set_rel_pathlist_hook

中文定义与说明

供插件在 set_rel_pathlist() 中接管处理的钩子。

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 (*set_rel_pathlist_hook_type) (PlannerInfo *root, RelOptInfo *rel, Index rti, RangeTblEntry *rte);
extern PGDLLIMPORT set_rel_pathlist_hook_type set_rel_pathlist_hook;

源码说明

允许插件调整此基表关系的路径集合。插件可调用 add_path() 添加新路径（例如 CustomPaths）；若支持并行，则可调用 add_partial_path()。也可以删除或修改核心代码添加的路径。

调用位置

• src/backend/optimizer/path/allpaths.c:543

核心调用上下文：src/backend/optimizer/path/allpaths.c:537–551

	 * Allow a plugin to editorialize on the set of Paths for this base
	 * relation.  It could add new paths (such as CustomPaths) by calling
	 * add_path(), or add_partial_path() if parallel aware.  It could also
	 * delete or modify paths added by the core code.
	 */
	if (set_rel_pathlist_hook)
		(*set_rel_pathlist_hook) (root, rel, rti, rte);

	/*
	 * If this is a baserel, we should normally consider gathering any partial
	 * paths we may have created for it.  We have to do this after calling the
	 * set_rel_pathlist_hook, else it cannot add partial paths to be included
	 * here.
	 *
	 * However, if this is an inheritance child, skip it.  Otherwise, we could