standard_ExecutorRun函数

//src/include/execurot/executor.h

extern void standard_ExecutorRun(QueryDesc *queryDesc,
			 ScanDirection direction, uint64 count, bool execute_once);

代码100分

代码100分//src/backend/executor/execMain.c

Assert(queryDesc != NULL);

estate = queryDesc->estate;

Assert(estate != NULL);
Assert(!(estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY));

/* 切换为每个查询对应的内存上下文 */
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);

/* 视情况开始执行器运行时间统计 */
if (queryDesc->totaltime)
	InstrStartNode(queryDesc->totaltime);

operation = queryDesc->operation;
dest = queryDesc->dest;

/* 若要发送元组，启动元组接收器 */
estate->es_processed = 0;

sendTuples = (operation == CMD_SELECT ||
		  queryDesc->plannedstmt->hasReturning);

if (sendTuples)
	dest->rStartup(dest, operation, queryDesc->tupDesc);

/* 执行plan */
if (!ScanDirectionIsNoMovement(direction))
{
	if (execute_once && queryDesc->already_executed)
		elog(ERROR, "can"t re-execute query flagged for single execution");
	queryDesc->already_executed = true;

	ExecutePlan(estate,
		queryDesc->planstate,
		queryDesc->plannedstmt->parallelModeNeeded,
		operation,
		sendTuples,
		count,
		direction,
		dest,
		execute_once);
}

/* 关闭元组接收器 */
if (sendTuples)
	dest->rShutdown(dest);

/* 结束执行器计时 */
if (queryDesc->totaltime)
	InstrStopNode(queryDesc->totaltime, estate->es_processed);

/* 切回内存上下文 */
MemoryContextSwitchTo(oldcontext);

ExecutorRun函数

void
ExecutorRun(QueryDesc *queryDesc,
			ScanDirection direction, uint64 count,
			bool execute_once)
{
	if (ExecutorRun_hook)
		(*ExecutorRun_hook) (queryDesc, direction, count, execute_once);
	else
		standard_ExecutorRun(queryDesc, direction, count, execute_once);
}

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