte_plan_ids = lappend_int(root->cte_plan_ids, splan->plan_id);
1041
1042 /* Label the subplan for EXPLAIN purposes */
1043 splan->plan_name = psprintf("CTE %s", cte->ctename);
1044
1045 /* Lastly, fill in the cost estimates for use later */
1047 }
1048}
Plan * create_plan(PlannerInfo *root, Path *best_path)
Definition: createplan.c:337
#define ERROR
Definition: elog.h:39
#define elog(elevel,...)
Definition: elog.h:225
List * lappend_int(List *list, int datum)
Definition: list.c:357
CmdType
Definition: nodes.h:265
@ CMD_SELECT
Definition: nodes.h:267
int assign_special_exec_param(PlannerInfo *root)
Definition: paramassign.c:711
@ CTEMaterializeNever
Definition: parsenodes.h:1649
@ CTEMaterializeDefault
Definition: parsenodes.h:1647
@ UPPERREL_FINAL
Definition: pathnodes.h:79
PlannerInfo * subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root, bool hasRecursion, double tuple_fraction, SetOperationStmt *setops)
Definition: planner.c:643
@ CTE_SUBLINK
Definition: primnodes.h:1021
static SPIPlanPtr splan
Definition: regress.c:268
RelOptInfo * fetch_upper_rel(PlannerInfo *root, UpperRelationKind kind, Relids relids)
Definition: relnode.c:1458
CTEMaterialize ctematerialized
Definition: parsenodes.h:1688
struct Path * cheapest_total_path
Definition: pathnodes.h:929
static bool contain_outer_selfref(Node *node)
Definition: subselect.c:1083
static bool contain_dml(Node *node)
Definition: subselect.c:1056
static void inline_cte(PlannerInfo *root, CommonTableExpr *cte)
Definition: subselect.c:1137

References Assert(), assign_special_exec_param(), RelOptInfo::cheapest_total_path, CMD_SELECT, contain_dml(), contain_outer_selfref(), contain_volatile_functions(), copyObject, cost_subplan(), create_plan(), CTE_SUBLINK, CommonTableExpr::ctematerialized, CTEMaterializeDefault, CTEMaterializeNever, CommonTableExpr::ctename, CommonTableExpr::ctequery, elog, ERROR, fetch_upper_rel(), get_first_col_type(), inline_cte(), lappend(), lappend_int(), lfirst, list_length(), list_make1_int, makeNode, NIL, plan, psprintf(), root, splan, subquery_planner(), and UPPERREL_FINAL.

Referenced by subquery_planner().

◆ SS_process_sublinks()

Node * SS_process_sublinks ( PlannerInfo root,
Node expr,
bool  isQual 
)

Definition at line 1946 of file subselect.c.

1947{
1949
1950 context.root = root;
1951 context.isTopQual = isQual;
1952 return process_sublinks_mutator(expr, &context);
1953}
static Node * process_sublinks_mutator(Node *node, process_sublinks_context *context)
Definition: subselect.c:1956

References process_sublinks_context::isTopQual, process_sublinks_mutator(), process_sublinks_context::root, and root.

Referenced by build_subplan(), and preprocess_expression().

◆ SS_replace_correlation_vars()

Node * SS_replace_correlation_vars ( PlannerInfo root,
Node expr 
)

Definition at line 1891 of file subselect.c.

1892{
1893 /* No setup needed for tree walk, so away we go */
1895}
static Node * replace_correlation_vars_mutator(Node *node, PlannerInfo *root)
Definition: subselect.c:1898

References replace_correlation_vars_mutator(), and root.

Referenced by preprocess_expression().