All large objects are placed in a single system table called
pg_largeobject. PostgreSQL also supports a storage system
called "TOAST" that automatically stores
values larger than a single database page into a secondary
storage area per table. This makes the large object facility
partially obsolete. One remaining advantage of the large object
facility is that it allows values up to 2 GB in size, whereas
TOASTed fields can be at most
1 GB. Also, large objects can be randomly modified using a
read/write API that is more efficient than performing such
operations using TOAST.
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