pg执行的时候表达式咋处理的

两个条件的Nestloop计算连接条件

select * from TEST_A,TEST_B where TEST_A.id2=TEST_B.id2 and TEST_A.id3>TEST_B.id3;

 

• ExecInterpExpr()时候打印点东西

p state->steps_len
$4 = 11

 

EEOP_INNER_FETCHSOME
EEOP_OUTER_FETCHSOME
EEOP_OUTER_VAR
EEOP_INNER_VAR
EEOP_FUNCEXPR_STRICT

• EEOP_QUAL

		EEO_CASE(EEOP_QUAL)
		{
			/* simplified version of BOOL_AND_STEP for use by ExecQual() */

			/* If argument (also result) is false or null ... */
			if (*op->resnull ||
				!DatumGetBool(*op->resvalue))
			{
				/* ... bail out early, returning FALSE */
				*op->resnull = false;
				*op->resvalue = BoolGetDatum(false);
				EEO_JUMP(op->d.qualexpr.jumpdone);
			}

			/*
			 * Otherwise, leave the TRUE value in place, in case this is the
			 * last qual.  Then, TRUE is the correct answer.
			 */

			EEO_NEXT();
		}

• 执行这个的时候
• 跳到了EEOP_DONE

揭露事情的真相

select * from test1 join test2 on test1.id1=test2.id3 ;

• 假定上面已按照NestLoop方式求解
• 那我想问判断相等需要经历几个步骤？
• 答案就是下面这几个！

EEOP_INNER_FETCHSOME
EEOP_OUTER_FETCHSOME

slot_getsomeattrs(innerslot, op->d.fetch.last_var);

EEOP_OUTER_VAR
EEOP_INNER_VAR

		EEO_CASE(EEOP_OUTER_VAR)
		{
			int			attnum = op->d.var.attnum;

			/* See EEOP_INNER_VAR comments */

			Assert(attnum >= 0 && attnum < outerslot->tts_nvalid);
			*op->resvalue = outerslot->tts_values[attnum];
			*op->resnull = outerslot->tts_isnull[attnum];

			EEO_NEXT();
		}

• 注意EEO_NEXT();这个宏会自动让op自增的哦！

EEOP_FUNCEXPR_STRICT
EEOP_QUAL

pg执行的时候表达式咋处理的

曾经我改错了源码，以至于生成的ExprState错了

• 这个适用于投影的表达式啊！

• select * from test3 , test4 where test3.id2=test4.id2 ;

• 共6个啊

• EEOP_SCAN_FETCHSOME

• EEOP_ASSIGN_SCAN_VAR

• EEOP_ASSIGN_SCAN_VAR

• EEOP_ASSIGN_SCAN_VAR

• EEOP_ASSIGN_SCAN_VAR

• EEOP_DONE

 

• 上面应该是投影！可惜是错的投影！
• 俺觉得正确的是下面这个

EEOP_INNER_FETCHSOME
EEOP_OUTER_FETCHSOME
EEOP_ASSIGN_OUTER_VAR
EEOP_ASSIGN_OUTER_VAR
EEOP_ASSIGN_INNER_VAR
EEOP_ASSIGN_INNER_VAR

曾经我改了源码，我发现我的源吗改错了以至于ExprState生错了

• select * from test3 , test4 where test3.id2=test4.id2 ;

$2 = {tag = {type = T_ExprState}, flags = 7 '\a', resnull = false, 
  resvalue = 0, resultslot = 0x0, steps = 0x1f79768, 
  evalfunc = 0x6a0821 <ExecInterpExprStillValid>, expr = 0x1f715a0, 
  evalfunc_private = 0x69e270 <ExecInterpExpr>, steps_len = 6, 
  steps_alloc = 16, parent = 0x1f699f0, ext_params = 0x0, 
  innermost_caseval = 0x0, innermost_casenull = 0x0, 
  innermost_domainval = 0x0, innermost_domainnull = 0x0}
(gdb) 

• 他只有六部
• 看看是那六部
• EEOP_SCAN_FETCHSOME
• EEOP_SCAN_VAR
• EEOP_SCAN_VAR
• EEOP_FUNCEXPR_STRICT
• EEOP_QUAL
• EEOP_DONE

select * from test3 , test4 where test3.id2=test4.id2 ;

• 六步骤

• EEOP_INNER_FETCHSOME

• EEOP_OUTER_FETCHSOME

• EEOP_OUTER_VAR

• EEOP_INNER_VAR

• EEOP_FUNCEXPR_STRICT

• EEOP_QUAL

• EEOP_DONE

select * from test1 where test1.id2=12 ;

• 在static TupleTableSlot *
  ExecSeqScan(PlanState *pstate)处设断点

 

/* ----------------------------------------------------------------
 *		ExecSeqScan(node)
 *
 *		Scans the relation sequentially and returns the next qualifying
 *		tuple.
 *		We call the ExecScan() routine and pass it the appropriate
 *		access method functions.
 * ----------------------------------------------------------------
 */
static TupleTableSlot *
ExecSeqScan(PlanState *pstate)
{
	SeqScanState *node = castNode(SeqScanState, pstate);

	return ExecScan(&node->ss,
					(ExecScanAccessMtd) SeqNext,
					(ExecScanRecheckMtd) SeqRecheck);
}

 

/* ----------------------------------------------------------------
 *
 *		Scans the relation using the 'access method' indicated and
 *		returns the next qualifying tuple in the direction specified
 *		in the global variable ExecDirection.
 *		The access method returns the next tuple and ExecScan() is
 *		responsible for checking the tuple returned against the qual-clause.
 *
 *		A 'recheck method' must also be provided that can check an
 *		arbitrary tuple of the relation against any qual conditions
 *		that are implemented internal to the access method.
 *
 *		Conditions:
 *		  -- the "cursor" maintained by the AMI is positioned at the tuple
 *			 returned previously.
 *
 *		Initial States:
 *		  -- the relation indicated is opened for scanning so that the
 *			 "cursor" is positioned before the first qualifying tuple.
 * ----------------------------------------------------------------
 */
TupleTableSlot *
ExecScan(ScanState *node,
		 ExecScanAccessMtd accessMtd,	/* function returning a tuple */
		 ExecScanRecheckMtd recheckMtd)
{
	ExprContext *econtext;
	ExprState  *qual;
	ProjectionInfo *projInfo;

	/*
	 * Fetch data from node
	 */
	qual = node->ps.qual;
	projInfo = node->ps.ps_ProjInfo;
	econtext = node->ps.ps_ExprContext;

	/* interrupt checks are in ExecScanFetch */

	/*
	 * If we have neither a qual to check nor a projection to do, just skip
	 * all the overhead and return the raw scan tuple.
	 */
	if (!qual && !projInfo)
	{
		ResetExprContext(econtext);
		return ExecScanFetch(node, accessMtd, recheckMtd);
	}

	/*
	 * Reset per-tuple memory context to free any expression evaluation
	 * storage allocated in the previous tuple cycle.
	 */
	ResetExprContext(econtext);

	/*
	 * get a tuple from the access method.  Loop until we obtain a tuple that
	 * passes the qualification.
	 */
	for (;;)
	{
		TupleTableSlot *slot;

		slot = ExecScanFetch(node, accessMtd, recheckMtd);

		/*
		 * if the slot returned by the accessMtd contains NULL, then it means
		 * there is nothing more to scan so we just return an empty slot,
		 * being careful to use the projection result slot so it has correct
		 * tupleDesc.
		 */
		if (TupIsNull(slot))
		{
			if (projInfo)
				return ExecClearTuple(projInfo->pi_state.resultslot);
			else
				return slot;
		}

		/*
		 * place the current tuple into the expr context
		 */
		econtext->ecxt_scantuple = slot;

		/*
		 * check that the current tuple satisfies the qual-clause
		 *
		 * check for non-null qual here to avoid a function call to ExecQual()
		 * when the qual is null ... saves only a few cycles, but they add up
		 * ...
		 */
		if (qual == NULL || ExecQual(qual, econtext))
		{
			/*
			 * Found a satisfactory scan tuple.
			 */
			if (projInfo)
			{
				/*
				 * Form a projection tuple, store it in the result tuple slot
				 * and return it.
				 */
				return ExecProject(projInfo);
			}
			else
			{
				/*
				 * Here, we aren't projecting, so just return scan tuple.
				 */
				return slot;
			}
		}
		else
			InstrCountFiltered1(node, 1);

		/*
		 * Tuple fails qual, so free per-tuple memory and try again.
		 */
		ResetExprContext(econtext);
	}
}

 

• 打印qual

$2 = {tag = {type = T_ExprState}, flags = 7 '\a', resnull = false, 
  resvalue = 0, resultslot = 0x0, steps = 0x29e01d0, 
  evalfunc = 0x6a0821 <ExecInterpExprStillValid>, expr = 0x29e7808, 
  evalfunc_private = 0x69e270 <ExecInterpExpr>, steps_len = 5, 
  steps_alloc = 16, parent = 0x29dfcb0, ext_params = 0x0, 
  innermost_caseval = 0x0, innermost_casenull = 0x0, 
  innermost_domainval = 0x0, innermost_domainnull = 0x0}

 

• 执行这个函数之前记得把econtext的ecxt_scantuple给赋一个元组啊！！
• 疑问来啦：那econtext的innerslot，outterslot为什么没被赋值
  • 因为这是扫描节点啊，如果这个是join节点的话你就得把你拿到的两个slot放到
  • econtext的innerslot，outterslot

/*
 * ExecQual - evaluate a qual prepared with ExecInitQual (possibly via
 * ExecPrepareQual).  Returns true if qual is satisfied, else false.
 *
 * Note: ExecQual used to have a third argument "resultForNull".  The
 * behavior of this function now corresponds to resultForNull == false.
 * If you want the resultForNull == true behavior, see ExecCheck.
 */
#ifndef FRONTEND
static inline bool
ExecQual(ExprState *state, ExprContext *econtext)
{
	Datum		ret;
	bool		isnull;

	/* short-circuit (here and in ExecInitQual) for empty restriction list */
	if (state == NULL)
		return true;

	/* verify that expression was compiled using ExecInitQual */
	Assert(state->flags & EEO_FLAG_IS_QUAL);

	ret = ExecEvalExprSwitchContext(state, econtext, &isnull);

	/* EEOP_QUAL should never return NULL */
	Assert(!isnull);

	return DatumGetBool(ret);
}
#endif

 

/*
 * ExecEvalExprSwitchContext
 *
 * Same as ExecEvalExpr, but get into the right allocation context explicitly.
 */
#ifndef FRONTEND
static inline Datum
ExecEvalExprSwitchContext(ExprState *state,
						  ExprContext *econtext,
						  bool *isNull)
{
	Datum		retDatum;
	MemoryContext oldContext;

	oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
	retDatum = state->evalfunc(state, econtext, isNull);
	MemoryContextSwitchTo(oldContext);
	return retDatum;
}
#endif

 

• 第一次执行EEOP_SCAN_FETCHSOME
• EEOP_SCAN_VAR
• EEOP_FUNCEXPR_STRICT
• EEOP_QUAL
• EEOP_DONE

#define EEO_SWITCH()		starteval: switch ((ExprEvalOp) op->opcode)
#define EEO_CASE(name)		case name:
#define EEO_DISPATCH()		goto starteval
#define EEO_OPCODE(opcode)	(opcode)


#define EEO_NEXT() \
	do { \
		op++; \
		EEO_DISPATCH(); \
	} while (0)

/*
 * Evaluate expression identified by "state" in the execution context
 * given by "econtext".  *isnull is set to the is-null flag for the result,
 * and the Datum value is the function result.
 *
 * As a special case, return the dispatch table's address if state is NULL.
 * This is used by ExecInitInterpreter to set up the dispatch_table global.
 * (Only applies when EEO_USE_COMPUTED_GOTO is defined.)
 */
static Datum
ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
{
	ExprEvalStep *op;
	TupleTableSlot *resultslot;
	TupleTableSlot *innerslot;
	TupleTableSlot *outerslot;
	TupleTableSlot *scanslot;

	/*
	 * This array has to be in the same order as enum ExprEvalOp.
	 */
#if defined(EEO_USE_COMPUTED_GOTO)
	static const void *const dispatch_table[] = {
		&&CASE_EEOP_DONE,
		&&CASE_EEOP_INNER_FETCHSOME,
		&&CASE_EEOP_OUTER_FETCHSOME,
		&&CASE_EEOP_SCAN_FETCHSOME,
		&&CASE_EEOP_INNER_VAR,
		&&CASE_EEOP_OUTER_VAR,
		&&CASE_EEOP_SCAN_VAR,
		&&CASE_EEOP_INNER_SYSVAR,
		&&CASE_EEOP_OUTER_SYSVAR,
		&&CASE_EEOP_SCAN_SYSVAR,
		&&CASE_EEOP_WHOLEROW,
		&&CASE_EEOP_ASSIGN_INNER_VAR,
		&&CASE_EEOP_ASSIGN_OUTER_VAR,
		&&CASE_EEOP_ASSIGN_SCAN_VAR,
		&&CASE_EEOP_ASSIGN_TMP,
		&&CASE_EEOP_ASSIGN_TMP_MAKE_RO,
		&&CASE_EEOP_CONST,
		&&CASE_EEOP_FUNCEXPR,
		&&CASE_EEOP_FUNCEXPR_STRICT,
		&&CASE_EEOP_FUNCEXPR_FUSAGE,
		&&CASE_EEOP_FUNCEXPR_STRICT_FUSAGE,
		&&CASE_EEOP_BOOL_AND_STEP_FIRST,
		&&CASE_EEOP_BOOL_AND_STEP,
		&&CASE_EEOP_BOOL_AND_STEP_LAST,
		&&CASE_EEOP_BOOL_OR_STEP_FIRST,
		&&CASE_EEOP_BOOL_OR_STEP,
		&&CASE_EEOP_BOOL_OR_STEP_LAST,
		&&CASE_EEOP_BOOL_NOT_STEP,
		&&CASE_EEOP_QUAL,
		&&CASE_EEOP_JUMP,
		&&CASE_EEOP_JUMP_IF_NULL,
		&&CASE_EEOP_JUMP_IF_NOT_NULL,
		&&CASE_EEOP_JUMP_IF_NOT_TRUE,
		&&CASE_EEOP_NULLTEST_ISNULL,
		&&CASE_EEOP_NULLTEST_ISNOTNULL,
		&&CASE_EEOP_NULLTEST_ROWISNULL,
		&&CASE_EEOP_NULLTEST_ROWISNOTNULL,
		&&CASE_EEOP_BOOLTEST_IS_TRUE,
		&&CASE_EEOP_BOOLTEST_IS_NOT_TRUE,
		&&CASE_EEOP_BOOLTEST_IS_FALSE,
		&&CASE_EEOP_BOOLTEST_IS_NOT_FALSE,
		&&CASE_EEOP_PARAM_EXEC,
		&&CASE_EEOP_PARAM_EXTERN,
		&&CASE_EEOP_PARAM_CALLBACK,
		&&CASE_EEOP_CASE_TESTVAL,
		&&CASE_EEOP_MAKE_READONLY,
		&&CASE_EEOP_IOCOERCE,
		&&CASE_EEOP_DISTINCT,
		&&CASE_EEOP_NOT_DISTINCT,
		&&CASE_EEOP_NULLIF,
		&&CASE_EEOP_SQLVALUEFUNCTION,
		&&CASE_EEOP_CURRENTOFEXPR,
		&&CASE_EEOP_NEXTVALUEEXPR,
		&&CASE_EEOP_ARRAYEXPR,
		&&CASE_EEOP_ARRAYCOERCE,
		&&CASE_EEOP_ROW,
		&&CASE_EEOP_ROWCOMPARE_STEP,
		&&CASE_EEOP_ROWCOMPARE_FINAL,
		&&CASE_EEOP_MINMAX,
		&&CASE_EEOP_FIELDSELECT,
		&&CASE_EEOP_FIELDSTORE_DEFORM,
		&&CASE_EEOP_FIELDSTORE_FORM,
		&&CASE_EEOP_ARRAYREF_SUBSCRIPT,
		&&CASE_EEOP_ARRAYREF_OLD,
		&&CASE_EEOP_ARRAYREF_ASSIGN,
		&&CASE_EEOP_ARRAYREF_FETCH,
		&&CASE_EEOP_DOMAIN_TESTVAL,
		&&CASE_EEOP_DOMAIN_NOTNULL,
		&&CASE_EEOP_DOMAIN_CHECK,
		&&CASE_EEOP_CONVERT_ROWTYPE,
		&&CASE_EEOP_SCALARARRAYOP,
		&&CASE_EEOP_XMLEXPR,
		&&CASE_EEOP_AGGREF,
		&&CASE_EEOP_GROUPING_FUNC,
		&&CASE_EEOP_WINDOW_FUNC,
		&&CASE_EEOP_SUBPLAN,
		&&CASE_EEOP_ALTERNATIVE_SUBPLAN,
		&&CASE_EEOP_AGG_STRICT_DESERIALIZE,
		&&CASE_EEOP_AGG_DESERIALIZE,
		&&CASE_EEOP_AGG_STRICT_INPUT_CHECK,
		&&CASE_EEOP_AGG_INIT_TRANS,
		&&CASE_EEOP_AGG_STRICT_TRANS_CHECK,
		&&CASE_EEOP_AGG_PLAIN_TRANS_BYVAL,
		&&CASE_EEOP_AGG_PLAIN_TRANS,
		&&CASE_EEOP_AGG_ORDERED_TRANS_DATUM,
		&&CASE_EEOP_AGG_ORDERED_TRANS_TUPLE,
		&&CASE_EEOP_LAST
	};

	StaticAssertStmt(EEOP_LAST + 1 == lengthof(dispatch_table),
					 "dispatch_table out of whack with ExprEvalOp");

	if (unlikely(state == NULL))
		return PointerGetDatum(dispatch_table);
#else
	Assert(state != NULL);
#endif							/* EEO_USE_COMPUTED_GOTO */

	/* setup state */
	op = state->steps;
	resultslot = state->resultslot;
	innerslot = econtext->ecxt_innertuple;
	outerslot = econtext->ecxt_outertuple;
	scanslot = econtext->ecxt_scantuple;

#if defined(EEO_USE_COMPUTED_GOTO)
	EEO_DISPATCH();
#endif

	EEO_SWITCH()
	{
		EEO_CASE(EEOP_DONE)
		{
			goto out;
		}

		EEO_CASE(EEOP_INNER_FETCHSOME)
		{
			/* XXX: worthwhile to check tts_nvalid inline first? */
			slot_getsomeattrs(innerslot, op->d.fetch.last_var);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_OUTER_FETCHSOME)
		{
			slot_getsomeattrs(outerslot, op->d.fetch.last_var);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_SCAN_FETCHSOME)
		{
			slot_getsomeattrs(scanslot, op->d.fetch.last_var);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_INNER_VAR)
		{
			int			attnum = op->d.var.attnum;

			/*
			 * Since we already extracted all referenced columns from the
			 * tuple with a FETCHSOME step, we can just grab the value
			 * directly out of the slot's decomposed-data arrays.  But let's
			 * have an Assert to check that that did happen.
			 */
			Assert(attnum >= 0 && attnum < innerslot->tts_nvalid);
			*op->resvalue = innerslot->tts_values[attnum];
			*op->resnull = innerslot->tts_isnull[attnum];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_OUTER_VAR)
		{
			int			attnum = op->d.var.attnum;

			/* See EEOP_INNER_VAR comments */

			Assert(attnum >= 0 && attnum < outerslot->tts_nvalid);
			*op->resvalue = outerslot->tts_values[attnum];
			*op->resnull = outerslot->tts_isnull[attnum];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_SCAN_VAR)
		{
			int			attnum = op->d.var.attnum;

			/* See EEOP_INNER_VAR comments */

			Assert(attnum >= 0 && attnum < scanslot->tts_nvalid);
			*op->resvalue = scanslot->tts_values[attnum];
			*op->resnull = scanslot->tts_isnull[attnum];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_INNER_SYSVAR)
		{
			int			attnum = op->d.var.attnum;
			Datum		d;

			/* these asserts must match defenses in slot_getattr */
			Assert(innerslot->tts_tuple != NULL);
			Assert(innerslot->tts_tuple != &(innerslot->tts_minhdr));

			/* heap_getsysattr has sufficient defenses against bad attnums */
			d = heap_getsysattr(innerslot->tts_tuple, attnum,
								innerslot->tts_tupleDescriptor,
								op->resnull);
			*op->resvalue = d;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_OUTER_SYSVAR)
		{
			int			attnum = op->d.var.attnum;
			Datum		d;

			/* these asserts must match defenses in slot_getattr */
			Assert(outerslot->tts_tuple != NULL);
			Assert(outerslot->tts_tuple != &(outerslot->tts_minhdr));

			/* heap_getsysattr has sufficient defenses against bad attnums */
			d = heap_getsysattr(outerslot->tts_tuple, attnum,
								outerslot->tts_tupleDescriptor,
								op->resnull);
			*op->resvalue = d;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_SCAN_SYSVAR)
		{
			int			attnum = op->d.var.attnum;
			Datum		d;

			/* these asserts must match defenses in slot_getattr */
			Assert(scanslot->tts_tuple != NULL);
			Assert(scanslot->tts_tuple != &(scanslot->tts_minhdr));

			/* heap_getsysattr has sufficient defenses against bad attnums */
			d = heap_getsysattr(scanslot->tts_tuple, attnum,
								scanslot->tts_tupleDescriptor,
								op->resnull);
			*op->resvalue = d;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_WHOLEROW)
		{
			/* too complex for an inline implementation */
			ExecEvalWholeRowVar(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ASSIGN_INNER_VAR)
		{
			int			resultnum = op->d.assign_var.resultnum;
			int			attnum = op->d.assign_var.attnum;

			/*
			 * We do not need CheckVarSlotCompatibility here; that was taken
			 * care of at compilation time.  But see EEOP_INNER_VAR comments.
			 */
			Assert(attnum >= 0 && attnum < innerslot->tts_nvalid);
			resultslot->tts_values[resultnum] = innerslot->tts_values[attnum];
			resultslot->tts_isnull[resultnum] = innerslot->tts_isnull[attnum];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ASSIGN_OUTER_VAR)
		{
			int			resultnum = op->d.assign_var.resultnum;
			int			attnum = op->d.assign_var.attnum;

			/*
			 * We do not need CheckVarSlotCompatibility here; that was taken
			 * care of at compilation time.  But see EEOP_INNER_VAR comments.
			 */
			Assert(attnum >= 0 && attnum < outerslot->tts_nvalid);
			resultslot->tts_values[resultnum] = outerslot->tts_values[attnum];
			resultslot->tts_isnull[resultnum] = outerslot->tts_isnull[attnum];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ASSIGN_SCAN_VAR)
		{
			int			resultnum = op->d.assign_var.resultnum;
			int			attnum = op->d.assign_var.attnum;

			/*
			 * We do not need CheckVarSlotCompatibility here; that was taken
			 * care of at compilation time.  But see EEOP_INNER_VAR comments.
			 */
			Assert(attnum >= 0 && attnum < scanslot->tts_nvalid);
			resultslot->tts_values[resultnum] = scanslot->tts_values[attnum];
			resultslot->tts_isnull[resultnum] = scanslot->tts_isnull[attnum];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ASSIGN_TMP)
		{
			int			resultnum = op->d.assign_tmp.resultnum;

			resultslot->tts_values[resultnum] = state->resvalue;
			resultslot->tts_isnull[resultnum] = state->resnull;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ASSIGN_TMP_MAKE_RO)
		{
			int			resultnum = op->d.assign_tmp.resultnum;

			resultslot->tts_isnull[resultnum] = state->resnull;
			if (!resultslot->tts_isnull[resultnum])
				resultslot->tts_values[resultnum] =
					MakeExpandedObjectReadOnlyInternal(state->resvalue);
			else
				resultslot->tts_values[resultnum] = state->resvalue;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_CONST)
		{
			*op->resnull = op->d.constval.isnull;
			*op->resvalue = op->d.constval.value;

			EEO_NEXT();
		}

		/*
		 * Function-call implementations. Arguments have previously been
		 * evaluated directly into fcinfo->args.
		 *
		 * As both STRICT checks and function-usage are noticeable performance
		 * wise, and function calls are a very hot-path (they also back
		 * operators!), it's worth having so many separate opcodes.
		 *
		 * Note: the reason for using a temporary variable "d", here and in
		 * other places, is that some compilers think "*op->resvalue = f();"
		 * requires them to evaluate op->resvalue into a register before
		 * calling f(), just in case f() is able to modify op->resvalue
		 * somehow.  The extra line of code can save a useless register spill
		 * and reload across the function call.
		 */
		EEO_CASE(EEOP_FUNCEXPR)
		{
			FunctionCallInfo fcinfo = op->d.func.fcinfo_data;
			Datum		d;

			fcinfo->isnull = false;
			d = op->d.func.fn_addr(fcinfo);
			*op->resvalue = d;
			*op->resnull = fcinfo->isnull;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_FUNCEXPR_STRICT)
		{
			FunctionCallInfo fcinfo = op->d.func.fcinfo_data;
			bool	   *argnull = fcinfo->argnull;
			int			argno;
			Datum		d;

			/* strict function, so check for NULL args */
			for (argno = 0; argno < op->d.func.nargs; argno++)
			{
				if (argnull[argno])
				{
					*op->resnull = true;
					goto strictfail;
				}
			}
			fcinfo->isnull = false;
			d = op->d.func.fn_addr(fcinfo);
			*op->resvalue = d;
			*op->resnull = fcinfo->isnull;

	strictfail:
			EEO_NEXT();
		}

		EEO_CASE(EEOP_FUNCEXPR_FUSAGE)
		{
			/* not common enough to inline */
			ExecEvalFuncExprFusage(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_FUNCEXPR_STRICT_FUSAGE)
		{
			/* not common enough to inline */
			ExecEvalFuncExprStrictFusage(state, op, econtext);

			EEO_NEXT();
		}

		/*
		 * If any of its clauses is FALSE, an AND's 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": perhaps one of the "don't
		 * knows" would have been FALSE if we'd known its value.  Only when
		 * all the inputs are known to be TRUE can we state confidently that
		 * the AND's result is TRUE.
		 */
		EEO_CASE(EEOP_BOOL_AND_STEP_FIRST)
		{
			*op->d.boolexpr.anynull = false;

			/*
			 * EEOP_BOOL_AND_STEP_FIRST resets anynull, otherwise it's the
			 * same as EEOP_BOOL_AND_STEP - so fall through to that.
			 */

			/* FALL THROUGH */
		}

		EEO_CASE(EEOP_BOOL_AND_STEP)
		{
			if (*op->resnull)
			{
				*op->d.boolexpr.anynull = true;
			}
			else if (!DatumGetBool(*op->resvalue))
			{
				/* result is already set to FALSE, need not change it */
				/* bail out early */
				EEO_JUMP(op->d.boolexpr.jumpdone);
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_BOOL_AND_STEP_LAST)
		{
			if (*op->resnull)
			{
				/* result is already set to NULL, need not change it */
			}
			else if (!DatumGetBool(*op->resvalue))
			{
				/* result is already set to FALSE, need not change it */

				/*
				 * No point jumping early to jumpdone - would be same target
				 * (as this is the last argument to the AND expression),
				 * except more expensive.
				 */
			}
			else if (*op->d.boolexpr.anynull)
			{
				*op->resvalue = (Datum) 0;
				*op->resnull = true;
			}
			else
			{
				/* result is already set to TRUE, need not change it */
			}

			EEO_NEXT();
		}

		/*
		 * If any of its clauses is TRUE, an OR's 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": 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.
		 */
		EEO_CASE(EEOP_BOOL_OR_STEP_FIRST)
		{
			*op->d.boolexpr.anynull = false;

			/*
			 * EEOP_BOOL_OR_STEP_FIRST resets anynull, otherwise it's the same
			 * as EEOP_BOOL_OR_STEP - so fall through to that.
			 */

			/* FALL THROUGH */
		}

		EEO_CASE(EEOP_BOOL_OR_STEP)
		{
			if (*op->resnull)
			{
				*op->d.boolexpr.anynull = true;
			}
			else if (DatumGetBool(*op->resvalue))
			{
				/* result is already set to TRUE, need not change it */
				/* bail out early */
				EEO_JUMP(op->d.boolexpr.jumpdone);
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_BOOL_OR_STEP_LAST)
		{
			if (*op->resnull)
			{
				/* result is already set to NULL, need not change it */
			}
			else if (DatumGetBool(*op->resvalue))
			{
				/* result is already set to TRUE, need not change it */

				/*
				 * No point jumping to jumpdone - would be same target (as
				 * this is the last argument to the AND expression), except
				 * more expensive.
				 */
			}
			else if (*op->d.boolexpr.anynull)
			{
				*op->resvalue = (Datum) 0;
				*op->resnull = true;
			}
			else
			{
				/* result is already set to FALSE, need not change it */
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_BOOL_NOT_STEP)
		{
			/*
			 * Evaluation of 'not' is simple... if expr is false, then return
			 * 'true' and vice versa.  It's safe to do this even on a
			 * nominally null value, so we ignore resnull; that means that
			 * NULL in produces NULL out, which is what we want.
			 */
			*op->resvalue = BoolGetDatum(!DatumGetBool(*op->resvalue));

			EEO_NEXT();
		}

		EEO_CASE(EEOP_QUAL)
		{
			/* simplified version of BOOL_AND_STEP for use by ExecQual() */

			/* If argument (also result) is false or null ... */
			if (*op->resnull ||
				!DatumGetBool(*op->resvalue))
			{
				/* ... bail out early, returning FALSE */
				*op->resnull = false;
				*op->resvalue = BoolGetDatum(false);
				EEO_JUMP(op->d.qualexpr.jumpdone);
			}

			/*
			 * Otherwise, leave the TRUE value in place, in case this is the
			 * last qual.  Then, TRUE is the correct answer.
			 */

			EEO_NEXT();
		}

		EEO_CASE(EEOP_JUMP)
		{
			/* Unconditionally jump to target step */
			EEO_JUMP(op->d.jump.jumpdone);
		}

		EEO_CASE(EEOP_JUMP_IF_NULL)
		{
			/* Transfer control if current result is null */
			if (*op->resnull)
				EEO_JUMP(op->d.jump.jumpdone);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_JUMP_IF_NOT_NULL)
		{
			/* Transfer control if current result is non-null */
			if (!*op->resnull)
				EEO_JUMP(op->d.jump.jumpdone);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_JUMP_IF_NOT_TRUE)
		{
			/* Transfer control if current result is null or false */
			if (*op->resnull || !DatumGetBool(*op->resvalue))
				EEO_JUMP(op->d.jump.jumpdone);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_NULLTEST_ISNULL)
		{
			*op->resvalue = BoolGetDatum(*op->resnull);
			*op->resnull = false;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_NULLTEST_ISNOTNULL)
		{
			*op->resvalue = BoolGetDatum(!*op->resnull);
			*op->resnull = false;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_NULLTEST_ROWISNULL)
		{
			/* out of line implementation: too large */
			ExecEvalRowNull(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_NULLTEST_ROWISNOTNULL)
		{
			/* out of line implementation: too large */
			ExecEvalRowNotNull(state, op, econtext);

			EEO_NEXT();
		}

		/* BooleanTest implementations for all booltesttypes */

		EEO_CASE(EEOP_BOOLTEST_IS_TRUE)
		{
			if (*op->resnull)
			{
				*op->resvalue = BoolGetDatum(false);
				*op->resnull = false;
			}
			/* else, input value is the correct output as well */

			EEO_NEXT();
		}

		EEO_CASE(EEOP_BOOLTEST_IS_NOT_TRUE)
		{
			if (*op->resnull)
			{
				*op->resvalue = BoolGetDatum(true);
				*op->resnull = false;
			}
			else
				*op->resvalue = BoolGetDatum(!DatumGetBool(*op->resvalue));

			EEO_NEXT();
		}

		EEO_CASE(EEOP_BOOLTEST_IS_FALSE)
		{
			if (*op->resnull)
			{
				*op->resvalue = BoolGetDatum(false);
				*op->resnull = false;
			}
			else
				*op->resvalue = BoolGetDatum(!DatumGetBool(*op->resvalue));

			EEO_NEXT();
		}

		EEO_CASE(EEOP_BOOLTEST_IS_NOT_FALSE)
		{
			if (*op->resnull)
			{
				*op->resvalue = BoolGetDatum(true);
				*op->resnull = false;
			}
			/* else, input value is the correct output as well */

			EEO_NEXT();
		}

		EEO_CASE(EEOP_PARAM_EXEC)
		{
			/* out of line implementation: too large */
			ExecEvalParamExec(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_PARAM_EXTERN)
		{
			/* out of line implementation: too large */
			ExecEvalParamExtern(state, op, econtext);
			EEO_NEXT();
		}

		EEO_CASE(EEOP_PARAM_CALLBACK)
		{
			/* allow an extension module to supply a PARAM_EXTERN value */
			op->d.cparam.paramfunc(state, op, econtext);
			EEO_NEXT();
		}

		EEO_CASE(EEOP_CASE_TESTVAL)
		{
			/*
			 * Normally upper parts of the expression tree have setup the
			 * values to be returned here, but some parts of the system
			 * currently misuse {caseValue,domainValue}_{datum,isNull} to set
			 * run-time data.  So if no values have been set-up, use
			 * ExprContext's.  This isn't pretty, but also not *that* ugly,
			 * and this is unlikely to be performance sensitive enough to
			 * worry about an extra branch.
			 */
			if (op->d.casetest.value)
			{
				*op->resvalue = *op->d.casetest.value;
				*op->resnull = *op->d.casetest.isnull;
			}
			else
			{
				*op->resvalue = econtext->caseValue_datum;
				*op->resnull = econtext->caseValue_isNull;
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_DOMAIN_TESTVAL)
		{
			/*
			 * See EEOP_CASE_TESTVAL comment.
			 */
			if (op->d.casetest.value)
			{
				*op->resvalue = *op->d.casetest.value;
				*op->resnull = *op->d.casetest.isnull;
			}
			else
			{
				*op->resvalue = econtext->domainValue_datum;
				*op->resnull = econtext->domainValue_isNull;
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_MAKE_READONLY)
		{
			/*
			 * Force a varlena value that might be read multiple times to R/O
			 */
			if (!*op->d.make_readonly.isnull)
				*op->resvalue =
					MakeExpandedObjectReadOnlyInternal(*op->d.make_readonly.value);
			*op->resnull = *op->d.make_readonly.isnull;

			EEO_NEXT();
		}

		EEO_CASE(EEOP_IOCOERCE)
		{
			/*
			 * Evaluate a CoerceViaIO node.  This can be quite a hot path, so
			 * inline as much work as possible.  The source value is in our
			 * result variable.
			 */
			char	   *str;

			/* call output function (similar to OutputFunctionCall) */
			if (*op->resnull)
			{
				/* output functions are not called on nulls */
				str = NULL;
			}
			else
			{
				FunctionCallInfo fcinfo_out;

				fcinfo_out = op->d.iocoerce.fcinfo_data_out;
				fcinfo_out->arg[0] = *op->resvalue;
				fcinfo_out->argnull[0] = false;

				fcinfo_out->isnull = false;
				str = DatumGetCString(FunctionCallInvoke(fcinfo_out));

				/* OutputFunctionCall assumes result isn't null */
				Assert(!fcinfo_out->isnull);
			}

			/* call input function (similar to InputFunctionCall) */
			if (!op->d.iocoerce.finfo_in->fn_strict || str != NULL)
			{
				FunctionCallInfo fcinfo_in;
				Datum		d;

				fcinfo_in = op->d.iocoerce.fcinfo_data_in;
				fcinfo_in->arg[0] = PointerGetDatum(str);
				fcinfo_in->argnull[0] = *op->resnull;
				/* second and third arguments are already set up */

				fcinfo_in->isnull = false;
				d = FunctionCallInvoke(fcinfo_in);
				*op->resvalue = d;

				/* Should get null result if and only if str is NULL */
				if (str == NULL)
				{
					Assert(*op->resnull);
					Assert(fcinfo_in->isnull);
				}
				else
				{
					Assert(!*op->resnull);
					Assert(!fcinfo_in->isnull);
				}
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_DISTINCT)
		{
			/*
			 * IS DISTINCT FROM must evaluate arguments (already done into
			 * fcinfo->arg/argnull) to determine whether they are NULL; if
			 * either is NULL then the result is determined.  If neither is
			 * NULL, then proceed to evaluate the comparison function, which
			 * is just the type's standard equality operator.  We need not
			 * care whether that function is strict.  Because the handling of
			 * nulls is different, we can't just reuse EEOP_FUNCEXPR.
			 */
			FunctionCallInfo fcinfo = op->d.func.fcinfo_data;

			/* check function arguments for NULLness */
			if (fcinfo->argnull[0] && fcinfo->argnull[1])
			{
				/* Both NULL? Then is not distinct... */
				*op->resvalue = BoolGetDatum(false);
				*op->resnull = false;
			}
			else if (fcinfo->argnull[0] || fcinfo->argnull[1])
			{
				/* Only one is NULL? Then is distinct... */
				*op->resvalue = BoolGetDatum(true);
				*op->resnull = false;
			}
			else
			{
				/* Neither null, so apply the equality function */
				Datum		eqresult;

				fcinfo->isnull = false;
				eqresult = op->d.func.fn_addr(fcinfo);
				/* Must invert result of "="; safe to do even if null */
				*op->resvalue = BoolGetDatum(!DatumGetBool(eqresult));
				*op->resnull = fcinfo->isnull;
			}

			EEO_NEXT();
		}

		/* see EEOP_DISTINCT for comments, this is just inverted */
		EEO_CASE(EEOP_NOT_DISTINCT)
		{
			FunctionCallInfo fcinfo = op->d.func.fcinfo_data;

			if (fcinfo->argnull[0] && fcinfo->argnull[1])
			{
				*op->resvalue = BoolGetDatum(true);
				*op->resnull = false;
			}
			else if (fcinfo->argnull[0] || fcinfo->argnull[1])
			{
				*op->resvalue = BoolGetDatum(false);
				*op->resnull = false;
			}
			else
			{
				Datum		eqresult;

				fcinfo->isnull = false;
				eqresult = op->d.func.fn_addr(fcinfo);
				*op->resvalue = eqresult;
				*op->resnull = fcinfo->isnull;
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_NULLIF)
		{
			/*
			 * The arguments are already evaluated into fcinfo->arg/argnull.
			 */
			FunctionCallInfo fcinfo = op->d.func.fcinfo_data;

			/* if either argument is NULL they can't be equal */
			if (!fcinfo->argnull[0] && !fcinfo->argnull[1])
			{
				Datum		result;

				fcinfo->isnull = false;
				result = op->d.func.fn_addr(fcinfo);

				/* if the arguments are equal return null */
				if (!fcinfo->isnull && DatumGetBool(result))
				{
					*op->resvalue = (Datum) 0;
					*op->resnull = true;

					EEO_NEXT();
				}
			}

			/* Arguments aren't equal, so return the first one */
			*op->resvalue = fcinfo->arg[0];
			*op->resnull = fcinfo->argnull[0];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_SQLVALUEFUNCTION)
		{
			/*
			 * Doesn't seem worthwhile to have an inline implementation
			 * efficiency-wise.
			 */
			ExecEvalSQLValueFunction(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_CURRENTOFEXPR)
		{
			/* error invocation uses space, and shouldn't ever occur */
			ExecEvalCurrentOfExpr(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_NEXTVALUEEXPR)
		{
			/*
			 * Doesn't seem worthwhile to have an inline implementation
			 * efficiency-wise.
			 */
			ExecEvalNextValueExpr(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ARRAYEXPR)
		{
			/* too complex for an inline implementation */
			ExecEvalArrayExpr(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ARRAYCOERCE)
		{
			/* too complex for an inline implementation */
			ExecEvalArrayCoerce(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ROW)
		{
			/* too complex for an inline implementation */
			ExecEvalRow(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ROWCOMPARE_STEP)
		{
			FunctionCallInfo fcinfo = op->d.rowcompare_step.fcinfo_data;
			Datum		d;

			/* force NULL result if strict fn and NULL input */
			if (op->d.rowcompare_step.finfo->fn_strict &&
				(fcinfo->argnull[0] || fcinfo->argnull[1]))
			{
				*op->resnull = true;
				EEO_JUMP(op->d.rowcompare_step.jumpnull);
			}

			/* Apply comparison function */
			fcinfo->isnull = false;
			d = op->d.rowcompare_step.fn_addr(fcinfo);
			*op->resvalue = d;

			/* force NULL result if NULL function result */
			if (fcinfo->isnull)
			{
				*op->resnull = true;
				EEO_JUMP(op->d.rowcompare_step.jumpnull);
			}
			*op->resnull = false;

			/* If unequal, no need to compare remaining columns */
			if (DatumGetInt32(*op->resvalue) != 0)
			{
				EEO_JUMP(op->d.rowcompare_step.jumpdone);
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ROWCOMPARE_FINAL)
		{
			int32		cmpresult = DatumGetInt32(*op->resvalue);
			RowCompareType rctype = op->d.rowcompare_final.rctype;

			*op->resnull = false;
			switch (rctype)
			{
					/* EQ and NE cases aren't allowed here */
				case ROWCOMPARE_LT:
					*op->resvalue = BoolGetDatum(cmpresult < 0);
					break;
				case ROWCOMPARE_LE:
					*op->resvalue = BoolGetDatum(cmpresult <= 0);
					break;
				case ROWCOMPARE_GE:
					*op->resvalue = BoolGetDatum(cmpresult >= 0);
					break;
				case ROWCOMPARE_GT:
					*op->resvalue = BoolGetDatum(cmpresult > 0);
					break;
				default:
					Assert(false);
					break;
			}

			EEO_NEXT();
		}

		EEO_CASE(EEOP_MINMAX)
		{
			/* too complex for an inline implementation */
			ExecEvalMinMax(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_FIELDSELECT)
		{
			/* too complex for an inline implementation */
			ExecEvalFieldSelect(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_FIELDSTORE_DEFORM)
		{
			/* too complex for an inline implementation */
			ExecEvalFieldStoreDeForm(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_FIELDSTORE_FORM)
		{
			/* too complex for an inline implementation */
			ExecEvalFieldStoreForm(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ARRAYREF_SUBSCRIPT)
		{
			/* Process an array subscript */

			/* too complex for an inline implementation */
			if (ExecEvalArrayRefSubscript(state, op))
			{
				EEO_NEXT();
			}
			else
			{
				/* Subscript is null, short-circuit ArrayRef to NULL */
				EEO_JUMP(op->d.arrayref_subscript.jumpdone);
			}
		}

		EEO_CASE(EEOP_ARRAYREF_OLD)
		{
			/*
			 * Fetch the old value in an arrayref assignment, in case it's
			 * referenced (via a CaseTestExpr) inside the assignment
			 * expression.
			 */

			/* too complex for an inline implementation */
			ExecEvalArrayRefOld(state, op);

			EEO_NEXT();
		}

		/*
		 * Perform ArrayRef assignment
		 */
		EEO_CASE(EEOP_ARRAYREF_ASSIGN)
		{
			/* too complex for an inline implementation */
			ExecEvalArrayRefAssign(state, op);

			EEO_NEXT();
		}

		/*
		 * Fetch subset of an array.
		 */
		EEO_CASE(EEOP_ARRAYREF_FETCH)
		{
			/* too complex for an inline implementation */
			ExecEvalArrayRefFetch(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_CONVERT_ROWTYPE)
		{
			/* too complex for an inline implementation */
			ExecEvalConvertRowtype(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_SCALARARRAYOP)
		{
			/* too complex for an inline implementation */
			ExecEvalScalarArrayOp(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_DOMAIN_NOTNULL)
		{
			/* too complex for an inline implementation */
			ExecEvalConstraintNotNull(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_DOMAIN_CHECK)
		{
			/* too complex for an inline implementation */
			ExecEvalConstraintCheck(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_XMLEXPR)
		{
			/* too complex for an inline implementation */
			ExecEvalXmlExpr(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_AGGREF)
		{
			/*
			 * Returns a Datum whose value is the precomputed aggregate value
			 * found in the given expression context.
			 */
			AggrefExprState *aggref = op->d.aggref.astate;

			Assert(econtext->ecxt_aggvalues != NULL);

			*op->resvalue = econtext->ecxt_aggvalues[aggref->aggno];
			*op->resnull = econtext->ecxt_aggnulls[aggref->aggno];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_GROUPING_FUNC)
		{
			/* too complex/uncommon for an inline implementation */
			ExecEvalGroupingFunc(state, op);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_WINDOW_FUNC)
		{
			/*
			 * Like Aggref, just return a precomputed value from the econtext.
			 */
			WindowFuncExprState *wfunc = op->d.window_func.wfstate;

			Assert(econtext->ecxt_aggvalues != NULL);

			*op->resvalue = econtext->ecxt_aggvalues[wfunc->wfuncno];
			*op->resnull = econtext->ecxt_aggnulls[wfunc->wfuncno];

			EEO_NEXT();
		}

		EEO_CASE(EEOP_SUBPLAN)
		{
			/* too complex for an inline implementation */
			ExecEvalSubPlan(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_ALTERNATIVE_SUBPLAN)
		{
			/* too complex for an inline implementation */
			ExecEvalAlternativeSubPlan(state, op, econtext);

			EEO_NEXT();
		}

		/* evaluate a strict aggregate deserialization function */
		EEO_CASE(EEOP_AGG_STRICT_DESERIALIZE)
		{
			bool	   *argnull = op->d.agg_deserialize.fcinfo_data->argnull;

			/* Don't call a strict deserialization function with NULL input */
			if (argnull[0])
				EEO_JUMP(op->d.agg_deserialize.jumpnull);

			/* fallthrough */
		}

		/* evaluate aggregate deserialization function (non-strict portion) */
		EEO_CASE(EEOP_AGG_DESERIALIZE)
		{
			FunctionCallInfo fcinfo = op->d.agg_deserialize.fcinfo_data;
			AggState   *aggstate = op->d.agg_deserialize.aggstate;
			MemoryContext oldContext;

			/*
			 * We run the deserialization functions in per-input-tuple memory
			 * context.
			 */
			oldContext = MemoryContextSwitchTo(aggstate->tmpcontext->ecxt_per_tuple_memory);
			fcinfo->isnull = false;
			*op->resvalue = FunctionCallInvoke(fcinfo);
			*op->resnull = fcinfo->isnull;
			MemoryContextSwitchTo(oldContext);

			EEO_NEXT();
		}

		/*
		 * Check that a strict aggregate transition / combination function's
		 * input is not NULL.
		 */
		EEO_CASE(EEOP_AGG_STRICT_INPUT_CHECK)
		{
			int			argno;
			bool	   *nulls = op->d.agg_strict_input_check.nulls;
			int			nargs = op->d.agg_strict_input_check.nargs;

			for (argno = 0; argno < nargs; argno++)
			{
				if (nulls[argno])
					EEO_JUMP(op->d.agg_strict_input_check.jumpnull);
			}
			EEO_NEXT();
		}

		/*
		 * Initialize an aggregate's first value if necessary.
		 */
		EEO_CASE(EEOP_AGG_INIT_TRANS)
		{
			AggState   *aggstate;
			AggStatePerGroup pergroup;

			aggstate = op->d.agg_init_trans.aggstate;
			pergroup = &aggstate->all_pergroups
				[op->d.agg_init_trans.setoff]
				[op->d.agg_init_trans.transno];

			/* If transValue has not yet been initialized, do so now. */
			if (pergroup->noTransValue)
			{
				AggStatePerTrans pertrans = op->d.agg_init_trans.pertrans;

				aggstate->curaggcontext = op->d.agg_init_trans.aggcontext;
				aggstate->current_set = op->d.agg_init_trans.setno;

				ExecAggInitGroup(aggstate, pertrans, pergroup);

				/* copied trans value from input, done this round */
				EEO_JUMP(op->d.agg_init_trans.jumpnull);
			}

			EEO_NEXT();
		}

		/* check that a strict aggregate's input isn't NULL */
		EEO_CASE(EEOP_AGG_STRICT_TRANS_CHECK)
		{
			AggState   *aggstate;
			AggStatePerGroup pergroup;

			aggstate = op->d.agg_strict_trans_check.aggstate;
			pergroup = &aggstate->all_pergroups
				[op->d.agg_strict_trans_check.setoff]
				[op->d.agg_strict_trans_check.transno];

			if (unlikely(pergroup->transValueIsNull))
				EEO_JUMP(op->d.agg_strict_trans_check.jumpnull);

			EEO_NEXT();
		}

		/*
		 * Evaluate aggregate transition / combine function that has a
		 * by-value transition type. That's a seperate case from the
		 * by-reference implementation because it's a bit simpler.
		 */
		EEO_CASE(EEOP_AGG_PLAIN_TRANS_BYVAL)
		{
			AggState   *aggstate;
			AggStatePerTrans pertrans;
			AggStatePerGroup pergroup;
			FunctionCallInfo fcinfo;
			MemoryContext oldContext;
			Datum		newVal;

			aggstate = op->d.agg_trans.aggstate;
			pertrans = op->d.agg_trans.pertrans;

			pergroup = &aggstate->all_pergroups
				[op->d.agg_trans.setoff]
				[op->d.agg_trans.transno];

			Assert(pertrans->transtypeByVal);

			fcinfo = &pertrans->transfn_fcinfo;

			/* cf. select_current_set() */
			aggstate->curaggcontext = op->d.agg_trans.aggcontext;
			aggstate->current_set = op->d.agg_trans.setno;

			/* set up aggstate->curpertrans for AggGetAggref() */
			aggstate->curpertrans = pertrans;

			/* invoke transition function in per-tuple context */
			oldContext = MemoryContextSwitchTo(aggstate->tmpcontext->ecxt_per_tuple_memory);

			fcinfo->arg[0] = pergroup->transValue;
			fcinfo->argnull[0] = pergroup->transValueIsNull;
			fcinfo->isnull = false; /* just in case transfn doesn't set it */

			newVal = FunctionCallInvoke(fcinfo);

			pergroup->transValue = newVal;
			pergroup->transValueIsNull = fcinfo->isnull;

			MemoryContextSwitchTo(oldContext);

			EEO_NEXT();
		}

		/*
		 * Evaluate aggregate transition / combine function that has a
		 * by-reference transition type.
		 *
		 * Could optimize a bit further by splitting off by-reference
		 * fixed-length types, but currently that doesn't seem worth it.
		 */
		EEO_CASE(EEOP_AGG_PLAIN_TRANS)
		{
			AggState   *aggstate;
			AggStatePerTrans pertrans;
			AggStatePerGroup pergroup;
			FunctionCallInfo fcinfo;
			MemoryContext oldContext;
			Datum		newVal;

			aggstate = op->d.agg_trans.aggstate;
			pertrans = op->d.agg_trans.pertrans;

			pergroup = &aggstate->all_pergroups
				[op->d.agg_trans.setoff]
				[op->d.agg_trans.transno];

			Assert(!pertrans->transtypeByVal);

			fcinfo = &pertrans->transfn_fcinfo;

			/* cf. select_current_set() */
			aggstate->curaggcontext = op->d.agg_trans.aggcontext;
			aggstate->current_set = op->d.agg_trans.setno;

			/* set up aggstate->curpertrans for AggGetAggref() */
			aggstate->curpertrans = pertrans;

			/* invoke transition function in per-tuple context */
			oldContext = MemoryContextSwitchTo(aggstate->tmpcontext->ecxt_per_tuple_memory);

			fcinfo->arg[0] = pergroup->transValue;
			fcinfo->argnull[0] = pergroup->transValueIsNull;
			fcinfo->isnull = false; /* just in case transfn doesn't set it */

			newVal = FunctionCallInvoke(fcinfo);

			/*
			 * For pass-by-ref datatype, must copy the new value into
			 * aggcontext and free the prior transValue.  But if transfn
			 * returned a pointer to its first input, we don't need to do
			 * anything.  Also, if transfn returned a pointer to a R/W
			 * expanded object that is already a child of the aggcontext,
			 * assume we can adopt that value without copying it.
			 */
			if (DatumGetPointer(newVal) != DatumGetPointer(pergroup->transValue))
				newVal = ExecAggTransReparent(aggstate, pertrans,
											  newVal, fcinfo->isnull,
											  pergroup->transValue,
											  pergroup->transValueIsNull);

			pergroup->transValue = newVal;
			pergroup->transValueIsNull = fcinfo->isnull;

			MemoryContextSwitchTo(oldContext);

			EEO_NEXT();
		}

		/* process single-column ordered aggregate datum */
		EEO_CASE(EEOP_AGG_ORDERED_TRANS_DATUM)
		{
			/* too complex for an inline implementation */
			ExecEvalAggOrderedTransDatum(state, op, econtext);

			EEO_NEXT();
		}

		/* process multi-column ordered aggregate tuple */
		EEO_CASE(EEOP_AGG_ORDERED_TRANS_TUPLE)
		{
			/* too complex for an inline implementation */
			ExecEvalAggOrderedTransTuple(state, op, econtext);

			EEO_NEXT();
		}

		EEO_CASE(EEOP_LAST)
		{
			/* unreachable */
			Assert(false);
			goto out;
		}
	}

out:
	*isnull = state->resnull;
	return state->resvalue;
}

这个结构体长啥样子

typedef struct ExprState
{
	Node		tag;

	uint8		flags;			/* bitmask of EEO_FLAG_* bits, see above */

	/*
	 * Storage for result value of a scalar expression, or for individual
	 * column results within expressions built by ExecBuildProjectionInfo().
	 */
#define FIELDNO_EXPRSTATE_RESNULL 2
	bool		resnull;
#define FIELDNO_EXPRSTATE_RESVALUE 3
	Datum		resvalue;

	/*
	 * If projecting a tuple result, this slot holds the result; else NULL.
	 */
#define FIELDNO_EXPRSTATE_RESULTSLOT 4
	TupleTableSlot *resultslot;

	/*
	 * Instructions to compute expression's return value.
	 */
	struct ExprEvalStep *steps;

	/*
	 * Function that actually evaluates the expression.  This can be set to
	 * different values depending on the complexity of the expression.
	 */
	ExprStateEvalFunc evalfunc;

	/* original expression tree, for debugging only */
	Expr	   *expr;

	/* private state for an evalfunc */
	void	   *evalfunc_private;

	/*
	 * XXX: following fields only needed during "compilation" (ExecInitExpr);
	 * could be thrown away afterwards.
	 */

	int			steps_len;		/* number of steps currently */
	int			steps_alloc;	/* allocated length of steps array */

	struct PlanState *parent;	/* parent PlanState node, if any */
	ParamListInfo ext_params;	/* for compiling PARAM_EXTERN nodes */

	Datum	   *innermost_caseval;
	bool	   *innermost_casenull;

	Datum	   *innermost_domainval;
	bool	   *innermost_domainnull;
} ExprState;