calls. Outside a transaction, the backend detects them as buffer
leaks; it sends a NOTICE, and frees them. This sometimes cause a
segmentation fault (at least on Linux). These indexes are initialized
on the first lo_read/lo_write/lo_tell call, and (normally) closed
on a lo_close call. Thus the buffer leaks appear when lo direct
access functions are used, and not with lo_import/lo_export functions
(libpq version calls lo_close before ending the command, and the
backend version uses another path).
The included patches (against recent snapshot, and against 6.3.2)
cause indexes to be closed on transaction end (that is on explicit
'END' statment, or on command termination outside trasaction blocks),
thus preventing the buffer leaks while increasing performance inside
transactions. Some (all?) 'classic' memory leaks are also removed.
I hope it will be ok.
--- Pascal ANDRE, graduated from Ecole Centrale Paris andre@via.ecp.fr
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.
I have implemented a framework of encoding translation between the
backend and the frontend. Also I have added a new variable setting
command:
SET CLIENT_ENCODING TO 'encoding';
Other features include:
Latin1 support more 8 bit cleaness
See doc/README.mb for more details. Note that the pacthes are
against May 30 snapshot.
Tatsuo Ishii
have > 20000 users and each (potentially) needs a separate database
which is > only accessible to them. Rather than having 20000 lines
in pg_hba.conf, > I've patched Postgres so that the special token
"sameuser" in the > database field of pg_hba.conf allows access
only to the username which > is connecting.
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.
o A new patch that contains the following changes:
-- The pg_pwd file is now cached in the postmaster's memory.
-- pg_pwd is reloaded when the postmaster detects a flag file creat()'ed
by a backend.
-- qsort() is used to sort loaded password entries, and bsearch() is
is used to find entries in the pg_pwd cache.
-- backends now copy the pg_user relation to pg_pwd.pid, and then
rename the temp file to be pg_pwd.
-- The delimiter for pg_pwd has been changed to a tab character.
Subject: [HACKERS] libpq/pqcomm stuff and Solaris byte order
I decided to go ahead with the required changes since no one else seems
to. I don't guarantee that it is perfect but with these changes the
package actually compiles. While I was at it I added to the Sparc
Solaris header to define the byte order. Note that NetBSD sets this
in the system headers so it wasn't required there.
In particular, someone may want to check whether I removed the correct
84 lines from backend/libpq/pqcomprim.c.
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
Subject: [HACKERS] password authentication
This patch adds support for plaintext password authentication. To use
it, you add a line like
host all 0.0.0.0 0.0.0.0 password pg_pwd.conf
to your pg_hba.conf, where 'pg_pwd.conf' is the name of a file containing
the usernames and password hashes in the format of the first two fields
of a Unix /etc/passwd file. (Of course, you can use a specific database
name or IP instead.)
Then, to connect with a password through libpq, you use the PQconnectdb()
function, specifying the "password=" tag in the connect string and also
adding the tag "authtype=password".
I also added a command-line switch '-u' to psql that tells it to prompt
for a username and password and use password authentication.
I'm able to get through a 'make' of the backend with no errors except
the occasional 'might not be initialized error', which is nothing major,
just annoying.
Have a few patches from D'Arcy to incorporate, but am waiting until I can
get a clean compile first, which I'm hoping to have before bed, or sometime
tomorrow.