explain_per_node_hook

中文定义与说明

供 EXPLAIN 插件在单个计划节点上输出额外字段的钩子。

以下中文为本站依据所列 PostgreSQL 源码注释编译的说明。

接口声明

typedef void (*explain_per_node_hook_type) (PlanState *planstate, List *ancestors, const char *relationship, const char *plan_name, struct ExplainState *es);
extern PGDLLIMPORT explain_per_node_hook_type explain_per_node_hook;

源码说明

允许插件输出额外信息。

调用位置

• src/backend/commands/explain.c:2319

核心调用上下文：src/backend/commands/explain.c:2313–2327

	if (es->workers_state)
		ExplainFlushWorkersState(es);
	es->workers_state = save_workers_state;

	/* Allow plugins to print additional information */
	if (explain_per_node_hook)
		(*explain_per_node_hook) (planstate, ancestors, relationship,
								  plan_name, es);

	/*
	 * If partition pruning was done during executor initialization, the
	 * number of child plans we'll display below will be less than the number
	 * of subplans that was specified in the plan.  To make this a bit less
	 * mysterious, emit an indication that this happened.  Note that this
	 * field is emitted now because we want it to be a property of the parent