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PostgreSQL Storage Manager (cont)

Components of storage subsystem:
  • mapping from relations to files   (RelFileNode)
  • abstraction for open relation pool   (storage/smgr)
  • functions for managing files   (storage/smgr/md.c)
  • file-descriptor pool   (storage/file)
PostgreSQL has two basic kinds of files:
  • heap files containing data (tuples)
  • index files containing index entries
Note: smgr designed for many storage devices; only mag disk handler used