Files
openGauss-server/src/gausskernel/runtime/executor/nodeSubplan.cpp
2023-03-12 19:16:08 -07:00

1243 lines
48 KiB
C++

/* -------------------------------------------------------------------------
*
* 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 <math.h>
#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);
}