Hash partitioning is useful when you want to partition a growing data
set evenly. This can be useful to keep table sizes reasonable, which
makes maintenance operations such as VACUUM faster, or to enable
partition-wise join.
At present, we still depend on constraint exclusion for partitioning
pruning, and the shape of the partition constraints for hash
partitioning is such that that doesn't work. Work is underway to fix
that, which should both improve performance and make partitioning
pruning work with hash partitioning.
Amul Sul, reviewed and tested by Dilip Kumar, Ashutosh Bapat, Yugo
Nagata, Rajkumar Raghuwanshi, Jesper Pedersen, and by me. A few
final tweaks also by me.
Discussion: http://postgr.es/m/CAAJ_b96fhpJAP=ALbETmeLk1Uni_GFZD938zgenhF49qgDTjaQ@mail.gmail.com
The lower case spellings are C and C++ standard and are used in most
parts of the PostgreSQL sources. The upper case spellings are only used
in some files/modules. So standardize on the standard spellings.
The APIs for ICU, Perl, and Windows define their own TRUE and FALSE, so
those are left as is when using those APIs.
In code comments, we use the lower-case spelling for the C concepts and
keep the upper-case spelling for the SQL concepts.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Previously server reserved WAL for last two checkpoints,
which used too much disk space for small servers.
Bumps PG_CONTROL_VERSION
Author: Simon Riggs <simon@2ndQuadrant.com>
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Add docs to explain this for other backup mechanisms
Author: David Steele <david@pgmasters.net>
Reviewed-by: Petr Jelinek <petr.jelinek@2ndQuadrant.com> et al
In the v10 branch, also back-patch the effects of 1ff01b390 and c29c57890
on these files, to reduce future maintenance issues. (I'd do it further
back, except that the 9.X branches differ anyway due to xlog-to-wal
link tag renaming.)
As usual, the release notes for other branches will be made by cutting
these down, but put them up for community review first. Note that a
fair percentage of the entries apply only to prior branches because
their issue was already fixed in 10.0.
This makes the produced HTML anchors upper case, making it backward
compatible with the previous (9.6) build system.
Reported-by: Thomas Kellerer <spam_eater@gmx.net>
Also make the link to pg_stat_replication more precise.
Author: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Jeff Janes <jeff.janes@gmail.com>
Document the order of changing certain settings when using hot-standby
servers. This is just a logical consequence of what was already
documented, but it gives the users some more practical advice.
Author: Yorick Peterse <yorickpeterse@gmail.com>
Reviewed-by: Aleksander Alekseev <a.alekseev@postgrespro.ru>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
CREATE USER is an alias for CREATE ROLE, not its own command any longer,
so clean up references to the 'sql-createuser' link to go to
'sql-createrole' instead.
In passing, change a few cases of 'CREATE USER' to be
'CREATE ROLE ... LOGIN'. The remaining cases appear reasonable and
also mention the distinction between 'CREATE ROLE' and 'CREATE USER'.
Also, don't say CREATE USER "assumes" LOGIN, but rather "includes".
Patch-by: David G. Johnston, with assumes->includes by me.
Discussion: https://postgr.es/m/CAKFQuwYrbhKV8hH4TEABrDRBwf=gKremF=mLPQ6X2yGqxgFpYA@mail.gmail.com
The change made by commit 906bfcad7 means that if you're writing
a parenthesized column list in UPDATE ... SET, but that column list
is only one column, you now need to write ROW(expression) on the
righthand side, not just a parenthesized expression. This was an
intentional change for spec compatibility and potential future
expansion of the possibilities for the RHS, but I'd neglected to
document it as a compatibility issue, figuring that hardly anyone
would bother with parenthesized syntax for a single target column.
I was wrong, as shown by questions from Justin Pryzby, Adam Brusselback,
and others. Move the release note item into the compatibility section
and point out the behavior change for a single target column.
Discussion: https://postgr.es/m/CAMjNa7cDLzPcs0xnRpkvqmJ6Vb6G3EH8CYGp9ZBjXdpFfTz6dg@mail.gmail.com
This is already present in the CREATE TABLE documentation, but it's
nicer not to have to refer to CREATE TABLE to find out the syntax
for ALTER TABLE.
Lætitia Avrot
This is the last major omission in our domains feature: you can now
make a domain over anything that's not a pseudotype.
The major complication from an implementation standpoint is that places
that might be creating tuples of a domain type now need to be prepared
to apply domain_check(). It seems better that unprepared code fail
with an error like "<type> is not composite" than that it silently fail
to apply domain constraints. Therefore, relevant infrastructure like
get_func_result_type() and lookup_rowtype_tupdesc() has been adjusted
to treat domain-over-composite as a distinct case that unprepared code
won't recognize, rather than just transparently treating it the same
as plain composite. This isn't a 100% solution to the possibility of
overlooked domain checks, but it catches most places.
In passing, improve typcache.c's support for domains (it can now cache
the identity of a domain's base type), and rewrite the argument handling
logic in jsonfuncs.c's populate_record[set]_worker to reduce duplicative
per-call lookups.
I believe this is code-complete so far as the core and contrib code go.
The PLs need varying amounts of work, which will be tackled in followup
patches.
Discussion: https://postgr.es/m/4206.1499798337@sss.pgh.pa.us
I was a bit surprised to find that domains were almost completely
unmentioned in the main SGML documentation, outside of the reference
pages for CREATE/ALTER/DROP DOMAIN. In particular, noplace was it
mentioned that we don't support domains over composite, making it
hard to document the planned fix for that.
Hence, add a section about domains to chapter 8 (Data Types).
Also, modernize the type system overview in section 37.2; it had never
heard of range types, and insisted on calling arrays base types, which
seems a bit odd from a user's perspective; furthermore it didn't fit well
with the fact that we now support arrays over types other than base types.
It seems appropriate to use the term "container types" to describe all of
arrays, composites, and ranges, so let's do that.
Also a few other minor improvements, notably improve an example query
in rowtypes.sgml by using a LATERAL function instead of an ad-hoc
OFFSET 0 clause.
In part this is mop-up for commit c12d570fa, which missed updating 37.2
to reflect the fact that it added arrays of domains. We could possibly
back-patch this without that claim, but I don't feel a strong need to.
IDs in SGML are case insensitive, and we have accumulated a mix of upper
and lower case IDs, including different variants of the same ID. In
XML, these will be case sensitive, so we need to fix up those
differences. Going to all lower case seems most straightforward, and
the current build process already makes all anchors and lower case
anyway during the SGML->XML conversion, so this doesn't create any
difference in the output right now. A future XML-only build process
would, however, maintain any mixed case ID spellings in the output, so
that is another reason to clean this up beforehand.
Author: Alexander Lakhin <exclusion@gmail.com>
We say 'OWNER TO' in the synopsis; let's use that form elsewhere.
There is a paragraph in the <note> section that refers to various
subcommands very loosely (including OWNER); I didn't think it was an
improvement to change that one.
This is a fairly inconsequential change, so no backpatch.
Author: Amit Langote
Discussion: https://postgr.es/m/69ec7b51-03e5-f523-95ce-c070ee790e70@lab.ntt.co.jp
For DocBook XML compatibility, don't use SGML empty tags (</>) anymore,
replace by the full tag name. Add a warning option to catch future
occurrences.
Alexander Lakhin, Jürgen Purtz
Up to now, there's been hard-wired assumptions that normal aggregates'
final functions never modify their transition states, while ordered-set
aggregates' final functions always do. This has always been a bit
limiting, and in particular it's getting in the way of improving the
built-in ordered-set aggregates to allow merging of transition states.
Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure
that lets the finalfn's behavior be declared explicitly.
There are now three possibilities for the finalfn behavior: it's purely
read-only, it trashes the transition state irrecoverably, or it changes
the state in such a way that no more transfn calls are possible but the
state can still be passed to other, compatible finalfns. There are no
examples of this third case today, but we'll shortly make the built-in
OSAs act like that.
This change allows user-defined aggregates to explicitly disclaim support
for use as window functions, and/or to prevent transition state merging,
if their implementations cannot handle that. While it was previously
possible to handle the window case with a run-time error check, there was
not any way to prevent transition state merging, which in retrospect is
something commit 804163bc2 should have provided for. But better late
than never.
In passing, split out pg_aggregate.c's extern function declarations into
a new header file pg_aggregate_fn.h, similarly to what we've done for
some other catalog headers, so that pg_aggregate.h itself can be safe
for frontend files to include. This lets pg_dump use the symbolic
names for relevant constants.
Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
The GRANT reference page, which lists the default privileges for new
objects, failed to mention that USAGE is granted by default for data
types and domains. As a lesser sin, it also did not specify anything
about the initial privileges for sequences, FDWs, foreign servers,
or large objects. Fix that, and add a comment to acldefault() in the
probably vain hope of getting people to maintain this list in future.
Noted by Laurenz Albe, though I editorialized on the wording a bit.
Back-patch to all supported branches, since they all have this behavior.
Discussion: https://postgr.es/m/1507620895.4152.1.camel@cybertec.at
Instead of joining two partitioned tables in their entirety we can, if
it is an equi-join on the partition keys, join the matching partitions
individually. This involves teaching the planner about "other join"
rels, which are related to regular join rels in the same way that
other member rels are related to baserels. This can use significantly
more CPU time and memory than regular join planning, because there may
now be a set of "other" rels not only for every base relation but also
for every join relation. In most practical cases, this probably
shouldn't be a problem, because (1) it's probably unusual to join many
tables each with many partitions using the partition keys for all
joins and (2) if you do that scenario then you probably have a big
enough machine to handle the increased memory cost of planning and (3)
the resulting plan is highly likely to be better, so what you spend in
planning you'll make up on the execution side. All the same, for now,
turn this feature off by default.
Currently, we can only perform joins between two tables whose
partitioning schemes are absolutely identical. It would be nice to
cope with other scenarios, such as extra partitions on one side or the
other with no match on the other side, but that will have to wait for
a future patch.
Ashutosh Bapat, reviewed and tested by Rajkumar Raghuwanshi, Amit
Langote, Rafia Sabih, Thomas Munro, Dilip Kumar, Antonin Houska, Amit
Khandekar, and by me. A few final adjustments by me.
Discussion: http://postgr.es/m/CAFjFpRfQ8GrQvzp3jA2wnLqrHmaXna-urjm_UY9BqXj=EaDTSA@mail.gmail.com
Discussion: http://postgr.es/m/CAFjFpRcitjfrULr5jfuKWRPsGUX0LQ0k8-yG0Qw2+1LBGNpMdw@mail.gmail.com
Haribabu Kommi, reviewed by Dilip Kumar and Rafia Sabih. Various
cosmetic changes by me to explain why this appears to be safe but
allowing inserts in parallel mode in general wouldn't be. Also, I
removed the REFRESH MATERIALIZED VIEW case from Haribabu's patch,
since I'm not convinced that case is OK, and hacked on the
documentation somewhat.
Discussion: http://postgr.es/m/CAJrrPGdo5bak6qnPWe8Kpi8g_jfQEs-G4SYmG9y+OFaw2-dPvA@mail.gmail.com
A lot of semi-internal code just prints out numeric SPI error codes,
which is not very helpful. We already have an API function to convert
the codes to a string, so let's make more use of that.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Not much to say about this; does what it says on the tin.
However, formerly, if there was a column list then the ANALYZE action was
implied; now it must be specified, or you get an error. This is because
it would otherwise be a bit unclear what the user meant if some tables
have column lists and some don't.
Nathan Bossart, reviewed by Michael Paquier and Masahiko Sawada, with some
editorialization by me
Discussion: https://postgr.es/m/E061A8E3-5E3D-494D-94F0-E8A9B312BBFC@amazon.com
Document better how to create custom collations and what locale strings
ICU accepts. Explain the ICU examples in more detail. Also update the
text on the CREATE COLLATION reference page a bit to take ICU more into
account.
Allowing arrays with a domain type as their element type was left un-done
in the original domain patch, but not for any very good reason. This
omission leads to such surprising results as array_agg() not working on
a domain column, because the parser can't identify a suitable output type
for the polymorphic aggregate.
In order to fix this, first clean up the APIs of coerce_to_domain() and
some internal functions in parse_coerce.c so that we consistently pass
around a CoercionContext along with CoercionForm. Previously, we sometimes
passed an "isExplicit" boolean flag instead, which is strictly less
information; and coerce_to_domain() didn't even get that, but instead had
to reverse-engineer isExplicit from CoercionForm. That's contrary to the
documentation in primnodes.h that says that CoercionForm only affects
display and not semantics. I don't think this change fixes any live bugs,
but it makes things more consistent. The main reason for doing it though
is that now build_coercion_expression() receives ccontext, which it needs
in order to be able to recursively invoke coerce_to_target_type().
Next, reimplement ArrayCoerceExpr so that the node does not directly know
any details of what has to be done to the individual array elements while
performing the array coercion. Instead, the per-element processing is
represented by a sub-expression whose input is a source array element and
whose output is a target array element. This simplifies life in
parse_coerce.c, because it can build that sub-expression by a recursive
invocation of coerce_to_target_type(). The executor now handles the
per-element processing as a compiled expression instead of hard-wired code.
The main advantage of this is that we can use a single ArrayCoerceExpr to
handle as many as three successive steps per element: base type conversion,
typmod coercion, and domain constraint checking. The old code used two
stacked ArrayCoerceExprs to handle type + typmod coercion, which was pretty
inefficient, and adding yet another array deconstruction to do domain
constraint checking seemed very unappetizing.
In the case where we just need a single, very simple coercion function,
doing this straightforwardly leads to a noticeable increase in the
per-array-element runtime cost. Hence, add an additional shortcut evalfunc
in execExprInterp.c that skips unnecessary overhead for that specific form
of expression. The runtime speed of simple cases is within 1% or so of
where it was before, while cases that previously required two levels of
array processing are significantly faster.
Finally, create an implicit array type for every domain type, as we do for
base types, enums, etc. Everything except the array-coercion case seems
to just work without further effort.
Tom Lane, reviewed by Andrew Dunstan
Discussion: https://postgr.es/m/9852.1499791473@sss.pgh.pa.us
Peter Eisentraut