Attached are diffs (from current cvs sources) to bring libpq.sgml
and libpq.3 up to date.
It appears that at various times in the past, people have made edits to
one or the other of these files but not both. I propagated some changes
from each into the other, but I don't think I caught every
inconsistency. It'd be real nice if the man pages could be
automatically generated from the SGML...
Making PQrequestCancel safe to call in a signal handler turned out to be
much easier than I feared. So here are the diffs.
Some notes:
* I modified the postmaster's packet "iodone" callback interface to allow
the callback routine to return a continue-or-drop-connection return
code; this was necessary to allow the connection to be closed after
receiving a Cancel, rather than proceeding to launch a new backend...
Being a neatnik, I also made the iodone proc have a typechecked
parameter list.
* I deleted all code I could find that had to do with OOB.
* I made some edits to ensure that all signals mentioned in the code
are referred to symbolically not by numbers ("SIGUSR2" not "2").
I think Bruce may have already done at least some of the same edits;
I hope that merging these patches is not too painful.
pg_notifies statement is eliminated, and callbacks defined by
pg_listen are instead invoked automatically from the Tcl idle loop
whenever a NOTIFY message is received.
I have done only cursory testing, so there may be problems still
lurking (particularly on non-Unix machines?). But it seems to
work.
Patch is against today's cvs sources. Note that this will not work
with the 6.3.2 release since it depends on the new libpq.
The diffs are a bit large so I've gzipped them. A patch to update
libpgtcl.sgml is included too.
regards, tom lane
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
Thomas G. Lockhart
Bruce Momjian
Marc G. Fournier