The current implementation supports exactly one IP address in a server
certificate's Common Name, which is brittle (the strings must match
exactly). This patch adds support for IPv4 and IPv6 addresses in a
server's Subject Alternative Names.
Per discussion on-list:
- If the client's expected host is an IP address, we allow fallback to
the Subject Common Name if an iPAddress SAN is not present, even if
a dNSName is present. This matches the behavior of NSS, in
violation of the relevant RFCs.
- We also, counter-intuitively, match IP addresses embedded in dNSName
SANs. From inspection this appears to have been the behavior since
the SAN matching feature was introduced in acd08d76.
- Unlike NSS, we don't map IPv4 to IPv6 addresses, or vice-versa.
Author: Jacob Champion <pchampion@vmware.com>
Co-authored-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Co-authored-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://www.postgresql.org/message-id/flat/9f5f20974cd3a4091a788cf7f00ab663d5fcdffe.camel@vmware.com
SSL has become the de facto term to mean an end-to-end encrypted channel
regardless of protocol used, even though the SSL protocol is deprecated.
Clarify what we mean with SSL in our documentation, especially for new
users who might be looking for TLS.
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/D4ABB281-6CFD-46C6-A4E0-8EC23A2977BC@yesql.se
Currently, libpq client code must have a connection handle
before it can query the "library" SSL attribute. This poses
problems if the client needs to know what SSL library is in
use before constructing a connection string.
Allow PQsslAttribute(NULL, "library") to return the library
in use -- currently, just "OpenSSL" or NULL. The new behavior
is announced with the LIBPQ_HAS_SSL_LIBRARY_DETECTION feature
macro, allowing clients to differentiate between a libpq that
was compiled without SSL support and a libpq that's just too
old to tell.
Author: Jacob Champion <pchampion@vmware.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/4c8b76ef434a96627170a31c3acd33cbfd6e41f1.camel@vmware.com
MERGE performs actions that modify rows in the target table using a
source table or query. MERGE provides a single SQL statement that can
conditionally INSERT/UPDATE/DELETE rows -- a task that would otherwise
require multiple PL statements. For example,
MERGE INTO target AS t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED AND t.balance > s.delta THEN
UPDATE SET balance = t.balance - s.delta
WHEN MATCHED THEN
DELETE
WHEN NOT MATCHED AND s.delta > 0 THEN
INSERT VALUES (s.sid, s.delta)
WHEN NOT MATCHED THEN
DO NOTHING;
MERGE works with regular tables, partitioned tables and inheritance
hierarchies, including column and row security enforcement, as well as
support for row and statement triggers and transition tables therein.
MERGE is optimized for OLTP and is parameterizable, though also useful
for large scale ETL/ELT. MERGE is not intended to be used in preference
to existing single SQL commands for INSERT, UPDATE or DELETE since there
is some overhead. MERGE can be used from PL/pgSQL.
MERGE does not support targetting updatable views or foreign tables, and
RETURNING clauses are not allowed either. These limitations are likely
fixable with sufficient effort. Rewrite rules are also not supported,
but it's not clear that we'd want to support them.
Author: Pavan Deolasee <pavan.deolasee@gmail.com>
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Author: Amit Langote <amitlangote09@gmail.com>
Author: Simon Riggs <simon.riggs@enterprisedb.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de> (earlier versions)
Reviewed-by: Peter Geoghegan <pg@bowt.ie> (earlier versions)
Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier versions)
Reviewed-by: Japin Li <japinli@hotmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Discussion: https://postgr.es/m/CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com
Discussion: https://postgr.es/m/CAH2-WzkJdBuxj9PO=2QaO9-3h3xGbQPZ34kJH=HukRekwM-GZg@mail.gmail.com
Discussion: https://postgr.es/m/20201231134736.GA25392@alvherre.pgsql
As currently implemented, failure of a PGEVT_CONNRESET callback
forces the PGconn into the CONNECTION_BAD state (without closing
the socket, which is inconsistent with other failure paths), and
prevents later callbacks from being called. This seems highly
questionable, and indeed is questioned by comments in the source.
Instead, let's just ignore the result value of PGEVT_CONNRESET
calls. Like the preceding commit, this converts event callbacks
into "pure observers" that cannot affect libpq's processing logic.
Discussion: https://postgr.es/m/3185105.1644960083@sss.pgh.pa.us
As currently implemented, failure of a PGEVT_RESULTCREATE callback
causes the PGresult to be converted to an error result. This is
intellectually inconsistent (shouldn't a failing callback likewise
prevent creation of the error result? what about side-effects on the
behavior seen by other event procs? why does PQfireResultCreateEvents
act differently from PQgetResult?), but more importantly it destroys
any promises we might wish to make about the behavior of libpq in
nontrivial operating modes, such as pipeline mode. For example,
it's not possible to promise that PGRES_PIPELINE_SYNC results will
be returned if an event callback fails on those. With this
definition, expecting applications to behave sanely in the face of
possibly-failing callbacks seems like a very big lift.
Hence, redefine the result of a callback failure as being simply
that that event procedure won't be called any more for this PGresult
(which was true already). Event procedures can still signal failure
back to the application through out-of-band mechanisms, for example
via their passthrough arguments.
Similarly, don't let failure of a PGEVT_RESULTCOPY callback prevent
PQcopyResult from succeeding. That definition allowed a misbehaving
event proc to break single-row mode (our sole internal use of
PQcopyResult), and it probably had equally deleterious effects for
outside uses.
Discussion: https://postgr.es/m/3185105.1644960083@sss.pgh.pa.us
If connectivity to the server has been lost or become flaky, the
user might well try to send a query cancel. It's highly annoying
if PQcancel hangs up in such a case, but that's exactly what's likely
to happen. To ameliorate this problem, apply the PGconn's
tcp_user_timeout and keepalives settings to the TCP connection used
to send the cancel. This should be safe on Unix machines, since POSIX
specifies that setsockopt() is async-signal-safe. We are guessing
that WSAIoctl(SIO_KEEPALIVE_VALS) is similarly safe on Windows.
(Note that at least in psql and our other frontend programs, there's
no safety issue involved anyway, since we run PQcancel in its own
thread rather than in a signal handler.)
Most of the value here comes from the expectation that tcp_user_timeout
will be applied as a connection timeout. That appears to happen on
Linux, even though its tcp(7) man page claims differently. The
keepalive options probably won't help much, but as long as we can
apply them for not much code, we might as well.
Jelte Fennema, reviewed by Fujii Masao and myself
Discussion: https://postgr.es/m/AM5PR83MB017870DE81FC84D5E21E9D1EF7AA9@AM5PR83MB0178.EURPRD83.prod.outlook.com
ssl_crl_file and ssl_crl_dir are both used to for client certificate
revocation, not server certificates. The description for the params
could be easily misread to mean the opposite however, as evidenced
by the bugreport leading to this fix. Similarly, expand sslcrl and
and sslcrldir to explicitly mention server certificates. While there
also mention sslcrldir where previously only sslcrl was discussed.
Backpatch down to v10, with the CRL dir fixes down to 14 where they
were introduced.
Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Discussion: https://postgr.es/m/20211202.135441.590555657708629486.horikyota.ntt@gmail.com
Discussion: https://postgr.es/m/CABWY_HCBUCjY1EJHrEGePGEaSZ5b29apgTohCyygtsqe_ySYng@mail.gmail.com
Backpatch-through: 10
The check for sslsni only checked for existence of the parameter
but not for the actual value of the param. This meant that the
SNI extension was always turned on. Fix by inspecting the value
of sslsni and only activate the SNI extension iff sslsni has been
enabled. Also update the docs to be more in line with how other
boolean params are documented.
Backpatch to 14 where sslsni was first implemented.
Reviewed-by: Tom Lane
Backpatch-through: 14, where sslni was added
When sending queries in pipeline mode, we were careless about leaving
the connection in the right state so that PQgetResult would behave
correctly; trying to read further results after sending a query after
having read a result with an error would sometimes hang. Fix by
ensuring internal libpq state is changed properly. All the state
changes were being done by the callers of pqAppendCmdQueueEntry(); it
would have become too repetitious to have this logic in each of them, so
instead put it all in that function and relieve callers of the
responsibility.
Add a test to verify this case. Without the code fix, this new test
hangs sometimes.
Also, document that PQisBusy() would return false when no queries are
pending result. This is not intuitively obvious, and NULL would be
obtained by calling PQgetResult() at that point, which is confusing.
Wording by Boris Kolpackov.
In passing, fix bogus use of "false" to mean "0", per Ranier Vilela.
Backpatch to 14.
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reported-by: Boris Kolpackov <boris@codesynthesis.com>
Discussion: https://postgr.es/m/boris.20210624103805@codesynthesis.com
This new libpq function allows the application to send an 'H' message,
which instructs the server to flush its outgoing buffer.
This hasn't been needed so far because the Sync message already requests
a buffer; and I failed to realize that this was needed in pipeline mode
because PQpipelineSync also causes the buffer to be flushed. However,
sometimes it is useful to request a flush without establishing a
synchronization point.
Backpatch to 14, where pipeline mode was introduced in libpq.
Reported-by: Boris Kolpackov <boris@codesynthesis.com>
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/202106252350.t76x73nt643j@alvherre.pgsql
This adds MITM and SNI as acronyms, as the documentation already had
them marked up with <acronym>.
While on it, make sure to spell man-in-the-middle with dashes
consistently, and add acronyms for those new terms where appropriate.
Author: Daniel Gustafsson
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/CE12DD5C-4BB3-4166-BC9A-39779568734C@yesql.se
We have a dozen PQset*() functions. PQresultSetInstanceData() and this
were the libpq setter functions having a different word order. Adopt
the majority word order.
Reviewed by Alvaro Herrera and Robert Haas, though this choice of name
was not unanimous.
Discussion: https://postgr.es/m/20210605060555.GA216695@rfd.leadboat.com
We've accumulated quite a mix of instances of "an SQL" and "a SQL" in the
documents. It would be good to be a bit more consistent with these.
The most recent version of the SQL standard I looked at seems to prefer
"an SQL". That seems like a good lead to follow, so here we change all
instances of "a SQL" to become "an SQL". Most instances correctly use
"an SQL" already, so it also makes sense to use the dominant variation in
order to minimise churn.
Additionally, there were some other abbreviations that needed to be
adjusted. FSM, SSPI, SRF and a few others. Also fix some pronounceable,
abbreviations to use "a" instead of "an". For example, "a SASL" instead
of "an SASL".
Here I've only adjusted the documents and error messages. Many others
still exist in source code comments. Translator hint comments seem to be
the biggest culprit. It currently does not seem worth the churn to change
these.
Discussion: https://postgr.es/m/CAApHDvpML27UqFXnrYO1MJddsKVMQoiZisPvsAGhKE_tsKXquw%40mail.gmail.com
This was missing in the section dedicated to the supported environment
variables of libpq. Oversight in f5465fa.
Reviewed-by: Daniel Gustafsson, Kyotaro Horiguchi
Discussion: https://postgr.es/m/YLhI0mLoRkY3u4Wj@paquier.xyz
Clarify libpq.sgml's description of service file locations and
semantics. Avoid use of backtick'ed pg_config calls to describe
paths; that doesn't work on Windows, and even on Unix it's an
idiom that not all readers may be instantly familiar with.
Don't overspecify the locations of include files, instead writing
only as much as you'd use in #include directives. The previous text
in these places was incorrect for some installations, depending on
where "postgresql" is in the install path.
Our convention for referencing the user's home directory seems
to be "~", so change the one place that spelled it "$HOME".
install-windows.sgml follows the platform convention of spelling
file paths with "\", so change the one place that used "/".
Haiying Tang and Tom Lane
Discussion: https://postgr.es/m/162149020918.26174.7150424047314144297@wrigleys.postgresql.org
Mention specifically that you can't call aggregates, window functions,
or procedures this way (the inability to call SRFs was already
mentioned).
Also, the claim that PQfn doesn't support NULL arguments or results
has been a lie since we invented protocol 3.0. Not sure why this
text was never updated for that, but do it now.
Discussion: https://postgr.es/m/2039442.1615317309@sss.pgh.pa.us
By default, have libpq set the TLS extension "Server Name Indication" (SNI).
This allows an SNI-aware SSL proxy to route connections. (This
requires a proxy that is aware of the PostgreSQL protocol, not just
any SSL proxy.)
In the future, this could also allow the server to use different SSL
certificates for different host specifications. (That would require
new server functionality. This would be the client-side functionality
for that.)
Since SNI makes the host name appear in cleartext in the network
traffic, this might be undesirable in some cases. Therefore, also add
a libpq connection option "sslsni" to turn it off.
Discussion: https://www.postgresql.org/message-id/flat/7289d5eb-62a5-a732-c3b9-438cee2cb709%40enterprisedb.com
Transform the PQtrace output format from its ancient (and mostly
useless) byte-level output format to a logical-message-level output,
making it much more usable. This implementation allows the printing
code to be written (as it indeed was) by looking at the protocol
documentation, which gives more confidence that the three (docs, trace
code and actual code) actually match.
Author: 岩田 彩 (Aya Iwata) <iwata.aya@fujitsu.com>
Reviewed-by: 綱川 貴之 (Takayuki Tsunakawa) <tsunakawa.takay@fujitsu.com>
Reviewed-by: Kirk Jamison <k.jamison@fujitsu.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: 黒田 隼人 (Hayato Kuroda) <kuroda.hayato@fujitsu.com>
Reviewed-by: "Nagaura, Ryohei" <nagaura.ryohei@jp.fujitsu.com>
Reviewed-by: Ryo Matsumura <matsumura.ryo@fujitsu.com>
Reviewed-by: Greg Nancarrow <gregn4422@gmail.com>
Reviewed-by: Jim Doty <jdoty@pivotal.io>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/71E660EB361DF14299875B198D4CE5423DE3FBA4@g01jpexmbkw25
Pipeline mode in libpq lets an application avoid the Sync messages in
the FE/BE protocol that are implicit in the old libpq API after each
query. The application can then insert Sync at its leisure with a new
libpq function PQpipelineSync. This can lead to substantial reductions
in query latency.
Co-authored-by: Craig Ringer <craig.ringer@enterprisedb.com>
Co-authored-by: Matthieu Garrigues <matthieu.garrigues@gmail.com>
Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Aya Iwata <iwata.aya@jp.fujitsu.com>
Reviewed-by: Daniel Vérité <daniel@manitou-mail.org>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Kirk Jamison <k.jamison@fujitsu.com>
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Nikhil Sontakke <nikhils@2ndquadrant.com>
Reviewed-by: Vaishnavi Prabakaran <VaishnaviP@fast.au.fujitsu.com>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Discussion: https://postgr.es/m/CAMsr+YFUjJytRyV4J-16bEoiZyH=4nj+sQ7JP9ajwz=B4dMMZw@mail.gmail.com
Discussion: https://postgr.es/m/CAJkzx4T5E-2cQe3dtv2R78dYFvz+in8PY7A8MArvLhs_pg75gg@mail.gmail.com
This partially reverts 096bbf7 and 9d2d457, undoing the libpq changes as
it could cause breakages in distributions that share one single libpq
version across multiple major versions of Postgres for extensions and
applications linking to that.
Note that the backend is unchanged here, and it still disables SSL
compression while simplifying the underlying catalogs that tracked if
compression was enabled or not for a SSL connection.
Per discussion with Tom Lane and Daniel Gustafsson.
Discussion: https://postgr.es/m/YEbq15JKJwIX+S6m@paquier.xyz
The authtype parameter was deprecated and made inactive in commit
d5bbe2aca5, but the environment variable was left defined and thus
tested with a getenv call even though the value is of no use. Also,
if it would exist it would be copied but never freed as the cleanup
code had been removed.
tty was deprecated in commit cb7fb3ca95 but most of the
infrastructure around it remained in place.
Author: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/DDDF36F3-582A-4C02-8598-9B464CC42B34@yesql.se
PostgreSQL disabled compression as of e3bdb2d and the documentation
recommends against using it since. Additionally, SSL compression has
been disabled in OpenSSL since version 1.1.0, and was disabled in many
distributions long before that. The most recent TLS version, TLSv1.3,
disallows compression at the protocol level.
This commit removes the feature itself, removing support for the libpq
parameter sslcompression (parameter still listed for compatibility
reasons with existing connection strings, just ignored), and removes
the equivalent field in pg_stat_ssl and de facto PgBackendSSLStatus.
Note that, on top of removing the ability to activate compression by
configuration, compression is actively disabled in both frontend and
backend to avoid overrides from local configurations.
A TAP test is added for deprecated SSL parameters to check after
backwards compatibility.
Bump catalog version.
Author: Daniel Gustafsson
Reviewed-by: Peter Eisentraut, Magnus Hagander, Michael Paquier
Discussion: https://postgr.es/m/7E384D48-11C5-441B-9EC3-F7DB1F8518F6@yesql.se
Protocol version 3 was introduced in PostgreSQL 7.4. There shouldn't be
many clients or servers left out there without version 3 support. But as
a courtesy, I kept just enough of the old protocol support that we can
still send the "unsupported protocol version" error in v2 format, so that
old clients can display the message properly. Likewise, libpq still
understands v2 ErrorResponse messages when establishing a connection.
The impetus to do this now is that I'm working on a patch to COPY
FROM, to always prefetch some data. We cannot do that safely with the
old protocol, because it requires parsing the input one byte at a time
to detect the end-of-copy marker.
Reviewed-by: Tom Lane, Alvaro Herrera, John Naylor
Discussion: https://www.postgresql.org/message-id/9ec25819-0a8a-d51a-17dc-4150bb3cca3b%40iki.fi
In addition to the existing options of "any" and "read-write", we
now support "read-only", "primary", "standby", and "prefer-standby".
"read-write" retains its previous meaning of "transactions are
read-write by default", and "read-only" inverts that. The other
three modes test specifically for hot-standby status, which is not
quite the same thing. (Setting default_transaction_read_only on
a primary server renders it read-only to this logic, but not a
standby.)
Furthermore, if talking to a v14 or later server, no extra network
round trip is needed to detect the session's status; the GUC_REPORT
variables delivered by the server are enough. When talking to an
older server, a SHOW or SELECT query is issued to detect session
read-only-ness or server hot-standby state, as needed.
Haribabu Kommi, Greg Nancarrow, Vignesh C, Tom Lane; reviewed at
various times by Laurenz Albe, Takayuki Tsunakawa, Peter Smith.
Discussion: https://postgr.es/m/CAF3+xM+8-ztOkaV9gHiJ3wfgENTq97QcjXQt+rbFQ6F7oNzt9A@mail.gmail.com
This allows clients to find out the setting at connection time without
having to expend a query round trip to do so; which is helpful when
trying to identify read/write servers. (One must also look at
in_hot_standby, but that's already GUC_REPORT, cf bf8a662c9.)
Modifying libpq to make use of this will come soon, but I felt it
cleaner to push the server change separately.
Haribabu Kommi, Greg Nancarrow, Vignesh C; reviewed at various times
by Laurenz Albe, Takayuki Tsunakawa, Peter Smith.
Discussion: https://postgr.es/m/CAF3+xM+8-ztOkaV9gHiJ3wfgENTq97QcjXQt+rbFQ6F7oNzt9A@mail.gmail.com
Break the synopsis into named parts to make it less confusing.
Make more than zero effort at applying SGML markup. Do a bit
of copy-editing of nearby text.
The synopsis revision is by Alvaro Herrera and Paul Förster,
the rest is my fault. Back-patch to v10 where multi-host
connection strings appeared.
Discussion: https://postgr.es/m/6E752D6B-487C-463E-B6E2-C32E7FB007EA@gmail.com
Add another method to specify CRLs, hashed directory method, for both
server and client side. This offers a means for server or libpq to
load only CRLs that are required to verify a certificate. The CRL
directory is specifed by separate GUC variables or connection options
ssl_crl_dir and sslcrldir, alongside the existing ssl_crl_file and
sslcrl, so both methods can be used at the same time.
Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/20200731.173911.904649928639357911.horikyota.ntt@gmail.com
libpq's error messages for connection failures pretty well stand on
their own, especially since commits 52a10224e/27a48e5a1. Prefixing
them with 'could not connect to database "foo"' or the like is just
redundant, and perhaps even misleading if the specific database name
isn't relevant to the failure. (When it is, we trust that the
backend's error message will include the DB name.) Indeed, psql
hasn't used any such prefix in a long time. So, make all our other
programs and documentation examples agree with psql's practice.
Discussion: https://postgr.es/m/1094524.1611266589@sss.pgh.pa.us
This text claimed that the reconnection would occur "to the same
server", but there is no such guarantee in the code, nor would
insisting on that be an improvement.
Back-patch to v10 where multi-host connection strings were added.
Discussion: https://postgr.es/m/1095901.1611268376@sss.pgh.pa.us
Aside from being queriable via SHOW, this value is sent to the client
immediately at session startup, and again later on if the server gets
promoted to primary during the session. The immediate report will be
used in an upcoming patch to avoid an extra round trip when trying to
connect to a primary server.
Haribabu Kommi, Greg Nancarrow, Tom Lane; reviewed at various times
by Laurenz Albe, Takayuki Tsunakawa, Peter Smith.
Discussion: https://postgr.es/m/CAF3+xM+8-ztOkaV9gHiJ3wfgENTq97QcjXQt+rbFQ6F7oNzt9A@mail.gmail.com
Unrecoverable errors detected by GSSAPI encryption can't just be
reported with elog(ERROR) or elog(FATAL), because attempting to
send the error report to the client is likely to lead to infinite
recursion or loss of protocol sync. Instead make this code do what
the SSL encryption code has long done, which is to just report any
such failure to the server log (with elevel COMMERROR), then pretend
we've lost the connection by returning errno = ECONNRESET.
Along the way, fix confusion about whether message translation is done
by pg_GSS_error() or its callers (the latter should do it), and make
the backend version of that function work more like the frontend
version.
Avoid allocating the port->gss struct until it's needed; we surely
don't need to allocate it in the postmaster.
Improve logging of "connection authorized" messages with GSS enabled.
(As part of this, I back-patched the code changes from dc11f31a1.)
Make BackendStatusShmemSize() account for the GSS-related space that
will be allocated by CreateSharedBackendStatus(). This omission
could possibly cause out-of-shared-memory problems with very high
max_connections settings.
Remove arbitrary, pointless restriction that only GSS authentication
can be used on a GSS-encrypted connection.
Improve documentation; notably, document the fact that libpq now
prefers GSS encryption over SSL encryption if both are possible.
Per report from Mikael Gustavsson. Back-patch to v12 where
this code was introduced.
Discussion: https://postgr.es/m/e5b0b6ed05764324a2f3fe7acfc766d5@smhi.se
The documentation omitted the critical tidbit that a keyword-array entry
is simply ignored if its corresponding value-array entry is NULL or an
empty string; it will *not* override any previously-obtained value for
the parameter. (See conninfo_array_parse().) I'd supposed that would
force the setting back to default, which is what led me into bug #16746;
but it doesn't.
While here, I couldn't resist the temptation to do some copy-editing,
both in the description of PQconnectdbParams() and in the section
about connection URI syntax.
Discussion: https://postgr.es/m/931505.1606618746@sss.pgh.pa.us
This is a variant of the normal Unix-domain sockets that don't use the
file system but a separate "abstract" namespace. At the user
interface, such sockets are represented by names starting with "@".
Supported on Linux and Windows right now.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/flat/6dee8574-b0ad-fc49-9c8c-2edc796f0033@2ndquadrant.com
The Windows documentation insists that every WSAStartup call should
have a matching WSACleanup call. However, if that ever had actual
relevance, it wasn't in this century. Every remotely-modern Windows
kernel is capable of cleaning up when a process exits without doing
that, and must be so to avoid resource leaks in case of a process
crash. Moreover, Postgres backends have done WSAStartup without
WSACleanup since commit 4cdf51e64 in 2004, and we've never seen any
indication of a problem with that.
libpq's habit of doing WSAStartup during connection start and
WSACleanup during shutdown is also rather inefficient, since a
series of non-overlapping connection requests leads to repeated,
quite expensive DLL unload/reload cycles. We document a workaround
for that (having the application call WSAStartup for itself), but
that's just a kluge. It's also worth noting that it's far from
uncommon for applications to exit without doing PQfinish, and
we've not heard reports of trouble from that either.
However, the real reason for acting on this is that recent
experiments by Alexander Lakhin suggest that calling WSACleanup
during PQfinish might be triggering the symptom we occasionally see
that a process using libpq fails to emit expected stdio output.
Therefore, let's change libpq so that it calls WSAStartup only
once per process, during the first connection attempt, and never
calls WSACleanup at all.
While at it, get rid of the only other WSACleanup call in our code
tree, in pg_dump/parallel.c; that presumably is equally useless.
If this proves to suppress the fairly-common ecpg test failures
we see on Windows, I'll back-patch, but for now let's just do it
in HEAD and see what happens.
Discussion: https://postgr.es/m/ac976d8c-03df-d6b8-025c-15a2de8d9af1@postgrespro.ru
Peter Eisentraut
Daniel Gustafsson
Alvaro Herrera
Tom Lane
Michael Paquier
Noah Misch
David Rowley
Bruce Momjian
Heikki Linnakangas