-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/protocol.sgml,v 1.35 2003/05/06 21:51:41 tgl Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/protocol.sgml,v 1.36 2003/05/06 23:10:04 tgl Exp $ -->
<chapter id="protocol">
<title>Frontend/Backend Protocol</title>
(but note that these exist only within a session, and are never shared
across sessions). Existing prepared statements and portals are
referenced by names assigned when they were created. In addition,
- an <quote>unnamed</> prepared statement and portal exist, for use with
- queries that are to be executed and forgotten. This is slightly
- more efficient than using named objects, since the backend knows that
- it need not save the object's state for re-use.
+ an <quote>unnamed</> prepared statement and portal exist. Although these
+ behave largely the same as named objects, operations on them are optimized
+ for the case of executing a query only once and then discarding it,
+ whereas operations on named objects are optimized on the expectation
+ of multiple uses.
</para>
</sect2>
</sect1>
zero or more CopyData messages (always one per row), followed by CopyDone.
The backend then reverts to the command-processing mode it was
in before the <command>COPY</> started, and sends CommandComplete.
- The frontend cannot abort the transfer (short of closing the connection),
+ The frontend cannot abort the transfer (except by closing the connection
+ or issuing a Cancel request),
but it can discard unwanted CopyData and CopyDone messages.
</para>
<literal>INSERT <replaceable>oid</replaceable>
<replaceable>rows</replaceable></literal>, where
<replaceable>rows</replaceable> is the number of rows
- inserted, and <replaceable>oid</replaceable> is the object ID
- of the inserted row if <Replaceable>rows</Replaceable> is 1,
- otherwise <Replaceable>oid</Replaceable> is 0.
+ inserted. <replaceable>oid</replaceable> is the object ID
+ of the inserted row if <Replaceable>rows</Replaceable> is 1
+ and the target table has OIDs;
+ otherwise <Replaceable>oid</Replaceable> is 0.
</Para>
<Para>