【PG-2】PostgreSQL存储管理器

最新推荐文章于 2025-02-12 00:04:12 发布

Tototototorres

最新推荐文章于 2025-02-12 00:04:12 发布

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分类专栏： postgresql 文章标签： postgresql 数据库

本文链接：https://blog.youkuaiyun.com/qq_47865838/article/details/138260672

2. PostgreSQL存储管理器

src/backend/storage

(base) torres@torresの机革:~/codes/postgresql-16.2/src/backend/storage$ ls
Makefile  buffer  file  freespace  ipc  large_object  lmgr  meson.build  objfiles.txt  page  smgr  sync

存储管理器—smgr

通用存储管理器 smgr，

typedef struct f_smgr
{
   
   
	void		(*smgr_init) (void);	/* may be NULL */
	void		(*smgr_shutdown) (void);	/* may be NULL */
	void		(*smgr_open) (SMgrRelation reln);
	void		(*smgr_close) (SMgrRelation reln, ForkNumber forknum);
	void		(*smgr_create) (SMgrRelation reln, ForkNumber forknum,
								bool isRedo);
	bool		(*smgr_exists) (SMgrRelation reln, ForkNumber forknum);
	void		(*smgr_unlink) (RelFileLocatorBackend rlocator, ForkNumber forknum,
								bool isRedo);
	void		(*smgr_extend) (SMgrRelation reln, ForkNumber forknum,
								BlockNumber blocknum, const void *buffer, bool skipFsync);
	void		(*smgr_zeroextend) (SMgrRelation reln, ForkNumber forknum,
									BlockNumber blocknum, int nblocks, bool skipFsync);
	bool		(*smgr_prefetch) (SMgrRelation reln, ForkNumber forknum,
								  BlockNumber blocknum);
	void		(*smgr_read) (SMgrRelation reln, ForkNumber forknum,
							  BlockNumber blocknum, void *buffer);
	void		(*smgr_write) (SMgrRelation reln, ForkNumber forknum,
							   BlockNumber blocknum, const void *buffer, bool skipFsync);
	void		(*smgr_writeback) (SMgrRelation reln, ForkNumber forknum,
								   BlockNumber blocknum, BlockNumber nblocks);
	BlockNumber (*smgr_nblocks) (SMgrRelation reln, ForkNumber forknum);
	void		(*smgr_truncate) (SMgrRelation reln, ForkNumber forknum,
								  BlockNumber nblocks);
	void		(*smgr_immedsync) (SMgrRelation reln, ForkNumber forknum);
} f_smgr;

// 函数指针赋值
static const f_smgr smgrsw[] = {
   
   
	/* magnetic disk */
	{
   
   
		.smgr_init = mdinit,
		.smgr_shutdown = NULL,
		.smgr_open = mdopen,
		.smgr_close = mdclose,
		.smgr_create = mdcreate,
		.smgr_exists = mdexists,
		.smgr_unlink = mdunlink,
		.smgr_extend = mdextend,
		.smgr_zeroextend = mdzeroextend,
		.smgr_prefetch = mdprefetch,
		.smgr_read = mdread,
		.smgr_write = mdwrite,
		.smgr_write