This adds support for load balancing connections with libpq using a
connection parameter: load_balance_hosts=<string>. When setting the
param to random, hosts and addresses will be connected to in random
order. This then results in load balancing across these addresses and
hosts when multiple clients or frequent connection setups are used.
The randomization employed performs two levels of shuffling:
1. The given hosts are randomly shuffled, before resolving them
one-by-one.
2. Once a host its addresses get resolved, the returned addresses
are shuffled, before trying to connect to them one-by-one.
Author: Jelte Fennema <postgres@jeltef.nl>
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Reviewed-by: Michael Banck <mbanck@gmx.net>
Reviewed-by: Andrey Borodin <amborodin86@gmail.com>
Discussion: https://postgr.es/m/PR3PR83MB04768E2FF04818EEB2179949F7A69@PR3PR83MB0476.EURPRD83.prod.outlook.
This refactors libpq to copy addrinfos returned by getaddrinfo to
memory owned by libpq such that future improvements can alter for
example the order of entries.
As a nice side effect of this refactor the mechanism for iteration
over addresses in PQconnectPoll is now identical to its iteration
over hosts.
Author: Jelte Fennema <postgres@jeltef.nl>
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Reviewed-by: Michael Banck <mbanck@gmx.net>
Reviewed-by: Andrey Borodin <amborodin86@gmail.com>
Discussion: https://postgr.es/m/PR3PR83MB04768E2FF04818EEB2179949F7A69@PR3PR83MB0476.EURPRD83.prod.outlook.com
gistBuildCallback tried to fetch the size of an index tuple that
might have already been freed by gistProcessEmptyingQueue.
While this seems to usually be harmless in production builds,
in principle it could result in a SIGSEGV, or more likely a bogus
value for indtuplesSize leading to poor page-split decisions later
in the build.
The memory management here is confusing and could stand to be
refactored, but for the moment it seems to be enough to fetch
the tuple size sooner. AFAICT the indtuples[Size] totals aren't
used in between these places; even if they were, the updated
values shouldn't be any worse to use. So just move the
incrementing of the totals up.
It's not very clear why our valgrind-using buildfarm animals
haven't noticed this problem, because the relevant code path
does seem to be exercised according to the code coverage report.
I think the reason that we didn't fix this bug after the first
report is that I'd wanted to try to understand that better.
However, now that it's been re-discovered let's just be pragmatic
and fix it already.
Original report by Alexander Lakhin (bug #16329),
later rediscovered by Egor Chindyaskin (bug #17874).
Patch by Alexander Lakhin (commentary by Pavel Borisov and me).
Back-patch to all supported branches.
Discussion: https://postgr.es/m/16329-7a6aa9b6fa1118a1@postgresql.org
Discussion: https://postgr.es/m/17874-63ca6c7ce42d2103@postgresql.org
This function has been a no-op for over a decade. Even if bufmgr
regains a need to be called during commit, it seems unlikely that
the most appropriate call points would be precisely here, so it's not
doing us much good as a placeholder either. Now, removing it probably
doesn't save any noticeable number of cycles --- but the main call is
inside the commit critical section, and the less work done there the
better.
Matthias van de Meent
Discussion: https://postgr.es/m/CAEze2Wi1=tLKbxZnXzcD+8fYKyKqBtivVakLQC_mYBsP4Y8qVA@mail.gmail.com
This commit introduces the SQL/JSON standard-conforming constructors for
JSON types:
JSON_ARRAY()
JSON_ARRAYAGG()
JSON_OBJECT()
JSON_OBJECTAGG()
Most of the functionality was already present in PostgreSQL-specific
functions, but these include some new functionality such as the ability
to skip or include NULL values, and to allow duplicate keys or throw
error when they are found, as well as the standard specified syntax to
specify output type and format.
Author: Nikita Glukhov <n.gluhov@postgrespro.ru>
Author: Teodor Sigaev <teodor@sigaev.ru>
Author: Oleg Bartunov <obartunov@gmail.com>
Author: Alexander Korotkov <aekorotkov@gmail.com>
Author: Amit Langote <amitlangote09@gmail.com>
Reviewers have included (in no particular order) Andres Freund, Alexander
Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu,
Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby.
Discussion: https://postgr.es/m/CAF4Au4w2x-5LTnN_bxky-mq4=WOqsGsxSpENCzHRAzSnEd8+WQ@mail.gmail.com
Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Discussion: https://postgr.es/m/20220616233130.rparivafipt6doj3@alap3.anarazel.de
Discussion: https://postgr.es/m/abd9b83b-aa66-f230-3d6d-734817f0995d%40postgresql.org
The standard collations "ucs_basic" and "unicode" were defined in
initdb, even though pg_collation.dat seems like the correct place for
them. It seems this was just forgotten during various reorganizations
of initdb and pg_collation.dat/.h over time.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/08b58ecd-0d50-9395-ed51-dc8294e3fd2b%40enterprisedb.com
In ancient times, these belonged to arguments or fields that were
actually of type long, but now they are not anymore, so this "L"
decoration is just confusing. (Some other 0L and other "L" constants
remain, where they are actually associated with a long type.)
When there are multiple publications for a subscription and one of those
publishes via the parent table by using publish_via_partition_root and the
other one directly publishes the child table, we end up copying the same
data twice during initial synchronization. The reason for this was that we
get both the parent and child tables from the publisher and try to copy
the data for both of them.
This patch extends the function pg_get_publication_tables() to take a
publication list as its input parameter. This allows us to exclude a
partition table whose ancestor is published by the same publication list.
This problem does exist in back-branches but we decide to fix it there in
a separate commit if required. The fix for back-branches requires quite
complicated changes to fetch the required table information from the
publisher as we can't update the function pg_get_publication_tables() in
back-branches. We are not sure whether we want to deviate and complicate
the code in back-branches for this problem as there are no field reports
yet.
Author: Wang wei
Reviewed-by: Peter Smith, Jacob Champion, Kuroda Hayato, Vignesh C, Osumi Takamichi, Amit Kapila
Discussion: https://postgr.es/m/OS0PR01MB57167F45D481F78CDC5986F794B99@OS0PR01MB5716.jpnprd01.prod.outlook.com
Commit ecb696527c added an XML ID attribute to one varlistentry in
create_subscription.sgml. Following 78ee60ed84, this commit adds XML ID
attributes to all varlistentries in create_subscription.sgml.
Additionally, links are added to refer to the subscription options,
enhancing the readability of documents.
Author: Kuroda Hayato
Reviewed-by: Peter Smith, Amit Kapila
Discussion: https://postgr.es/m/TYAPR01MB58667AE04D291924671E2051F5879@TYAPR01MB5866.jpnprd01.prod.outlook.com
The pg_dump Compressor API has three basic callbacks - Allocate, Write
and End. The gzip implementation (since e9960732a) wrongly assumed the
Write function would always be called, and deferred the initialization
of the internal compression system until the first such call. But when
there's no data to compress (e.g. for empty LO), this would result in
not finalizing the compression state (because it was not actually
initialized), producing invalid dump.
Fixed by initializing the internal compression system in the Allocate
call, whenever the caller provides the Write. For decompression the
state is not needed, so we leave the private_data member unpopulated.
Introduces a pg_dump TAP test compressing an empty large object.
This also rearranges the functions to their original order, to make
diffs against older code simpler to understand. Finally, replace an
unreachable pg_fatal() with a simple assert check.
Reported-by: Justin Pryzby
Author: Justin Pryzby, Georgios Kokolatos
Reviewed-by: Georgios Kokolatos, Tomas Vondra
https://postgr.es/m/20230228235834.GC30529%40telsasoft.com
For ICU collations, ensure that the locale's language exists in ICU,
and that the locale can be opened.
Basic validation helps avoid minor mistakes and misspellings, which
often fall back to the root locale instead of the intended
locale. It's even more important to avoid such mistakes in ICU
versions 54 and earlier, where the same (misspelled) locale string
could fall back to different locales depending on the environment.
Discussion: https://postgr.es/m/11b1eeb7e7667fdd4178497aeb796c48d26e69b9.camel@j-davis.com
Discussion: https://postgr.es/m/df2efad0cae7c65180df8e5ebb709e5eb4f2a82b.camel@j-davis.com
Reviewed-by: Peter Eisentraut
Commit e88754a196 caused that case
to be reported as corruption, but Peter Geoghegan pointed out that
it can legitimately happen in the case of a speculative insertion
that aborts, so we'd better not flag it as corruption after all.
Back-patch to v14, like the commit that introduced the issue.
Discussion: http://postgr.es/m/CAH2-WzmEabzcPTxSY-NXKH6Qt3FkAPYHGQSe2PtvGgj17ZQkCw@mail.gmail.com
Commit 0276ae42dd taught pg_walinspect's pg_get_wal_record_info()
function to output NULLs rather than empty strings for its record
description and block_ref output parameters. However, it inadvertently
moved the function call that sets fpi_length until after it was already
set. As a result, pg_get_wal_record_info() always output spurious
fpi_length values of 0.
Fix by switching the order back (but keep the behavioral change).
Author: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Discussion: https://postgr.es/m/CAH2-WzkJmgSYkt6-smQ+57SxSmov+EKqFZdSimFewosoL_JKoA@mail.gmail.com
MERGE planning could fail with "variable not found in subplan target
list" if the target table is partitioned and all its partitions are
excluded at plan time, or in the case where it has no partitions but
used to have some. This happened because distribute_row_identity_vars
thought it didn't need to make the target table's reltarget list
fully valid; but if we generate a join plan then that is required
because the dummy Result node's tlist will be made from the reltarget.
The same logic appears in distribute_row_identity_vars in v14,
but AFAICS the problem is unreachable in that branch for lack of
MERGE. In other updating statements, the target table is always
inner-joined to any other tables, so if the target is known dummy
then the whole plan reduces to dummy, so no join nodes are created.
So I'll refrain from back-patching this code change to v14 for now.
Per report from Alvaro Herrera.
Discussion: https://postgr.es/m/20230328112248.6as34mlx5sr4kltg@alvherre.pgsql
The extra checks done in check_icu_locale() are not necessary. An
existing comment already pointed out that the checks would be done
during post-bootstrap initialization, when the locale is opened by the
backend. This was a mistake in commit 27b62377b4.
This commit creates a simpler function default_icu_locale() to just
return the locale of the default collator.
Discussion: https://postgr.es/m/04182066-7655-344a-b8b7-040b1b2490fb%40enterprisedb.com
Reviewed-by: Peter Eisentraut
To support older ICU versions, we rely on
icu_set_collation_attributes() to do error checking that is handled
directly by ucol_open() in newer ICU versions. Commit 3b50275b12
introduced a slight inconsistency, where the error report includes the
fixed-up locale string, rather than the locale string passed to
pg_ucol_open().
Refactor slightly so that pg_ucol_open() handles the errors from both
ucol_open() and icu_set_collation_attributes(), making it easier to
see any differences between the error reports. It also makes
pg_ucol_open() responsible for closing the UCollator on error, which
seems like the right place.
Discussion: https://postgr.es/m/04182066-7655-344a-b8b7-040b1b2490fb%40enterprisedb.com
Reviewed-by: Peter Eisentraut
Change the columns attndims, attstattarget, and attinhcount from int32
to int16, and reorder a bit. This saves some space (currently 4
bytes) in pg_attribute and tuple descriptors, which translates into
small performance benefits and/or room for new columns in pg_attribute
needed by future features.
attndims and attinhcount are never realistically used with values
larger than int16. Just to be sure, add some overflow checks.
attstattarget is currently limited explicitly to 10000.
For consistency, pg_constraint.coninhcount is also changed like
attinhcount.
Discussion: https://www.postgresql.org/message-id/flat/d07ffc2b-e0e8-77f7-38fb-be921dff71af%40enterprisedb.com
Two new macros are added with their respective functions switched to
use them. These are for functions with millisecond stats, with and
without "xact" in their names (for the stats that can be tracked within
a transaction).
While on it, prefix the macro for float8 on database entries with "_MS",
as it does a us->ms conversion, based on a suggestion from Andres
Freund.
Author: Bertrand Drouvot
Discussion: https://postgr.es/m/6e2efb4f-6fd0-807e-f6bf-94207db8183a@gmail.com
find_composite_type_dependencies() ignored indexes, which is a poor
decision because an expression index could have a stored column of
a composite (or other container) type even when the underlying table
does not. Teach it to detect such cases and error out. We have to
work a bit harder than for other relations because the pg_depend entry
won't identify the specific index column of concern, but it's not much
new code.
This does not address bug #17872's original complaint that dropping
a column in such a type might lead to violations of the uniqueness
property that a unique index is supposed to ensure. That seems of
much less concern to me because it won't lead to crashes.
Per bug #17872 from Alexander Lakhin. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/17872-d0fbb799dc3fd85d@postgresql.org
Commit bbc1376b39 checked that if
a redirected line pointer pointed to a tuple, the tuple should be
marked both HEAP_ONLY_TUPLE and HEAP_UPDATED. But Andres Freund
pointed out that *any* tuple that is marked HEAP_ONLY_TUPLE should
be marked HEAP_UPDATED, not just one that is the target of a
redirected line pointer. Do that instead.
To see why this is better, consider a redirect line pointer A
which points to a heap-only tuple B which points (via CTID)
to another heap-only tuple C. With the old code, we'd complain
if B was not marked HEAP_UPDATED, but with this change, we'll
complain if either B or C is not marked HEAP_UPDATED.
(Note that, with or without this commit, if either B or C were
not marked HEAP_ONLY_TUPLE, we would also complain about that.)
Discussion: http://postgr.es/m/CA%2BTgmobLypZx%3DcOH%2ByY1GZmCruaoucHm77A6y_-Bo%3Dh-_3H28g%40mail.gmail.com
Commit bbc1376b39 added a new lp_valid[]
array which records whether or not a line pointer was thought to be
valid, but entries could sometimes get set to true in cases where that
wasn't actually safe. Fix that.
Suppose A is a redirect line pointer and B is the other line pointer
to which it points. The old code could mishandle this situation in a
couple of different ways. First, if B was unused, we'd complain about
corruption but still set lp_valid[A] = true, causing later code
to try to access the B as if it were pointing to a tuple. Second,
if B was dead, we wouldn't complain about corruption at all, which is
an oversight, and would also set lp_valid[A] = true, which would
again confuse later code. Fix all that.
In the case where B is a redirect, the old code was correct, but
refactor things a bit anyway so that all of these cases are handled
more symmetrically. Also add an Assert() and some comments.
Andres Freund and Robert Haas
Discussion: http://postgr.es/m/20230323172607.y3lejpntjnuis5vv%40awork3.anarazel.de
Commit 4c8d65408 incorrectly stated that Homebrew has changed its
prefix for Apple M1 machines, but the prefix change applies to all
Apple Silicon based machines. Fix by writing Apple Silicon instead
of Apple M1.
Reported-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://postgr.es/m/87mt3ys8ng.fsf@wibble.ilmari.org
Replace the hardcoded value with a GUC such that the iteration
count can be raised in order to increase protection against
brute-force attacks. The hardcoded value for SCRAM iteration
count was defined to be 4096, which is taken from RFC 7677, so
set the default for the GUC to 4096 to match. In RFC 7677 the
recommendation is at least 15000 iterations but 4096 is listed
as a SHOULD requirement given that it's estimated to yield a
0.5s processing time on a mobile handset of the time of RFC
writing (late 2015).
Raising the iteration count of SCRAM will make stored passwords
more resilient to brute-force attacks at a higher computational
cost during connection establishment. Lowering the count will
reduce computational overhead during connections at the tradeoff
of reducing strength against brute-force attacks.
There are however platforms where even a modest iteration count
yields a too high computational overhead, with weaker password
encryption schemes chosen as a result. In these situations,
SCRAM with a very low iteration count still gives benefits over
weaker schemes like md5, so we allow the iteration count to be
set to one at the low end.
The new GUC is intentionally generically named such that it can
be made to support future SCRAM standards should they emerge.
At that point the value can be made into key:value pairs with
an undefined key as a default which will be backwards compatible
with this.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Jonathan S. Katz <jkatz@postgresql.org>
Discussion: https://postgr.es/m/F72E7BC7-189F-4B17-BF47-9735EB72C364@yesql.se
This improves a few things in pg_walinspect:
- Return NULL rather than empty strings in pg_get_wal_records_info() for
the block references and the record description if there is no
information provided by the fallback. This point has been raised by
Peter Geoghegan.
- Add a check on XLogRecHasAnyBlockRefs() for pg_get_wal_block_info(),
to directly skip records that have no block references. This speeds up
the function a bit, depending on the number of records that have no
block references.
Author: Bharath Rupireddy
Reviewed-by: Kyotaro Horiguchi, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACWL9RG8sGJHinggRNBTxgRWJTSxCkB+cE6=t3Phh=Ey+A@mail.gmail.com
Word-smith section 22.1 ("Database Roles") a little bit in hopes
of removing confusion about how the bootstrap superuser's name
is chosen.
While here, I couldn't help noticing that the claim that the bootstrap
superuser is the only initially-existing role has been a lie since
we started to invent predefined roles. We don't want too much detail
in this very introductory text, but it seems worth changing it to say
that it's the only initially-existing login-capable role.
Per documentation comment from Maja Zaloznik.
Discussion: https://postgr.es/m/167931662853.3349090.18217722739345182859@wrigleys.postgresql.org
The nested-arrays code path in ExecEvalArrayExpr() used palloc to
allocate the result array, whereas every other array-creating function
has used palloc0 since 18c0b4ecc. This mostly works, but unused bits
past the end of the nulls bitmap may end up undefined. That causes
valgrind complaints with -DWRITE_READ_PARSE_PLAN_TREES, and could
cause planner misbehavior as cited in 18c0b4ecc. There seems no very
good reason why we should strive to avoid palloc0 in just this one case,
so fix it the easy way with s/palloc/palloc0/.
While looking at that I noted that we also failed to check for overflow
of "nbytes" and "nitems" while summing the sizes of the sub-arrays,
potentially allowing a crash due to undersized output allocation.
For "nbytes", follow the policy used by other array-munging code of
checking for overflow after each addition. (As elsewhere, the last
addition of the array's overhead space doesn't need an extra check,
since palloc itself will catch a value between 1Gb and 2Gb.)
For "nitems", there's no very good reason to sum the inputs at all,
since we can perfectly well use ArrayGetNItems' result instead of
ignoring it.
Per discussion of this bug, also remove redundant zeroing of the
nulls bitmap in array_set_element and array_set_slice.
Patch by Alexander Lakhin and myself, per bug #17858 from Alexander
Lakhin; thanks also to Richard Guo. These bugs are a dozen years old,
so back-patch to all supported branches.
Discussion: https://postgr.es/m/17858-8fd287fd3663d051@postgresql.org
When extracting an attr from a cached tuple in the syscache with
SysCacheGetAttr the isnull parameter must be checked in case the
attr cannot be NULL. For cases when this is known beforehand, a
wrapper is introduced which perform the errorhandling internally
on behalf of the caller, invoking an elog in case of a NULL attr.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/AD76405E-DB45-46B6-941F-17B1EB3A9076@yesql.se
The "partitions_total" and "partitions_done" fields were updated
as though the current level of partitioning was the only one.
In multi-level cases, not only could partitions_total change
over the course of the command, but partitions_done could go
backwards or exceed the currently-reported partitions_total.
Fix by setting partitions_total to the total number of direct
and indirect children once at command start, and then just
incrementing partitions_done at appropriate points. Invent
a new progress monitoring function "pgstat_progress_incr_param"
to simplify doing the latter. We can avoid adding cost for the
former when doing CREATE INDEX, because ProcessUtility already
enumerates the children and it's pretty easy to pass the count
down to DefineIndex. In principle the same could be done in
ALTER TABLE, but that's structurally difficult; for now, just
eat the cost of an extra find_all_inheritors scan in that case.
Ilya Gladyshev and Justin Pryzby
Discussion: https://postgr.es/m/a15f904a70924ffa4ca25c3c744cff31e0e6e143.camel@gmail.com
These were causing "contents ... exceed the available area"
warnings in PDF builds, and also didn't quite follow our markup
conventions for function examples. To fix the overwidth
problem, reduce the number of fields shown in one example,
and also insert &zwsp; to let the header line be broken in
a reasonable place.
Discussion: https://postgr.es/m/20230324194701.dqkzcdtlcikseo22@awork3.anarazel.de
This provides a very simple way to see the generic plan for a
parameterized query. Without this, it's necessary to define
a prepared statement and temporarily change plan_cache_mode,
which is a bit tedious.
One thing that's a bit of a hack perhaps is that we disable
execution-time partition pruning when the GENERIC_PLAN option
is given. That's because the pruning code may attempt to
fetch the value of one of the parameters, which would fail.
Laurenz Albe, reviewed by Julien Rouhaud, Christoph Berg,
Michel Pelletier, Jim Jones, and myself
Discussion: https://postgr.es/m/0a29b954b10b57f0d135fe12aa0909bd41883eb0.camel@cybertec.at
In e522049f23 I accidentally forgot to add meson_bin to the argument list for
install-quiet. That kind of works on some platforms because the executable is
just 'python', wich the path to meson in an argument. But on windows meson
might be installed as an executable.
Reported-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://postgr.es/m/b36dd6a4-748a-4737-54d5-dc8a50fdbe4b@dunslane.net
ICU versions 53 and earlier rely on icu_set_collation_attributes() to
process the attributes in the locale string. Avoid leaking the
already-opened UCollator object if an error is encountered.
Discussion: https://postgr.es/m/04182066-7655-344a-b8b7-040b1b2490fb%40enterprisedb.com
Reviewed-by: Peter Eisentraut
In such cases, get_xid_status() doesn't set its output parameter (the
third argument), so we shouldn't fall through to code which will test
the value of that parameter. There are five existing calls to
get_xid_status(), three of which seem to already handle this case
properly. This commit tries to fix the other two.
If we're checking xmin and find that it is invalid (i.e. 0) just
report that as corruption, similar to what's already done in the
three cases that seem correct. If we're checking xmax and find
that's invalid, that's fine: it just means that the tuple hasn't
been updated or deleted.
Thanks to Andres Freund and valgrind for finding this problem, and
also to Andres for having a look at the patch. This bug seems to go
all the way back to where verify_heapam was first introduced, but
wasn't detected until recently, possibly because of the new test cases
added for update chain verification. Back-patch to v14, where this
code showed up.
Discussion: http://postgr.es/m/CA+TgmoZAYzQZqyUparXy_ks3OEOfLD9-bEXt8N-2tS1qghX9gQ@mail.gmail.com
The fields of NLSVERSIONINFOEX are of type DWORD, which is unsigned
long, so the results of the computations being printed are also of
type unsigned long.
The sslcertmode option controls whether the server is allowed and/or
required to request a certificate from the client. There are three
modes:
- "allow" is the default and follows the current behavior, where a
configured client certificate is sent if the server requests one
(via one of its default locations or sslcert). With the current
implementation, will happen whenever TLS is negotiated.
- "disable" causes the client to refuse to send a client certificate
even if sslcert is configured or if a client certificate is available in
one of its default locations.
- "require" causes the client to fail if a client certificate is never
sent and the server opens a connection anyway. This doesn't add any
additional security, since there is no guarantee that the server is
validating the certificate correctly, but it may helpful to troubleshoot
more complicated TLS setups.
sslcertmode=require requires SSL_CTX_set_cert_cb(), available since
OpenSSL 1.0.2. Note that LibreSSL does not include it.
Using a connection parameter different than require_auth has come up as
the simplest design because certificate authentication does not rely
directly on any of the AUTH_REQ_* codes, and one may want to require a
certificate to be sent in combination of a given authentication method,
like SCRAM-SHA-256.
TAP tests are added in src/test/ssl/, some of them relying on sslinfo to
check if a certificate has been set. These are compatible across all
the versions of OpenSSL supported on HEAD (currently down to 1.0.1).
Author: Jacob Champion
Reviewed-by: Aleksander Alekseev, Peter Eisentraut, David G. Johnston,
Michael Paquier
Discussion: https://postgr.es/m/9e5a8ccddb8355ea9fa4b75a1e3a9edc88a70cd3.camel@vmware.com
