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> The large object implementation breaks large
objects up into <SPAN
CLASS="QUOTE"
>"chunks"</SPAN
> and stores the chunks in
rows in the database. A B-tree index guarantees fast
searches for the correct chunk number when doing random
access reads and writes.
</P
><P
> As of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 9.0, large objects have an owner
and a set of access permissions, which can be managed using
<A
HREF="sql-grant.html"
>GRANT</A
> and
<A
HREF="sql-revoke.html"
>REVOKE</A
>.
For compatibility with prior releases, see
<A
HREF="runtime-config-compatible.html#GUC-LO-COMPAT-PRIVILEGES"
>lo_compat_privileges</A
>.
<TT
CLASS="LITERAL"
>SELECT</TT
> privileges are required to read a large
object, and
<TT
CLASS="LITERAL"
>UPDATE</TT
> privileges are required to write to or
truncate it.
Only the large object owner (or the database superuser) can unlink, comment
on, or change the owner of a large object.
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