/* ------------------------------------------------------------------------- * * nodeSubplan.cpp * routines to support subselects * * Portions Copyright (c) 2020 Huawei Technologies Co.,Ltd. * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION * src/gausskernel/runtime/executor/nodeSubplan.cpp * * ------------------------------------------------------------------------- * * INTERFACE ROUTINES * ExecSubPlan - process a subselect * ExecInitSubPlan - initialize a subselect */ #include "postgres.h" #include "knl/knl_variable.h" #include #include "miscadmin.h" #include "access/tableam.h" #include "executor/executor.h" #include "executor/node/nodeSubplan.h" #include "nodes/makefuncs.h" #include "optimizer/clauses.h" #include "utils/array.h" #include "utils/lsyscache.h" #include "utils/memutils.h" Datum ExecAlternativeSubPlan(AlternativeSubPlanState* node, ExprContext* econtext, bool* isNull, ExprDoneCond* isDone); static Datum ExecHashSubPlan(SubPlanState* node, ExprContext* econtext, bool* isNull); static Datum ExecScanSubPlan(SubPlanState* node, ExprContext* econtext, bool* isNull); /* ---------------------------------------------------------------- * ExecSubPlan * ---------------------------------------------------------------- */ Datum ExecSubPlan(SubPlanState* node, ExprContext* econtext, bool* isNull, ExprDoneCond* isDone) { SubPlan* sub_plan = (SubPlan*)node->xprstate.expr; EState* estate = node->planstate->state; ScanDirection direction; Datum retval; CHECK_FOR_INTERRUPTS(); /* Set default values for result flags: non-null, not a set result */ *isNull = false; if (isDone != NULL) { *isDone = ExprSingleResult; } /* Sanity checks */ if (sub_plan->subLinkType == CTE_SUBLINK) { ereport(ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_CHECK_VIOLATION), errmsg("CTE subplans should not be executed"))); } if (sub_plan->setParam != NIL) { ereport(ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED), errmsg("cannot set parent params from subquery"))); } /* * When executing a SubPlan in an expression, the EState's direction field was left alone, * resulting in an attempt to execute the subplan backwards if it was encountered during a * backwards scan of a cursor. Under this condition, saving estate->es_direction first. Then * forward scan mode is forcibly set. After the subplan is executed, restore the estate->es_direction. */ direction = estate->es_direction; estate->es_direction = ForwardScanDirection; /* Select appropriate evaluation strategy */ if (sub_plan->useHashTable) { retval = ExecHashSubPlan(node, econtext, isNull); } else { retval = ExecScanSubPlan(node, econtext, isNull); } /* restore the configuration of direction */ estate->es_direction = direction; return retval; } /* * ExecHashSubPlan: store subselect result in an in-memory hash table */ static Datum ExecHashSubPlan(SubPlanState* node, ExprContext* econtext, bool* isNull) { SubPlan* sub_plan = (SubPlan*)node->xprstate.expr; PlanState* plan_state = node->planstate; TupleTableSlot* slot = NULL; /* Shouldn't have any direct correlation Vars */ if (sub_plan->parParam != NIL || node->args != NIL) { ereport(ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED), errmsg("hashed subplan with direct correlation not supported"))); } /* * If first time through or we need to rescan the subplan, build the hash * table. */ if (node->hashtable == NULL || plan_state->chgParam != NULL) { buildSubPlanHash(node, econtext); } /* * The result for an empty subplan is always FALSE; no need to evaluate * lefthand side. */ *isNull = false; if (!node->havehashrows && !node->havenullrows) { return BoolGetDatum(false); } /* * Evaluate lefthand expressions and form a projection tuple. First we * have to set the econtext to use (hack alert!). */ node->projLeft->pi_exprContext = econtext; slot = ExecProject(node->projLeft, NULL); /* * Note: because we are typically called in a per-tuple context, we have * to explicitly clear the projected tuple before returning. Otherwise, * we'll have a double-free situation: the per-tuple context will probably * be reset before we're called again, and then the tuple slot will think * it still needs to free the tuple. */ /* * If the LHS is all non-null, probe for an exact match in the main hash * table. If we find one, the result is TRUE. Otherwise, scan the * partly-null table to see if there are any rows that aren't provably * unequal to the LHS; if so, the result is UNKNOWN. (We skip that part * if we don't care about UNKNOWN.) Otherwise, the result is FALSE. * * Note: the reason we can avoid a full scan of the main hash table is * that the combining operators are assumed never to yield NULL when both * inputs are non-null. If they were to do so, we might need to produce * UNKNOWN instead of FALSE because of an UNKNOWN result in comparing the * LHS to some main-table entry --- which is a comparison we will not even * make, unless there's a chance match of hash keys. */ if (slotNoNulls(slot)) { if (node->havehashrows && FindTupleHashEntry(node->hashtable, slot, node->cur_eq_funcs, node->lhs_hash_funcs) != NULL) { (void)ExecClearTuple(slot); return BoolGetDatum(true); } if (node->havenullrows && findPartialMatch(node->hashnulls, slot, node->cur_eq_funcs)) { (void)ExecClearTuple(slot); *isNull = true; return BoolGetDatum(false); } (void)ExecClearTuple(slot); return BoolGetDatum(false); } /* * When the LHS is partly or wholly NULL, we can never return TRUE. If we * don't care about UNKNOWN, just return FALSE. Otherwise, if the LHS is * wholly NULL, immediately return UNKNOWN. (Since the combining * operators are strict, the result could only be FALSE if the sub-select * were empty, but we already handled that case.) Otherwise, we must scan * both the main and partly-null tables to see if there are any rows that * aren't provably unequal to the LHS; if so, the result is UNKNOWN. * Otherwise, the result is FALSE. */ if (node->hashnulls == NULL) { (void)ExecClearTuple(slot); return BoolGetDatum(false); } if (slotAllNulls(slot)) { (void)ExecClearTuple(slot); *isNull = true; return BoolGetDatum(false); } /* Scan partly-null table first, since more likely to get a match */ if (node->havenullrows && findPartialMatch(node->hashnulls, slot, node->cur_eq_funcs)) { (void)ExecClearTuple(slot); *isNull = true; return BoolGetDatum(false); } if (node->havehashrows && findPartialMatch(node->hashtable, slot, node->cur_eq_funcs)) { (void)ExecClearTuple(slot); *isNull = true; return BoolGetDatum(false); } (void)ExecClearTuple(slot); return BoolGetDatum(false); } /* * ExecScanSubPlan: default case where we have to rescan subplan each time */ static Datum ExecScanSubPlan(SubPlanState* node, ExprContext* econtext, bool* isNull) { SubPlan* sub_plan = (SubPlan*)node->xprstate.expr; PlanState* planstate = node->planstate; SubLinkType sub_link_type = sub_plan->subLinkType; MemoryContext oldcontext = NULL; TupleTableSlot* slot = NULL; Datum result; bool found = false; /* TRUE if got at least one subplan tuple */ ListCell* pvar = NULL; ListCell* l = NULL; ArrayBuildState* astate = NULL; /* * We are probably in a short-lived expression-evaluation context. Switch * to the per-query context for manipulating the child plan's chgParam, * calling ExecProcNode on it, etc. */ oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory); /* * Set Params of this plan from parent plan correlation values. (Any * calculation we have to do is done in the parent econtext, since the * Param values don't need to have per-query lifetime.) */ Assert(list_length(sub_plan->parParam) == list_length(node->args)); forboth(l, sub_plan->parParam, pvar, node->args) { int paramid = lfirst_int(l); ParamExecData* prm = &(econtext->ecxt_param_exec_vals[paramid]); prm->value = ExecEvalExprSwitchContext((ExprState*)lfirst(pvar), econtext, &(prm->isnull), NULL); // // When the correlated subplan is running under vector engine, and upper plan pass the parameters to the // subplan, this parameter is used in vector expression ExecEvalVecParamExec. ExecEvalVecParamExec need build // paramVector for each parameter, and this need the parameter isChanged = true, So it is necessary to set // isChanged = true when parameter is changed. prm->isChanged = true; // this variable is used in vector expression planstate->chgParam = bms_add_member(planstate->chgParam, paramid); } /* * When the correlated subplan is running under vector engine, subplan should skip early free * OrigValue stores the value of the outermost subplan, should also skip early deinit consumer. */ bool orig_early_free = planstate->state->es_skip_early_free; bool orig_early_deinit = planstate->state->es_skip_early_deinit_consumer; planstate->state->es_skip_early_free = true; planstate->state->es_skip_early_deinit_consumer = true; /* * Now that we've set up its parameters, we can reset the subplan. */ ExecReScan(planstate); /* * For all sublink types except EXPR_SUBLINK and ARRAY_SUBLINK, the result * is boolean as are the results of the combining operators. We combine * results across tuples (if the subplan produces more than one) using OR * semantics for ANY_SUBLINK or AND semantics for ALL_SUBLINK. * (ROWCOMPARE_SUBLINK doesn't allow multiple tuples from the subplan.) * NULL results from the combining operators are handled according to the * usual SQL semantics for OR and AND. The result for no input tuples is * FALSE for ANY_SUBLINK, TRUE for ALL_SUBLINK, NULL for * ROWCOMPARE_SUBLINK. * * For EXPR_SUBLINK we require the subplan to produce no more than one * tuple, else an error is raised. If zero tuples are produced, we return * NULL. Assuming we get a tuple, we just use its first column (there can * be only one non-junk column in this case). * * For ARRAY_SUBLINK we allow the subplan to produce any number of tuples, * and form an array of the first column's values. Note in particular * that we produce a zero-element array if no tuples are produced (this is * a change from pre-8.3 behavior of returning NULL). */ result = BoolGetDatum(sub_link_type == ALL_SUBLINK); *isNull = false; for (slot = ExecProcNode(planstate); !TupIsNull(slot); slot = ExecProcNode(planstate)) { TupleDesc tdesc = slot->tts_tupleDescriptor; Datum rowresult; bool rownull = false; int col; ListCell* plst = NULL; /* Get the Table Accessor Method*/ Assert(slot != NULL && slot->tts_tupleDescriptor != NULL); if (sub_link_type == EXISTS_SUBLINK) { found = true; result = BoolGetDatum(true); break; } if (sub_link_type == EXPR_SUBLINK) { /* cannot allow multiple input tuples for EXPR sublink */ if (found) ereport(ERROR, (errmodule(MOD_EXECUTOR), (errcode(ERRCODE_CARDINALITY_VIOLATION), errmsg("more than one row returned by a subquery used as an expression")))); found = true; /* * We need to copy the subplan's tuple in case the result is of * pass-by-ref type --- our return value will point into this * copied tuple! Can't use the subplan's instance of the tuple * since it won't still be valid after next ExecProcNode() call. * node->curTuple keeps track of the copied tuple for eventual * freeing. */ if (node->curTuple) tableam_tops_free_tuple(node->curTuple); node->curTuple = ExecCopySlotTuple(slot); result = tableam_tops_tuple_getattr(node->curTuple, 1, tdesc, isNull); /* keep scanning subplan to make sure there's only one tuple */ continue; } if (sub_link_type == ARRAY_SUBLINK) { Datum dvalue; bool disnull = false; found = true; /* stash away current value */ Assert(sub_plan->firstColType == tdesc->attrs[0].atttypid); dvalue = tableam_tslot_getattr(slot, 1, &disnull); astate = accumArrayResult(astate, dvalue, disnull, sub_plan->firstColType, oldcontext); /* keep scanning subplan to collect all values */ continue; } /* cannot allow multiple input tuples for ROWCOMPARE sublink either */ if (sub_link_type == ROWCOMPARE_SUBLINK && found) ereport(ERROR, (errmodule(MOD_EXECUTOR), (errcode(ERRCODE_CARDINALITY_VIOLATION), errmsg("more than one row returned by a subquery used as an expression")))); found = true; /* * For ALL, ANY, and ROWCOMPARE sublinks, load up the Params * representing the columns of the sub-select, and then evaluate the * combining expression. */ col = 1; foreach (plst, sub_plan->paramIds) { int paramid = lfirst_int(plst); ParamExecData* prmdata = NULL; prmdata = &(econtext->ecxt_param_exec_vals[paramid]); Assert(prmdata->execPlan == NULL); prmdata->value = tableam_tslot_getattr(slot, col, &(prmdata->isnull)); col++; } rowresult = ExecEvalExprSwitchContext(node->testexpr, econtext, &rownull, NULL); if (sub_link_type == ANY_SUBLINK) { /* combine across rows per OR semantics */ if (rownull) *isNull = true; else if (DatumGetBool(rowresult)) { result = BoolGetDatum(true); *isNull = false; break; /* needn't look at any more rows */ } } else if (sub_link_type == ALL_SUBLINK) { /* combine across rows per AND semantics */ if (rownull) *isNull = true; else if (!DatumGetBool(rowresult)) { result = BoolGetDatum(false); *isNull = false; break; /* needn't look at any more rows */ } } else { /* must be ROWCOMPARE_SUBLINK */ result = rowresult; *isNull = rownull; } } MemoryContextSwitchTo(oldcontext); if (sub_link_type == ARRAY_SUBLINK) { /* We return the result in the caller's context */ if (astate != NULL) result = makeArrayResult(astate, oldcontext); else result = PointerGetDatum(construct_empty_array(sub_plan->firstColType)); } else if (!found) { /* * deal with empty subplan result. result/isNull were previously * initialized correctly for all sublink types except EXPR and * ROWCOMPARE; for those, return NULL. */ if (sub_link_type == EXPR_SUBLINK || sub_link_type == ROWCOMPARE_SUBLINK) { result = (Datum)0; *isNull = true; } } planstate->state->es_skip_early_free = orig_early_free; planstate->state->es_skip_early_deinit_consumer = orig_early_deinit; return result; } /* * buildSubPlanHash: load hash table by scanning subplan output. */ void buildSubPlanHash(SubPlanState* node, ExprContext* econtext) { SubPlan* subplan = (SubPlan*)node->xprstate.expr; PlanState* planstate = node->planstate; int ncols = list_length(subplan->paramIds); ExprContext* innerecontext = node->innerecontext; MemoryContext oldcontext = NULL; long nbuckets; TupleTableSlot* slot = NULL; Assert(subplan->subLinkType == ANY_SUBLINK); /* * If we already had any hash tables, destroy 'em; then create empty hash * table(s). * * If we need to distinguish accurately between FALSE and UNKNOWN (i.e., * NULL) results of the IN operation, then we have to store subplan output * rows that are partly or wholly NULL. We store such rows in a separate * hash table that we expect will be much smaller than the main table. (We * can use hashing to eliminate partly-null rows that are not distinct. We * keep them separate to minimize the cost of the inevitable full-table * searches; see findPartialMatch.) * * If it's not necessary to distinguish FALSE and UNKNOWN, then we don't * need to store subplan output rows that contain NULL. */ MemoryContextReset(node->hashtablecxt); node->hashtable = NULL; node->hashnulls = NULL; node->havehashrows = false; node->havenullrows = false; nbuckets = (long)Min(planstate->plan->plan_rows, (double)LONG_MAX); if (nbuckets < 1) { nbuckets = 1; } node->hashtable = BuildTupleHashTable(ncols, node->keyColIdx, node->tab_eq_funcs, node->tab_hash_funcs, nbuckets, sizeof(TupleHashEntryData), node->hashtablecxt, node->hashtempcxt, u_sess->attr.attr_memory.work_mem, node->tab_collations); if (!subplan->unknownEqFalse) { if (ncols == 1) { nbuckets = 1; /* there can only be one entry */ } else { nbuckets /= 16; if (nbuckets < 1) { nbuckets = 1; } } node->hashnulls = BuildTupleHashTable(ncols, node->keyColIdx, node->tab_eq_funcs, node->tab_hash_funcs, nbuckets, sizeof(TupleHashEntryData), node->hashtablecxt, node->hashtempcxt, u_sess->attr.attr_memory.work_mem, node->tab_collations); } /* * We are probably in a short-lived expression-evaluation context. Switch * to the per-query context for manipulating the child plan. */ oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory); /* * Scan the subplan and load the hash table(s). Note that when there are * duplicate rows coming out of the sub-select, only one copy is stored. */ bool orig_early_free = planstate->state->es_skip_early_free; planstate->state->es_skip_early_free = true; /* * Reset subplan to start. */ ExecReScan(planstate); for (slot = ExecProcNode(planstate); !TupIsNull(slot); slot = ExecProcNode(planstate)) { int col = 1; ListCell* plst = NULL; bool isnew = false; /* Get the Table Accessor Method*/ Assert(slot->tts_tupleDescriptor != NULL); /* * Load up the Params representing the raw sub-select outputs, then * form the projection tuple to store in the hashtable. */ foreach (plst, subplan->paramIds) { int paramid = lfirst_int(plst); ParamExecData* prmdata = &(innerecontext->ecxt_param_exec_vals[paramid]); Assert(prmdata->execPlan == NULL); prmdata->value = tableam_tslot_getattr(slot, col, &(prmdata->isnull)); col++; } slot = ExecProject(node->projRight, NULL); /* * If result contains any nulls, store separately or not at all. */ if (slotNoNulls(slot)) { (void)LookupTupleHashEntry(node->hashtable, slot, &isnew); node->havehashrows = true; } else if (node->hashnulls) { (void)LookupTupleHashEntry(node->hashnulls, slot, &isnew); node->havenullrows = true; } /* * Reset innerecontext after each inner tuple to free any memory used * during ExecProject. */ ResetExprContext(innerecontext); } planstate->state->es_skip_early_free = orig_early_free; /* * Since the projected tuples are in the sub-query's context and not the * main context, we'd better clear the tuple slot before there's any * chance of a reset of the sub-query's context. Else we will have the * potential for a double free attempt. (XXX possibly no longer needed, * but can't hurt.) */ if (node->projRight->pi_state.is_flt_frame) { (void)ExecClearTuple(node->projRight->pi_state.resultslot); } else { (void)ExecClearTuple(node->projRight->pi_slot); } MemoryContextSwitchTo(oldcontext); } /* * findPartialMatch: does the hashtable contain an entry that is not * provably distinct from the tuple? * * We have to scan the whole hashtable; we can't usefully use hashkeys * to guide probing, since we might get partial matches on tuples with * hashkeys quite unrelated to what we'd get from the given tuple. * * Caller must provide the equality functions to use, since in cross-type * cases these are different from the hashtable's internal functions. */ bool findPartialMatch(TupleHashTable hashtable, TupleTableSlot* slot, FmgrInfo* eqfunctions) { int num_cols = hashtable->numCols; AttrNumber* key_col_idx = hashtable->keyColIdx; TupleHashIterator hashiter; TupleHashEntry entry; InitTupleHashIterator(hashtable, &hashiter); while ((entry = ScanTupleHashTable(&hashiter)) != NULL) { CHECK_FOR_INTERRUPTS(); ExecStoreMinimalTuple(entry->firstTuple, hashtable->tableslot, false); if (!execTuplesUnequal(slot, hashtable->tableslot, num_cols, key_col_idx, eqfunctions, hashtable->tempcxt, hashtable->tab_collations)) { TermTupleHashIterator(&hashiter); return true; } } /* No TermTupleHashIterator call needed here */ return false; } /* * slotAllNulls: is the slot completely NULL? * * This does not test for dropped columns, which is OK because we only * use it on projected tuples. */ bool slotAllNulls(TupleTableSlot* slot) { /* Get the Table Accessor Method*/ Assert(slot != NULL && slot->tts_tupleDescriptor != NULL); int ncols = slot->tts_tupleDescriptor->natts; int i; for (i = 1; i <= ncols; i++) { if (!tableam_tslot_attisnull(slot, i)) return false; } return true; } /* * slotNoNulls: is the slot entirely not NULL? * * This does not test for dropped columns, which is OK because we only * use it on projected tuples. */ bool slotNoNulls(TupleTableSlot* slot) { /* Get the Table Accessor Method*/ Assert(slot != NULL && slot->tts_tupleDescriptor != NULL); int ncols = slot->tts_tupleDescriptor->natts; int i; for (i = 1; i <= ncols; i++) { if (tableam_tslot_attisnull(slot, i)) return false; } return true; } /* ---------------------------------------------------------------- * ExecInitSubPlan * * Create a SubPlanState for a SubPlan; this is the SubPlan-specific part * of ExecInitExpr(). We split it out so that it can be used for InitPlans * as well as regular SubPlans. Note that we don't link the SubPlan into * the parent's subPlan list, because that shouldn't happen for InitPlans. * Instead, ExecInitExpr() does that one part. * ---------------------------------------------------------------- */ SubPlanState* ExecInitSubPlan(SubPlan* subplan, PlanState* parent) { SubPlanState* sstate = makeNode(SubPlanState); EState* estate = parent->state; sstate->xprstate.evalfunc = (ExprStateEvalFunc)ExecSubPlan; sstate->xprstate.expr = (Expr*)subplan; sstate->xprstate.is_flt_frame = estate->es_is_flt_frame; /* Link the SubPlanState to already-initialized subplan */ sstate->planstate = (PlanState*)list_nth(estate->es_subplanstates, subplan->plan_id - 1); /* Initialize subexpressions */ sstate->testexpr = ExecInitExpr((Expr*)subplan->testexpr, parent); sstate->args = ExecInitExprList(subplan->args, parent); /* * initialize my state */ sstate->curTuple = NULL; sstate->curArray = PointerGetDatum(NULL); sstate->projLeft = NULL; sstate->projRight = NULL; sstate->hashtable = NULL; sstate->hashnulls = NULL; sstate->hashtablecxt = NULL; sstate->hashtempcxt = NULL; sstate->innerecontext = NULL; sstate->keyColIdx = NULL; sstate->tab_hash_funcs = NULL; sstate->tab_eq_funcs = NULL; sstate->lhs_hash_funcs = NULL; sstate->cur_eq_funcs = NULL; /* * If this plan is un-correlated or undirect correlated one and want to * set params for parent plan then mark parameters as needing evaluation. * * A CTE subplan's output parameter is never to be evaluated in the normal * way, so skip this in that case. * * Note that in the case of un-correlated subqueries we don't care about * setting parent->chgParam here: indices take care about it, for others - * it doesn't matter... */ if (subplan->setParam != NIL && subplan->subLinkType != CTE_SUBLINK) { ListCell* lst = NULL; foreach (lst, subplan->setParam) { int paramid = lfirst_int(lst); ParamExecData* prm = &(estate->es_param_exec_vals[paramid]); prm->execPlan = sstate; } } /* * If we are going to hash the subquery output, initialize relevant stuff. * (We don't create the hashtable until needed, though.) */ if (subplan->useHashTable) { int ncols = 0; int i = 0; TupleDesc tup_desc = NULL; TupleTableSlot* slot = NULL; List* oplist = NIL; List* lefttlist = NIL; List* righttlist = NIL; List* leftptlist = NIL; List* rightptlist = NIL; ListCell* l = NULL; /* We need a memory context to hold the hash table(s) */ sstate->hashtablecxt = AllocSetContextCreate(CurrentMemoryContext, "Subplan HashTable Context", ALLOCSET_DEFAULT_MINSIZE, ALLOCSET_DEFAULT_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE); /* and a small one for the hash tables to use as temp storage */ sstate->hashtempcxt = AllocSetContextCreate(CurrentMemoryContext, "Subplan HashTable Temp Context", ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_SMALL_MAXSIZE); /* and a short-lived exprcontext for function evaluation */ sstate->innerecontext = CreateExprContext(estate); /* Silly little array of column numbers 1..n */ ncols = list_length(subplan->paramIds); sstate->keyColIdx = (AttrNumber*)palloc(ncols * sizeof(AttrNumber)); for (i = 0; i < ncols; i++) sstate->keyColIdx[i] = i + 1; /* * We use ExecProject to evaluate the lefthand and righthand * expression lists and form tuples. (You might think that we could * use the sub-select's output tuples directly, but that is not the * case if we had to insert any run-time coercions of the sub-select's * output datatypes; anyway this avoids storing any resjunk columns * that might be in the sub-select's output.) Run through the * combining expressions to build tlists for the lefthand and * righthand sides. We need both the ExprState list (for ExecProject) * and the underlying parse Exprs (for ExecTypeFromTL). * * We also extract the combining operators themselves to initialize * the equality and hashing functions for the hash tables. */ if (estate->es_is_flt_frame) { if (IsA(subplan->testexpr, OpExpr)) { /* single combining operator */ oplist = list_make1(subplan->testexpr); } else if (and_clause((Node *) subplan->testexpr)) { /* multiple combining operators */ Assert(IsA(subplan->testexpr, BoolExpr)); oplist = castNode(BoolExpr, subplan->testexpr)->args; } else { /* shouldn't see anything else in a hashable subplan */ ereport(ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE), errmsg("unrecognized testexpr type: %d in a hash subplan", (int)nodeTag(subplan->testexpr)))); oplist = NIL; /* keep compiler quiet */ } Assert(list_length(oplist) == ncols); lefttlist = righttlist = NIL; sstate->tab_hash_funcs = (FmgrInfo*)palloc(ncols * sizeof(FmgrInfo)); sstate->tab_eq_funcs = (FmgrInfo*)palloc(ncols * sizeof(FmgrInfo)); sstate->lhs_hash_funcs = (FmgrInfo*)palloc(ncols * sizeof(FmgrInfo)); sstate->cur_eq_funcs = (FmgrInfo*)palloc(ncols * sizeof(FmgrInfo)); i = 1; foreach (l, oplist) { OpExpr* opexpr = (OpExpr*)lfirst(l); Oid rhs_eq_oper; Oid left_hashfn; Oid right_hashfn; Assert(IsA(opexpr, OpExpr)); Assert(list_length(opexpr->args) == 2); /* Process lefthand argument */ Expr* expr = (Expr *) linitial(opexpr->args); TargetEntry* tle = makeTargetEntry(expr, i, NULL, false); lefttlist = lappend(lefttlist, tle); /* Process righthand argument */ expr = (Expr *) lsecond(opexpr->args); tle = makeTargetEntry(expr, i, NULL, false); righttlist = lappend(righttlist, tle); /* Lookup the equality function (potentially cross-type) */ fmgr_info(opexpr->opfuncid, &sstate->cur_eq_funcs[i - 1]); fmgr_info_set_expr((Node*)opexpr, &sstate->cur_eq_funcs[i - 1]); /* Look up the equality function for the RHS type */ if (!get_compatible_hash_operators(opexpr->opno, NULL, &rhs_eq_oper)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("could not find compatible hash operator for operator %u for subplan", opexpr->opno))); fmgr_info(get_opcode(rhs_eq_oper), &sstate->tab_eq_funcs[i - 1]); /* Lookup the associated hash functions */ if (!get_op_hash_functions(opexpr->opno, &left_hashfn, &right_hashfn)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("could not find hash function for hash operator %u for subplan", opexpr->opno))); fmgr_info(left_hashfn, &sstate->lhs_hash_funcs[i - 1]); fmgr_info(right_hashfn, &sstate->tab_hash_funcs[i - 1]); i++; } /* * Construct tupdescs, slots and projection nodes for left and right * sides. The lefthand expressions will be evaluated in the parent * plan node's exprcontext, which we don't have access to here. * Fortunately we can just pass NULL for now and fill it in later * (hack alert!). The righthand expressions will be evaluated in our * own innerecontext. */ // slot contains virtual tuple, so set the default tableAm type to HEAP tup_desc = ExecTypeFromTL(lefttlist, false, false); slot = ExecInitExtraTupleSlot(estate); ExecSetSlotDescriptor(slot, tup_desc); sstate->projLeft = ExecBuildProjectionInfo(lefttlist, NULL, slot, parent, NULL); // slot contains virtual tuple, so set the default tableAm type to HEAP tup_desc = ExecTypeFromTL(righttlist, false, false); slot = ExecInitExtraTupleSlot(estate); ExecSetSlotDescriptor(slot, tup_desc); sstate->projRight = ExecBuildProjectionInfo(righttlist, sstate->innerecontext, slot, sstate->planstate, NULL); } else { if (IsA(sstate->testexpr->expr, OpExpr)) { /* single combining operator */ oplist = list_make1(sstate->testexpr); } else if (and_clause((Node*)sstate->testexpr->expr)) { /* multiple combining operators */ Assert(IsA(sstate->testexpr, BoolExprState)); oplist = ((BoolExprState*)sstate->testexpr)->args; } else { /* shouldn't see anything else in a hashable subplan */ ereport(ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE), errmsg("unrecognized testexpr type: %d in a hash subplan", (int)nodeTag(sstate->testexpr->expr)))); oplist = NIL; /* keep compiler quiet */ } Assert(list_length(oplist) == ncols); lefttlist = righttlist = NIL; leftptlist = rightptlist = NIL; sstate->tab_hash_funcs = (FmgrInfo*)palloc(ncols * sizeof(FmgrInfo)); sstate->tab_eq_funcs = (FmgrInfo*)palloc(ncols * sizeof(FmgrInfo)); sstate->lhs_hash_funcs = (FmgrInfo*)palloc(ncols * sizeof(FmgrInfo)); sstate->cur_eq_funcs = (FmgrInfo*)palloc(ncols * sizeof(FmgrInfo)); i = 1; foreach (l, oplist) { FuncExprState* fstate = (FuncExprState*)lfirst(l); OpExpr* opexpr = (OpExpr*)fstate->xprstate.expr; Oid rhs_eq_oper; Oid left_hashfn; Oid right_hashfn; Assert(IsA(fstate, FuncExprState)); Assert(IsA(opexpr, OpExpr)); Assert(list_length(fstate->args) == 2); /* Process lefthand argument */ ExprState* exstate = (ExprState*)linitial(fstate->args); Expr* expr = exstate->expr; TargetEntry* tle = makeTargetEntry(expr, i, NULL, false); GenericExprState* tlestate = makeNode(GenericExprState); tlestate->xprstate.expr = (Expr*)tle; tlestate->xprstate.evalfunc = NULL; tlestate->arg = exstate; lefttlist = lappend(lefttlist, tlestate); leftptlist = lappend(leftptlist, tle); /* Process righthand argument */ exstate = (ExprState*)lsecond(fstate->args); expr = exstate->expr; tle = makeTargetEntry(expr, i, NULL, false); tlestate = makeNode(GenericExprState); tlestate->xprstate.expr = (Expr*)tle; tlestate->xprstate.evalfunc = NULL; tlestate->arg = exstate; righttlist = lappend(righttlist, tlestate); rightptlist = lappend(rightptlist, tle); /* Lookup the equality function (potentially cross-type) */ fmgr_info(opexpr->opfuncid, &sstate->cur_eq_funcs[i - 1]); fmgr_info_set_expr((Node*)opexpr, &sstate->cur_eq_funcs[i - 1]); /* Look up the equality function for the RHS type */ if (!get_compatible_hash_operators(opexpr->opno, NULL, &rhs_eq_oper)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("could not find compatible hash operator for operator %u for subplan", opexpr->opno))); fmgr_info(get_opcode(rhs_eq_oper), &sstate->tab_eq_funcs[i - 1]); /* Lookup the associated hash functions */ if (!get_op_hash_functions(opexpr->opno, &left_hashfn, &right_hashfn)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("could not find hash function for hash operator %u for subplan", opexpr->opno))); fmgr_info(left_hashfn, &sstate->lhs_hash_funcs[i - 1]); fmgr_info(right_hashfn, &sstate->tab_hash_funcs[i - 1]); i++; } /* * Construct tupdescs, slots and projection nodes for left and right * sides. The lefthand expressions will be evaluated in the parent * plan node's exprcontext, which we don't have access to here. * Fortunately we can just pass NULL for now and fill it in later * (hack alert!). The righthand expressions will be evaluated in our * own innerecontext. */ // slot contains virtual tuple, so set the default tableAm type to HEAP tup_desc = ExecTypeFromTL(leftptlist, false, false, TableAmHeap); slot = ExecInitExtraTupleSlot(estate); ExecSetSlotDescriptor(slot, tup_desc); sstate->projLeft = ExecBuildProjectionInfoByRecursion(lefttlist, NULL, slot, NULL); // slot contains virtual tuple, so set the default tableAm type to HEAP tup_desc = ExecTypeFromTL(rightptlist, false, false, TableAmHeap); slot = ExecInitExtraTupleSlot(estate); ExecSetSlotDescriptor(slot, tup_desc); sstate->projRight = ExecBuildProjectionInfoByRecursion(righttlist, sstate->innerecontext, slot, NULL); } } return sstate; } /* ---------------------------------------------------------------- * ExecSetParamPlan * * Executes an InitPlan subplan and sets its output parameters. * * This is called from ExecEvalParamExec() when the value of a PARAM_EXEC * parameter is requested and the param's execPlan field is set (indicating * that the param has not yet been evaluated). This allows lazy evaluation * of initplans: we don't run the subplan until/unless we need its output. * Note that this routine MUST clear the execPlan fields of the plan's * output parameters after evaluating them! * ---------------------------------------------------------------- */ void ExecSetParamPlan(SubPlanState* node, ExprContext* econtext) { SubPlan* subplan = (SubPlan*)node->xprstate.expr; PlanState* planstate = node->planstate; SubLinkType sub_link_type = subplan->subLinkType; EState* estate = planstate->state; ScanDirection direction = estate->es_direction; TupleTableSlot* slot = NULL; ListCell* l = NULL; bool found = false; ArrayBuildState* astate = NULL; if (sub_link_type == ANY_SUBLINK || sub_link_type == ALL_SUBLINK) ereport(ERROR, (errmodule(MOD_EXECUTOR), errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("ANY/ALL subselect unsupported as initplan"))); if (sub_link_type == CTE_SUBLINK) ereport(ERROR, (errmodule(MOD_EXECUTOR), errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("CTE subplans should not be executed when execute subplan"))); /* * When executing a SubPlan in an expression, the EState's direction field was left alone, * resulting in an attempt to execute the subplan backwards if it was encountered during a * backwards scan of a cursor. Under this condition, saving estate->es_direction first. Then * forward scan mode is forcibly set. After the subplan is executed, restore the estate->es_direction. */ estate->es_direction = ForwardScanDirection; /* * Must switch to per-query memory context. */ MemoryContext oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory); /* * Run the plan. (If it needs to be rescanned, the first ExecProcNode * call will take care of that.) */ for (slot = ExecProcNode(planstate); !TupIsNull(slot); slot = ExecProcNode(planstate)) { TupleDesc tdesc = slot->tts_tupleDescriptor; /* Get the Table Accessor Method*/ Assert(slot->tts_tupleDescriptor != NULL); int i = 1; if (sub_link_type == EXISTS_SUBLINK) { /* There can be only one setParam... */ int paramid = linitial_int(subplan->setParam); ParamExecData* prm = &(econtext->ecxt_param_exec_vals[paramid]); prm->execPlan = NULL; prm->value = BoolGetDatum(true); prm->isnull = false; found = true; break; } if (sub_link_type == ARRAY_SUBLINK) { Datum dvalue; bool disnull = false; found = true; /* stash away current value */ Assert(subplan->firstColType == tdesc->attrs[0].atttypid); dvalue = tableam_tslot_getattr(slot, 1, &disnull); astate = accumArrayResult(astate, dvalue, disnull, subplan->firstColType, oldcontext); /* keep scanning subplan to collect all values */ continue; } if (found && (sub_link_type == EXPR_SUBLINK || sub_link_type == ROWCOMPARE_SUBLINK)) ereport(ERROR, (errcode(ERRCODE_CARDINALITY_VIOLATION), errmsg("more than one row returned by a subquery used as an expression"))); found = true; /* * We need to copy the subplan's tuple into our own context, in case * any of the params are pass-by-ref type --- the pointers stored in * the param structs will point at this copied tuple! node->curTuple * keeps track of the copied tuple for eventual freeing. */ if (node->curTuple) tableam_tops_free_tuple(node->curTuple); node->curTuple = ExecCopySlotTuple(slot); /* * Now set all the setParam params from the columns of the tuple */ foreach (l, subplan->setParam) { int paramid = lfirst_int(l); ParamExecData* prm = &(econtext->ecxt_param_exec_vals[paramid]); prm->execPlan = NULL; prm->value = tableam_tops_tuple_getattr(node->curTuple, i, tdesc, &(prm->isnull)); i++; } } if (sub_link_type == ARRAY_SUBLINK) { /* There can be only one setParam... */ int paramid = linitial_int(subplan->setParam); ParamExecData* prm = &(econtext->ecxt_param_exec_vals[paramid]); /* * We build the result array in query context so it won't disappear; * to avoid leaking memory across repeated calls, we have to remember * the latest value, much as for curTuple above. */ if (node->curArray != PointerGetDatum(NULL)) pfree(DatumGetPointer(node->curArray)); if (astate != NULL) node->curArray = makeArrayResult(astate, econtext->ecxt_per_query_memory); else { MemoryContextSwitchTo(econtext->ecxt_per_query_memory); node->curArray = PointerGetDatum(construct_empty_array(subplan->firstColType)); } prm->execPlan = NULL; prm->value = node->curArray; prm->isnull = false; } else if (!found) { if (sub_link_type == EXISTS_SUBLINK) { /* There can be only one setParam... */ int paramid = linitial_int(subplan->setParam); ParamExecData* prm = &(econtext->ecxt_param_exec_vals[paramid]); prm->execPlan = NULL; prm->value = BoolGetDatum(false); prm->isnull = false; } else { foreach (l, subplan->setParam) { int paramid = lfirst_int(l); ParamExecData* prm = &(econtext->ecxt_param_exec_vals[paramid]); prm->execPlan = NULL; prm->value = (Datum)0; prm->isnull = true; } } } MemoryContextSwitchTo(oldcontext); /* restore the configuration of direction */ estate->es_direction = direction; } /* * Mark an initplan as needing recalculation */ void ExecReScanSetParamPlan(SubPlanState* node, PlanState* parent) { PlanState* planstate = node->planstate; SubPlan* subplan = (SubPlan*)node->xprstate.expr; EState* estate = parent->state; ListCell* l = NULL; /* sanity checks */ if (subplan->parParam != NIL) ereport(ERROR, (errmodule(MOD_EXECUTOR), errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("direct correlated subquery unsupported as initplan"))); if (subplan->setParam == NIL) ereport(ERROR, (errmodule(MOD_EXECUTOR), errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("setParam list of initplan is empty"))); if (bms_is_empty(planstate->plan->extParam)) ereport(ERROR, (errmodule(MOD_EXECUTOR), errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("extParam set of initplan is empty"))); /* * Don't actually re-scan: it'll happen inside ExecSetParamPlan if needed. */ /* * Mark this subplan's output parameters as needing recalculation. * * CTE subplans are never executed via parameter recalculation; instead * they get run when called by nodeCtescan.c. So don't mark the output * parameter of a CTE subplan as dirty, but do set the chgParam bit for it * so that dependent plan nodes will get told to rescan. */ foreach (l, subplan->setParam) { int paramid = lfirst_int(l); ParamExecData* prm = &(estate->es_param_exec_vals[paramid]); if (subplan->subLinkType != CTE_SUBLINK) prm->execPlan = node; parent->chgParam = bms_add_member(parent->chgParam, paramid); } } /* * ExecInitAlternativeSubPlan * * Initialize for execution of one of a set of alternative subplans. */ AlternativeSubPlanState* ExecInitAlternativeSubPlan(AlternativeSubPlan* asplan, PlanState* parent) { AlternativeSubPlanState* asstate = makeNode(AlternativeSubPlanState); double num_calls; SubPlan* subplan1 = NULL; SubPlan* subplan2 = NULL; Cost cost1; Cost cost2; if (parent->state->es_is_flt_frame) { ListCell *lc; asstate->xprstate.expr = (Expr *)asplan; asstate->xprstate.is_flt_frame = true; /* * Initialize subplans. (Can we get away with only initializing the one * we're going to use?) */ foreach (lc, asplan->subplans) { SubPlan *sp = castNode(SubPlan, lfirst(lc)); SubPlanState *sps = ExecInitSubPlan(sp, parent); asstate->subplans = lappend(asstate->subplans, sps); parent->subPlan = lappend(parent->subPlan, sps); } } else { asstate->xprstate.evalfunc = (ExprStateEvalFunc)ExecAlternativeSubPlan; asstate->xprstate.expr = (Expr *)asplan; asstate->xprstate.is_flt_frame = false; /* * Initialize subplans. (Can we get away with only initializing the one * we're going to use?) */ asstate->subplans = (List *)ExecInitExprByRecursion((Expr *)asplan->subplans, parent); } /* * Select the one to be used. For this, we need an estimate of the number * of executions of the subplan. We use the number of output rows * expected from the parent plan node. This is a good estimate if we are * in the parent's targetlist, and an underestimate (but probably not by * more than a factor of 2) if we are in the qual. */ num_calls = parent->plan->plan_rows; /* * The planner saved enough info so that we don't have to work very hard * to estimate the total cost, given the number-of-calls estimate. */ Assert(list_length(asplan->subplans) == 2); subplan1 = (SubPlan*)linitial(asplan->subplans); subplan2 = (SubPlan*)lsecond(asplan->subplans); cost1 = subplan1->startup_cost + num_calls * subplan1->per_call_cost; cost2 = subplan2->startup_cost + num_calls * subplan2->per_call_cost; if (cost1 < cost2) asstate->active = 0; else asstate->active = 1; return asstate; } /* * ExecAlternativeSubPlan * * Execute one of a set of alternative subplans. * * Note: in future we might consider changing to different subplans on the * fly, in case the original rowcount estimate turns out to be way off. */ Datum ExecAlternativeSubPlan( AlternativeSubPlanState* node, ExprContext* econtext, bool* isNull, ExprDoneCond* isDone) { /* Just pass control to the active subplan */ SubPlanState* activesp = (SubPlanState*)list_nth(node->subplans, node->active); Assert(IsA(activesp, SubPlanState)); return ExecSubPlan(activesp, econtext, isNull, isDone); }