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Another round of protocol changes. Backend-to-frontend messages now all

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have length words.  COPY OUT reimplemented per new protocol: it doesn't
need \. anymore, thank goodness.  COPY BINARY to/from frontend works,
at least as far as the backend is concerned --- libpq's PQgetline API
is not up to snuff, and will have to be replaced with something that is
null-safe.  libpq uses message length words for performance improvement
(no cycles wasted rescanning long messages), but not yet for error
recovery.
This commit is contained in:
Tom Lane
2003-04-22 00:08:07 +00:00
parent ca944bd2d4
commit 5ed27e35f3
22 changed files with 782 additions and 357 deletions
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44
src/backend/libpq/pqcomm.c
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@@ -12,15 +12,16 @@
* No other messages can be sent while COPY OUT is in progress; and if the
* copy is aborted by an elog(ERROR), we need to close out the copy so that
* the frontend gets back into sync. Therefore, these routines have to be
* aware of COPY OUT state.
* aware of COPY OUT state. (New COPY-OUT is message-based and does *not*
* set the DoingCopyOut flag.)
*
* NOTE: generally, it's a bad idea to emit outgoing messages directly with
* pq_putbytes(), especially if the message would require multiple calls
* to send. Instead, use the routines in pqformat.c to construct the message
* in a buffer and then emit it in one call to pq_putmessage. This helps
* ensure that the channel will not be clogged by an incomplete message
* if execution is aborted by elog(ERROR) partway through the message.
* The only non-libpq code that should call pq_putbytes directly is COPY OUT.
* in a buffer and then emit it in one call to pq_putmessage. This ensures
* that the channel will not be clogged by an incomplete message if execution
* is aborted by elog(ERROR) partway through the message. The only non-libpq
* code that should call pq_putbytes directly is old-style COPY OUT.
*
* At one time, libpq was shared between frontend and backend, but now
* the backend's "backend/libpq" is quite separate from "interfaces/libpq".
@@ -29,7 +30,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Header: /cvsroot/pgsql/src/backend/libpq/pqcomm.c,v 1.150 2003/04/19 00:02:29 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/libpq/pqcomm.c,v 1.151 2003/04/22 00:08:06 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -846,13 +847,17 @@ pq_flush(void)
* pq_putmessage - send a normal message (suppressed in COPY OUT mode)
*
* If msgtype is not '\0', it is a message type code to place before
* the message body (len counts only the body size!).
* If msgtype is '\0', then the buffer already includes the type code.
* the message body. If msgtype is '\0', then the message has no type
* code (this is only valid in pre-3.0 protocols).
*
* All normal messages are suppressed while COPY OUT is in progress.
* (In practice only a few messages might get emitted then; dropping
* them is annoying, but at least they will still appear in the
* postmaster log.)
* len is the length of the message body data at *s. In protocol 3.0
* and later, a message length word (equal to len+4 because it counts
* itself too) is inserted by this routine.
*
* All normal messages are suppressed while old-style COPY OUT is in
* progress. (In practice only a few notice messages might get emitted
* then; dropping them is annoying, but at least they will still appear
* in the postmaster log.)
*
* returns 0 if OK, EOF if trouble
* --------------------------------
@@ -865,6 +870,14 @@ pq_putmessage(char msgtype, const char *s, size_t len)
if (msgtype)
if (pq_putbytes(&msgtype, 1))
return EOF;
if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
{
uint32 n32;
n32 = htonl((uint32) (len + 4));
if (pq_putbytes((char *) &n32, 4))
return EOF;
}
return pq_putbytes(s, len);
}
@@ -880,12 +893,13 @@ pq_startcopyout(void)
}
/* --------------------------------
* pq_endcopyout - end a COPY OUT transfer
* pq_endcopyout - end an old-style COPY OUT transfer
*
* If errorAbort is indicated, we are aborting a COPY OUT due to an error,
* and must send a terminator line. Since a partial data line might have
* been emitted, send a couple of newlines first (the first one could
* get absorbed by a backslash...)
* get absorbed by a backslash...) Note that old-style COPY OUT does
* not allow binary transfers, so a textual terminator is always correct.
* --------------------------------
*/
void
@@ -893,8 +907,8 @@ pq_endcopyout(bool errorAbort)
{
if (!DoingCopyOut)
return;
DoingCopyOut = false;
if (errorAbort)
pq_putbytes("\n\n\\.\n", 5);
/* in non-error case, copy.c will have emitted the terminator line */
DoingCopyOut = false;
}