PQconnectStart
PQconnectPoll
PQresetStart
PQresetPoll
PQsetenvStart
PQsetenvPoll
PQsetenvAbort
and brings into the published interface
PQsetenv.
The first four are asynchronous analogues of PQconnectdb and PQreset -
they allow an application to connect to the DB without blocking on
remote I/O.
The PQsetenv functions perform an environment negotiation with the
server.
Internal to libpq, pqReadReady and pqWriteReady have been made available
across the library (they were previously static functions inside
fe-misc.c). A lot of internal rearrangement has been necessary to
support these changes.
The API documentation has been updated also.
Caveats:
o The Windows code does not default to using non-blocking sockets,
since I have no documentation: Define WIN32_NON_BLOCKING_CONNECTIONS to
do that.
o The SSL code still blocks.
Ewan Mellor.
* Add use of 'const' for varibles in source tree
(which is misspelled, btw.)
I went through the front-end libpq code and did so. This affects in
particular the various accessor functions (such as PQdb() and
PQgetvalue()) as well as, by necessity, the internal helpers they use.
I have been really thorough in that regard, perhaps some people will find
it annoying that things like
char * foo = PQgetvalue(res, 0, 0)
will generate a warning. On the other hand it _should_ generate one. This
is no real compatibility break, although a few clients will have to be
fixed to suppress warnings. (Which again would be in the spirit of the
above TODO.)
In addition I replaced some int's by size_t's and removed some warnings
(and generated some new ones -- grmpf!). Also I rewrote PQoidStatus (so it
actually honors the const!) and supplied a new function PQoidValue that
returns a proper Oid type. This is only front-end stuff, none of the
communicaton stuff was touched.
The psql patch also adds some new consts to honor the new libpq situation,
as well as fixes a fatal condition that resulted when using the -V
(--version) option and there is no database listening.
So, to summarize, the psql you should definitely put in (with or without
the libpq). If you think I went too far with the const-mania in libpq, let
me know and I'll make adjustments. If you approve it, I will also update
the docs.
-Peter
--
Peter Eisentraut Sernanders vaeg 10:115
When drawing up a very simple "text-drawing" of how the negotiation is done,
I realised I had done this last part (fallback) in a very stupid way. Patch
#4 fixes this, and does it in a much better way.
Included is also the simple text-drawing of how the negotiation is done.
//Magnus
message under a kernel that only returns one packet per recv() call. This
didn't use to matter much, but it starts to get annoying with multi-megabyte
EXPLAIN VERBOSE responses...
error/notice message lengths, and number of fields per tuple. Add
pqexpbuffer.c/.h, a frontend version of backend's stringinfo module.
This is first step in applying Mike Ansley's long-query patches,
even though he didn't do any of these particular changes...
do the right thing: look for a NOTICE message from the backend before we
close our side of the socket. 6.4 libpq did not reliably print the backend's
hara-kiri message, 'The Postmaster has informed me ...', because it only
did the right thing if connection closure was detected during a read
attempt instead of a write attempt.
structs from libpq-fe.h, as we previously discussed.
There turned out to be sloppy coding practices in more places than
I had realized :-(, but all in all I think it was a well-worth-while
exercise.
I ended up adding several routines to libpq's API in order to respond
to application requirements that were exposed by this work. I owe the
docs crew updates for libpq.sgml to describe these changes. I'm way too
tired to work on the docs tonight, however.
This is the last major change I intend to submit for 6.4. I do want
to see if I can make libpgtcl work with Tcl 8.0 before we go final,
but hopefully that will be a minor bug fix.
From: Tom Lane <tgl@sss.pgh.pa.us>
Attached is a patch for this weekend's work on libpq. I've dealt
with several issues:
<for details: see message, in pgsql-patches archive for above data>
couple weeks ago on the hackers and interfaces lists:
1. When the backend sends a NOTICE message and closes the connection
(typically, because it was told to by the postmaster after
another backend coredumped), libpq will now print the notice
and close the connection cleanly. Formerly, the frontend app
would usually terminate ungracefully due to a SIGPIPE. (I am
not sure if 6.3.2 behaved that way, but the current cvs sources
do...)
2. libpq's various printouts to stderr are now fed through a single
"notice processor" routine, which can be overridden by the
application to direct notices someplace else. This should ease
porting libpq to Windows.
I also noticed and fixed a problem in PQprint: when sending output
to a pager subprocess, it would disable SIGPIPE in case the pager
terminates early (this is good) --- but afterwards it reset SIGPIPE
to SIG_DFL, rather than restoring the application's prior setting
(bad).
regards, tom lane
Through some minor changes, I have been able to compile the libpq
client libraries on the Win32 platform. Since the libpq communications
part has been rewritten, this has become much easier. Enclosed is
a patch that will allow at least Microsoft Visual C++ to compile
libpq into both a static and a dynamic library. I will take a look
at porting the psql frontend as well, but I figured it was a good
idea to send in these patches first - so no major changes are done
to the files before it gets applied (if it does).
Regards,
Magnus Hagander
1. Rewritten libpq to allow asynchronous clients.
2. Implemented client side of cancel protocol in library,
and patched psql.c to send a cancel request upon SIGINT. The
backend doesn't notice it yet :-(
3. Implemented 'Z' protocol message addition and renaming of
copy in/out start messages. These are implemented conditionally,
ie, the client protocol version is checked; so the code should
still work with 1.0 clients.
4. Revised protocol and libpq sgml documents (don't have an SGML
compiler, though, so there may be some markup glitches here).
What remains to be done:
1. Implement addition of atttypmod field to RowDescriptor messages.
The client-side code is there but ifdef'd out. I have no idea
what to change on the backend side. The field should be sent
only if protocol >= 2.0, of course.
2. Implement backend response to cancel requests received as OOB
messages. (This prolly need not be conditional on protocol
version; just do it if you get SIGURG.)
3. Update libpq.3. (I'm hoping this can be generated mechanically
from libpq.sgml... if not, will do it by hand.) Is there any
other doco to fix?
4. Update non-libpq interfaces as necessary. I patched libpgtcl
so that it would compile, but haven't tested it. Dunno what
needs to be done with the other interfaces.
Have at it!
Tom Lane
I've completed the patch to fix the protocol and authentication issues I
was discussing a couple of weeks ago. The particular changes are:
- the protocol has a version number
- network byte order is used throughout
- the pg_hba.conf file is used to specify what method is used to
authenticate a frontend (either password, ident, trust, reject, krb4
or krb5)
- support for multiplexed backends is removed
- appropriate changes to man pages
- the -a switch to many programs to specify an authentication service
no longer has any effect
- the libpq.so version number has changed to 1.1
The new backend still supports the old protocol so old interfaces won't
break.
Subject: [HACKERS] Patch for io routines
I am currently trying to improve on the front-backend communication
routines; and noticed that lots of code are duplicated for libpq and
the backend. This is a first patch that tries to share code between
the two, more to follow.
mjl
Here are a few minor fixes to Postgres95. Mostly I have added const
to some of the char pointers. There was also a missing header file
and a place where it looks like "==" was used when "=" was meant.
I also changed some variables from Pfin and Pfout tp pfin and pfout
because the latter shadow global variables and that just seems like
an unsafe practice which I like to avoid.
Submitted by: "D'Arcy J.M. Cain" <darcy@druid.druid.com>
Bruce Momjian
Tom Lane
Marc G. Fournier
Bryan Henderson