This makes such log entries more useful, since the cause of the error
can be dependent on the parameter values.
Author: Alexey Bashtanov, Álvaro Herrera
Discussion: https://postgr.es/m/0146a67b-a22a-0519-9082-bc29756b93a2@imap.cc
Reviewed-by: Peter Eisentraut, Andres Freund, Tom Lane
Change default of ssl_min_protocol_version to TLSv1.2 (from TLSv1,
which means 1.0). Older versions are still supported, just not by
default.
TLS 1.0 is widely deprecated, and TLS 1.1 only slightly less so. All
OpenSSL versions that support TLS 1.1 also support TLS 1.2, so there
would be very little reason to, say, set the default to TLS 1.1
instead on grounds of better compatibility.
The test suite overrides this new setting, so it can still run with
older OpenSSL versions.
Discussion: https://www.postgresql.org/message-id/flat/b327f8df-da98-054d-0cc5-b76a857cfed9%402ndquadrant.com
Make allow_system_table_mods settable at run time by superusers. It
was previously postmaster start only.
We don't want to make system catalog DDL wide-open, but there are
occasionally useful things to do like setting reloptions or statistics
on a busy system table, and blocking those doesn't help anyone. Also,
this enables the possibility of writing a test suite for this setting.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/8b00ea5e-28a7-88ba-e848-21528b632354%402ndquadrant.com
Instead of deciding to serialize a transaction merely based on the
number of changes in that xact (toplevel or subxact), this makes
the decisions based on amount of memory consumed by the changes.
The memory limit is defined by a new logical_decoding_work_mem GUC,
so for example we can do this
SET logical_decoding_work_mem = '128kB'
to reduce the memory usage of walsenders or set the higher value to
reduce disk writes. The minimum value is 64kB.
When adding a change to a transaction, we account for the size in
two places. Firstly, in the ReorderBuffer, which is then used to
decide if we reached the total memory limit. And secondly in the
transaction the change belongs to, so that we can pick the largest
transaction to evict (and serialize to disk).
We still use max_changes_in_memory when loading changes serialized
to disk. The trouble is we can't use the memory limit directly as
there might be multiple subxact serialized, we need to read all of
them but we don't know how many are there (and which subxact to
read first).
We do not serialize the ReorderBufferTXN entries, so if there is a
transaction with many subxacts, most memory may be in this type of
objects. Those records are not included in the memory accounting.
We also do not account for INTERNAL_TUPLECID changes, which are
kept in a separate list and not evicted from memory. Transactions
with many CTID changes may consume significant amounts of memory,
but we can't really do much about that.
The current eviction algorithm is very simple - the transaction is
picked merely by size, while it might be useful to also consider age
(LSN) of the changes for example. With the new Generational memory
allocator, evicting the oldest changes would make it more likely
the memory gets actually pfreed.
The logical_decoding_work_mem can be set in postgresql.conf, in which
case it serves as the default for all publishers on that instance.
Author: Tomas Vondra, with changes by Dilip Kumar and Amit Kapila
Reviewed-by: Dilip Kumar and Amit Kapila
Tested-By: Vignesh C
Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
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
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
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
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
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
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
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
Commit aa27977fe2 introduced this
restriction for pg_temp.function_name(arg); do likewise for types
created in temporary schemas. Programs that this breaks should add
"pg_temp." schema qualification or switch to arg::type_name syntax.
Back-patch to 9.4 (all supported versions).
Reviewed by Tom Lane. Reported by Tom Lane.
Security: CVE-2019-10208
This reverts commit 88bdbd3f74.
As committed, statement sampling used the existing duration threshold
(log_min_duration_statement) when decide which statements to sample.
The issue is that even the longest statements are subject to sampling,
and so may not end up logged. An improvement was proposed, introducing
a second duration threshold, but it would not be backwards compatible.
So we've decided to revert this feature - the separate threshold should
be part of the feature itself.
Discussion: https://postgr.es/m/CAFj8pRDS8tQ3Wviw9%3DAvODyUciPSrGeMhJi_WPE%2BEB8%2B4gLL-Q%40mail.gmail.com
The interaction of these parameters was a bit confused/confusing,
and in fact v11 entirely misses the opportunity to apply partition
constraints when a partition is accessed directly (rather than
indirectly from its parent).
In HEAD, establish the principle that enable_partition_pruning controls
partition pruning and nothing else. When accessing a partition via its
parent, we do partition pruning (if enabled by enable_partition_pruning)
and then there is no need to consider partition constraints in the
constraint_exclusion logic. When accessing a partition directly, its
partition constraints are applied by the constraint_exclusion logic,
only if constraint_exclusion = on.
In v11, we can't have such a clean division of these GUCs' effects,
partly because we don't want to break compatibility too much in a
released branch, and partly because the clean coding requires
inheritance_planner to have applied partition pruning to a partitioned
target table, which it doesn't in v11. However, we can tweak things
enough to cover the missed case, which seems like a good idea since
it's potentially a performance regression from v10. This patch keeps
v11's previous behavior in which enable_partition_pruning overrides
constraint_exclusion for an inherited target table, though.
In HEAD, also teach relation_excluded_by_constraints that it's okay to use
inheritable constraints when trying to prune a traditional inheritance
tree. This might not be thought worthy of effort given that that feature
is semi-deprecated now, but we have enough infrastructure that it only
takes a couple more lines of code to do it correctly.
Amit Langote and Tom Lane
Discussion: https://postgr.es/m/9813f079-f16b-61c8-9ab7-4363cab28d80@lab.ntt.co.jp
Discussion: https://postgr.es/m/29069.1555970894@sss.pgh.pa.us
This fixes a couple of grammar mistakes, typos and inconsistencies in
the documentation. Particularly, the configuration parsing allows only
"kB" to mean kilobyte but there were references in the docs to "KB".
Some instances of the latter are still in the code comments. Some
parameter values were mentioned with "Minus-one", and using directly
"-1" with proper markups is more helpful to the reader.
Some of these have been pointed out by Justin, and some others are
things I bumped into.
Author: Justin Pryzby, Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20190330224333.GQ5815@telsasoft.com
Commit ca4103025d left a few loose ends. The most important one
(broken pg_dump output) is already fixed by virtue of commit
3b23552ad8, but some things remained:
* When ALTER TABLE rewrites tables, the indexes must remain in the
tablespace they were originally in. This didn't work because
index recreation during ALTER TABLE runs manufactured SQL (yuck),
which runs afoul of default_tablespace in competition with the parent
relation tablespace. To fix, reset default_tablespace to the empty
string temporarily, and add the TABLESPACE clause as appropriate.
* Setting a partitioned rel's tablespace to the database default is
confusing; if it worked, it would direct the partitions to that
tablespace regardless of default_tablespace. But in reality it does
not work, and making it work is a larger project. Therefore, throw
an error when this condition is detected, to alert the unwary.
Add some docs and tests, too.
Author: Álvaro Herrera
Discussion: https://postgr.es/m/CAKJS1f_1c260nOt_vBJ067AZ3JXptXVRohDVMLEBmudX1YEx-A@mail.gmail.com
Similarly to the set of parameters for keepalive, a connection parameter
for libpq is added as well as a backend GUC, called tcp_user_timeout.
Increasing the TCP user timeout is useful to allow a connection to
survive extended periods without end-to-end connection, and decreasing
it allows application to fail faster. By default, the parameter is 0,
which makes the connection use the system default, and follows a logic
close to the keepalive parameters in its handling. When connecting
through a Unix-socket domain, the parameters have no effect.
Author: Ryohei Nagaura
Reviewed-by: Fabien Coelho, Robert Haas, Kyotaro Horiguchi, Kirk
Jamison, Mikalai Keida, Takayuki Tsunakawa, Andrei Yahorau
Discussion: https://postgr.es/m/EDA4195584F5064680D8130B1CA91C45367328@G01JPEXMBYT04
This adds documentation about the user oriented parts of table access
methods (i.e. the default_table_access_method GUC and the USING clause
for CREATE TABLE etc), adds a basic chapter about the table access
method interface, and adds a note to storage.sgml that it's contents
don't necessarily apply for non-builtin AMs.
Author: Haribabu Kommi and Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
This is useful to obtain a view of the different transaction types in an
application, regardless of the durations of the statements each runs.
Author: Adrien Nayrat
Reviewed-by: Masahiko Sawada, Hayato Kuroda, Andres Freund
On at least ZFS, it can be beneficial to create new WAL files every
time and not to bother zero-filling them. Since it's not clear which
other filesystems might benefit from one or both of those things,
add individual GUCs to control those two behaviors independently and
make only very general statements in the docs.
Author: Jerry Jelinek, with some adjustments by Thomas Munro
Reviewed-by: Alvaro Herrera, Andres Freund, Tomas Vondra, Robert Haas and others
Discussion: https://postgr.es/m/CACPQ5Fo00QR7LNAcd1ZjgoBi4y97%2BK760YABs0vQHH5dLdkkMA%40mail.gmail.com
Historically guc.c has just refused examples like set work_mem = '30.1GB',
but it seems more useful for it to take that and round off the value to
some reasonable approximation of what the user said. Just rounding to
the parameter's native unit would work, but it would lead to rather
silly-looking settings, such as 31562138kB for this example. Instead
let's round to the nearest multiple of the next smaller unit (if any),
producing 30822MB.
Also, do the units conversion math in floating point and round to integer
(if needed) only at the end. This produces saner results for inputs that
aren't exact multiples of the parameter's native unit, and removes another
difference in the behavior for integer vs. float parameters.
In passing, document the ability to use hex or octal input where it
ought to be documented.
Discussion: https://postgr.es/m/1798.1552165479@sss.pgh.pa.us
This reverts commit bd09503e63.
Per discussion, it seems like what we should do instead is to
reduce the default value of autovacuum_vacuum_cost_delay by the
same factor. That's functionally equivalent as long as the
platform can accurately service the smaller delay request, which
should be true on anything released in the last 10 years or more.
And smaller, more-closely-spaced delays are better in terms of
providing a steady I/O load.
Discussion: https://postgr.es/m/28720.1552101086@sss.pgh.pa.us
This change makes it possible to specify sub-millisecond delays,
which work well on most modern platforms, though that was not true
when the cost-delay feature was designed.
To support this without breaking existing configuration entries,
improve guc.c to allow floating-point GUCs to have units. Also,
allow "us" (microseconds) as an input/output unit for time-unit GUCs.
(It's not allowed as a base unit, at least not yet.)
Likewise change the autovacuum_vacuum_cost_delay reloption to be
floating-point; this forces a catversion bump because the layout of
StdRdOptions changes.
This patch doesn't in itself change the default values or allowed
ranges for these parameters, and it should not affect the behavior
for any already-allowed setting for them.
Discussion: https://postgr.es/m/1798.1552165479@sss.pgh.pa.us
The original 200 default value was set back in f425b605f4 when the cost
delay settings were first added. Hardware has improved quite a bit since
then and we've also made improvements such as sorting buffers during
checkpoints (9cd00c457e) which should result in less random writes.
This low default value was reportedly causing problems with badly
configured servers and in the absence of a native method to remove
excessive bloat from tables without incurring an AccessExclusiveLock, this
often made cleaning up the damage caused by badly configured auto-vacuums
difficult.
It seems more likely that someone will notice that auto-vacuum is running
too quickly than too slowly, so let's go all out and multiple the default
value for the setting by 10. With the default vacuum_cost_page_dirty and
autovacuum_vacuum_cost_delay (assuming a page size of 8192 bytes), this
allows autovacuum a theoretical maximum dirty write rate of around 39MB/s
instead of just 3.9MB/s.
Author: David Rowley
Discussion: https://postgr.es/m/CAKJS1f_YbXC2qTMPyCbmsPiKvZYwpuQNQMohiRXLj1r=8_rYvw@mail.gmail.com
Reflecting an updated parameter value requires a server restart, which
was not mentioned in the documentation and in postgresql.conf.sample.
Reported-by: Thomas Poty
Discussion: https://postgr.es/m/15659-0cd812f13027a2d8@postgresql.org
By default, the fallback_application_name for a physical walreceiver
is "walreceiver". This means that multiple standbys cannot be
distinguished easily on a primary, for example in pg_stat_activity or
synchronous_standby_names.
If cluster_name is set, use that for fallback_application_name in the
walreceiver. (If it's not set, it remains "walreceiver".) If someone
set cluster_name to identify their instance, we might as well use that
by default to identify the node remotely as well. It's still possible
to specify another application_name in primary_conninfo explicitly.
Reviewed-by: Euler Taveira <euler@timbira.com.br>
Discussion: https://www.postgresql.org/message-id/flat/1257eaee-4874-e791-e83a-46720c72cac7@2ndquadrant.com
Previously, floating-point output was done by rounding to a specific
decimal precision; by default, to 6 or 15 decimal digits (losing
information) or as requested using extra_float_digits. Drivers that
wanted exact float values, and applications like pg_dump that must
preserve values exactly, set extra_float_digits=3 (or sometimes 2 for
historical reasons, though this isn't enough for float4).
Unfortunately, decimal rounded output is slow enough to become a
noticable bottleneck when dealing with large result sets or COPY of
large tables when many floating-point values are involved.
Floating-point output can be done much faster when the output is not
rounded to a specific decimal length, but rather is chosen as the
shortest decimal representation that is closer to the original float
value than to any other value representable in the same precision. The
recently published Ryu algorithm by Ulf Adams is both relatively
simple and remarkably fast.
Accordingly, change float4out/float8out to output shortest decimal
representations if extra_float_digits is greater than 0, and make that
the new default. Applications that need rounded output can set
extra_float_digits back to 0 or below, and take the resulting
performance hit.
We make one concession to portability for systems with buggy
floating-point input: we do not output decimal values that fall
exactly halfway between adjacent representable binary values (which
would rely on the reader doing round-to-nearest-even correctly). This
is known to be a problem at least for VS2013 on Windows.
Our version of the Ryu code originates from
https://github.com/ulfjack/ryu/ at commit c9c3fb1979, but with the
following (significant) modifications:
- Output format is changed to use fixed-point notation for small
exponents, as printf would, and also to use lowercase 'e', a
minimum of 2 exponent digits, and a mandatory sign on the exponent,
to keep the formatting as close as possible to previous output.
- The output of exact midpoint values is disabled as noted above.
- The integer fast-path code is changed somewhat (since we have
fixed-point output and the upstream did not).
- Our project style has been largely applied to the code with the
exception of C99 declaration-after-statement, which has been
retained as an exception to our present policy.
- Most of upstream's debugging and conditionals are removed, and we
use our own configure tests to determine things like uint128
availability.
Changing the float output format obviously affects a number of
regression tests. This patch uses an explicit setting of
extra_float_digits=0 for test output that is not expected to be
exactly reproducible (e.g. due to numerical instability or differing
algorithms for transcendental functions).
Conversions from floats to numeric are unchanged by this patch. These
may appear in index expressions and it is not yet clear whether any
change should be made, so that can be left for another day.
This patch assumes that the only supported floating point format is
now IEEE format, and the documentation is updated to reflect that.
Code by me, adapting the work of Ulf Adams and other contributors.
References:
https://dl.acm.org/citation.cfm?id=3192369
Reviewed-by: Tom Lane, Andres Freund, Donald Dong
Discussion: https://postgr.es/m/87r2el1bx6.fsf@news-spur.riddles.org.uk
Since its introduction, max_wal_senders is counted as part of
max_connections when it comes to define how many connection slots can be
used for replication connections with a WAL sender context. This can
lead to confusion for some users, as it could be possible to block a
base backup or replication from happening because other backend sessions
are already taken for other purposes by an application, and
superuser-only connection slots are not a correct solution to handle
that case.
This commit makes max_wal_senders independent of max_connections for its
handling of PGPROC entries in ProcGlobal, meaning that connection slots
for WAL senders are handled using their own free queue, like autovacuum
workers and bgworkers.
One compatibility issue that this change creates is that a standby now
requires to have a value of max_wal_senders at least equal to its
primary. So, if a standby created enforces the value of
max_wal_senders to be lower than that, then this could break failovers.
Normally this should not be an issue though, as any settings of a
standby are inherited from its primary as postgresql.conf gets normally
copied as part of a base backup, so parameters would be consistent.
Author: Alexander Kukushkin
Reviewed-by: Kyotaro Horiguchi, Petr Jelínek, Masahiko Sawada, Oleksii
Kliukin
Discussion: https://postgr.es/m/CAFh8B=nBzHQeYAu0b8fjK-AF1X4+_p6GRtwG+cCgs6Vci2uRuQ@mail.gmail.com
This value represents the default behavior of using the current
timeline. Previously, this was represented by an empty string.
(Before the removal of recovery.conf, this setting could not be chosen
explicitly but was used when recovery_target_timeline was not
mentioned at all.)
Discussion: https://www.postgresql.org/message-id/flat/6dd2c23a-4162-8469-410f-bfe146e28c0c@2ndquadrant.com/
Reviewed-by: David Steele <david@pgmasters.net>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
"$user" in a search_path string is replaced by CURRENT_USER not
SESSION_USER. (It actually was SESSION_USER in the initial implementation,
but we changed it shortly later, and evidently forgot to fix the docs to
match.)
Noted by antonov@stdpr.ru
Discussion: https://postgr.es/m/159151fb45d490c8d31ea9707e9ba99d@stdpr.ru
Alvaro Herrera
Peter Eisentraut
Amit Kapila
Tomas Vondra
Tom Lane
Fujii Masao
Bruce Momjian
Alexander Korotkov
Michael Paquier
Noah Misch
Andres Freund
Thomas Munro
Andrew Dunstan
Andrew Gierth