get_relation_info_hook

中文定义与说明

供插件在 get_relation_info() 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 (*get_relation_info_hook_type) (PlannerInfo *root, Oid relationObjectId, bool inhparent, RelOptInfo *rel);
extern PGDLLIMPORT get_relation_info_hook_type get_relation_info_hook;

源码说明

允许插件调整从系统目录取得的信息，例如改变假定的关系大小、移除索引，或向 indexlist 加入假想索引。

调用位置

• src/backend/optimizer/util/plancat.c:575

核心调用上下文：src/backend/optimizer/util/plancat.c:569–583

	/*
	 * Allow a plugin to editorialize on the info we obtained from the
	 * catalogs.  Actions might include altering the assumed relation size,
	 * removing an index, or adding a hypothetical index to the indexlist.
	 */
	if (get_relation_info_hook)
		(*get_relation_info_hook) (root, relationObjectId, inhparent, rel);
}

/*
 * get_relation_foreign_keys -
 *	  Retrieves foreign key information for a given relation.
 *
 * ForeignKeyOptInfos for relevant foreign keys are created and added to
 * root->fkey_list.  We do this now while we have the relcache entry open.