The example of expansion of multiple views claimed that the resulting
subquery nest would not get fully flattened because of an aggregate
function. There's no aggregate in the example, though, only a user
defined function confusingly named MIN(). In a modern server, the
reason for the non-flattening is that MIN() is volatile, but I'm
unsure whether that was true back when this text was written.
Let's reduce the confusion level by using LEAST() instead (which
we didn't have at the time this example was created). And then
we can just say that the planner will flatten the sub-queries, so
the rewrite system doesn't have to.
Noted by Paul Jungwirth. This text is old enough to vote, so
back-patch to all supported branches.
Discussion: https://postgr.es/m/CA+renyXZFnmp9PcvX1EVR2dR=XG5e6E-AELr8AHCNZ8RYrpnPw@mail.gmail.com
The previous statement that using a passphrase disables the ability to
change the server's SSL configuration without a server restart was no
longer completely true since the introduction of
ssl_passphrase_command_supports_reload.
Add some support for automatically showing backtraces in certain error
situations in the server. Backtraces are shown on assertion failure;
also, a new setting backtrace_functions can be set to a list of C
function names, and all ereport()s and elog()s from the mentioned
functions will have backtraces generated. Finally, the function
errbacktrace() can be manually added to an ereport() call to generate a
backtrace for that call.
Authors: Peter Eisentraut, Álvaro Herrera
Discussion: https://postgr.es/m//5f48cb47-bf1e-05b6-7aae-3bf2cd01586d@2ndquadrant.com
Discussion: https://postgr.es/m/CAMsr+YGL+yfWE=JvbUbnpWtrRZNey7hJ07+zT4bYJdVp4Szdrg@mail.gmail.com
Currently, postgres_fdw does not support preparing a remote transaction
for two-phase commit even in the case where the remote transaction is
read-only, but the old error message appeared to imply that that was not
supported only if the remote transaction modified remote tables. Change
the message so as to include the case where the remote transaction is
read-only.
Also fix a comment above the message.
Also add a note about the lack of supporting PREPARE TRANSACTION to the
postgres_fdw documentation.
Reported-by: Gilles Darold
Author: Gilles Darold and Etsuro Fujita
Reviewed-by: Michael Paquier and Kyotaro Horiguchi
Backpatch-through: 9.4
Discussion: https://postgr.es/m/08600ed3-3084-be70-65ba-279ab19618a5%40darold.net
This allows logging a sample of statements, without incurring excessive
log traffic (which may impact performance). This can be useful when
analyzing workloads with lots of short queries.
The sampling is configured using two new GUC parameters:
* log_min_duration_sample - minimum required statement duration
* log_statement_sample_rate - sample rate (0.0 - 1.0)
Only statements with duration exceeding log_min_duration_sample are
considered for sampling. To enable sampling, both those GUCs have to
be set correctly.
The existing log_min_duration_statement GUC has a higher priority, i.e.
statements with duration exceeding log_min_duration_statement will be
always logged, irrespectedly of how the sampling is configured. This
means only configurations
log_min_duration_sample < log_min_duration_statement
do actually sample the statements, instead of logging everything.
Author: Adrien Nayrat
Reviewed-by: David Rowley, Vik Fearing, Tomas Vondra
Discussion: https://postgr.es/m/bbe0a1a8-a8f7-3be2-155a-888e661cc06c@anayrat.info
The docs do say which GUCs can be changed only by superusers, but we
forgot to mention this for the new log_transaction_sample_rate. This
GUC was introduced in PostgreSQL 12, so backpatch accordingly.
Author: Adrien Nayrat
Backpatch-through: 12
Since commit d26a810eb, we've defined bool as being either _Bool from
<stdbool.h>, or "unsigned char"; but that commit overlooked the fact
that probes.d has "#define bool char". For consistency, make it say
"unsigned char" instead. This should be strictly a cosmetic change,
but it seems best to be in sync.
Formally, in the now-normal case where we're using <stdbool.h>, it'd
be better to write "#define bool _Bool". However, then we'd need
some build infrastructure to inject that configuration choice into
probes.d, and it doesn't seem worth the trouble. We only use
<stdbool.h> if sizeof(_Bool) is 1, so having DTrace think that
bool parameters are "unsigned char" should be close enough.
Back-patch to v12 where d26a810eb came in.
Discussion: https://postgr.es/m/CAA4eK1LmaKO7Du9M9Lo=kxGU8sB6aL8fa3sF6z6d5yYYVe3BuQ@mail.gmail.com
This commit allows --init-steps option in pgbench to accept "G" character
meaning server-side data generation as an initialization step.
With "G", only limited queries are sent from pgbench client and
then data is actually generated in the server. This might make
the initialization phase faster if the bandwidth between pgbench client
and the server is low.
Author: Fabien Coelho
Reviewed-by: Anna Endo, Ibrar Ahmed, Fujii Masao
Discussion: https://postgr.es/m/alpine.DEB.2.21.1904061826420.3678@lancre
Since 898e5e32, this command uses partially ShareUpdateExclusiveLock,
but the docs did not get the call.
Author: Justin Pryzby
Reviewed-by: Amit Langote, Álvaro Herrera, Michael Paquier
Discussion: https://postgr.es/m/20191028001207.GB23808@telsasoft.com
Backpatch-through: 12
This clarifies more how to use and how to take advantage of constraints
when attaching a new partition.
Author: Justin Pryzby
Reviewed-by: Amit Langote, Álvaro Herrera, Michael Paquier
Discussion: https://postgr.es/m/20191028001207.GB23808@telsasoft.com
Backpatch-through: 10
When we added the GUC units feature, we didn't make any great effort
to adjust the documentation of individual GUCs; they tended to still
say things like "this is the number of milliseconds that ...", even
though users might prefer to write some other units, and SHOW might
even show the value in other units. Commit 6c9fb69f2 made an effort
to improve this situation, but I thought it made things less readable
by injecting units information in mid-sentence. It also wasn't very
consistent, and did not touch all the GUCs that have units.
To improve matters, standardize on the phrasing "If this value is
specified without units, it is taken as <units>". Also, try to
standardize where this is mentioned, right before the specification
of the default. (In a couple of places, doing that would've required
more rewriting than seemed justified, so I wasn't 100% consistent
about that.) I also tried to use the phrases "amount of time",
"amount of memory", etc rather than describing the contents of GUCs
in other ways, as those were the majority usage in places that weren't
overcommitting to a particular unit. (I left "length of time" alone
in a couple of places, though.)
I failed to resist the temptation to copy-edit some awkward text, too.
Backpatch to v12, like 6c9fb69f2, mainly because v12 hasn't diverged
much from HEAD yet.
Discussion: https://postgr.es/m/15882.1571942223@sss.pgh.pa.us
Remove SQL_LANGUAGES, which was eliminated in SQL:2008, and
SQL_PACKAGES and SQL_SIZING_PROFILES, which were eliminated in
SQL:2011. Since they were dropped by the SQL standard, the
information in them was no longer updated and therefore no longer
useful.
This also removes the feature-package association information in
sql_feature_packages.txt, but for the time begin we are keeping the
information which features are in the Core package (that is, mandatory
SQL features). Maybe at some point someone wants to invent a way to
store that that does not involve using the "package" mechanism
anymore.
Discussion https://www.postgresql.org/message-id/flat/91334220-7900-071b-9327-0c6ecd012017%402ndquadrant.com
Historically, we started the timer (if StatementTimeout > 0) at the
beginning of a simple-Query message and usually let it run until the
end, so that the timeout limit applied to the entire query string,
and intra-string changes of the statement_timeout GUC had no effect.
But, confusingly, a COMMIT within the string would reset the state
and allow a fresh timeout cycle to start with the current setting.
Commit f8e5f156b changed the behavior of statement_timeout for extended
query protocol, and as an apparently-unintended side effect, a change in
the statement_timeout GUC during a multi-statement simple-Query message
might have an effect immediately --- but only if it was going from
"disabled" to "enabled".
This is all pretty confusing, not to mention completely undocumented.
Let's change things so that the timeout is always reset between queries
of a multi-query string, whether they're transaction control commands
or not. Thus the active timeout setting is applied to each query in
the string, separately. This costs a few more cycles if statement_timeout
is active, but it provides much more intuitive behavior, especially if one
changes statement_timeout in one of the queries of the string.
Also, add something to the documentation to explain all this.
Per bug #16035 from Raj Mohite. Although this is a bug fix, I'm hesitant
to back-patch it; conceivably somebody has worked out the old behavior
and is depending on it. (But note that this change should make the
behavior less restrictive in most cases, since the timeout will now
be applied to shorter segments of code.)
Discussion: https://postgr.es/m/16035-456e6e69ebfd4374@postgresql.org
In v11 or before, this setting could not take effect in crash recovery
because it's specified in recovery.conf and crash recovery always
starts without recovery.conf. But commit 2dedf4d9a8 integrated
recovery.conf into postgresql.conf and which unexpectedly allowed
this setting to take effect even in crash recovery. This is definitely
not good behavior.
To fix the issue, this commit makes crash recovery always ignore
recovery_min_apply_delay setting.
Back-patch to v12 where the issue was added.
Author: Fujii Masao
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/CAHGQGwEyD6HdZLfdWc+95g=VQFPR4zQL4n+yHxQgGEGjaSVheQ@mail.gmail.com
Discussion: https://postgr.es/m/e445616d-023e-a268-8aa1-67b8b335340c@pgmasters.net
Using glibc's version string to detect potential collation definition
changes is not 100% reliable, but it's better than nothing. Currently
this affects only collations explicitly provided by "libc". More work
will be needed to handle the default collation.
Author: Thomas Munro, based on a suggestion from Christoph Berg
Reviewed-by: Peter Eisentraut
Discussion: https://postgr.es/m/4b76c6d4-ae5e-0dc6-7d0d-b5c796a07e34%402ndquadrant.com
This fixes multiple areas of the documentation:
- COPY for its past compatibility section.
- SET ROLE mentioning INHERITS instead of INHERIT
- PREPARE referring to stmt_name, that is not present.
- Extension documentation about format name with upgrade scripts.
Backpatch down to 9.4 for the relevant parts.
Author: Alexander Lakhin
Discussion: https://postgr.es/m/bf95233a-9943-b341-e2ff-a860c28af481@gmail.com
Backpatch-through: 9.4
Previously, our docs would say "Specifies the number of milliseconds"
but it wasn't clear that "milliseconds" was merely the default unit.
New text says "Specifies duration (defaults to milliseconds)", which is
clearer.
Reported-by: basil.bourque@gmail.com
Discussion: https://postgr.es/m/15912-2e35e9026f61230b@postgresql.org
Backpatch-through: 12
This includes a couple of changes around the new behavior of pg_rewind
which enforces recovery to happen once on a cluster not shut down
cleanly:
- Some comments and documentation improvements.
- Shutdown the cluster to rewind with immediate mode in all the tests,
this allows to check after the forced recovery behavior which is wanted
as new default.
- Use -F for the forced recovery step, so as postgres does not use
fsync. This was useless as a final sync is done once the tool is done.
Author: Michael Paquier
Reviewed-by: Alexey Kondratov
Discussion: https://postgr.es/m/20191004083721.GA1829@paquier.xyz
Commit aa087ec64 was a bit over-hasty about the doc changes needed
while splitting pg_statistic_ext_data off from pg_statistic_ext.
It duplicated one para and inserted another in what seems to me
to be the wrong section. Fix that up, and in passing do some minor
copy-editing.
Per report from noborusai.
Discussion: https://postgr.es/m/CAAM3qnLXLUz4mOBkqa8jxigpKhKNxzSuvwpjvCRPvO5EqWjxSg@mail.gmail.com
These new options allow users to partition the pgbench_accounts table by
specifying the number of partitions and partitioning method. The values
allowed for partitioning method are range and hash.
This feature allows users to measure the overhead of partitioning if any.
Author: Fabien COELHO
Reviewed-by: Amit Kapila, Amit Langote, Dilip Kumar, Asif Rehman, and
Alvaro Herrera
Discussion: https://postgr.es/m/alpine.DEB.2.21.1907230826190.7008@lancre
The behavior described in the PREPARE man page applies only for the
default plan_cache_mode setting, so explain that properly. Rewrite
some of the text while I'm here. Per suggestion from Bruce.
Discussion: https://postgr.es/m/20190930155505.GA21095@momjian.us
This commit adds a mention that the order of columns specified during
multi-column most-common-value statistics is insignificant, and tries to
simplify examples.
Discussion: https://postgr.es/m/20190828162238.GA8360@momjian.us
Backpatch-through: 12
If we don't do this, the rewind fails if the server wasn't cleanly shut
down, which seems unhelpful serving no purpose.
Also provide a new option --no-ensure-shutdown to suppress this
behavior, for alleged advanced usage that prefers to avoid the crash
recovery.
Authors: Paul Guo, Jimmy Yih, Ashwin Agrawal
Reviewed-by: Álvaro Herrera
Discussion: https://postgr.es/m/CAEET0ZEffUkXc48pg2iqARQgGRYDiiVxDu+yYek_bTwJF+q=Uw@mail.gmail.com
The documentation states that no target settings will be used when
standby.signal is present, but this is not quite the case since
recovery_target_timeline is a valid recovery target for a standby.
Update the documentation with this exception.
Author: David Steele <david@pgmasters.net>
Discussion: https://www.postgresql.org/message-id/flat/e445616d-023e-a268-8aa1-67b8b335340c%40pgmasters.net
This commit implements jsonpath .datetime() method as it's specified in
SQL/JSON standard. There are no-argument and single-argument versions of
this method. No-argument version selects first of ISO datetime formats
matching input string. Single-argument version accepts template string as
its argument.
Additionally to .datetime() method itself this commit also implements
comparison ability of resulting date and time values. There is some difficulty
because exising jsonb_path_*() functions are immutable, while comparison of
timezoned and non-timezoned types involves current timezone. At first, current
timezone could be changes in session. Moreover, timezones themselves are not
immutable and could be updated. This is why we let existing immutable functions
throw errors on such non-immutable comparison. In the same time this commit
provides jsonb_path_*_tz() functions which are stable and support operations
involving timezones. As new functions are added to the system catalog,
catversion is bumped.
Support of .datetime() method was the only blocker prevents T832 from being
marked as supported. sql_features.txt is updated correspondingly.
Extracted from original patch by Nikita Glukhov, Teodor Sigaev, Oleg Bartunov.
Heavily revised by me. Comments were adjusted by Liudmila Mantrova.
Discussion: https://postgr.es/m/fcc6fc6a-b497-f39a-923d-aa34d0c588e8%402ndQuadrant.com
Discussion: https://postgr.es/m/CAPpHfdsZgYEra_PeCLGNoXOWYx6iU-S3wF8aX0ObQUcZU%2B4XTw%40mail.gmail.com
Author: Alexander Korotkov, Nikita Glukhov, Teodor Sigaev, Oleg Bartunov, Liudmila Mantrova
Reviewed-by: Anastasia Lubennikova, Peter Eisentraut
The array <@ and @> operators do not worry about duplicates: if every
member of array X matches some element of array Y, then X is contained
in Y, even if several members of X get matched to the same Y member.
This was not explicitly stated in the docs though, so improve matters.
Discussion: https://postgr.es/m/156614120484.1310.310161642239149585@wrigleys.postgresql.org
This reverts commit bd7c95f0c1,
along with assorted follow-on fixes. There are some questions
about the definition and implementation of that statement, and
we don't have time to resolve them before v13 release. Rather
than ship the feature and then have backwards-compatibility
concerns constraining any redesign, let's remove it for now
and try again later.
Discussion: https://postgr.es/m/TY2PR01MB2443EC8286995378AEB7D9F8F5B10@TY2PR01MB2443.jpnprd01.prod.outlook.com
Provide some documentation about the differences between XQuery
regular expressions and those supported by Spencer's regex engine.
Since SQL now exposes XQuery regexps with the LIKE_REGEX operator,
I made this a standalone section designed to help somebody who
has to translate a LIKE_REGEX query to Postgres. (Eventually we might
extend Spencer's engine to allow precise implementation of XQuery,
but not today.)
Reference that in the jsonpath docs, provide definitions of the
XQuery flag letters, and add a description of the JavaScript-inspired
string literal syntax used within jsonpath. Also point out explicitly
that backslashes used within like_regex patterns will need to be doubled.
This also syncs the docs with the decision implemented in commit
d5b90cd64 to desupport XQuery's 'x' flag for now.
Jonathan Katz and Tom Lane
Discussion: https://postgr.es/m/CAPpHfdvDci4iqNF9fhRkTqhe-5_8HmzeLt56drH%2B_Rv2rNRqfg@mail.gmail.com
Tom Lane
Peter Eisentraut
Alvaro Herrera
Etsuro Fujita
Bruce Momjian
Tomas Vondra
Fujii Masao
Michael Paquier
Thomas Munro
Amit Kapila
Alexander Korotkov
Jeff Davis