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postgresql/src/backend/executor/execQual.c

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/*-------------------------------------------------------------------------
*
* execQual.c
* Routines to evaluate qualification and targetlist expressions
*
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/executor/execQual.c
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* ExecEvalExpr - (now a macro) evaluate an expression, return a datum
* ExecEvalExprSwitchContext - same, but switch into eval memory context
* ExecQual - return true/false if qualification is satisfied
* ExecProject - form a new tuple by projecting the given tuple
*
* NOTES
* The more heavily used ExecEvalExpr routines, such as ExecEvalScalarVar,
* are hotspots. Making these faster will speed up the entire system.
*
* ExecProject() is used to make tuple projections. Rather then
* trying to speed it up, the execution plan should be pre-processed
* to facilitate attribute sharing between nodes wherever possible,
* instead of doing needless copying. -cim 5/31/91
*
* During expression evaluation, we check_stack_depth only in
* ExecMakeFunctionResultSet/ExecMakeFunctionResultNoSets rather than at
* every single node. This is a compromise that trades off precision of
* the stack limit setting to gain speed.
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "access/nbtree.h"
#include "access/tupconvert.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_type.h"
#include "executor/execdebug.h"
#include "executor/nodeSubplan.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/planner.h"
#include "parser/parse_coerce.h"
#include "parser/parsetree.h"
#include "pgstat.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/date.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/timestamp.h"
#include "utils/typcache.h"
#include "utils/xml.h"
/* static function decls */
static Datum ExecEvalArrayRef(ArrayRefExprState *astate,
ExprContext *econtext,
bool *isNull);
static bool isAssignmentIndirectionExpr(ExprState *exprstate);
static Datum ExecEvalAggref(AggrefExprState *aggref,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalWindowFunc(WindowFuncExprState *wfunc,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalScalarVar(ExprState *exprstate, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalScalarVarFast(ExprState *exprstate, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalWholeRowVar(WholeRowVarExprState *wrvstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalWholeRowFast(WholeRowVarExprState *wrvstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalWholeRowSlow(WholeRowVarExprState *wrvstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalConst(ExprState *exprstate, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalParamExec(ExprState *exprstate, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalParamExtern(ExprState *exprstate, ExprContext *econtext,
bool *isNull);
static void init_fcache(Oid foid, Oid input_collation, FuncExprState *fcache,
MemoryContext fcacheCxt, bool allowSRF, bool needDescForSRF);
static void ShutdownFuncExpr(Datum arg);
static TupleDesc get_cached_rowtype(Oid type_id, int32 typmod,
TupleDesc *cache_field, ExprContext *econtext);
static void ShutdownTupleDescRef(Datum arg);
static void ExecEvalFuncArgs(FunctionCallInfo fcinfo,
List *argList, ExprContext *econtext);
static void ExecPrepareTuplestoreResult(FuncExprState *fcache,
ExprContext *econtext,
Tuplestorestate *resultStore,
TupleDesc resultDesc);
static void tupledesc_match(TupleDesc dst_tupdesc, TupleDesc src_tupdesc);
static Datum ExecMakeFunctionResultNoSets(FuncExprState *fcache,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalFunc(FuncExprState *fcache, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalOper(FuncExprState *fcache, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalDistinct(FuncExprState *fcache, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalScalarArrayOp(ScalarArrayOpExprState *sstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalNot(BoolExprState *notclause, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalOr(BoolExprState *orExpr, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalAnd(BoolExprState *andExpr, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalConvertRowtype(ConvertRowtypeExprState *cstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalCase(CaseExprState *caseExpr, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalCaseTestExpr(ExprState *exprstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalArray(ArrayExprState *astate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalRow(RowExprState *rstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalRowCompare(RowCompareExprState *rstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalCoalesce(CoalesceExprState *coalesceExpr,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalMinMax(MinMaxExprState *minmaxExpr,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalSQLValueFunction(ExprState *svfExpr,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalXml(XmlExprState *xmlExpr, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalNullIf(FuncExprState *nullIfExpr,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalNullTest(NullTestState *nstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalBooleanTest(GenericExprState *bstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalCoerceToDomain(CoerceToDomainState *cstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalCoerceToDomainValue(ExprState *exprstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalFieldSelect(FieldSelectState *fstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalFieldStore(FieldStoreState *fstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalRelabelType(GenericExprState *exprstate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalCoerceViaIO(CoerceViaIOState *iostate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalArrayCoerceExpr(ArrayCoerceExprState *astate,
ExprContext *econtext,
bool *isNull);
static Datum ExecEvalCurrentOfExpr(ExprState *exprstate, ExprContext *econtext,
bool *isNull);
static Datum ExecEvalGroupingFuncExpr(GroupingFuncExprState *gstate,
ExprContext *econtext,
bool *isNull);
/* ----------------------------------------------------------------
* ExecEvalExpr routines
*
* Recursively evaluate a targetlist or qualification expression.
*
* Each of the following routines having the signature
* Datum ExecEvalFoo(ExprState *expression,
* ExprContext *econtext,
* bool *isNull);
* is responsible for evaluating one type or subtype of ExprState node.
* They are normally called via the ExecEvalExpr macro, which makes use of
* the function pointer set up when the ExprState node was built by
* ExecInitExpr. (In some cases, we change this pointer later to avoid
* re-executing one-time overhead.)
*
* Note: for notational simplicity we declare these functions as taking the
* specific type of ExprState that they work on. This requires casting when
* assigning the function pointer in ExecInitExpr. Be careful that the
* function signature is declared correctly, because the cast suppresses
* automatic checking!
*
*
* All these functions share this calling convention:
*
* Inputs:
* expression: the expression state tree to evaluate
* econtext: evaluation context information
*
* Outputs:
* return value: Datum value of result
* *isNull: set to TRUE if result is NULL (actual return value is
* meaningless if so); set to FALSE if non-null result
*
* The caller should already have switched into the temporary memory
* context econtext->ecxt_per_tuple_memory. The convenience entry point
* ExecEvalExprSwitchContext() is provided for callers who don't prefer to
* do the switch in an outer loop. We do not do the switch in these routines
* because it'd be a waste of cycles during nested expression evaluation.
* ----------------------------------------------------------------
*/
/*----------
* ExecEvalArrayRef
*
* This function takes an ArrayRef and returns the extracted Datum
* if it's a simple reference, or the modified array value if it's
* an array assignment (i.e., array element or slice insertion).
*
* NOTE: if we get a NULL result from a subscript expression, we return NULL
* when it's an array reference, or raise an error when it's an assignment.
*----------
*/
static Datum
ExecEvalArrayRef(ArrayRefExprState *astate,
ExprContext *econtext,
bool *isNull)
{
ArrayRef *arrayRef = (ArrayRef *) astate->xprstate.expr;
Datum array_source;
bool isAssignment = (arrayRef->refassgnexpr != NULL);
bool eisnull;
ListCell *l;
int i = 0,
j = 0;
IntArray upper,
lower;
bool upperProvided[MAXDIM],
lowerProvided[MAXDIM];
int *lIndex;
array_source = ExecEvalExpr(astate->refexpr,
econtext,
isNull);
/*
* If refexpr yields NULL, and it's a fetch, then result is NULL. In the
* assignment case, we'll cons up something below.
*/
if (*isNull)
{
if (!isAssignment)
return (Datum) NULL;
}
foreach(l, astate->refupperindexpr)
{
ExprState *eltstate = (ExprState *) lfirst(l);
if (i >= MAXDIM)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("number of array dimensions (%d) exceeds the maximum allowed (%d)",
i + 1, MAXDIM)));
if (eltstate == NULL)
{
/* Slice bound is omitted, so use array's upper bound */
Assert(astate->reflowerindexpr != NIL);
upperProvided[i++] = false;
continue;
}
upperProvided[i] = true;
upper.indx[i++] = DatumGetInt32(ExecEvalExpr(eltstate,
econtext,
&eisnull));
/* If any index expr yields NULL, result is NULL or error */
if (eisnull)
{
if (isAssignment)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("array subscript in assignment must not be null")));
*isNull = true;
return (Datum) NULL;
}
}
if (astate->reflowerindexpr != NIL)
{
foreach(l, astate->reflowerindexpr)
{
ExprState *eltstate = (ExprState *) lfirst(l);
if (j >= MAXDIM)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("number of array dimensions (%d) exceeds the maximum allowed (%d)",
j + 1, MAXDIM)));
if (eltstate == NULL)
{
/* Slice bound is omitted, so use array's lower bound */
lowerProvided[j++] = false;
continue;
}
lowerProvided[j] = true;
lower.indx[j++] = DatumGetInt32(ExecEvalExpr(eltstate,
econtext,
&eisnull));
/* If any index expr yields NULL, result is NULL or error */
if (eisnull)
{
if (isAssignment)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("array subscript in assignment must not be null")));
*isNull = true;
return (Datum) NULL;
}
}
/* this can't happen unless parser messed up */
if (i != j)
elog(ERROR, "upper and lower index lists are not same length");
lIndex = lower.indx;
}
else
lIndex = NULL;
if (isAssignment)
{
Datum sourceData;
Datum save_datum;
bool save_isNull;
/*
* We might have a nested-assignment situation, in which the
* refassgnexpr is itself a FieldStore or ArrayRef that needs to
* obtain and modify the previous value of the array element or slice
* being replaced. If so, we have to extract that value from the
* array and pass it down via the econtext's caseValue. It's safe to
* reuse the CASE mechanism because there cannot be a CASE between
* here and where the value would be needed, and an array assignment
* can't be within a CASE either. (So saving and restoring the
* caseValue is just paranoia, but let's do it anyway.)
*
* Since fetching the old element might be a nontrivial expense, do it
* only if the argument appears to actually need it.
*/
save_datum = econtext->caseValue_datum;
save_isNull = econtext->caseValue_isNull;
if (isAssignmentIndirectionExpr(astate->refassgnexpr))
{
if (*isNull)
{
/* whole array is null, so any element or slice is too */
econtext->caseValue_datum = (Datum) 0;
econtext->caseValue_isNull = true;
}
else if (lIndex == NULL)
{
econtext->caseValue_datum =
array_get_element(array_source, i,
upper.indx,
astate->refattrlength,
astate->refelemlength,
astate->refelembyval,
astate->refelemalign,
&econtext->caseValue_isNull);
}
else
{
/* this is currently unreachable */
econtext->caseValue_datum =
array_get_slice(array_source, i,
upper.indx, lower.indx,
upperProvided, lowerProvided,
astate->refattrlength,
astate->refelemlength,
astate->refelembyval,
astate->refelemalign);
econtext->caseValue_isNull = false;
}
}
else
{
/* argument shouldn't need caseValue, but for safety set it null */
econtext->caseValue_datum = (Datum) 0;
econtext->caseValue_isNull = true;
}
/*
* Evaluate the value to be assigned into the array.
*/
sourceData = ExecEvalExpr(astate->refassgnexpr,
econtext,
&eisnull);
econtext->caseValue_datum = save_datum;
econtext->caseValue_isNull = save_isNull;
/*
* For an assignment to a fixed-length array type, both the original
* array and the value to be assigned into it must be non-NULL, else
* we punt and return the original array.
*/
if (astate->refattrlength > 0) /* fixed-length array? */
if (eisnull || *isNull)
return array_source;
/*
* For assignment to varlena arrays, we handle a NULL original array
* by substituting an empty (zero-dimensional) array; insertion of the
* new element will result in a singleton array value. It does not
* matter whether the new element is NULL.
*/
if (*isNull)
{
array_source = PointerGetDatum(construct_empty_array(arrayRef->refelemtype));
*isNull = false;
}
if (lIndex == NULL)
return array_set_element(array_source, i,
upper.indx,
sourceData,
eisnull,
astate->refattrlength,
astate->refelemlength,
astate->refelembyval,
astate->refelemalign);
else
return array_set_slice(array_source, i,
upper.indx, lower.indx,
upperProvided, lowerProvided,
sourceData,
eisnull,
astate->refattrlength,
astate->refelemlength,
astate->refelembyval,
astate->refelemalign);
}
if (lIndex == NULL)
return array_get_element(array_source, i,
upper.indx,
astate->refattrlength,
astate->refelemlength,
astate->refelembyval,
astate->refelemalign,
isNull);
else
return array_get_slice(array_source, i,
upper.indx, lower.indx,
upperProvided, lowerProvided,
astate->refattrlength,
astate->refelemlength,
astate->refelembyval,
astate->refelemalign);
}
/*
* Helper for ExecEvalArrayRef: is expr a nested FieldStore or ArrayRef
* that might need the old element value passed down?
*
* (We could use this in ExecEvalFieldStore too, but in that case passing
* the old value is so cheap there's no need.)
*/
static bool
isAssignmentIndirectionExpr(ExprState *exprstate)
{
if (exprstate == NULL)
return false; /* just paranoia */
if (IsA(exprstate, FieldStoreState))
{
FieldStore *fstore = (FieldStore *) exprstate->expr;
if (fstore->arg && IsA(fstore->arg, CaseTestExpr))
return true;
}
else if (IsA(exprstate, ArrayRefExprState))
{
ArrayRef *arrayRef = (ArrayRef *) exprstate->expr;
if (arrayRef->refexpr && IsA(arrayRef->refexpr, CaseTestExpr))
return true;
}
return false;
}
/* ----------------------------------------------------------------
* ExecEvalAggref
*
* Returns a Datum whose value is the value of the precomputed
* aggregate found in the given expression context.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalAggref(AggrefExprState *aggref, ExprContext *econtext,
bool *isNull)
{
if (econtext->ecxt_aggvalues == NULL) /* safety check */
elog(ERROR, "no aggregates in this expression context");
*isNull = econtext->ecxt_aggnulls[aggref->aggno];
return econtext->ecxt_aggvalues[aggref->aggno];
}
/* ----------------------------------------------------------------
* ExecEvalWindowFunc
*
* Returns a Datum whose value is the value of the precomputed
* window function found in the given expression context.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalWindowFunc(WindowFuncExprState *wfunc, ExprContext *econtext,
bool *isNull)
{
if (econtext->ecxt_aggvalues == NULL) /* safety check */
elog(ERROR, "no window functions in this expression context");
*isNull = econtext->ecxt_aggnulls[wfunc->wfuncno];
return econtext->ecxt_aggvalues[wfunc->wfuncno];
}
/* ----------------------------------------------------------------
* ExecEvalScalarVar
*
* Returns a Datum whose value is the value of a scalar (not whole-row)
* range variable with respect to given expression context.
*
* Note: ExecEvalScalarVar is executed only the first time through in a given
* plan; it changes the ExprState's function pointer to pass control directly
* to ExecEvalScalarVarFast after making one-time checks.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalScalarVar(ExprState *exprstate, ExprContext *econtext,
bool *isNull)
{
Var *variable = (Var *) exprstate->expr;
TupleTableSlot *slot;
AttrNumber attnum;
/* Get the input slot and attribute number we want */
switch (variable->varno)
{
case INNER_VAR: /* get the tuple from the inner node */
slot = econtext->ecxt_innertuple;
break;
case OUTER_VAR: /* get the tuple from the outer node */
slot = econtext->ecxt_outertuple;
break;
/* INDEX_VAR is handled by default case */
default: /* get the tuple from the relation being
* scanned */
slot = econtext->ecxt_scantuple;
break;
}
attnum = variable->varattno;
/* This was checked by ExecInitExpr */
Assert(attnum != InvalidAttrNumber);
/*
* If it's a user attribute, check validity (bogus system attnums will be
* caught inside slot_getattr). What we have to check for here is the
* possibility of an attribute having been changed in type since the plan
* tree was created. Ideally the plan will get invalidated and not
* re-used, but just in case, we keep these defenses. Fortunately it's
* sufficient to check once on the first time through.
*
* Note: we allow a reference to a dropped attribute. slot_getattr will
* force a NULL result in such cases.
*
* Note: ideally we'd check typmod as well as typid, but that seems
* impractical at the moment: in many cases the tupdesc will have been
* generated by ExecTypeFromTL(), and that can't guarantee to generate an
* accurate typmod in all cases, because some expression node types don't
* carry typmod.
*/
if (attnum > 0)
{
TupleDesc slot_tupdesc = slot->tts_tupleDescriptor;
Form_pg_attribute attr;
if (attnum > slot_tupdesc->natts) /* should never happen */
elog(ERROR, "attribute number %d exceeds number of columns %d",
attnum, slot_tupdesc->natts);
attr = slot_tupdesc->attrs[attnum - 1];
/* can't check type if dropped, since atttypid is probably 0 */
if (!attr->attisdropped)
{
if (variable->vartype != attr->atttypid)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("attribute %d has wrong type", attnum),
errdetail("Table has type %s, but query expects %s.",
format_type_be(attr->atttypid),
format_type_be(variable->vartype))));
}
}
/* Skip the checking on future executions of node */
exprstate->evalfunc = ExecEvalScalarVarFast;
/* Fetch the value from the slot */
return slot_getattr(slot, attnum, isNull);
}
/* ----------------------------------------------------------------
* ExecEvalScalarVarFast
*
* Returns a Datum for a scalar variable.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalScalarVarFast(ExprState *exprstate, ExprContext *econtext,
bool *isNull)
{
Var *variable = (Var *) exprstate->expr;
TupleTableSlot *slot;
AttrNumber attnum;
/* Get the input slot and attribute number we want */
switch (variable->varno)
{
case INNER_VAR: /* get the tuple from the inner node */
slot = econtext->ecxt_innertuple;
break;
case OUTER_VAR: /* get the tuple from the outer node */
slot = econtext->ecxt_outertuple;
break;
/* INDEX_VAR is handled by default case */
default: /* get the tuple from the relation being
* scanned */
slot = econtext->ecxt_scantuple;
break;
}
attnum = variable->varattno;
/* Fetch the value from the slot */
return slot_getattr(slot, attnum, isNull);
}
/* ----------------------------------------------------------------
* ExecEvalWholeRowVar
*
* Returns a Datum whose value is the value of a whole-row range
* variable with respect to given expression context.
*
* Note: ExecEvalWholeRowVar is executed only the first time through in a
* given plan; it changes the ExprState's function pointer to pass control
* directly to ExecEvalWholeRowFast or ExecEvalWholeRowSlow after making
* one-time checks.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalWholeRowVar(WholeRowVarExprState *wrvstate, ExprContext *econtext,
bool *isNull)
{
Var *variable = (Var *) wrvstate->xprstate.expr;
TupleTableSlot *slot;
TupleDesc output_tupdesc;
MemoryContext oldcontext;
bool needslow = false;
/* This was checked by ExecInitExpr */
Assert(variable->varattno == InvalidAttrNumber);
/* Get the input slot we want */
switch (variable->varno)
{
case INNER_VAR: /* get the tuple from the inner node */
slot = econtext->ecxt_innertuple;
break;
case OUTER_VAR: /* get the tuple from the outer node */
slot = econtext->ecxt_outertuple;
break;
/* INDEX_VAR is handled by default case */
default: /* get the tuple from the relation being
* scanned */
slot = econtext->ecxt_scantuple;
break;
}
/*
* If the input tuple came from a subquery, it might contain "resjunk"
* columns (such as GROUP BY or ORDER BY columns), which we don't want to
* keep in the whole-row result. We can get rid of such columns by
* passing the tuple through a JunkFilter --- but to make one, we have to
* lay our hands on the subquery's targetlist. Fortunately, there are not
* very many cases where this can happen, and we can identify all of them
* by examining our parent PlanState. We assume this is not an issue in
* standalone expressions that don't have parent plans. (Whole-row Vars
* can occur in such expressions, but they will always be referencing
* table rows.)
*/
if (wrvstate->parent)
{
PlanState *subplan = NULL;
switch (nodeTag(wrvstate->parent))
{
case T_SubqueryScanState:
subplan = ((SubqueryScanState *) wrvstate->parent)->subplan;
break;
case T_CteScanState:
subplan = ((CteScanState *) wrvstate->parent)->cteplanstate;
break;
default:
break;
}
if (subplan)
{
bool junk_filter_needed = false;
ListCell *tlist;
/* Detect whether subplan tlist actually has any junk columns */
foreach(tlist, subplan->plan->targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tlist);
if (tle->resjunk)
{
junk_filter_needed = true;
break;
}
}
/* If so, build the junkfilter in the query memory context */
if (junk_filter_needed)
{
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
wrvstate->wrv_junkFilter =
ExecInitJunkFilter(subplan->plan->targetlist,
ExecGetResultType(subplan)->tdhasoid,
ExecInitExtraTupleSlot(wrvstate->parent->state));
MemoryContextSwitchTo(oldcontext);
}
}
}
/* Apply the junkfilter if any */
if (wrvstate->wrv_junkFilter != NULL)
slot = ExecFilterJunk(wrvstate->wrv_junkFilter, slot);
/*
* If the Var identifies a named composite type, we must check that the
* actual tuple type is compatible with it.
*/
if (variable->vartype != RECORDOID)
{
TupleDesc var_tupdesc;
TupleDesc slot_tupdesc;
int i;
/*
* We really only care about numbers of attributes and data types.
* Also, we can ignore type mismatch on columns that are dropped in
* the destination type, so long as (1) the physical storage matches
* or (2) the actual column value is NULL. Case (1) is helpful in
* some cases involving out-of-date cached plans, while case (2) is
* expected behavior in situations such as an INSERT into a table with
* dropped columns (the planner typically generates an INT4 NULL
* regardless of the dropped column type). If we find a dropped
* column and cannot verify that case (1) holds, we have to use
* ExecEvalWholeRowSlow to check (2) for each row.
*/
var_tupdesc = lookup_rowtype_tupdesc(variable->vartype, -1);
slot_tupdesc = slot->tts_tupleDescriptor;
if (var_tupdesc->natts != slot_tupdesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("table row type and query-specified row type do not match"),
errdetail_plural("Table row contains %d attribute, but query expects %d.",
"Table row contains %d attributes, but query expects %d.",
slot_tupdesc->natts,
slot_tupdesc->natts,
var_tupdesc->natts)));
for (i = 0; i < var_tupdesc->natts; i++)
{
Form_pg_attribute vattr = var_tupdesc->attrs[i];
Form_pg_attribute sattr = slot_tupdesc->attrs[i];
if (vattr->atttypid == sattr->atttypid)
continue; /* no worries */
if (!vattr->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("table row type and query-specified row type do not match"),
errdetail("Table has type %s at ordinal position %d, but query expects %s.",
format_type_be(sattr->atttypid),
i + 1,
format_type_be(vattr->atttypid))));
if (vattr->attlen != sattr->attlen ||
vattr->attalign != sattr->attalign)
needslow = true; /* need runtime check for null */
}
/*
* Use the variable's declared rowtype as the descriptor for the
* output values, modulo possibly assigning new column names below. In
* particular, we *must* absorb any attisdropped markings.
*/
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
output_tupdesc = CreateTupleDescCopy(var_tupdesc);
MemoryContextSwitchTo(oldcontext);
ReleaseTupleDesc(var_tupdesc);
}
else
{
/*
* In the RECORD case, we use the input slot's rowtype as the
* descriptor for the output values, modulo possibly assigning new
* column names below.
*/
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
output_tupdesc = CreateTupleDescCopy(slot->tts_tupleDescriptor);
MemoryContextSwitchTo(oldcontext);
}
/*
* Construct a tuple descriptor for the composite values we'll produce,
* and make sure its record type is "blessed". The main reason to do this
* is to be sure that operations such as row_to_json() will see the
* desired column names when they look up the descriptor from the type
* information embedded in the composite values.
*
* We already got the correct physical datatype info above, but now we
* should try to find the source RTE and adopt its column aliases, in case
* they are different from the original rowtype's names. For example, in
* "SELECT foo(t) FROM tab t(x,y)", the first two columns in the composite
* output should be named "x" and "y" regardless of tab's column names.
*
* If we can't locate the RTE, assume the column names we've got are OK.
* (As of this writing, the only cases where we can't locate the RTE are
* in execution of trigger WHEN clauses, and then the Var will have the
* trigger's relation's rowtype, so its names are fine.) Also, if the
* creator of the RTE didn't bother to fill in an eref field, assume our
* column names are OK. (This happens in COPY, and perhaps other places.)
*/
if (econtext->ecxt_estate &&
variable->varno <= list_length(econtext->ecxt_estate->es_range_table))
{
RangeTblEntry *rte = rt_fetch(variable->varno,
econtext->ecxt_estate->es_range_table);
if (rte->eref)
ExecTypeSetColNames(output_tupdesc, rte->eref->colnames);
}
/* Bless the tupdesc if needed, and save it in the execution state */
wrvstate->wrv_tupdesc = BlessTupleDesc(output_tupdesc);
/* Skip all the above on future executions of node */
if (needslow)
wrvstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalWholeRowSlow;
else
wrvstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalWholeRowFast;
/* Fetch the value */
return (*wrvstate->xprstate.evalfunc) ((ExprState *) wrvstate, econtext,
isNull);
}
/* ----------------------------------------------------------------
* ExecEvalWholeRowFast
*
* Returns a Datum for a whole-row variable.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalWholeRowFast(WholeRowVarExprState *wrvstate, ExprContext *econtext,
bool *isNull)
{
Var *variable = (Var *) wrvstate->xprstate.expr;
TupleTableSlot *slot;
HeapTupleHeader dtuple;
*isNull = false;
/* Get the input slot we want */
switch (variable->varno)
{
case INNER_VAR: /* get the tuple from the inner node */
slot = econtext->ecxt_innertuple;
break;
case OUTER_VAR: /* get the tuple from the outer node */
slot = econtext->ecxt_outertuple;
break;
/* INDEX_VAR is handled by default case */
default: /* get the tuple from the relation being
* scanned */
slot = econtext->ecxt_scantuple;
break;
}
/* Apply the junkfilter if any */
if (wrvstate->wrv_junkFilter != NULL)
slot = ExecFilterJunk(wrvstate->wrv_junkFilter, slot);
/*
* Copy the slot tuple and make sure any toasted fields get detoasted.
*/
dtuple = DatumGetHeapTupleHeader(ExecFetchSlotTupleDatum(slot));
/*
* Label the datum with the composite type info we identified before.
*/
HeapTupleHeaderSetTypeId(dtuple, wrvstate->wrv_tupdesc->tdtypeid);
HeapTupleHeaderSetTypMod(dtuple, wrvstate->wrv_tupdesc->tdtypmod);
return PointerGetDatum(dtuple);
}
/* ----------------------------------------------------------------
* ExecEvalWholeRowSlow
*
* Returns a Datum for a whole-row variable, in the "slow" case where
* we can't just copy the subplan's output.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalWholeRowSlow(WholeRowVarExprState *wrvstate, ExprContext *econtext,
bool *isNull)
{
Var *variable = (Var *) wrvstate->xprstate.expr;
TupleTableSlot *slot;
HeapTuple tuple;
TupleDesc tupleDesc;
TupleDesc var_tupdesc;
HeapTupleHeader dtuple;
int i;
*isNull = false;
/* Get the input slot we want */
switch (variable->varno)
{
case INNER_VAR: /* get the tuple from the inner node */
slot = econtext->ecxt_innertuple;
break;
case OUTER_VAR: /* get the tuple from the outer node */
slot = econtext->ecxt_outertuple;
break;
/* INDEX_VAR is handled by default case */
default: /* get the tuple from the relation being
* scanned */
slot = econtext->ecxt_scantuple;
break;
}
/* Apply the junkfilter if any */
if (wrvstate->wrv_junkFilter != NULL)
slot = ExecFilterJunk(wrvstate->wrv_junkFilter, slot);
tuple = ExecFetchSlotTuple(slot);
tupleDesc = slot->tts_tupleDescriptor;
/* wrv_tupdesc is a good enough representation of the Var's rowtype */
Assert(variable->vartype != RECORDOID);
var_tupdesc = wrvstate->wrv_tupdesc;
/* Check to see if any dropped attributes are non-null */
for (i = 0; i < var_tupdesc->natts; i++)
{
Form_pg_attribute vattr = var_tupdesc->attrs[i];
Form_pg_attribute sattr = tupleDesc->attrs[i];
if (!vattr->attisdropped)
continue; /* already checked non-dropped cols */
if (heap_attisnull(tuple, i + 1))
continue; /* null is always okay */
if (vattr->attlen != sattr->attlen ||
vattr->attalign != sattr->attalign)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("table row type and query-specified row type do not match"),
errdetail("Physical storage mismatch on dropped attribute at ordinal position %d.",
i + 1)));
}
/*
* Copy the slot tuple and make sure any toasted fields get detoasted.
*/
dtuple = DatumGetHeapTupleHeader(ExecFetchSlotTupleDatum(slot));
/*
* Label the datum with the composite type info we identified before.
*/
HeapTupleHeaderSetTypeId(dtuple, wrvstate->wrv_tupdesc->tdtypeid);
HeapTupleHeaderSetTypMod(dtuple, wrvstate->wrv_tupdesc->tdtypmod);
return PointerGetDatum(dtuple);
}
/* ----------------------------------------------------------------
* ExecEvalConst
*
* Returns the value of a constant.
*
* Note that for pass-by-ref datatypes, we return a pointer to the
* actual constant node. This is one of the reasons why functions
* must treat their input arguments as read-only.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalConst(ExprState *exprstate, ExprContext *econtext,
bool *isNull)
{
Const *con = (Const *) exprstate->expr;
*isNull = con->constisnull;
return con->constvalue;
}
/* ----------------------------------------------------------------
* ExecEvalParamExec
*
* Returns the value of a PARAM_EXEC parameter.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalParamExec(ExprState *exprstate, ExprContext *econtext,
bool *isNull)
{
Param *expression = (Param *) exprstate->expr;
int thisParamId = expression->paramid;
ParamExecData *prm;
/*
* PARAM_EXEC params (internal executor parameters) are stored in the
* ecxt_param_exec_vals array, and can be accessed by array index.
*/
prm = &(econtext->ecxt_param_exec_vals[thisParamId]);
if (prm->execPlan != NULL)
{
/* Parameter not evaluated yet, so go do it */
ExecSetParamPlan(prm->execPlan, econtext);
/* ExecSetParamPlan should have processed this param... */
Assert(prm->execPlan == NULL);
}
*isNull = prm->isnull;
return prm->value;
}
/* ----------------------------------------------------------------
* ExecEvalParamExtern
*
* Returns the value of a PARAM_EXTERN parameter.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalParamExtern(ExprState *exprstate, ExprContext *econtext,
bool *isNull)
{
Param *expression = (Param *) exprstate->expr;
int thisParamId = expression->paramid;
ParamListInfo paramInfo = econtext->ecxt_param_list_info;
/*
* PARAM_EXTERN parameters must be sought in ecxt_param_list_info.
*/
if (paramInfo &&
thisParamId > 0 && thisParamId <= paramInfo->numParams)
{
ParamExternData *prm = &paramInfo->params[thisParamId - 1];
/* give hook a chance in case parameter is dynamic */
if (!OidIsValid(prm->ptype) && paramInfo->paramFetch != NULL)
(*paramInfo->paramFetch) (paramInfo, thisParamId);
if (OidIsValid(prm->ptype))
{
/* safety check in case hook did something unexpected */
if (prm->ptype != expression->paramtype)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("type of parameter %d (%s) does not match that when preparing the plan (%s)",
thisParamId,
format_type_be(prm->ptype),
format_type_be(expression->paramtype))));
*isNull = prm->isnull;
return prm->value;
}
}
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("no value found for parameter %d", thisParamId)));
return (Datum) 0; /* keep compiler quiet */
}
/* ----------------------------------------------------------------
* ExecEvalOper / ExecEvalFunc support routines
* ----------------------------------------------------------------
*/
/*
* GetAttributeByName
* GetAttributeByNum
*
* These functions return the value of the requested attribute
* out of the given tuple Datum.
* C functions which take a tuple as an argument are expected
* to use these. Ex: overpaid(EMP) might call GetAttributeByNum().
* Note: these are actually rather slow because they do a typcache
* lookup on each call.
*/
Datum
GetAttributeByNum(HeapTupleHeader tuple,
AttrNumber attrno,
bool *isNull)
{
Datum result;
Oid tupType;
int32 tupTypmod;
TupleDesc tupDesc;
HeapTupleData tmptup;
if (!AttributeNumberIsValid(attrno))
elog(ERROR, "invalid attribute number %d", attrno);
if (isNull == NULL)
elog(ERROR, "a NULL isNull pointer was passed");
if (tuple == NULL)
{
/* Kinda bogus but compatible with old behavior... */
*isNull = true;
return (Datum) 0;
}
tupType = HeapTupleHeaderGetTypeId(tuple);
tupTypmod = HeapTupleHeaderGetTypMod(tuple);
tupDesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
/*
* heap_getattr needs a HeapTuple not a bare HeapTupleHeader. We set all
* the fields in the struct just in case user tries to inspect system
* columns.
*/
tmptup.t_len = HeapTupleHeaderGetDatumLength(tuple);
ItemPointerSetInvalid(&(tmptup.t_self));
tmptup.t_tableOid = InvalidOid;
tmptup.t_data = tuple;
result = heap_getattr(&tmptup,
attrno,
tupDesc,
isNull);
ReleaseTupleDesc(tupDesc);
return result;
}
Datum
GetAttributeByName(HeapTupleHeader tuple, const char *attname, bool *isNull)
{
AttrNumber attrno;
Datum result;
Oid tupType;
int32 tupTypmod;
TupleDesc tupDesc;
HeapTupleData tmptup;
int i;
if (attname == NULL)
elog(ERROR, "invalid attribute name");
if (isNull == NULL)
elog(ERROR, "a NULL isNull pointer was passed");
if (tuple == NULL)
{
/* Kinda bogus but compatible with old behavior... */
*isNull = true;
return (Datum) 0;
}
tupType = HeapTupleHeaderGetTypeId(tuple);
tupTypmod = HeapTupleHeaderGetTypMod(tuple);
tupDesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
attrno = InvalidAttrNumber;
for (i = 0; i < tupDesc->natts; i++)
{
if (namestrcmp(&(tupDesc->attrs[i]->attname), attname) == 0)
{
attrno = tupDesc->attrs[i]->attnum;
break;
}
}
if (attrno == InvalidAttrNumber)
elog(ERROR, "attribute \"%s\" does not exist", attname);
/*
* heap_getattr needs a HeapTuple not a bare HeapTupleHeader. We set all
* the fields in the struct just in case user tries to inspect system
* columns.
*/
tmptup.t_len = HeapTupleHeaderGetDatumLength(tuple);
ItemPointerSetInvalid(&(tmptup.t_self));
tmptup.t_tableOid = InvalidOid;
tmptup.t_data = tuple;
result = heap_getattr(&tmptup,
attrno,
tupDesc,
isNull);
ReleaseTupleDesc(tupDesc);
return result;
}
/*
* init_fcache - initialize a FuncExprState node during first use
*/
static void
init_fcache(Oid foid, Oid input_collation, FuncExprState *fcache,
MemoryContext fcacheCxt, bool allowSRF, bool needDescForSRF)
{
AclResult aclresult;
/* Check permission to call function */
aclresult = pg_proc_aclcheck(foid, GetUserId(), ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_PROC, get_func_name(foid));
InvokeFunctionExecuteHook(foid);
/*
* Safety check on nargs. Under normal circumstances this should never
* fail, as parser should check sooner. But possibly it might fail if
* server has been compiled with FUNC_MAX_ARGS smaller than some functions
* declared in pg_proc?
*/
if (list_length(fcache->args) > FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg_plural("cannot pass more than %d argument to a function",
"cannot pass more than %d arguments to a function",
FUNC_MAX_ARGS,
FUNC_MAX_ARGS)));
/* Set up the primary fmgr lookup information */
fmgr_info_cxt(foid, &(fcache->func), fcacheCxt);
fmgr_info_set_expr((Node *) fcache->xprstate.expr, &(fcache->func));
/* Initialize the function call parameter struct as well */
InitFunctionCallInfoData(fcache->fcinfo_data, &(fcache->func),
list_length(fcache->args),
input_collation, NULL, NULL);
/* If function returns set, check if that's allowed by caller */
if (fcache->func.fn_retset && !allowSRF)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
/* Otherwise, ExecInitExpr should have marked the fcache correctly */
Assert(fcache->func.fn_retset == fcache->funcReturnsSet);
/* If function returns set, prepare expected tuple descriptor */
if (fcache->func.fn_retset && needDescForSRF)
{
TypeFuncClass functypclass;
Oid funcrettype;
TupleDesc tupdesc;
MemoryContext oldcontext;
functypclass = get_expr_result_type(fcache->func.fn_expr,
&funcrettype,
&tupdesc);
/* Must save tupdesc in fcache's context */
oldcontext = MemoryContextSwitchTo(fcacheCxt);
if (functypclass == TYPEFUNC_COMPOSITE)
{
/* Composite data type, e.g. a table's row type */
Assert(tupdesc);
/* Must copy it out of typcache for safety */
fcache->funcResultDesc = CreateTupleDescCopy(tupdesc);
fcache->funcReturnsTuple = true;
}
else if (functypclass == TYPEFUNC_SCALAR)
{
/* Base data type, i.e. scalar */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc,
(AttrNumber) 1,
NULL,
funcrettype,
-1,
0);
fcache->funcResultDesc = tupdesc;
fcache->funcReturnsTuple = false;
}
else if (functypclass == TYPEFUNC_RECORD)
{
/* This will work if function doesn't need an expectedDesc */
fcache->funcResultDesc = NULL;
fcache->funcReturnsTuple = true;
}
else
{
/* Else, we will fail if function needs an expectedDesc */
fcache->funcResultDesc = NULL;
}
MemoryContextSwitchTo(oldcontext);
}
else
fcache->funcResultDesc = NULL;
/* Initialize additional state */
fcache->funcResultStore = NULL;
fcache->funcResultSlot = NULL;
fcache->shutdown_reg = false;
}
/*
* callback function in case a FuncExpr returning a set needs to be shut down
* before it has been run to completion
*/
static void
ShutdownFuncExpr(Datum arg)
{
FuncExprState *fcache = (FuncExprState *) DatumGetPointer(arg);
/* If we have a slot, make sure it's let go of any tuplestore pointer */
if (fcache->funcResultSlot)
ExecClearTuple(fcache->funcResultSlot);
/* Release any open tuplestore */
if (fcache->funcResultStore)
tuplestore_end(fcache->funcResultStore);
fcache->funcResultStore = NULL;
/* Clear any active set-argument state */
fcache->setArgsValid = false;
/* execUtils will deregister the callback... */
fcache->shutdown_reg = false;
}
/*
* get_cached_rowtype: utility function to lookup a rowtype tupdesc
*
* type_id, typmod: identity of the rowtype
* cache_field: where to cache the TupleDesc pointer in expression state node
* (field must be initialized to NULL)
* econtext: expression context we are executing in
*
* NOTE: because the shutdown callback will be called during plan rescan,
* must be prepared to re-do this during any node execution; cannot call
* just once during expression initialization
*/
static TupleDesc
get_cached_rowtype(Oid type_id, int32 typmod,
TupleDesc *cache_field, ExprContext *econtext)
{
TupleDesc tupDesc = *cache_field;
/* Do lookup if no cached value or if requested type changed */
if (tupDesc == NULL ||
type_id != tupDesc->tdtypeid ||
typmod != tupDesc->tdtypmod)
{
tupDesc = lookup_rowtype_tupdesc(type_id, typmod);
if (*cache_field)
{
/* Release old tupdesc; but callback is already registered */
ReleaseTupleDesc(*cache_field);
}
else
{
/* Need to register shutdown callback to release tupdesc */
RegisterExprContextCallback(econtext,
ShutdownTupleDescRef,
PointerGetDatum(cache_field));
}
*cache_field = tupDesc;
}
return tupDesc;
}
/*
* Callback function to release a tupdesc refcount at expression tree shutdown
*/
static void
ShutdownTupleDescRef(Datum arg)
{
TupleDesc *cache_field = (TupleDesc *) DatumGetPointer(arg);
if (*cache_field)
ReleaseTupleDesc(*cache_field);
*cache_field = NULL;
}
/*
* Evaluate arguments for a function.
*/
static void
ExecEvalFuncArgs(FunctionCallInfo fcinfo,
List *argList,
ExprContext *econtext)
{
int i;
ListCell *arg;
i = 0;
foreach(arg, argList)
{
ExprState *argstate = (ExprState *) lfirst(arg);
fcinfo->arg[i] = ExecEvalExpr(argstate,
econtext,
&fcinfo->argnull[i]);
i++;
}
Assert(i == fcinfo->nargs);
}
/*
* ExecPrepareTuplestoreResult
*
* Subroutine for ExecMakeFunctionResultSet: prepare to extract rows from a
* tuplestore function result. We must set up a funcResultSlot (unless
* already done in a previous call cycle) and verify that the function
* returned the expected tuple descriptor.
*/
static void
ExecPrepareTuplestoreResult(FuncExprState *fcache,
ExprContext *econtext,
Tuplestorestate *resultStore,
TupleDesc resultDesc)
{
fcache->funcResultStore = resultStore;
if (fcache->funcResultSlot == NULL)
{
/* Create a slot so we can read data out of the tuplestore */
TupleDesc slotDesc;
MemoryContext oldcontext;
oldcontext = MemoryContextSwitchTo(fcache->func.fn_mcxt);
/*
* If we were not able to determine the result rowtype from context,
* and the function didn't return a tupdesc, we have to fail.
*/
if (fcache->funcResultDesc)
slotDesc = fcache->funcResultDesc;
else if (resultDesc)
{
/* don't assume resultDesc is long-lived */
slotDesc = CreateTupleDescCopy(resultDesc);
}
else
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning setof record called in "
"context that cannot accept type record")));
slotDesc = NULL; /* keep compiler quiet */
}
fcache->funcResultSlot = MakeSingleTupleTableSlot(slotDesc);
MemoryContextSwitchTo(oldcontext);
}
/*
* If function provided a tupdesc, cross-check it. We only really need to
* do this for functions returning RECORD, but might as well do it always.
*/
if (resultDesc)
{
if (fcache->funcResultDesc)
tupledesc_match(fcache->funcResultDesc, resultDesc);
/*
* If it is a dynamically-allocated TupleDesc, free it: it is
* typically allocated in a per-query context, so we must avoid
* leaking it across multiple usages.
*/
if (resultDesc->tdrefcount == -1)
FreeTupleDesc(resultDesc);
}
/* Register cleanup callback if we didn't already */
if (!fcache->shutdown_reg)
{
RegisterExprContextCallback(econtext,
ShutdownFuncExpr,
PointerGetDatum(fcache));
fcache->shutdown_reg = true;
}
}
/*
* Check that function result tuple type (src_tupdesc) matches or can
* be considered to match what the query expects (dst_tupdesc). If
* they don't match, ereport.
*
* We really only care about number of attributes and data type.
* Also, we can ignore type mismatch on columns that are dropped in the
* destination type, so long as the physical storage matches. This is
* helpful in some cases involving out-of-date cached plans.
*/
static void
tupledesc_match(TupleDesc dst_tupdesc, TupleDesc src_tupdesc)
{
int i;
if (dst_tupdesc->natts != src_tupdesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("function return row and query-specified return row do not match"),
errdetail_plural("Returned row contains %d attribute, but query expects %d.",
"Returned row contains %d attributes, but query expects %d.",
src_tupdesc->natts,
src_tupdesc->natts, dst_tupdesc->natts)));
for (i = 0; i < dst_tupdesc->natts; i++)
{
Form_pg_attribute dattr = dst_tupdesc->attrs[i];
Form_pg_attribute sattr = src_tupdesc->attrs[i];
if (IsBinaryCoercible(sattr->atttypid, dattr->atttypid))
continue; /* no worries */
if (!dattr->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("function return row and query-specified return row do not match"),
errdetail("Returned type %s at ordinal position %d, but query expects %s.",
format_type_be(sattr->atttypid),
i + 1,
format_type_be(dattr->atttypid))));
if (dattr->attlen != sattr->attlen ||
dattr->attalign != sattr->attalign)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("function return row and query-specified return row do not match"),
errdetail("Physical storage mismatch on dropped attribute at ordinal position %d.",
i + 1)));
}
}
/*
* ExecMakeFunctionResultSet
*
* Evaluate the arguments to a set-returning function and then call the
* function itself. The argument expressions may not contain set-returning
* functions (the planner is supposed to have separated evaluation for those).
*/
Datum
ExecMakeFunctionResultSet(FuncExprState *fcache,
ExprContext *econtext,
bool *isNull,
ExprDoneCond *isDone)
{
List *arguments;
Datum result;
FunctionCallInfo fcinfo;
PgStat_FunctionCallUsage fcusage;
ReturnSetInfo rsinfo;
bool callit;
int i;
restart:
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
/*
* Initialize function cache if first time through. The expression node
* could be either a FuncExpr or an OpExpr.
*/
if (fcache->func.fn_oid == InvalidOid)
{
if (IsA(fcache->xprstate.expr, FuncExpr))
{
FuncExpr *func = (FuncExpr *) fcache->xprstate.expr;
init_fcache(func->funcid, func->inputcollid, fcache,
econtext->ecxt_per_query_memory, true, true);
}
else if (IsA(fcache->xprstate.expr, OpExpr))
{
OpExpr *op = (OpExpr *) fcache->xprstate.expr;
init_fcache(op->opfuncid, op->inputcollid, fcache,
econtext->ecxt_per_query_memory, true, true);
}
else
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(fcache->xprstate.expr));
/* shouldn't get here otherwise */
Assert(fcache->func.fn_retset);
}
/*
* If a previous call of the function returned a set result in the form of
* a tuplestore, continue reading rows from the tuplestore until it's
* empty.
*/
if (fcache->funcResultStore)
{
if (tuplestore_gettupleslot(fcache->funcResultStore, true, false,
fcache->funcResultSlot))
{
*isDone = ExprMultipleResult;
if (fcache->funcReturnsTuple)
{
/* We must return the whole tuple as a Datum. */
*isNull = false;
return ExecFetchSlotTupleDatum(fcache->funcResultSlot);
}
else
{
/* Extract the first column and return it as a scalar. */
return slot_getattr(fcache->funcResultSlot, 1, isNull);
}
}
/* Exhausted the tuplestore, so clean up */
tuplestore_end(fcache->funcResultStore);
fcache->funcResultStore = NULL;
*isDone = ExprEndResult;
*isNull = true;
return (Datum) 0;
}
/*
* arguments is a list of expressions to evaluate before passing to the
* function manager. We skip the evaluation if it was already done in the
* previous call (ie, we are continuing the evaluation of a set-valued
* function). Otherwise, collect the current argument values into fcinfo.
*/
fcinfo = &fcache->fcinfo_data;
arguments = fcache->args;
if (!fcache->setArgsValid)
ExecEvalFuncArgs(fcinfo, arguments, econtext);
else
{
/* Reset flag (we may set it again below) */
fcache->setArgsValid = false;
}
/*
* Now call the function, passing the evaluated parameter values.
*/
/* Prepare a resultinfo node for communication. */
fcinfo->resultinfo = (Node *) &rsinfo;
rsinfo.type = T_ReturnSetInfo;
rsinfo.econtext = econtext;
rsinfo.expectedDesc = fcache->funcResultDesc;
rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize);
/* note we do not set SFRM_Materialize_Random or _Preferred */
rsinfo.returnMode = SFRM_ValuePerCall;
/* isDone is filled below */
rsinfo.setResult = NULL;
rsinfo.setDesc = NULL;
/*
* If function is strict, and there are any NULL arguments, skip calling
* the function.
*/
callit = true;
if (fcache->func.fn_strict)
{
for (i = 0; i < fcinfo->nargs; i++)
{
if (fcinfo->argnull[i])
{
callit = false;
break;
}
}
}
if (callit)
{
pgstat_init_function_usage(fcinfo, &fcusage);
fcinfo->isnull = false;
rsinfo.isDone = ExprSingleResult;
result = FunctionCallInvoke(fcinfo);
*isNull = fcinfo->isnull;
*isDone = rsinfo.isDone;
pgstat_end_function_usage(&fcusage,
rsinfo.isDone != ExprMultipleResult);
}
else
{
/* for a strict SRF, result for NULL is an empty set */
result = (Datum) 0;
*isNull = true;
*isDone = ExprEndResult;
}
/* Which protocol does function want to use? */
if (rsinfo.returnMode == SFRM_ValuePerCall)
{
if (*isDone != ExprEndResult)
{
/*
* Save the current argument values to re-use on the next call.
*/
if (*isDone == ExprMultipleResult)
{
fcache->setArgsValid = true;
/* Register cleanup callback if we didn't already */
if (!fcache->shutdown_reg)
{
RegisterExprContextCallback(econtext,
ShutdownFuncExpr,
PointerGetDatum(fcache));
fcache->shutdown_reg = true;
}
}
}
}
else if (rsinfo.returnMode == SFRM_Materialize)
{
/* check we're on the same page as the function author */
if (rsinfo.isDone != ExprSingleResult)
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("table-function protocol for materialize mode was not followed")));
if (rsinfo.setResult != NULL)
{
/* prepare to return values from the tuplestore */
ExecPrepareTuplestoreResult(fcache, econtext,
rsinfo.setResult,
rsinfo.setDesc);
/* loop back to top to start returning from tuplestore */
goto restart;
}
/* if setResult was left null, treat it as empty set */
*isDone = ExprEndResult;
*isNull = true;
result = (Datum) 0;
}
else
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("unrecognized table-function returnMode: %d",
(int) rsinfo.returnMode)));
return result;
}
/*
* ExecMakeFunctionResultNoSets
*
* Evaluate a function or operator node with a non-set-returning function.
* Assumes init_fcache() already done. Hand-tuned for speed.
*/
static Datum
ExecMakeFunctionResultNoSets(FuncExprState *fcache,
ExprContext *econtext,
bool *isNull)
{
ListCell *arg;
Datum result;
FunctionCallInfo fcinfo;
PgStat_FunctionCallUsage fcusage;
int i;
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
/* inlined, simplified version of ExecEvalFuncArgs */
fcinfo = &fcache->fcinfo_data;
i = 0;
foreach(arg, fcache->args)
{
ExprState *argstate = (ExprState *) lfirst(arg);
fcinfo->arg[i] = ExecEvalExpr(argstate,
econtext,
&fcinfo->argnull[i]);
i++;
}
/*
* If function is strict, and there are any NULL arguments, skip calling
* the function and return NULL.
*/
if (fcache->func.fn_strict)
{
while (--i >= 0)
{
if (fcinfo->argnull[i])
{
*isNull = true;
return (Datum) 0;
}
}
}
pgstat_init_function_usage(fcinfo, &fcusage);
fcinfo->isnull = false;
result = FunctionCallInvoke(fcinfo);
*isNull = fcinfo->isnull;
pgstat_end_function_usage(&fcusage, true);
return result;
}
/*
* ExecMakeTableFunctionResult
*
* Evaluate a table function, producing a materialized result in a Tuplestore
* object.
*/
Tuplestorestate *
ExecMakeTableFunctionResult(ExprState *funcexpr,
ExprContext *econtext,
MemoryContext argContext,
TupleDesc expectedDesc,
bool randomAccess)
{
Tuplestorestate *tupstore = NULL;
TupleDesc tupdesc = NULL;
Oid funcrettype;
bool returnsTuple;
bool returnsSet = false;
FunctionCallInfoData fcinfo;
PgStat_FunctionCallUsage fcusage;
ReturnSetInfo rsinfo;
HeapTupleData tmptup;
MemoryContext callerContext;
MemoryContext oldcontext;
bool direct_function_call;
bool first_time = true;
callerContext = CurrentMemoryContext;
funcrettype = exprType((Node *) funcexpr->expr);
returnsTuple = type_is_rowtype(funcrettype);
/*
* Prepare a resultinfo node for communication. We always do this even if
* not expecting a set result, so that we can pass expectedDesc. In the
* generic-expression case, the expression doesn't actually get to see the
* resultinfo, but set it up anyway because we use some of the fields as
* our own state variables.
*/
rsinfo.type = T_ReturnSetInfo;
rsinfo.econtext = econtext;
rsinfo.expectedDesc = expectedDesc;
rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize | SFRM_Materialize_Preferred);
if (randomAccess)
rsinfo.allowedModes |= (int) SFRM_Materialize_Random;
rsinfo.returnMode = SFRM_ValuePerCall;
/* isDone is filled below */
rsinfo.setResult = NULL;
rsinfo.setDesc = NULL;
/*
* Normally the passed expression tree will be a FuncExprState, since the
* grammar only allows a function call at the top level of a table
* function reference. However, if the function doesn't return set then
* the planner might have replaced the function call via constant-folding
* or inlining. So if we see any other kind of expression node, execute
* it via the general ExecEvalExpr() code; the only difference is that we
* don't get a chance to pass a special ReturnSetInfo to any functions
* buried in the expression.
*/
if (funcexpr && IsA(funcexpr, FuncExprState) &&
IsA(funcexpr->expr, FuncExpr))
{
FuncExprState *fcache = (FuncExprState *) funcexpr;
/*
* This path is similar to ExecMakeFunctionResultSet.
*/
direct_function_call = true;
/*
* Initialize function cache if first time through
*/
if (fcache->func.fn_oid == InvalidOid)
{
FuncExpr *func = (FuncExpr *) fcache->xprstate.expr;
init_fcache(func->funcid, func->inputcollid, fcache,
econtext->ecxt_per_query_memory, true, false);
}
returnsSet = fcache->func.fn_retset;
InitFunctionCallInfoData(fcinfo, &(fcache->func),
list_length(fcache->args),
fcache->fcinfo_data.fncollation,
NULL, (Node *) &rsinfo);
/*
* Evaluate the function's argument list.
*
* We can't do this in the per-tuple context: the argument values
* would disappear when we reset that context in the inner loop. And
* the caller's CurrentMemoryContext is typically a query-lifespan
* context, so we don't want to leak memory there. We require the
* caller to pass a separate memory context that can be used for this,
* and can be reset each time through to avoid bloat.
*/
MemoryContextReset(argContext);
oldcontext = MemoryContextSwitchTo(argContext);
ExecEvalFuncArgs(&fcinfo, fcache->args, econtext);
MemoryContextSwitchTo(oldcontext);
/*
* If function is strict, and there are any NULL arguments, skip
* calling the function and act like it returned NULL (or an empty
* set, in the returns-set case).
*/
if (fcache->func.fn_strict)
{
int i;
for (i = 0; i < fcinfo.nargs; i++)
{
if (fcinfo.argnull[i])
goto no_function_result;
}
}
}
else
{
/* Treat funcexpr as a generic expression */
direct_function_call = false;
InitFunctionCallInfoData(fcinfo, NULL, 0, InvalidOid, NULL, NULL);
}
/*
* Switch to short-lived context for calling the function or expression.
*/
MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
/*
* Loop to handle the ValuePerCall protocol (which is also the same
* behavior needed in the generic ExecEvalExpr path).
*/
for (;;)
{
Datum result;
CHECK_FOR_INTERRUPTS();
/*
* reset per-tuple memory context before each call of the function or
* expression. This cleans up any local memory the function may leak
* when called.
*/
ResetExprContext(econtext);
/* Call the function or expression one time */
if (direct_function_call)
{
pgstat_init_function_usage(&fcinfo, &fcusage);
fcinfo.isnull = false;
rsinfo.isDone = ExprSingleResult;
result = FunctionCallInvoke(&fcinfo);
pgstat_end_function_usage(&fcusage,
rsinfo.isDone != ExprMultipleResult);
}
else
{
result = ExecEvalExpr(funcexpr, econtext, &fcinfo.isnull);
rsinfo.isDone = ExprSingleResult;
}
/* Which protocol does function want to use? */
if (rsinfo.returnMode == SFRM_ValuePerCall)
{
/*
* Check for end of result set.
*/
if (rsinfo.isDone == ExprEndResult)
break;
/*
* If first time through, build tuplestore for result. For a
* scalar function result type, also make a suitable tupdesc.
*/
if (first_time)
{
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
rsinfo.setResult = tupstore;
if (!returnsTuple)
{
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc,
(AttrNumber) 1,
"column",
funcrettype,
-1,
0);
rsinfo.setDesc = tupdesc;
}
MemoryContextSwitchTo(oldcontext);
}
/*
* Store current resultset item.
*/
if (returnsTuple)
{
if (!fcinfo.isnull)
{
HeapTupleHeader td = DatumGetHeapTupleHeader(result);
if (tupdesc == NULL)
{
/*
* This is the first non-NULL result from the
* function. Use the type info embedded in the
* rowtype Datum to look up the needed tupdesc. Make
* a copy for the query.
*/
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupdesc = lookup_rowtype_tupdesc_copy(HeapTupleHeaderGetTypeId(td),
HeapTupleHeaderGetTypMod(td));
rsinfo.setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
}
else
{
/*
* Verify all later returned rows have same subtype;
* necessary in case the type is RECORD.
*/
if (HeapTupleHeaderGetTypeId(td) != tupdesc->tdtypeid ||
HeapTupleHeaderGetTypMod(td) != tupdesc->tdtypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("rows returned by function are not all of the same row type")));
}
/*
* tuplestore_puttuple needs a HeapTuple not a bare
* HeapTupleHeader, but it doesn't need all the fields.
*/
tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
tmptup.t_data = td;
tuplestore_puttuple(tupstore, &tmptup);
}
else
{
/*
* NULL result from a tuple-returning function; expand it
* to a row of all nulls. We rely on the expectedDesc to
* form such rows. (Note: this would be problematic if
* tuplestore_putvalues saved the tdtypeid/tdtypmod from
* the provided descriptor, since that might not match
* what we get from the function itself. But it doesn't.)
*/
int natts = expectedDesc->natts;
bool *nullflags;
nullflags = (bool *) palloc(natts * sizeof(bool));
memset(nullflags, true, natts * sizeof(bool));
tuplestore_putvalues(tupstore, expectedDesc, NULL, nullflags);
}
}
else
{
/* Scalar-type case: just store the function result */
tuplestore_putvalues(tupstore, tupdesc, &result, &fcinfo.isnull);
}
/*
* Are we done?
*/
if (rsinfo.isDone != ExprMultipleResult)
break;
}
else if (rsinfo.returnMode == SFRM_Materialize)
{
/* check we're on the same page as the function author */
if (!first_time || rsinfo.isDone != ExprSingleResult)
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("table-function protocol for materialize mode was not followed")));
/* Done evaluating the set result */
break;
}
else
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("unrecognized table-function returnMode: %d",
(int) rsinfo.returnMode)));
first_time = false;
}
no_function_result:
/*
* If we got nothing from the function (ie, an empty-set or NULL result),
* we have to create the tuplestore to return, and if it's a
* non-set-returning function then insert a single all-nulls row. As
* above, we depend on the expectedDesc to manufacture the dummy row.
*/
if (rsinfo.setResult == NULL)
{
MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
rsinfo.setResult = tupstore;
if (!returnsSet)
{
int natts = expectedDesc->natts;
bool *nullflags;
MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
nullflags = (bool *) palloc(natts * sizeof(bool));
memset(nullflags, true, natts * sizeof(bool));
tuplestore_putvalues(tupstore, expectedDesc, NULL, nullflags);
}
}
/*
* If function provided a tupdesc, cross-check it. We only really need to
* do this for functions returning RECORD, but might as well do it always.
*/
if (rsinfo.setDesc)
{
tupledesc_match(expectedDesc, rsinfo.setDesc);
/*
* If it is a dynamically-allocated TupleDesc, free it: it is
* typically allocated in a per-query context, so we must avoid
* leaking it across multiple usages.
*/
if (rsinfo.setDesc->tdrefcount == -1)
FreeTupleDesc(rsinfo.setDesc);
}
MemoryContextSwitchTo(callerContext);
/* All done, pass back the tuplestore */
return rsinfo.setResult;
}
/* ----------------------------------------------------------------
* ExecEvalFunc
* ExecEvalOper
*
* Evaluate the functional result of a list of arguments by calling the
* function manager.
* ----------------------------------------------------------------
*/
/* ----------------------------------------------------------------
* ExecEvalFunc
* ----------------------------------------------------------------
*/
static Datum
ExecEvalFunc(FuncExprState *fcache,
ExprContext *econtext,
bool *isNull)
{
/* This is called only the first time through */
FuncExpr *func = (FuncExpr *) fcache->xprstate.expr;
/* Initialize function lookup info */
init_fcache(func->funcid, func->inputcollid, fcache,
econtext->ecxt_per_query_memory, false, false);
/* Change the evalfunc pointer to save a few cycles in additional calls */
fcache->xprstate.evalfunc = (ExprStateEvalFunc) ExecMakeFunctionResultNoSets;
return ExecMakeFunctionResultNoSets(fcache, econtext, isNull);
}
/* ----------------------------------------------------------------
* ExecEvalOper
* ----------------------------------------------------------------
*/
static Datum
ExecEvalOper(FuncExprState *fcache,
ExprContext *econtext,
bool *isNull)
{
/* This is called only the first time through */
OpExpr *op = (OpExpr *) fcache->xprstate.expr;
/* Initialize function lookup info */
init_fcache(op->opfuncid, op->inputcollid, fcache,
econtext->ecxt_per_query_memory, false, false);
/* Change the evalfunc pointer to save a few cycles in additional calls */
fcache->xprstate.evalfunc = (ExprStateEvalFunc) ExecMakeFunctionResultNoSets;
return ExecMakeFunctionResultNoSets(fcache, econtext, isNull);
}
/* ----------------------------------------------------------------
* ExecEvalDistinct
*
* IS DISTINCT FROM must evaluate arguments to determine whether
* they are NULL; if either is NULL then the result is already
* known. If neither is NULL, then proceed to evaluate the
* function. Note that this is *always* derived from the equals
* operator, but since we need special processing of the arguments
* we can not simply reuse ExecEvalOper() or ExecEvalFunc().
* ----------------------------------------------------------------
*/
static Datum
ExecEvalDistinct(FuncExprState *fcache,
ExprContext *econtext,
bool *isNull)
{
Datum result;
FunctionCallInfo fcinfo;
/* Set non-null as default */
*isNull = false;
/*
* Initialize function cache if first time through
*/
if (fcache->func.fn_oid == InvalidOid)
{
DistinctExpr *op = (DistinctExpr *) fcache->xprstate.expr;
init_fcache(op->opfuncid, op->inputcollid, fcache,
econtext->ecxt_per_query_memory, false, false);
}
/*
* Evaluate arguments
*/
fcinfo = &fcache->fcinfo_data;
ExecEvalFuncArgs(fcinfo, fcache->args, econtext);
Assert(fcinfo->nargs == 2);
if (fcinfo->argnull[0] && fcinfo->argnull[1])
{
/* Both NULL? Then is not distinct... */
result = BoolGetDatum(FALSE);
}
else if (fcinfo->argnull[0] || fcinfo->argnull[1])
{
/* Only one is NULL? Then is distinct... */
result = BoolGetDatum(TRUE);
}
else
{
fcinfo->isnull = false;
result = FunctionCallInvoke(fcinfo);
*isNull = fcinfo->isnull;
/* Must invert result of "=" */
result = BoolGetDatum(!DatumGetBool(result));
}
return result;
}
/*
* ExecEvalScalarArrayOp
*
* Evaluate "scalar op ANY/ALL (array)". The operator always yields boolean,
* and we combine the results across all array elements using OR and AND
* (for ANY and ALL respectively). Of course we short-circuit as soon as
* the result is known.
*/
static Datum
ExecEvalScalarArrayOp(ScalarArrayOpExprState *sstate,
ExprContext *econtext,
bool *isNull)
{
ScalarArrayOpExpr *opexpr = (ScalarArrayOpExpr *) sstate->fxprstate.xprstate.expr;
bool useOr = opexpr->useOr;
ArrayType *arr;
int nitems;
Datum result;
bool resultnull;
FunctionCallInfo fcinfo;
int i;
int16 typlen;
bool typbyval;
char typalign;
char *s;
bits8 *bitmap;
int bitmask;
/* Set non-null as default */
*isNull = false;
/*
* Initialize function cache if first time through
*/
if (sstate->fxprstate.func.fn_oid == InvalidOid)
{
init_fcache(opexpr->opfuncid, opexpr->inputcollid, &sstate->fxprstate,
econtext->ecxt_per_query_memory, false, false);
}
/*
* Evaluate arguments
*/
fcinfo = &sstate->fxprstate.fcinfo_data;
ExecEvalFuncArgs(fcinfo, sstate->fxprstate.args, econtext);
Assert(fcinfo->nargs == 2);
/*
* If the array is NULL then we return NULL --- it's not very meaningful
* to do anything else, even if the operator isn't strict.
*/
if (fcinfo->argnull[1])
{
*isNull = true;
return (Datum) 0;
}
/* Else okay to fetch and detoast the array */
arr = DatumGetArrayTypeP(fcinfo->arg[1]);
/*
* If the array is empty, we return either FALSE or TRUE per the useOr
* flag. This is correct even if the scalar is NULL; since we would
* evaluate the operator zero times, it matters not whether it would want
* to return NULL.
*/
nitems = ArrayGetNItems(ARR_NDIM(arr), ARR_DIMS(arr));
if (nitems <= 0)
return BoolGetDatum(!useOr);
/*
* If the scalar is NULL, and the function is strict, return NULL; no
* point in iterating the loop.
*/
if (fcinfo->argnull[0] && sstate->fxprstate.func.fn_strict)
{
*isNull = true;
return (Datum) 0;
}
/*
* We arrange to look up info about the element type only once per series
* of calls, assuming the element type doesn't change underneath us.
*/
if (sstate->element_type != ARR_ELEMTYPE(arr))
{
get_typlenbyvalalign(ARR_ELEMTYPE(arr),
&sstate->typlen,
&sstate->typbyval,
&sstate->typalign);
sstate->element_type = ARR_ELEMTYPE(arr);
}
typlen = sstate->typlen;
typbyval = sstate->typbyval;
typalign = sstate->typalign;
result = BoolGetDatum(!useOr);
resultnull = false;
/* Loop over the array elements */
s = (char *) ARR_DATA_PTR(arr);
bitmap = ARR_NULLBITMAP(arr);
bitmask = 1;
for (i = 0; i < nitems; i++)
{
Datum elt;
Datum thisresult;
/* Get array element, checking for NULL */
if (bitmap && (*bitmap & bitmask) == 0)
{
fcinfo->arg[1] = (Datum) 0;
fcinfo->argnull[1] = true;
}
else
{
elt = fetch_att(s, typbyval, typlen);
s = att_addlength_pointer(s, typlen, s);
s = (char *) att_align_nominal(s, typalign);
fcinfo->arg[1] = elt;
fcinfo->argnull[1] = false;
}
/* Call comparison function */
if (fcinfo->argnull[1] && sstate->fxprstate.func.fn_strict)
{
fcinfo->isnull = true;
thisresult = (Datum) 0;
}
else
{
fcinfo->isnull = false;
thisresult = FunctionCallInvoke(fcinfo);
}
/* Combine results per OR or AND semantics */
if (fcinfo->isnull)
resultnull = true;
else if (useOr)
{
if (DatumGetBool(thisresult))
{
result = BoolGetDatum(true);
resultnull = false;
break; /* needn't look at any more elements */
}
}
else
{
if (!DatumGetBool(thisresult))
{
result = BoolGetDatum(false);
resultnull = false;
break; /* needn't look at any more elements */
}
}
/* advance bitmap pointer if any */
if (bitmap)
{
bitmask <<= 1;
if (bitmask == 0x100)
{
bitmap++;
bitmask = 1;
}
}
}
*isNull = resultnull;
return result;
}
/* ----------------------------------------------------------------
* ExecEvalNot
* ExecEvalOr
* ExecEvalAnd
*
* Evaluate boolean expressions, with appropriate short-circuiting.
*
* The query planner reformulates clause expressions in the
* qualification to conjunctive normal form. If we ever get
* an AND to evaluate, we can be sure that it's not a top-level
* clause in the qualification, but appears lower (as a function
* argument, for example), or in the target list. Not that you
* need to know this, mind you...
* ----------------------------------------------------------------
*/
static Datum
ExecEvalNot(BoolExprState *notclause, ExprContext *econtext,
bool *isNull)
{
ExprState *clause = linitial(notclause->args);
Datum expr_value;
expr_value = ExecEvalExpr(clause, econtext, isNull);
/*
* if the expression evaluates to null, then we just cascade the null back
* to whoever called us.
*/
if (*isNull)
return expr_value;
/*
* evaluation of 'not' is simple.. expr is false, then return 'true' and
* vice versa.
*/
return BoolGetDatum(!DatumGetBool(expr_value));
}
/* ----------------------------------------------------------------
* ExecEvalOr
* ----------------------------------------------------------------
*/
static Datum
ExecEvalOr(BoolExprState *orExpr, ExprContext *econtext,
bool *isNull)
{
List *clauses = orExpr->args;
ListCell *clause;
bool AnyNull;
AnyNull = false;
/*
* If any of the clauses is TRUE, the OR result is TRUE regardless of the
* states of the rest of the clauses, so we can stop evaluating and return
* TRUE immediately. If none are TRUE and one or more is NULL, we return
* NULL; otherwise we return FALSE. This makes sense when you interpret
* NULL as "don't know": if we have a TRUE then the OR is TRUE even if we
* aren't sure about some of the other inputs. If all the known inputs are
* FALSE, but we have one or more "don't knows", then we have to report
* that we "don't know" what the OR's result should be --- perhaps one of
* the "don't knows" would have been TRUE if we'd known its value. Only
* when all the inputs are known to be FALSE can we state confidently that
* the OR's result is FALSE.
*/
foreach(clause, clauses)
{
ExprState *clausestate = (ExprState *) lfirst(clause);
Datum clause_value;
clause_value = ExecEvalExpr(clausestate, econtext, isNull);
/*
* if we have a non-null true result, then return it.
*/
if (*isNull)
AnyNull = true; /* remember we got a null */
else if (DatumGetBool(clause_value))
return clause_value;
}
/* AnyNull is true if at least one clause evaluated to NULL */
*isNull = AnyNull;
return BoolGetDatum(false);
}
/* ----------------------------------------------------------------
* ExecEvalAnd
* ----------------------------------------------------------------
*/
static Datum
ExecEvalAnd(BoolExprState *andExpr, ExprContext *econtext,
bool *isNull)
{
List *clauses = andExpr->args;
ListCell *clause;
bool AnyNull;
AnyNull = false;
/*
* If any of the clauses is FALSE, the AND result is FALSE regardless of
* the states of the rest of the clauses, so we can stop evaluating and
* return FALSE immediately. If none are FALSE and one or more is NULL,
* we return NULL; otherwise we return TRUE. This makes sense when you
* interpret NULL as "don't know", using the same sort of reasoning as for
* OR, above.
*/
foreach(clause, clauses)
{
ExprState *clausestate = (ExprState *) lfirst(clause);
Datum clause_value;
clause_value = ExecEvalExpr(clausestate, econtext, isNull);
/*
* if we have a non-null false result, then return it.
*/
if (*isNull)
AnyNull = true; /* remember we got a null */
else if (!DatumGetBool(clause_value))
return clause_value;
}
/* AnyNull is true if at least one clause evaluated to NULL */
*isNull = AnyNull;
return BoolGetDatum(!AnyNull);
}
/* ----------------------------------------------------------------
* ExecEvalConvertRowtype
*
* Evaluate a rowtype coercion operation. This may require
* rearranging field positions.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalConvertRowtype(ConvertRowtypeExprState *cstate,
ExprContext *econtext,
bool *isNull)
{
ConvertRowtypeExpr *convert = (ConvertRowtypeExpr *) cstate->xprstate.expr;
HeapTuple result;
Datum tupDatum;
HeapTupleHeader tuple;
HeapTupleData tmptup;
tupDatum = ExecEvalExpr(cstate->arg, econtext, isNull);
/* this test covers the isDone exception too: */
if (*isNull)
return tupDatum;
tuple = DatumGetHeapTupleHeader(tupDatum);
/* Lookup tupdescs if first time through or after rescan */
if (cstate->indesc == NULL)
{
get_cached_rowtype(exprType((Node *) convert->arg), -1,
&cstate->indesc, econtext);
cstate->initialized = false;
}
if (cstate->outdesc == NULL)
{
get_cached_rowtype(convert->resulttype, -1,
&cstate->outdesc, econtext);
cstate->initialized = false;
}
/*
* We used to be able to assert that incoming tuples are marked with
* exactly the rowtype of cstate->indesc. However, now that
* ExecEvalWholeRowVar might change the tuples' marking to plain RECORD
* due to inserting aliases, we can only make this weak test:
*/
Assert(HeapTupleHeaderGetTypeId(tuple) == cstate->indesc->tdtypeid ||
HeapTupleHeaderGetTypeId(tuple) == RECORDOID);
/* if first time through, initialize conversion map */
if (!cstate->initialized)
{
MemoryContext old_cxt;
/* allocate map in long-lived memory context */
old_cxt = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
/* prepare map from old to new attribute numbers */
cstate->map = convert_tuples_by_name(cstate->indesc,
cstate->outdesc,
gettext_noop("could not convert row type"));
cstate->initialized = true;
MemoryContextSwitchTo(old_cxt);
}
/*
* No-op if no conversion needed (not clear this can happen here).
*/
if (cstate->map == NULL)
return tupDatum;
/*
* do_convert_tuple needs a HeapTuple not a bare HeapTupleHeader.
*/
tmptup.t_len = HeapTupleHeaderGetDatumLength(tuple);
tmptup.t_data = tuple;
result = do_convert_tuple(&tmptup, cstate->map);
return HeapTupleGetDatum(result);
}
/* ----------------------------------------------------------------
* ExecEvalCase
*
* Evaluate a CASE clause. Will have boolean expressions
* inside the WHEN clauses, and will have expressions
* for results.
* - thomas 1998-11-09
* ----------------------------------------------------------------
*/
static Datum
ExecEvalCase(CaseExprState *caseExpr, ExprContext *econtext,
bool *isNull)
{
List *clauses = caseExpr->args;
ListCell *clause;
Datum save_datum;
bool save_isNull;
/*
* If there's a test expression, we have to evaluate it and save the value
* where the CaseTestExpr placeholders can find it. We must save and
* restore prior setting of econtext's caseValue fields, in case this node
* is itself within a larger CASE. Furthermore, don't assign to the
* econtext fields until after returning from evaluation of the test
* expression. We used to pass &econtext->caseValue_isNull to the
* recursive call, but that leads to aliasing that variable within said
* call, which can (and did) produce bugs when the test expression itself
* contains a CASE.
*
* If there's no test expression, we don't actually need to save and
* restore these fields; but it's less code to just do so unconditionally.
*/
save_datum = econtext->caseValue_datum;
save_isNull = econtext->caseValue_isNull;
if (caseExpr->arg)
{
Datum arg_value;
bool arg_isNull;
arg_value = ExecEvalExpr(caseExpr->arg,
econtext,
&arg_isNull);
/* Since caseValue_datum may be read multiple times, force to R/O */
econtext->caseValue_datum =
MakeExpandedObjectReadOnly(arg_value,
arg_isNull,
caseExpr->argtyplen);
econtext->caseValue_isNull = arg_isNull;
}
/*
* we evaluate each of the WHEN clauses in turn, as soon as one is true we
* return the corresponding result. If none are true then we return the
* value of the default clause, or NULL if there is none.
*/
foreach(clause, clauses)
{
CaseWhenState *wclause = lfirst(clause);
Datum clause_value;
bool clause_isNull;
clause_value = ExecEvalExpr(wclause->expr,
econtext,
&clause_isNull);
/*
* if we have a true test, then we return the result, since the case
* statement is satisfied. A NULL result from the test is not
* considered true.
*/
if (DatumGetBool(clause_value) && !clause_isNull)
{
econtext->caseValue_datum = save_datum;
econtext->caseValue_isNull = save_isNull;
return ExecEvalExpr(wclause->result,
econtext,
isNull);
}
}
econtext->caseValue_datum = save_datum;
econtext->caseValue_isNull = save_isNull;
if (caseExpr->defresult)
{
return ExecEvalExpr(caseExpr->defresult,
econtext,
isNull);
}
*isNull = true;
return (Datum) 0;
}
/*
* ExecEvalCaseTestExpr
*
* Return the value stored by CASE.
*/
static Datum
ExecEvalCaseTestExpr(ExprState *exprstate,
ExprContext *econtext,
bool *isNull)
{
*isNull = econtext->caseValue_isNull;
return econtext->caseValue_datum;
}
/*
* ExecEvalGroupingFuncExpr
*
* Return a bitmask with a bit for each (unevaluated) argument expression
* (rightmost arg is least significant bit).
*
* A bit is set if the corresponding expression is NOT part of the set of
* grouping expressions in the current grouping set.
*/
static Datum
ExecEvalGroupingFuncExpr(GroupingFuncExprState *gstate,
ExprContext *econtext,
bool *isNull)
{
int result = 0;
int attnum = 0;
Bitmapset *grouped_cols = gstate->aggstate->grouped_cols;
ListCell *lc;
*isNull = false;
foreach(lc, (gstate->clauses))
{
attnum = lfirst_int(lc);
result = result << 1;
if (!bms_is_member(attnum, grouped_cols))
result = result | 1;
}
return (Datum) result;
}
/* ----------------------------------------------------------------
* ExecEvalArray - ARRAY[] expressions
* ----------------------------------------------------------------
*/
static Datum
ExecEvalArray(ArrayExprState *astate, ExprContext *econtext,
bool *isNull)
{
ArrayExpr *arrayExpr = (ArrayExpr *) astate->xprstate.expr;
ArrayType *result;
ListCell *element;
Oid element_type = arrayExpr->element_typeid;
int ndims = 0;
int dims[MAXDIM];
int lbs[MAXDIM];
/* Set non-null as default */
*isNull = false;
if (!arrayExpr->multidims)
{
/* Elements are presumably of scalar type */
int nelems;
Datum *dvalues;
bool *dnulls;
int i = 0;
ndims = 1;
nelems = list_length(astate->elements);
/* Shouldn't happen here, but if length is 0, return empty array */
if (nelems == 0)
return PointerGetDatum(construct_empty_array(element_type));
dvalues = (Datum *) palloc(nelems * sizeof(Datum));
dnulls = (bool *) palloc(nelems * sizeof(bool));
/* loop through and build array of datums */
foreach(element, astate->elements)
{
ExprState *e = (ExprState *) lfirst(element);
dvalues[i] = ExecEvalExpr(e, econtext, &dnulls[i]);
i++;
}
/* setup for 1-D array of the given length */
dims[0] = nelems;
lbs[0] = 1;
result = construct_md_array(dvalues, dnulls, ndims, dims, lbs,
element_type,
astate->elemlength,
astate->elembyval,
astate->elemalign);
}
else
{
/* Must be nested array expressions */
int nbytes = 0;
int nitems = 0;
int outer_nelems = 0;
int elem_ndims = 0;
int *elem_dims = NULL;
int *elem_lbs = NULL;
bool firstone = true;
bool havenulls = false;
bool haveempty = false;
char **subdata;
bits8 **subbitmaps;
int *subbytes;
int *subnitems;
int i;
int32 dataoffset;
char *dat;
int iitem;
i = list_length(astate->elements);
subdata = (char **) palloc(i * sizeof(char *));
subbitmaps = (bits8 **) palloc(i * sizeof(bits8 *));
subbytes = (int *) palloc(i * sizeof(int));
subnitems = (int *) palloc(i * sizeof(int));
/* loop through and get data area from each element */
foreach(element, astate->elements)
{
ExprState *e = (ExprState *) lfirst(element);
bool eisnull;
Datum arraydatum;
ArrayType *array;
int this_ndims;
arraydatum = ExecEvalExpr(e, econtext, &eisnull);
/* temporarily ignore null subarrays */
if (eisnull)
{
haveempty = true;
continue;
}
array = DatumGetArrayTypeP(arraydatum);
/* run-time double-check on element type */
if (element_type != ARR_ELEMTYPE(array))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("cannot merge incompatible arrays"),
errdetail("Array with element type %s cannot be "
"included in ARRAY construct with element type %s.",
format_type_be(ARR_ELEMTYPE(array)),
format_type_be(element_type))));
this_ndims = ARR_NDIM(array);
/* temporarily ignore zero-dimensional subarrays */
if (this_ndims <= 0)
{
haveempty = true;
continue;
}
if (firstone)
{
/* Get sub-array details from first member */
elem_ndims = this_ndims;
ndims = elem_ndims + 1;
if (ndims <= 0 || ndims > MAXDIM)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("number of array dimensions (%d) exceeds " \
"the maximum allowed (%d)", ndims, MAXDIM)));
elem_dims = (int *) palloc(elem_ndims * sizeof(int));
memcpy(elem_dims, ARR_DIMS(array), elem_ndims * sizeof(int));
elem_lbs = (int *) palloc(elem_ndims * sizeof(int));
memcpy(elem_lbs, ARR_LBOUND(array), elem_ndims * sizeof(int));
firstone = false;
}
else
{
/* Check other sub-arrays are compatible */
if (elem_ndims != this_ndims ||
memcmp(elem_dims, ARR_DIMS(array),
elem_ndims * sizeof(int)) != 0 ||
memcmp(elem_lbs, ARR_LBOUND(array),
elem_ndims * sizeof(int)) != 0)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("multidimensional arrays must have array "
"expressions with matching dimensions")));
}
subdata[outer_nelems] = ARR_DATA_PTR(array);
subbitmaps[outer_nelems] = ARR_NULLBITMAP(array);
subbytes[outer_nelems] = ARR_SIZE(array) - ARR_DATA_OFFSET(array);
nbytes += subbytes[outer_nelems];
subnitems[outer_nelems] = ArrayGetNItems(this_ndims,
ARR_DIMS(array));
nitems += subnitems[outer_nelems];
havenulls |= ARR_HASNULL(array);
outer_nelems++;
}
/*
* If all items were null or empty arrays, return an empty array;
* otherwise, if some were and some weren't, raise error. (Note: we
* must special-case this somehow to avoid trying to generate a 1-D
* array formed from empty arrays. It's not ideal...)
*/
if (haveempty)
{
if (ndims == 0) /* didn't find any nonempty array */
return PointerGetDatum(construct_empty_array(element_type));
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("multidimensional arrays must have array "
"expressions with matching dimensions")));
}
/* setup for multi-D array */
dims[0] = outer_nelems;
lbs[0] = 1;
for (i = 1; i < ndims; i++)
{
dims[i] = elem_dims[i - 1];
lbs[i] = elem_lbs[i - 1];
}
if (havenulls)
{
dataoffset = ARR_OVERHEAD_WITHNULLS(ndims, nitems);
nbytes += dataoffset;
}
else
{
dataoffset = 0; /* marker for no null bitmap */
nbytes += ARR_OVERHEAD_NONULLS(ndims);
}
result = (ArrayType *) palloc(nbytes);
SET_VARSIZE(result, nbytes);
result->ndim = ndims;
result->dataoffset = dataoffset;
result->elemtype = element_type;
memcpy(ARR_DIMS(result), dims, ndims * sizeof(int));
memcpy(ARR_LBOUND(result), lbs, ndims * sizeof(int));
dat = ARR_DATA_PTR(result);
iitem = 0;
for (i = 0; i < outer_nelems; i++)
{
memcpy(dat, subdata[i], subbytes[i]);
dat += subbytes[i];
if (havenulls)
array_bitmap_copy(ARR_NULLBITMAP(result), iitem,
subbitmaps[i], 0,
subnitems[i]);
iitem += subnitems[i];
}
}
return PointerGetDatum(result);
}
/* ----------------------------------------------------------------
* ExecEvalRow - ROW() expressions
* ----------------------------------------------------------------
*/
static Datum
ExecEvalRow(RowExprState *rstate,
ExprContext *econtext,
bool *isNull)
{
HeapTuple tuple;
Datum *values;
bool *isnull;
int natts;
ListCell *arg;
int i;
/* Set non-null as default */
*isNull = false;
/* Allocate workspace */
natts = rstate->tupdesc->natts;
values = (Datum *) palloc0(natts * sizeof(Datum));
isnull = (bool *) palloc(natts * sizeof(bool));
/* preset to nulls in case rowtype has some later-added columns */
memset(isnull, true, natts * sizeof(bool));
/* Evaluate field values */
i = 0;
foreach(arg, rstate->args)
{
ExprState *e = (ExprState *) lfirst(arg);
values[i] = ExecEvalExpr(e, econtext, &isnull[i]);
i++;
}
tuple = heap_form_tuple(rstate->tupdesc, values, isnull);
pfree(values);
pfree(isnull);
return HeapTupleGetDatum(tuple);
}
/* ----------------------------------------------------------------
* ExecEvalRowCompare - ROW() comparison-op ROW()
* ----------------------------------------------------------------
*/
static Datum
ExecEvalRowCompare(RowCompareExprState *rstate,
ExprContext *econtext,
bool *isNull)
{
bool result;
RowCompareType rctype = ((RowCompareExpr *) rstate->xprstate.expr)->rctype;
int32 cmpresult = 0;
ListCell *l;
ListCell *r;
int i;
*isNull = true; /* until we get a result */
i = 0;
forboth(l, rstate->largs, r, rstate->rargs)
{
ExprState *le = (ExprState *) lfirst(l);
ExprState *re = (ExprState *) lfirst(r);
FunctionCallInfoData locfcinfo;
InitFunctionCallInfoData(locfcinfo, &(rstate->funcs[i]), 2,
rstate->collations[i],
NULL, NULL);
locfcinfo.arg[0] = ExecEvalExpr(le, econtext,
&locfcinfo.argnull[0]);
locfcinfo.arg[1] = ExecEvalExpr(re, econtext,
&locfcinfo.argnull[1]);
if (rstate->funcs[i].fn_strict &&
(locfcinfo.argnull[0] || locfcinfo.argnull[1]))
return (Datum) 0; /* force NULL result */
locfcinfo.isnull = false;
cmpresult = DatumGetInt32(FunctionCallInvoke(&locfcinfo));
if (locfcinfo.isnull)
return (Datum) 0; /* force NULL result */
if (cmpresult != 0)
break; /* no need to compare remaining columns */
i++;
}
switch (rctype)
{
/* EQ and NE cases aren't allowed here */
case ROWCOMPARE_LT:
result = (cmpresult < 0);
break;
case ROWCOMPARE_LE:
result = (cmpresult <= 0);
break;
case ROWCOMPARE_GE:
result = (cmpresult >= 0);
break;
case ROWCOMPARE_GT:
result = (cmpresult > 0);
break;
default:
elog(ERROR, "unrecognized RowCompareType: %d", (int) rctype);
result = 0; /* keep compiler quiet */
break;
}
*isNull = false;
return BoolGetDatum(result);
}
/* ----------------------------------------------------------------
* ExecEvalCoalesce
* ----------------------------------------------------------------
*/
static Datum
ExecEvalCoalesce(CoalesceExprState *coalesceExpr, ExprContext *econtext,
bool *isNull)
{
ListCell *arg;
/* Simply loop through until something NOT NULL is found */
foreach(arg, coalesceExpr->args)
{
ExprState *e = (ExprState *) lfirst(arg);
Datum value;
value = ExecEvalExpr(e, econtext, isNull);
if (!*isNull)
return value;
}
/* Else return NULL */
*isNull = true;
return (Datum) 0;
}
/* ----------------------------------------------------------------
* ExecEvalMinMax
* ----------------------------------------------------------------
*/
static Datum
ExecEvalMinMax(MinMaxExprState *minmaxExpr, ExprContext *econtext,
bool *isNull)
{
Datum result = (Datum) 0;
MinMaxExpr *minmax = (MinMaxExpr *) minmaxExpr->xprstate.expr;
Oid collation = minmax->inputcollid;
MinMaxOp op = minmax->op;
FunctionCallInfoData locfcinfo;
ListCell *arg;
*isNull = true; /* until we get a result */
InitFunctionCallInfoData(locfcinfo, &minmaxExpr->cfunc, 2,
collation, NULL, NULL);
locfcinfo.argnull[0] = false;
locfcinfo.argnull[1] = false;
foreach(arg, minmaxExpr->args)
{
ExprState *e = (ExprState *) lfirst(arg);
Datum value;
bool valueIsNull;
int32 cmpresult;
value = ExecEvalExpr(e, econtext, &valueIsNull);
if (valueIsNull)
continue; /* ignore NULL inputs */
if (*isNull)
{
/* first nonnull input, adopt value */
result = value;
*isNull = false;
}
else
{
/* apply comparison function */
locfcinfo.arg[0] = result;
locfcinfo.arg[1] = value;
locfcinfo.isnull = false;
cmpresult = DatumGetInt32(FunctionCallInvoke(&locfcinfo));
if (locfcinfo.isnull) /* probably should not happen */
continue;
if (cmpresult > 0 && op == IS_LEAST)
result = value;
else if (cmpresult < 0 && op == IS_GREATEST)
result = value;
}
}
return result;
}
/* ----------------------------------------------------------------
* ExecEvalSQLValueFunction
* ----------------------------------------------------------------
*/
static Datum
ExecEvalSQLValueFunction(ExprState *svfExpr,
ExprContext *econtext,
bool *isNull)
{
Datum result = (Datum) 0;
SQLValueFunction *svf = (SQLValueFunction *) svfExpr->expr;
FunctionCallInfoData fcinfo;
*isNull = false;
/*
* Note: current_schema() can return NULL. current_user() etc currently
* cannot, but might as well code those cases the same way for safety.
*/
switch (svf->op)
{
case SVFOP_CURRENT_DATE:
result = DateADTGetDatum(GetSQLCurrentDate());
break;
case SVFOP_CURRENT_TIME:
case SVFOP_CURRENT_TIME_N:
result = TimeTzADTPGetDatum(GetSQLCurrentTime(svf->typmod));
break;
case SVFOP_CURRENT_TIMESTAMP:
case SVFOP_CURRENT_TIMESTAMP_N:
result = TimestampTzGetDatum(GetSQLCurrentTimestamp(svf->typmod));
break;
case SVFOP_LOCALTIME:
case SVFOP_LOCALTIME_N:
result = TimeADTGetDatum(GetSQLLocalTime(svf->typmod));
break;
case SVFOP_LOCALTIMESTAMP:
case SVFOP_LOCALTIMESTAMP_N:
result = TimestampGetDatum(GetSQLLocalTimestamp(svf->typmod));
break;
case SVFOP_CURRENT_ROLE:
case SVFOP_CURRENT_USER:
case SVFOP_USER:
InitFunctionCallInfoData(fcinfo, NULL, 0, InvalidOid, NULL, NULL);
result = current_user(&fcinfo);
*isNull = fcinfo.isnull;
break;
case SVFOP_SESSION_USER:
InitFunctionCallInfoData(fcinfo, NULL, 0, InvalidOid, NULL, NULL);
result = session_user(&fcinfo);
*isNull = fcinfo.isnull;
break;
case SVFOP_CURRENT_CATALOG:
InitFunctionCallInfoData(fcinfo, NULL, 0, InvalidOid, NULL, NULL);
result = current_database(&fcinfo);
*isNull = fcinfo.isnull;
break;
case SVFOP_CURRENT_SCHEMA:
InitFunctionCallInfoData(fcinfo, NULL, 0, InvalidOid, NULL, NULL);
result = current_schema(&fcinfo);
*isNull = fcinfo.isnull;
break;
}
return result;
}
/* ----------------------------------------------------------------
* ExecEvalXml
* ----------------------------------------------------------------
*/
static Datum
ExecEvalXml(XmlExprState *xmlExpr, ExprContext *econtext,
bool *isNull)
{
XmlExpr *xexpr = (XmlExpr *) xmlExpr->xprstate.expr;
Datum value;
bool isnull;
ListCell *arg;
ListCell *narg;
*isNull = true; /* until we get a result */
switch (xexpr->op)
{
case IS_XMLCONCAT:
{
List *values = NIL;
foreach(arg, xmlExpr->args)
{
ExprState *e = (ExprState *) lfirst(arg);
value = ExecEvalExpr(e, econtext, &isnull);
if (!isnull)
values = lappend(values, DatumGetPointer(value));
}
if (list_length(values) > 0)
{
*isNull = false;
return PointerGetDatum(xmlconcat(values));
}
else
return (Datum) 0;
}
break;
case IS_XMLFOREST:
{
StringInfoData buf;
initStringInfo(&buf);
forboth(arg, xmlExpr->named_args, narg, xexpr->arg_names)
{
ExprState *e = (ExprState *) lfirst(arg);
char *argname = strVal(lfirst(narg));
value = ExecEvalExpr(e, econtext, &isnull);
if (!isnull)
{
appendStringInfo(&buf, "<%s>%s</%s>",
argname,
map_sql_value_to_xml_value(value, exprType((Node *) e->expr), true),
argname);
*isNull = false;
}
}
if (*isNull)
{
pfree(buf.data);
return (Datum) 0;
}
else
{
text *result;
result = cstring_to_text_with_len(buf.data, buf.len);
pfree(buf.data);
return PointerGetDatum(result);
}
}
break;
case IS_XMLELEMENT:
*isNull = false;
return PointerGetDatum(xmlelement(xmlExpr, econtext));
break;
case IS_XMLPARSE:
{
ExprState *e;
text *data;
bool preserve_whitespace;
/* arguments are known to be text, bool */
Assert(list_length(xmlExpr->args) == 2);
e = (ExprState *) linitial(xmlExpr->args);
value = ExecEvalExpr(e, econtext, &isnull);
if (isnull)
return (Datum) 0;
data = DatumGetTextPP(value);
e = (ExprState *) lsecond(xmlExpr->args);
value = ExecEvalExpr(e, econtext, &isnull);
if (isnull) /* probably can't happen */
return (Datum) 0;
preserve_whitespace = DatumGetBool(value);
*isNull = false;
return PointerGetDatum(xmlparse(data,
xexpr->xmloption,
preserve_whitespace));
}
break;
case IS_XMLPI:
{
ExprState *e;
text *arg;
/* optional argument is known to be text */
Assert(list_length(xmlExpr->args) <= 1);
if (xmlExpr->args)
{
e = (ExprState *) linitial(xmlExpr->args);
value = ExecEvalExpr(e, econtext, &isnull);
if (isnull)
arg = NULL;
else
arg = DatumGetTextPP(value);
}
else
{
arg = NULL;
isnull = false;
}
return PointerGetDatum(xmlpi(xexpr->name, arg, isnull, isNull));
}
break;
case IS_XMLROOT:
{
ExprState *e;
xmltype *data;
text *version;
int standalone;
/* arguments are known to be xml, text, int */
Assert(list_length(xmlExpr->args) == 3);
e = (ExprState *) linitial(xmlExpr->args);
value = ExecEvalExpr(e, econtext, &isnull);
if (isnull)
return (Datum) 0;
data = DatumGetXmlP(value);
e = (ExprState *) lsecond(xmlExpr->args);
value = ExecEvalExpr(e, econtext, &isnull);
if (isnull)
version = NULL;
else
version = DatumGetTextPP(value);
e = (ExprState *) lthird(xmlExpr->args);
value = ExecEvalExpr(e, econtext, &isnull);
standalone = DatumGetInt32(value);
*isNull = false;
return PointerGetDatum(xmlroot(data,
version,
standalone));
}
break;
case IS_XMLSERIALIZE:
{
ExprState *e;
/* argument type is known to be xml */
Assert(list_length(xmlExpr->args) == 1);
e = (ExprState *) linitial(xmlExpr->args);
value = ExecEvalExpr(e, econtext, &isnull);
if (isnull)
return (Datum) 0;
*isNull = false;
return PointerGetDatum(xmltotext_with_xmloption(DatumGetXmlP(value), xexpr->xmloption));
}
break;
case IS_DOCUMENT:
{
ExprState *e;
/* optional argument is known to be xml */
Assert(list_length(xmlExpr->args) == 1);
e = (ExprState *) linitial(xmlExpr->args);
value = ExecEvalExpr(e, econtext, &isnull);
if (isnull)
return (Datum) 0;
else
{
*isNull = false;
return BoolGetDatum(xml_is_document(DatumGetXmlP(value)));
}
}
break;
}
elog(ERROR, "unrecognized XML operation");
return (Datum) 0;
}
/* ----------------------------------------------------------------
* ExecEvalNullIf
*
* Note that this is *always* derived from the equals operator,
* but since we need special processing of the arguments
* we can not simply reuse ExecEvalOper() or ExecEvalFunc().
* ----------------------------------------------------------------
*/
static Datum
ExecEvalNullIf(FuncExprState *nullIfExpr,
ExprContext *econtext,
bool *isNull)
{
Datum result;
FunctionCallInfo fcinfo;
/*
* Initialize function cache if first time through
*/
if (nullIfExpr->func.fn_oid == InvalidOid)
{
NullIfExpr *op = (NullIfExpr *) nullIfExpr->xprstate.expr;
init_fcache(op->opfuncid, op->inputcollid, nullIfExpr,
econtext->ecxt_per_query_memory, false, false);
}
/*
* Evaluate arguments
*/
fcinfo = &nullIfExpr->fcinfo_data;
ExecEvalFuncArgs(fcinfo, nullIfExpr->args, econtext);
Assert(fcinfo->nargs == 2);
/* if either argument is NULL they can't be equal */
if (!fcinfo->argnull[0] && !fcinfo->argnull[1])
{
fcinfo->isnull = false;
result = FunctionCallInvoke(fcinfo);
/* if the arguments are equal return null */
if (!fcinfo->isnull && DatumGetBool(result))
{
*isNull = true;
return (Datum) 0;
}
}
/* else return first argument */
*isNull = fcinfo->argnull[0];
return fcinfo->arg[0];
}
/* ----------------------------------------------------------------
* ExecEvalNullTest
*
* Evaluate a NullTest node.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalNullTest(NullTestState *nstate,
ExprContext *econtext,
bool *isNull)
{
NullTest *ntest = (NullTest *) nstate->xprstate.expr;
Datum result;
result = ExecEvalExpr(nstate->arg, econtext, isNull);
if (ntest->argisrow && !(*isNull))
{
/*
* The SQL standard defines IS [NOT] NULL for a non-null rowtype
* argument as:
*
* "R IS NULL" is true if every field is the null value.
*
* "R IS NOT NULL" is true if no field is the null value.
*
* This definition is (apparently intentionally) not recursive; so our
* tests on the fields are primitive attisnull tests, not recursive
* checks to see if they are all-nulls or no-nulls rowtypes.
*
* The standard does not consider the possibility of zero-field rows,
* but here we consider them to vacuously satisfy both predicates.
*/
HeapTupleHeader tuple;
Oid tupType;
int32 tupTypmod;
TupleDesc tupDesc;
HeapTupleData tmptup;
int att;
tuple = DatumGetHeapTupleHeader(result);
tupType = HeapTupleHeaderGetTypeId(tuple);
tupTypmod = HeapTupleHeaderGetTypMod(tuple);
/* Lookup tupdesc if first time through or if type changes */
tupDesc = get_cached_rowtype(tupType, tupTypmod,
&nstate->argdesc, econtext);
/*
* heap_attisnull needs a HeapTuple not a bare HeapTupleHeader.
*/
tmptup.t_len = HeapTupleHeaderGetDatumLength(tuple);
tmptup.t_data = tuple;
for (att = 1; att <= tupDesc->natts; att++)
{
/* ignore dropped columns */
if (tupDesc->attrs[att - 1]->attisdropped)
continue;
if (heap_attisnull(&tmptup, att))
{
/* null field disproves IS NOT NULL */
if (ntest->nulltesttype == IS_NOT_NULL)
return BoolGetDatum(false);
}
else
{
/* non-null field disproves IS NULL */
if (ntest->nulltesttype == IS_NULL)
return BoolGetDatum(false);
}
}
return BoolGetDatum(true);
}
else
{
/* Simple scalar-argument case, or a null rowtype datum */
switch (ntest->nulltesttype)
{
case IS_NULL:
if (*isNull)
{
*isNull = false;
return BoolGetDatum(true);
}
else
return BoolGetDatum(false);
case IS_NOT_NULL:
if (*isNull)
{
*isNull = false;
return BoolGetDatum(false);
}
else
return BoolGetDatum(true);
default:
elog(ERROR, "unrecognized nulltesttype: %d",
(int) ntest->nulltesttype);
return (Datum) 0; /* keep compiler quiet */
}
}
}
/* ----------------------------------------------------------------
* ExecEvalBooleanTest
*
* Evaluate a BooleanTest node.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalBooleanTest(GenericExprState *bstate,
ExprContext *econtext,
bool *isNull)
{
BooleanTest *btest = (BooleanTest *) bstate->xprstate.expr;
Datum result;
result = ExecEvalExpr(bstate->arg, econtext, isNull);
switch (btest->booltesttype)
{
case IS_TRUE:
if (*isNull)
{
*isNull = false;
return BoolGetDatum(false);
}
else if (DatumGetBool(result))
return BoolGetDatum(true);
else
return BoolGetDatum(false);
case IS_NOT_TRUE:
if (*isNull)
{
*isNull = false;
return BoolGetDatum(true);
}
else if (DatumGetBool(result))
return BoolGetDatum(false);
else
return BoolGetDatum(true);
case IS_FALSE:
if (*isNull)
{
*isNull = false;
return BoolGetDatum(false);
}
else if (DatumGetBool(result))
return BoolGetDatum(false);
else
return BoolGetDatum(true);
case IS_NOT_FALSE:
if (*isNull)
{
*isNull = false;
return BoolGetDatum(true);
}
else if (DatumGetBool(result))
return BoolGetDatum(true);
else
return BoolGetDatum(false);
case IS_UNKNOWN:
if (*isNull)
{
*isNull = false;
return BoolGetDatum(true);
}
else
return BoolGetDatum(false);
case IS_NOT_UNKNOWN:
if (*isNull)
{
*isNull = false;
return BoolGetDatum(false);
}
else
return BoolGetDatum(true);
default:
elog(ERROR, "unrecognized booltesttype: %d",
(int) btest->booltesttype);
return (Datum) 0; /* keep compiler quiet */
}
}
/*
* ExecEvalCoerceToDomain
*
* Test the provided data against the domain constraint(s). If the data
* passes the constraint specifications, pass it through (return the
* datum) otherwise throw an error.
*/
static Datum
ExecEvalCoerceToDomain(CoerceToDomainState *cstate, ExprContext *econtext,
bool *isNull)
{
CoerceToDomain *ctest = (CoerceToDomain *) cstate->xprstate.expr;
Datum result;
ListCell *l;
result = ExecEvalExpr(cstate->arg, econtext, isNull);
/* Make sure we have up-to-date constraints */
UpdateDomainConstraintRef(cstate->constraint_ref);
foreach(l, cstate->constraint_ref->constraints)
{
DomainConstraintState *con = (DomainConstraintState *) lfirst(l);
switch (con->constrainttype)
{
case DOM_CONSTRAINT_NOTNULL:
if (*isNull)
ereport(ERROR,
(errcode(ERRCODE_NOT_NULL_VIOLATION),
errmsg("domain %s does not allow null values",
format_type_be(ctest->resulttype)),
errdatatype(ctest->resulttype)));
break;
case DOM_CONSTRAINT_CHECK:
{
Datum conResult;
bool conIsNull;
Datum save_datum;
bool save_isNull;
/*
* Set up value to be returned by CoerceToDomainValue
* nodes. We must save and restore prior setting of
* econtext's domainValue fields, in case this node is
* itself within a check expression for another domain.
*
* Also, if we are working with a read-write expanded
* datum, be sure that what we pass to CHECK expressions
* is a read-only pointer; else called functions might
* modify or even delete the expanded object.
*/
save_datum = econtext->domainValue_datum;
save_isNull = econtext->domainValue_isNull;
econtext->domainValue_datum =
MakeExpandedObjectReadOnly(result, *isNull,
cstate->constraint_ref->tcache->typlen);
econtext->domainValue_isNull = *isNull;
conResult = ExecEvalExpr(con->check_expr, econtext,
&conIsNull);
if (!conIsNull &&
!DatumGetBool(conResult))
ereport(ERROR,
(errcode(ERRCODE_CHECK_VIOLATION),
errmsg("value for domain %s violates check constraint \"%s\"",
format_type_be(ctest->resulttype),
con->name),
errdomainconstraint(ctest->resulttype,
con->name)));
econtext->domainValue_datum = save_datum;
econtext->domainValue_isNull = save_isNull;
break;
}
default:
elog(ERROR, "unrecognized constraint type: %d",
(int) con->constrainttype);
break;
}
}
/* If all has gone well (constraints did not fail) return the datum */
return result;
}
/*
* ExecEvalCoerceToDomainValue
*
* Return the value stored by CoerceToDomain.
*/
static Datum
ExecEvalCoerceToDomainValue(ExprState *exprstate,
ExprContext *econtext,
bool *isNull)
{
*isNull = econtext->domainValue_isNull;
return econtext->domainValue_datum;
}
/* ----------------------------------------------------------------
* ExecEvalFieldSelect
*
* Evaluate a FieldSelect node.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalFieldSelect(FieldSelectState *fstate,
ExprContext *econtext,
bool *isNull)
{
FieldSelect *fselect = (FieldSelect *) fstate->xprstate.expr;
AttrNumber fieldnum = fselect->fieldnum;
Datum result;
Datum tupDatum;
HeapTupleHeader tuple;
Oid tupType;
int32 tupTypmod;
TupleDesc tupDesc;
Form_pg_attribute attr;
HeapTupleData tmptup;
tupDatum = ExecEvalExpr(fstate->arg, econtext, isNull);
if (*isNull)
return tupDatum;
tuple = DatumGetHeapTupleHeader(tupDatum);
tupType = HeapTupleHeaderGetTypeId(tuple);
tupTypmod = HeapTupleHeaderGetTypMod(tuple);
/* Lookup tupdesc if first time through or if type changes */
tupDesc = get_cached_rowtype(tupType, tupTypmod,
&fstate->argdesc, econtext);
/*
* Find field's attr record. Note we don't support system columns here: a
* datum tuple doesn't have valid values for most of the interesting
* system columns anyway.
*/
if (fieldnum <= 0) /* should never happen */
elog(ERROR, "unsupported reference to system column %d in FieldSelect",
fieldnum);
if (fieldnum > tupDesc->natts) /* should never happen */
elog(ERROR, "attribute number %d exceeds number of columns %d",
fieldnum, tupDesc->natts);
attr = tupDesc->attrs[fieldnum - 1];
/* Check for dropped column, and force a NULL result if so */
if (attr->attisdropped)
{
*isNull = true;
return (Datum) 0;
}
/* Check for type mismatch --- possible after ALTER COLUMN TYPE? */
/* As in ExecEvalScalarVar, we should but can't check typmod */
if (fselect->resulttype != attr->atttypid)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("attribute %d has wrong type", fieldnum),
errdetail("Table has type %s, but query expects %s.",
format_type_be(attr->atttypid),
format_type_be(fselect->resulttype))));
/* heap_getattr needs a HeapTuple not a bare HeapTupleHeader */
tmptup.t_len = HeapTupleHeaderGetDatumLength(tuple);
tmptup.t_data = tuple;
result = heap_getattr(&tmptup,
fieldnum,
tupDesc,
isNull);
return result;
}
/* ----------------------------------------------------------------
* ExecEvalFieldStore
*
* Evaluate a FieldStore node.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalFieldStore(FieldStoreState *fstate,
ExprContext *econtext,
bool *isNull)
{
FieldStore *fstore = (FieldStore *) fstate->xprstate.expr;
HeapTuple tuple;
Datum tupDatum;
TupleDesc tupDesc;
Datum *values;
bool *isnull;
Datum save_datum;
bool save_isNull;
ListCell *l1,
*l2;
tupDatum = ExecEvalExpr(fstate->arg, econtext, isNull);
/* Lookup tupdesc if first time through or after rescan */
tupDesc = get_cached_rowtype(fstore->resulttype, -1,
&fstate->argdesc, econtext);
/* Allocate workspace */
values = (Datum *) palloc(tupDesc->natts * sizeof(Datum));
isnull = (bool *) palloc(tupDesc->natts * sizeof(bool));
if (!*isNull)
{
/*
* heap_deform_tuple needs a HeapTuple not a bare HeapTupleHeader. We
* set all the fields in the struct just in case.
*/
HeapTupleHeader tuphdr;
HeapTupleData tmptup;
tuphdr = DatumGetHeapTupleHeader(tupDatum);
tmptup.t_len = HeapTupleHeaderGetDatumLength(tuphdr);
ItemPointerSetInvalid(&(tmptup.t_self));
tmptup.t_tableOid = InvalidOid;
tmptup.t_data = tuphdr;
heap_deform_tuple(&tmptup, tupDesc, values, isnull);
}
else
{
/* Convert null input tuple into an all-nulls row */
memset(isnull, true, tupDesc->natts * sizeof(bool));
}
/* Result is never null */
*isNull = false;
save_datum = econtext->caseValue_datum;
save_isNull = econtext->caseValue_isNull;
forboth(l1, fstate->newvals, l2, fstore->fieldnums)
{
ExprState *newval = (ExprState *) lfirst(l1);
AttrNumber fieldnum = lfirst_int(l2);
Assert(fieldnum > 0 && fieldnum <= tupDesc->natts);
/*
* Use the CaseTestExpr mechanism to pass down the old value of the
* field being replaced; this is needed in case the newval is itself a
* FieldStore or ArrayRef that has to obtain and modify the old value.
* It's safe to reuse the CASE mechanism because there cannot be a
* CASE between here and where the value would be needed, and a field
* assignment can't be within a CASE either. (So saving and restoring
* the caseValue is just paranoia, but let's do it anyway.)
*/
econtext->caseValue_datum = values[fieldnum - 1];
econtext->caseValue_isNull = isnull[fieldnum - 1];
values[fieldnum - 1] = ExecEvalExpr(newval,
econtext,
&isnull[fieldnum - 1]);
}
econtext->caseValue_datum = save_datum;
econtext->caseValue_isNull = save_isNull;
tuple = heap_form_tuple(tupDesc, values, isnull);
pfree(values);
pfree(isnull);
return HeapTupleGetDatum(tuple);
}
/* ----------------------------------------------------------------
* ExecEvalRelabelType
*
* Evaluate a RelabelType node.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalRelabelType(GenericExprState *exprstate,
ExprContext *econtext,
bool *isNull)
{
return ExecEvalExpr(exprstate->arg, econtext, isNull);
}
/* ----------------------------------------------------------------
* ExecEvalCoerceViaIO
*
* Evaluate a CoerceViaIO node.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalCoerceViaIO(CoerceViaIOState *iostate,
ExprContext *econtext,
bool *isNull)
{
Datum result;
Datum inputval;
char *string;
inputval = ExecEvalExpr(iostate->arg, econtext, isNull);
if (*isNull)
string = NULL; /* output functions are not called on nulls */
else
string = OutputFunctionCall(&iostate->outfunc, inputval);
result = InputFunctionCall(&iostate->infunc,
string,
iostate->intypioparam,
-1);
/* The input function cannot change the null/not-null status */
return result;
}
/* ----------------------------------------------------------------
* ExecEvalArrayCoerceExpr
*
* Evaluate an ArrayCoerceExpr node.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalArrayCoerceExpr(ArrayCoerceExprState *astate,
ExprContext *econtext,
bool *isNull)
{
ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) astate->xprstate.expr;
Datum result;
FunctionCallInfoData locfcinfo;
result = ExecEvalExpr(astate->arg, econtext, isNull);
if (*isNull)
return result; /* nothing to do */
/*
* If it's binary-compatible, modify the element type in the array header,
* but otherwise leave the array as we received it.
*/
if (!OidIsValid(acoerce->elemfuncid))
{
/* Detoast input array if necessary, and copy in any case */
ArrayType *array = DatumGetArrayTypePCopy(result);
ARR_ELEMTYPE(array) = astate->resultelemtype;
PG_RETURN_ARRAYTYPE_P(array);
}
/* Initialize function cache if first time through */
if (astate->elemfunc.fn_oid == InvalidOid)
{
AclResult aclresult;
/* Check permission to call function */
aclresult = pg_proc_aclcheck(acoerce->elemfuncid, GetUserId(),
ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_PROC,
get_func_name(acoerce->elemfuncid));
InvokeFunctionExecuteHook(acoerce->elemfuncid);
/* Set up the primary fmgr lookup information */
fmgr_info_cxt(acoerce->elemfuncid, &(astate->elemfunc),
econtext->ecxt_per_query_memory);
fmgr_info_set_expr((Node *) acoerce, &(astate->elemfunc));
}
/*
* Use array_map to apply the function to each array element.
*
* We pass on the desttypmod and isExplicit flags whether or not the
* function wants them.
*
* Note: coercion functions are assumed to not use collation.
*/
InitFunctionCallInfoData(locfcinfo, &(astate->elemfunc), 3,
InvalidOid, NULL, NULL);
locfcinfo.arg[0] = result;
locfcinfo.arg[1] = Int32GetDatum(acoerce->resulttypmod);
locfcinfo.arg[2] = BoolGetDatum(acoerce->isExplicit);
locfcinfo.argnull[0] = false;
locfcinfo.argnull[1] = false;
locfcinfo.argnull[2] = false;
return array_map(&locfcinfo, astate->resultelemtype, astate->amstate);
}
/* ----------------------------------------------------------------
* ExecEvalCurrentOfExpr
*
* The planner should convert CURRENT OF into a TidScan qualification, or some
* other special handling in a ForeignScan node. So we have to be able to do
* ExecInitExpr on a CurrentOfExpr, but we shouldn't ever actually execute it.
* If we get here, we suppose we must be dealing with CURRENT OF on a foreign
* table whose FDW doesn't handle it, and complain accordingly.
* ----------------------------------------------------------------
*/
static Datum
ExecEvalCurrentOfExpr(ExprState *exprstate, ExprContext *econtext,
bool *isNull)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("WHERE CURRENT OF is not supported for this table type")));
return 0; /* keep compiler quiet */
}
/*
* ExecEvalExprSwitchContext
*
* Same as ExecEvalExpr, but get into the right allocation context explicitly.
*/
Datum
ExecEvalExprSwitchContext(ExprState *expression,
ExprContext *econtext,
bool *isNull)
{
Datum retDatum;
MemoryContext oldContext;
oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
retDatum = ExecEvalExpr(expression, econtext, isNull);
MemoryContextSwitchTo(oldContext);
return retDatum;
}
/*
* ExecInitExpr: prepare an expression tree for execution
*
* This function builds and returns an ExprState tree paralleling the given
* Expr node tree. The ExprState tree can then be handed to ExecEvalExpr
* for execution. Because the Expr tree itself is read-only as far as
* ExecInitExpr and ExecEvalExpr are concerned, several different executions
* of the same plan tree can occur concurrently.
*
* This must be called in a memory context that will last as long as repeated
* executions of the expression are needed. Typically the context will be
* the same as the per-query context of the associated ExprContext.
*
* Any Aggref, WindowFunc, or SubPlan nodes found in the tree are added to the
* lists of such nodes held by the parent PlanState. Otherwise, we do very
* little initialization here other than building the state-node tree. Any
* nontrivial work associated with initializing runtime info for a node should
* happen during the first actual evaluation of that node. (This policy lets
* us avoid work if the node is never actually evaluated.)
*
* Note: there is no ExecEndExpr function; we assume that any resource
* cleanup needed will be handled by just releasing the memory context
* in which the state tree is built. Functions that require additional
* cleanup work can register a shutdown callback in the ExprContext.
*
* 'node' is the root of the expression tree to examine
* 'parent' is the PlanState node that owns the expression.
*
* 'parent' may be NULL if we are preparing an expression that is not
* associated with a plan tree. (If so, it can't have aggs or subplans.)
* This case should usually come through ExecPrepareExpr, not directly here.
*/
ExprState *
ExecInitExpr(Expr *node, PlanState *parent)
{
ExprState *state;
if (node == NULL)
return NULL;
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
switch (nodeTag(node))
{
case T_Var:
/* varattno == InvalidAttrNumber means it's a whole-row Var */
if (((Var *) node)->varattno == InvalidAttrNumber)
{
WholeRowVarExprState *wstate = makeNode(WholeRowVarExprState);
wstate->parent = parent;
wstate->wrv_tupdesc = NULL;
wstate->wrv_junkFilter = NULL;
state = (ExprState *) wstate;
state->evalfunc = (ExprStateEvalFunc) ExecEvalWholeRowVar;
}
else
{
state = makeNode(ExprState);
state->evalfunc = ExecEvalScalarVar;
}
break;
case T_Const:
state = makeNode(ExprState);
state->evalfunc = ExecEvalConst;
break;
case T_Param:
state = makeNode(ExprState);
switch (((Param *) node)->paramkind)
{
case PARAM_EXEC:
state->evalfunc = ExecEvalParamExec;
break;
case PARAM_EXTERN:
state->evalfunc = ExecEvalParamExtern;
break;
default:
elog(ERROR, "unrecognized paramkind: %d",
(int) ((Param *) node)->paramkind);
break;
}
break;
case T_CoerceToDomainValue:
state = makeNode(ExprState);
state->evalfunc = ExecEvalCoerceToDomainValue;
break;
case T_CaseTestExpr:
state = makeNode(ExprState);
state->evalfunc = ExecEvalCaseTestExpr;
break;
case T_Aggref:
{
AggrefExprState *astate = makeNode(AggrefExprState);
astate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalAggref;
if (parent && IsA(parent, AggState))
{
AggState *aggstate = (AggState *) parent;
aggstate->aggs = lcons(astate, aggstate->aggs);
aggstate->numaggs++;
}
else
{
/* planner messed up */
elog(ERROR, "Aggref found in non-Agg plan node");
}
state = (ExprState *) astate;
}
break;
case T_GroupingFunc:
{
GroupingFunc *grp_node = (GroupingFunc *) node;
GroupingFuncExprState *grp_state = makeNode(GroupingFuncExprState);
Agg *agg = NULL;
if (!parent || !IsA(parent, AggState) ||!IsA(parent->plan, Agg))
elog(ERROR, "parent of GROUPING is not Agg node");
grp_state->aggstate = (AggState *) parent;
agg = (Agg *) (parent->plan);
if (agg->groupingSets)
grp_state->clauses = grp_node->cols;
else
grp_state->clauses = NIL;
state = (ExprState *) grp_state;
state->evalfunc = (ExprStateEvalFunc) ExecEvalGroupingFuncExpr;
}
break;
case T_WindowFunc:
{
WindowFunc *wfunc = (WindowFunc *) node;
WindowFuncExprState *wfstate = makeNode(WindowFuncExprState);
wfstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalWindowFunc;
if (parent && IsA(parent, WindowAggState))
{
WindowAggState *winstate = (WindowAggState *) parent;
int nfuncs;
winstate->funcs = lcons(wfstate, winstate->funcs);
nfuncs = ++winstate->numfuncs;
if (wfunc->winagg)
winstate->numaggs++;
wfstate->args = (List *) ExecInitExpr((Expr *) wfunc->args,
parent);
wfstate->aggfilter = ExecInitExpr(wfunc->aggfilter,
parent);
/*
* Complain if the windowfunc's arguments contain any
* windowfuncs; nested window functions are semantically
* nonsensical. (This should have been caught earlier,
* but we defend against it here anyway.)
*/
if (nfuncs != winstate->numfuncs)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("window function calls cannot be nested")));
}
else
{
/* planner messed up */
elog(ERROR, "WindowFunc found in non-WindowAgg plan node");
}
state = (ExprState *) wfstate;
}
break;
case T_ArrayRef:
{
ArrayRef *aref = (ArrayRef *) node;
ArrayRefExprState *astate = makeNode(ArrayRefExprState);
astate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalArrayRef;
astate->refupperindexpr = (List *)
ExecInitExpr((Expr *) aref->refupperindexpr, parent);
astate->reflowerindexpr = (List *)
ExecInitExpr((Expr *) aref->reflowerindexpr, parent);
astate->refexpr = ExecInitExpr(aref->refexpr, parent);
astate->refassgnexpr = ExecInitExpr(aref->refassgnexpr,
parent);
/* do one-time catalog lookups for type info */
astate->refattrlength = get_typlen(aref->refarraytype);
get_typlenbyvalalign(aref->refelemtype,
&astate->refelemlength,
&astate->refelembyval,
&astate->refelemalign);
state = (ExprState *) astate;
}
break;
case T_FuncExpr:
{
FuncExpr *funcexpr = (FuncExpr *) node;
FuncExprState *fstate = makeNode(FuncExprState);
fstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalFunc;
fstate->args = (List *)
ExecInitExpr((Expr *) funcexpr->args, parent);
fstate->func.fn_oid = InvalidOid; /* not initialized */
fstate->funcReturnsSet = funcexpr->funcretset;
state = (ExprState *) fstate;
}
break;
case T_OpExpr:
{
OpExpr *opexpr = (OpExpr *) node;
FuncExprState *fstate = makeNode(FuncExprState);
fstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalOper;
fstate->args = (List *)
ExecInitExpr((Expr *) opexpr->args, parent);
fstate->func.fn_oid = InvalidOid; /* not initialized */
fstate->funcReturnsSet = opexpr->opretset;
state = (ExprState *) fstate;
}
break;
case T_DistinctExpr:
{
DistinctExpr *distinctexpr = (DistinctExpr *) node;
FuncExprState *fstate = makeNode(FuncExprState);
fstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalDistinct;
fstate->args = (List *)
ExecInitExpr((Expr *) distinctexpr->args, parent);
fstate->func.fn_oid = InvalidOid; /* not initialized */
fstate->funcReturnsSet = false; /* not supported */
state = (ExprState *) fstate;
}
break;
case T_NullIfExpr:
{
NullIfExpr *nullifexpr = (NullIfExpr *) node;
FuncExprState *fstate = makeNode(FuncExprState);
fstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalNullIf;
fstate->args = (List *)
ExecInitExpr((Expr *) nullifexpr->args, parent);
fstate->func.fn_oid = InvalidOid; /* not initialized */
fstate->funcReturnsSet = false; /* not supported */
state = (ExprState *) fstate;
}
break;
case T_ScalarArrayOpExpr:
{
ScalarArrayOpExpr *opexpr = (ScalarArrayOpExpr *) node;
ScalarArrayOpExprState *sstate = makeNode(ScalarArrayOpExprState);
sstate->fxprstate.xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalScalarArrayOp;
sstate->fxprstate.args = (List *)
ExecInitExpr((Expr *) opexpr->args, parent);
sstate->fxprstate.func.fn_oid = InvalidOid; /* not initialized */
sstate->fxprstate.funcReturnsSet = false; /* not supported */
sstate->element_type = InvalidOid; /* ditto */
state = (ExprState *) sstate;
}
break;
case T_BoolExpr:
{
BoolExpr *boolexpr = (BoolExpr *) node;
BoolExprState *bstate = makeNode(BoolExprState);
switch (boolexpr->boolop)
{
case AND_EXPR:
bstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalAnd;
break;
case OR_EXPR:
bstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalOr;
break;
case NOT_EXPR:
bstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalNot;
break;
default:
elog(ERROR, "unrecognized boolop: %d",
(int) boolexpr->boolop);
break;
}
bstate->args = (List *)
ExecInitExpr((Expr *) boolexpr->args, parent);
state = (ExprState *) bstate;
}
break;
case T_SubPlan:
{
SubPlan *subplan = (SubPlan *) node;
SubPlanState *sstate;
if (!parent)
elog(ERROR, "SubPlan found with no parent plan");
sstate = ExecInitSubPlan(subplan, parent);
/* Add SubPlanState nodes to parent->subPlan */
parent->subPlan = lappend(parent->subPlan, sstate);
state = (ExprState *) sstate;
}
break;
case T_AlternativeSubPlan:
{
AlternativeSubPlan *asplan = (AlternativeSubPlan *) node;
AlternativeSubPlanState *asstate;
if (!parent)
elog(ERROR, "AlternativeSubPlan found with no parent plan");
asstate = ExecInitAlternativeSubPlan(asplan, parent);
state = (ExprState *) asstate;
}
break;
case T_FieldSelect:
{
FieldSelect *fselect = (FieldSelect *) node;
FieldSelectState *fstate = makeNode(FieldSelectState);
fstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalFieldSelect;
fstate->arg = ExecInitExpr(fselect->arg, parent);
fstate->argdesc = NULL;
state = (ExprState *) fstate;
}
break;
case T_FieldStore:
{
FieldStore *fstore = (FieldStore *) node;
FieldStoreState *fstate = makeNode(FieldStoreState);
fstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalFieldStore;
fstate->arg = ExecInitExpr(fstore->arg, parent);
fstate->newvals = (List *) ExecInitExpr((Expr *) fstore->newvals, parent);
fstate->argdesc = NULL;
state = (ExprState *) fstate;
}
break;
case T_RelabelType:
{
RelabelType *relabel = (RelabelType *) node;
GenericExprState *gstate = makeNode(GenericExprState);
gstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalRelabelType;
gstate->arg = ExecInitExpr(relabel->arg, parent);
state = (ExprState *) gstate;
}
break;
case T_CoerceViaIO:
{
CoerceViaIO *iocoerce = (CoerceViaIO *) node;
CoerceViaIOState *iostate = makeNode(CoerceViaIOState);
Oid iofunc;
bool typisvarlena;
iostate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalCoerceViaIO;
iostate->arg = ExecInitExpr(iocoerce->arg, parent);
/* lookup the result type's input function */
getTypeInputInfo(iocoerce->resulttype, &iofunc,
&iostate->intypioparam);
fmgr_info(iofunc, &iostate->infunc);
/* lookup the input type's output function */
getTypeOutputInfo(exprType((Node *) iocoerce->arg),
&iofunc, &typisvarlena);
fmgr_info(iofunc, &iostate->outfunc);
state = (ExprState *) iostate;
}
break;
case T_ArrayCoerceExpr:
{
ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) node;
ArrayCoerceExprState *astate = makeNode(ArrayCoerceExprState);
astate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalArrayCoerceExpr;
astate->arg = ExecInitExpr(acoerce->arg, parent);
astate->resultelemtype = get_element_type(acoerce->resulttype);
if (astate->resultelemtype == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("target type is not an array")));
/* Arrays over domains aren't supported yet */
Assert(getBaseType(astate->resultelemtype) ==
astate->resultelemtype);
astate->elemfunc.fn_oid = InvalidOid; /* not initialized */
astate->amstate = (ArrayMapState *) palloc0(sizeof(ArrayMapState));
state = (ExprState *) astate;
}
break;
case T_ConvertRowtypeExpr:
{
ConvertRowtypeExpr *convert = (ConvertRowtypeExpr *) node;
ConvertRowtypeExprState *cstate = makeNode(ConvertRowtypeExprState);
cstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalConvertRowtype;
cstate->arg = ExecInitExpr(convert->arg, parent);
state = (ExprState *) cstate;
}
break;
case T_CaseExpr:
{
CaseExpr *caseexpr = (CaseExpr *) node;
CaseExprState *cstate = makeNode(CaseExprState);
List *outlist = NIL;
ListCell *l;
cstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalCase;
cstate->arg = ExecInitExpr(caseexpr->arg, parent);
foreach(l, caseexpr->args)
{
CaseWhen *when = castNode(CaseWhen, lfirst(l));
CaseWhenState *wstate = makeNode(CaseWhenState);
wstate->xprstate.evalfunc = NULL; /* not used */
wstate->xprstate.expr = (Expr *) when;
wstate->expr = ExecInitExpr(when->expr, parent);
wstate->result = ExecInitExpr(when->result, parent);
outlist = lappend(outlist, wstate);
}
cstate->args = outlist;
cstate->defresult = ExecInitExpr(caseexpr->defresult, parent);
if (caseexpr->arg)
cstate->argtyplen = get_typlen(exprType((Node *) caseexpr->arg));
state = (ExprState *) cstate;
}
break;
case T_ArrayExpr:
{
ArrayExpr *arrayexpr = (ArrayExpr *) node;
ArrayExprState *astate = makeNode(ArrayExprState);
List *outlist = NIL;
ListCell *l;
astate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalArray;
foreach(l, arrayexpr->elements)
{
Expr *e = (Expr *) lfirst(l);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
}
astate->elements = outlist;
/* do one-time catalog lookup for type info */
get_typlenbyvalalign(arrayexpr->element_typeid,
&astate->elemlength,
&astate->elembyval,
&astate->elemalign);
state = (ExprState *) astate;
}
break;
case T_RowExpr:
{
RowExpr *rowexpr = (RowExpr *) node;
RowExprState *rstate = makeNode(RowExprState);
Form_pg_attribute *attrs;
List *outlist = NIL;
ListCell *l;
int i;
rstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalRow;
/* Build tupdesc to describe result tuples */
if (rowexpr->row_typeid == RECORDOID)
{
/* generic record, use types of given expressions */
rstate->tupdesc = ExecTypeFromExprList(rowexpr->args);
}
else
{
/* it's been cast to a named type, use that */
rstate->tupdesc = lookup_rowtype_tupdesc_copy(rowexpr->row_typeid, -1);
}
/* In either case, adopt RowExpr's column aliases */
ExecTypeSetColNames(rstate->tupdesc, rowexpr->colnames);
/* Bless the tupdesc in case it's now of type RECORD */
BlessTupleDesc(rstate->tupdesc);
/* Set up evaluation, skipping any deleted columns */
Assert(list_length(rowexpr->args) <= rstate->tupdesc->natts);
attrs = rstate->tupdesc->attrs;
i = 0;
foreach(l, rowexpr->args)
{
Expr *e = (Expr *) lfirst(l);
ExprState *estate;
if (!attrs[i]->attisdropped)
{
/*
* Guard against ALTER COLUMN TYPE on rowtype since
* the RowExpr was created. XXX should we check
* typmod too? Not sure we can be sure it'll be the
* same.
*/
if (exprType((Node *) e) != attrs[i]->atttypid)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("ROW() column has type %s instead of type %s",
format_type_be(exprType((Node *) e)),
format_type_be(attrs[i]->atttypid))));
}
else
{
/*
* Ignore original expression and insert a NULL. We
* don't really care what type of NULL it is, so
* always make an int4 NULL.
*/
e = (Expr *) makeNullConst(INT4OID, -1, InvalidOid);
}
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
i++;
}
rstate->args = outlist;
state = (ExprState *) rstate;
}
break;
case T_RowCompareExpr:
{
RowCompareExpr *rcexpr = (RowCompareExpr *) node;
RowCompareExprState *rstate = makeNode(RowCompareExprState);
int nopers = list_length(rcexpr->opnos);
List *outlist;
ListCell *l;
ListCell *l2;
ListCell *l3;
int i;
rstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalRowCompare;
Assert(list_length(rcexpr->largs) == nopers);
outlist = NIL;
foreach(l, rcexpr->largs)
{
Expr *e = (Expr *) lfirst(l);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
}
rstate->largs = outlist;
Assert(list_length(rcexpr->rargs) == nopers);
outlist = NIL;
foreach(l, rcexpr->rargs)
{
Expr *e = (Expr *) lfirst(l);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
}
rstate->rargs = outlist;
Assert(list_length(rcexpr->opfamilies) == nopers);
rstate->funcs = (FmgrInfo *) palloc(nopers * sizeof(FmgrInfo));
rstate->collations = (Oid *) palloc(nopers * sizeof(Oid));
i = 0;
forthree(l, rcexpr->opnos, l2, rcexpr->opfamilies, l3, rcexpr->inputcollids)
{
Oid opno = lfirst_oid(l);
Oid opfamily = lfirst_oid(l2);
Oid inputcollid = lfirst_oid(l3);
int strategy;
Oid lefttype;
Oid righttype;
Oid proc;
get_op_opfamily_properties(opno, opfamily, false,
&strategy,
&lefttype,
&righttype);
proc = get_opfamily_proc(opfamily,
lefttype,
righttype,
BTORDER_PROC);
/*
* If we enforced permissions checks on index support
* functions, we'd need to make a check here. But the
* index support machinery doesn't do that, and neither
* does this code.
*/
fmgr_info(proc, &(rstate->funcs[i]));
rstate->collations[i] = inputcollid;
i++;
}
state = (ExprState *) rstate;
}
break;
case T_CoalesceExpr:
{
CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;
CoalesceExprState *cstate = makeNode(CoalesceExprState);
List *outlist = NIL;
ListCell *l;
cstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalCoalesce;
foreach(l, coalesceexpr->args)
{
Expr *e = (Expr *) lfirst(l);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
}
cstate->args = outlist;
state = (ExprState *) cstate;
}
break;
case T_MinMaxExpr:
{
MinMaxExpr *minmaxexpr = (MinMaxExpr *) node;
MinMaxExprState *mstate = makeNode(MinMaxExprState);
List *outlist = NIL;
ListCell *l;
TypeCacheEntry *typentry;
mstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalMinMax;
foreach(l, minmaxexpr->args)
{
Expr *e = (Expr *) lfirst(l);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
}
mstate->args = outlist;
/* Look up the btree comparison function for the datatype */
typentry = lookup_type_cache(minmaxexpr->minmaxtype,
TYPECACHE_CMP_PROC);
if (!OidIsValid(typentry->cmp_proc))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("could not identify a comparison function for type %s",
format_type_be(minmaxexpr->minmaxtype))));
/*
* If we enforced permissions checks on index support
* functions, we'd need to make a check here. But the index
* support machinery doesn't do that, and neither does this
* code.
*/
fmgr_info(typentry->cmp_proc, &(mstate->cfunc));
state = (ExprState *) mstate;
}
break;
case T_SQLValueFunction:
state = makeNode(ExprState);
state->evalfunc = ExecEvalSQLValueFunction;
break;
case T_XmlExpr:
{
XmlExpr *xexpr = (XmlExpr *) node;
XmlExprState *xstate = makeNode(XmlExprState);
List *outlist;
ListCell *arg;
xstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalXml;
outlist = NIL;
foreach(arg, xexpr->named_args)
{
Expr *e = (Expr *) lfirst(arg);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
}
xstate->named_args = outlist;
outlist = NIL;
foreach(arg, xexpr->args)
{
Expr *e = (Expr *) lfirst(arg);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
}
xstate->args = outlist;
state = (ExprState *) xstate;
}
break;
case T_NullTest:
{
NullTest *ntest = (NullTest *) node;
NullTestState *nstate = makeNode(NullTestState);
nstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalNullTest;
nstate->arg = ExecInitExpr(ntest->arg, parent);
nstate->argdesc = NULL;
state = (ExprState *) nstate;
}
break;
case T_BooleanTest:
{
BooleanTest *btest = (BooleanTest *) node;
GenericExprState *gstate = makeNode(GenericExprState);
gstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalBooleanTest;
gstate->arg = ExecInitExpr(btest->arg, parent);
state = (ExprState *) gstate;
}
break;
case T_CoerceToDomain:
{
CoerceToDomain *ctest = (CoerceToDomain *) node;
CoerceToDomainState *cstate = makeNode(CoerceToDomainState);
cstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalCoerceToDomain;
cstate->arg = ExecInitExpr(ctest->arg, parent);
/* We spend an extra palloc to reduce header inclusions */
cstate->constraint_ref = (DomainConstraintRef *)
palloc(sizeof(DomainConstraintRef));
InitDomainConstraintRef(ctest->resulttype,
cstate->constraint_ref,
CurrentMemoryContext);
state = (ExprState *) cstate;
}
break;
case T_CurrentOfExpr:
state = makeNode(ExprState);
state->evalfunc = ExecEvalCurrentOfExpr;
break;
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *) node;
GenericExprState *gstate = makeNode(GenericExprState);
gstate->xprstate.evalfunc = NULL; /* not used */
gstate->arg = ExecInitExpr(tle->expr, parent);
state = (ExprState *) gstate;
}
break;
case T_List:
{
List *outlist = NIL;
ListCell *l;
foreach(l, (List *) node)
{
outlist = lappend(outlist,
ExecInitExpr((Expr *) lfirst(l),
parent));
}
/* Don't fall through to the "common" code below */
return (ExprState *) outlist;
}
default:
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(node));
state = NULL; /* keep compiler quiet */
break;
}
/* Common code for all state-node types */
state->expr = node;
return state;
}
/*
* ExecPrepareExpr --- initialize for expression execution outside a normal
* Plan tree context.
*
* This differs from ExecInitExpr in that we don't assume the caller is
* already running in the EState's per-query context. Also, we run the
* passed expression tree through expression_planner() to prepare it for
* execution. (In ordinary Plan trees the regular planning process will have
* made the appropriate transformations on expressions, but for standalone
* expressions this won't have happened.)
*/
ExprState *
ExecPrepareExpr(Expr *node, EState *estate)
{
ExprState *result;
MemoryContext oldcontext;
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
node = expression_planner(node);
result = ExecInitExpr(node, NULL);
MemoryContextSwitchTo(oldcontext);
return result;
}
/* ----------------------------------------------------------------
* ExecQual / ExecTargetList / ExecProject
* ----------------------------------------------------------------
*/
/* ----------------------------------------------------------------
* ExecQual
*
* Evaluates a conjunctive boolean expression (qual list) and
* returns true iff none of the subexpressions are false.
* (We also return true if the list is empty.)
*
* If some of the subexpressions yield NULL but none yield FALSE,
* then the result of the conjunction is NULL (ie, unknown)
* according to three-valued boolean logic. In this case,
* we return the value specified by the "resultForNull" parameter.
*
* Callers evaluating WHERE clauses should pass resultForNull=FALSE,
* since SQL specifies that tuples with null WHERE results do not
* get selected. On the other hand, callers evaluating constraint
* conditions should pass resultForNull=TRUE, since SQL also specifies
* that NULL constraint conditions are not failures.
*
* NOTE: it would not be correct to use this routine to evaluate an
* AND subclause of a boolean expression; for that purpose, a NULL
* result must be returned as NULL so that it can be properly treated
* in the next higher operator (cf. ExecEvalAnd and ExecEvalOr).
* This routine is only used in contexts where a complete expression
* is being evaluated and we know that NULL can be treated the same
* as one boolean result or the other.
*
* ----------------------------------------------------------------
*/
bool
ExecQual(List *qual, ExprContext *econtext, bool resultForNull)
{
bool result;
MemoryContext oldContext;
ListCell *l;
/*
* debugging stuff
*/
EV_printf("ExecQual: qual is ");
EV_nodeDisplay(qual);
EV_printf("\n");
/*
* Run in short-lived per-tuple context while computing expressions.
*/
oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
/*
* Evaluate the qual conditions one at a time. If we find a FALSE result,
* we can stop evaluating and return FALSE --- the AND result must be
* FALSE. Also, if we find a NULL result when resultForNull is FALSE, we
* can stop and return FALSE --- the AND result must be FALSE or NULL in
* that case, and the caller doesn't care which.
*
* If we get to the end of the list, we can return TRUE. This will happen
* when the AND result is indeed TRUE, or when the AND result is NULL (one
* or more NULL subresult, with all the rest TRUE) and the caller has
* specified resultForNull = TRUE.
*/
result = true;
foreach(l, qual)
{
ExprState *clause = (ExprState *) lfirst(l);
Datum expr_value;
bool isNull;
expr_value = ExecEvalExpr(clause, econtext, &isNull);
if (isNull)
{
if (resultForNull == false)
{
result = false; /* treat NULL as FALSE */
break;
}
}
else
{
if (!DatumGetBool(expr_value))
{
result = false; /* definitely FALSE */
break;
}
}
}
MemoryContextSwitchTo(oldContext);
return result;
}
/*
* Number of items in a tlist (including any resjunk items!)
*/
int
ExecTargetListLength(List *targetlist)
{
/* This used to be more complex, but fjoins are dead */
return list_length(targetlist);
}
/*
* Number of items in a tlist, not including any resjunk items
*/
int
ExecCleanTargetListLength(List *targetlist)
{
int len = 0;
ListCell *tl;
foreach(tl, targetlist)
{
TargetEntry *curTle = castNode(TargetEntry, lfirst(tl));
if (!curTle->resjunk)
len++;
}
return len;
}
/*
* ExecTargetList
* Evaluates a targetlist with respect to the given
* expression context.
*
* tupdesc must describe the rowtype of the expected result.
*
* Results are stored into the passed values and isnull arrays.
*
* Since fields of the result tuple might be multiply referenced in higher
* plan nodes, we have to force any read/write expanded values to read-only
* status. It's a bit annoying to have to do that for every projected
* expression; in the future, consider teaching the planner to detect
* actually-multiply-referenced Vars and insert an expression node that
* would do that only where really required.
*/
static void
ExecTargetList(List *targetlist,
TupleDesc tupdesc,
ExprContext *econtext,
Datum *values,
bool *isnull)
{
Form_pg_attribute *att = tupdesc->attrs;
MemoryContext oldContext;
ListCell *tl;
/*
* Run in short-lived per-tuple context while computing expressions.
*/
oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
/*
* evaluate all the expressions in the target list
*/
foreach(tl, targetlist)
{
GenericExprState *gstate = (GenericExprState *) lfirst(tl);
TargetEntry *tle = (TargetEntry *) gstate->xprstate.expr;
AttrNumber resind = tle->resno - 1;
values[resind] = ExecEvalExpr(gstate->arg,
econtext,
&isnull[resind]);
values[resind] = MakeExpandedObjectReadOnly(values[resind],
isnull[resind],
att[resind]->attlen);
}
MemoryContextSwitchTo(oldContext);
}
/*
* ExecProject
*
* projects a tuple based on projection info and stores
* it in the previously specified tuple table slot.
*
* Note: the result is always a virtual tuple; therefore it
* may reference the contents of the exprContext's scan tuples
* and/or temporary results constructed in the exprContext.
* If the caller wishes the result to be valid longer than that
* data will be valid, he must call ExecMaterializeSlot on the
* result slot.
*/
TupleTableSlot *
ExecProject(ProjectionInfo *projInfo)
{
TupleTableSlot *slot;
ExprContext *econtext;
int numSimpleVars;
/*
* sanity checks
*/
Assert(projInfo != NULL);
/*
* get the projection info we want
*/
slot = projInfo->pi_slot;
econtext = projInfo->pi_exprContext;
/*
* Clear any former contents of the result slot. This makes it safe for
* us to use the slot's Datum/isnull arrays as workspace.
*/
ExecClearTuple(slot);
/*
* Force extraction of all input values that we'll need. The
* Var-extraction loops below depend on this, and we are also prefetching
* all attributes that will be referenced in the generic expressions.
*/
if (projInfo->pi_lastInnerVar > 0)
slot_getsomeattrs(econtext->ecxt_innertuple,
projInfo->pi_lastInnerVar);
if (projInfo->pi_lastOuterVar > 0)
slot_getsomeattrs(econtext->ecxt_outertuple,
projInfo->pi_lastOuterVar);
if (projInfo->pi_lastScanVar > 0)
slot_getsomeattrs(econtext->ecxt_scantuple,
projInfo->pi_lastScanVar);
/*
* Assign simple Vars to result by direct extraction of fields from source
* slots ... a mite ugly, but fast ...
*/
numSimpleVars = projInfo->pi_numSimpleVars;
if (numSimpleVars > 0)
{
Datum *values = slot->tts_values;
bool *isnull = slot->tts_isnull;
int *varSlotOffsets = projInfo->pi_varSlotOffsets;
int *varNumbers = projInfo->pi_varNumbers;
int i;
if (projInfo->pi_directMap)
{
/* especially simple case where vars go to output in order */
for (i = 0; i < numSimpleVars; i++)
{
char *slotptr = ((char *) econtext) + varSlotOffsets[i];
TupleTableSlot *varSlot = *((TupleTableSlot **) slotptr);
int varNumber = varNumbers[i] - 1;
values[i] = varSlot->tts_values[varNumber];
isnull[i] = varSlot->tts_isnull[varNumber];
}
}
else
{
/* we have to pay attention to varOutputCols[] */
int *varOutputCols = projInfo->pi_varOutputCols;
for (i = 0; i < numSimpleVars; i++)
{
char *slotptr = ((char *) econtext) + varSlotOffsets[i];
TupleTableSlot *varSlot = *((TupleTableSlot **) slotptr);
int varNumber = varNumbers[i] - 1;
int varOutputCol = varOutputCols[i] - 1;
values[varOutputCol] = varSlot->tts_values[varNumber];
isnull[varOutputCol] = varSlot->tts_isnull[varNumber];
}
}
}
/*
* If there are any generic expressions, evaluate them.
*/
if (projInfo->pi_targetlist)
{
ExecTargetList(projInfo->pi_targetlist,
slot->tts_tupleDescriptor,
econtext,
slot->tts_values,
slot->tts_isnull);
}
/*
* Mark the result slot as containing a valid virtual tuple.
*/
return ExecStoreVirtualTuple(slot);
}
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