This SQL standard functionality allows to aggregate data by different
GROUP BY clauses at once. Each grouping set returns rows with columns
grouped by in other sets set to NULL.
This could previously be achieved by doing each grouping as a separate
query, conjoined by UNION ALLs. Besides being considerably more concise,
grouping sets will in many cases be faster, requiring only one scan over
the underlying data.
The current implementation of grouping sets only supports using sorting
for input. Individual sets that share a sort order are computed in one
pass. If there are sets that don't share a sort order, additional sort &
aggregation steps are performed. These additional passes are sourced by
the previous sort step; thus avoiding repeated scans of the source data.
The code is structured in a way that adding support for purely using
hash aggregation or a mix of hashing and sorting is possible. Sorting
was chosen to be supported first, as it is the most generic method of
implementation.
Instead of, as in an earlier versions of the patch, representing the
chain of sort and aggregation steps as full blown planner and executor
nodes, all but the first sort are performed inside the aggregation node
itself. This avoids the need to do some unusual gymnastics to handle
having to return aggregated and non-aggregated tuples from underlying
nodes, as well as having to shut down underlying nodes early to limit
memory usage. The optimizer still builds Sort/Agg node to describe each
phase, but they're not part of the plan tree, but instead additional
data for the aggregation node. They're a convenient and preexisting way
to describe aggregation and sorting. The first (and possibly only) sort
step is still performed as a separate execution step. That retains
similarity with existing group by plans, makes rescans fairly simple,
avoids very deep plans (leading to slow explains) and easily allows to
avoid the sorting step if the underlying data is sorted by other means.
A somewhat ugly side of this patch is having to deal with a grammar
ambiguity between the new CUBE keyword and the cube extension/functions
named cube (and rollup). To avoid breaking existing deployments of the
cube extension it has not been renamed, neither has cube been made a
reserved keyword. Instead precedence hacking is used to make GROUP BY
cube(..) refer to the CUBE grouping sets feature, and not the function
cube(). To actually group by a function cube(), unlikely as that might
be, the function name has to be quoted.
Needs a catversion bump because stored rules may change.
Author: Andrew Gierth and Atri Sharma, with contributions from Andres Freund
Reviewed-By: Andres Freund, Noah Misch, Tom Lane, Svenne Krap, Tomas
Vondra, Erik Rijkers, Marti Raudsepp, Pavel Stehule
Discussion: CAOeZVidmVRe2jU6aMk_5qkxnB7dfmPROzM7Ur8JPW5j8Y5X-Lw@mail.gmail.com
DST law changes in Egypt, Mongolia, Palestine.
Historical corrections for Canada and Chile.
Revised zone abbreviation for America/Adak (HST/HDT not HAST/HADT).
This lets BRIN be used with R-Tree-like indexing strategies.
Also provided are operator classes for range types, box and inet/cidr.
The infrastructure provided here should be sufficient to create operator
classes for similar datatypes; for instance, opclasses for PostGIS
geometries should be doable, though we didn't try to implement one.
(A box/point opclass was also submitted, but we ripped it out before
commit because the handling of floating point comparisons in existing
code is inconsistent and would generate corrupt indexes.)
Author: Emre Hasegeli. Cosmetic changes by me
Review: Andreas Karlsson
For upcoming BRIN opclasses, it's convenient to have strategy numbers
defined in a single place. Since there's nothing appropriate, create
it. The StrategyNumber typedef now lives there, as well as existing
strategy numbers for B-trees (from skey.h) and R-tree-and-friends (from
gist.h). skey.h is forced to include stratnum.h because of the
StrategyNumber typedef, but gist.h is not; extensions that currently
rely on gist.h for rtree strategy numbers might need to add a new
A few .c files can stop including skey.h and/or gist.h, which is a nice
side benefit.
Per discussion:
https://www.postgresql.org/message-id/20150514232132.GZ2523@alvh.no-ip.org
Authored by Emre Hasegeli and Álvaro.
(It's not clear to me why bootscanner.l has any #include lines at all.)
Contrib module implementing a tablesample method
that allows you to limit the sample by a hard time
limit.
Petr Jelinek
Reviewed by Michael Paquier, Amit Kapila and
Simon Riggs
Contrib module implementing a tablesample method
that allows you to limit the sample by a hard row
limit.
Petr Jelinek
Reviewed by Michael Paquier, Amit Kapila and
Simon Riggs
Our previous code for GB18030 <-> UTF8 conversion only covered Unicode code
points up to U+FFFF, but the actual spec defines conversions for all code
points up to U+10FFFF. That would be rather impractical as a lookup table,
but fortunately there is a simple algorithmic conversion between the
additional code points and the equivalent GB18030 byte patterns. Make use
of the just-added callback facility in LocalToUtf/UtfToLocal to perform the
additional conversions.
Having created the infrastructure to do that, we can use the same code to
map certain linearly-related subranges of the Unicode space below U+FFFF,
allowing removal of the corresponding lookup table entries. This more
than halves the lookup table size, which is a substantial savings;
utf8_and_gb18030.so drops from nearly a megabyte to about half that.
In support of doing that, replace ISO10646-GB18030.TXT with the data file
gb-18030-2000.xml (retrieved from
http://source.icu-project.org/repos/icu/data/trunk/charset/data/xml/ )
in which these subranges have been deleted from the simple lookup entries.
Per bug #12845 from Arjen Nienhuis. The conversion code added here is
based on his proposed patch, though I whacked it around rather heavily.
Add a TABLESAMPLE clause to SELECT statements that allows
user to specify random BERNOULLI sampling or block level
SYSTEM sampling. Implementation allows for extensible
sampling functions to be written, using a standard API.
Basic version follows SQLStandard exactly. Usable
concrete use cases for the sampling API follow in later
commits.
Petr Jelinek
Reviewed by Michael Paquier and Simon Riggs
The expected-output files for these tests were broken by the recent
addition of a warning for hash indexes. Update them.
Also add a test case for GB18030 encoding, similar to the other ones.
This is a pretty weak test, but it's better than nothing.
The expected output contained some floating point values which might get
rounded slightly differently on different platforms. The exact output isn't
very interesting in this test, so just round it.
Per buildfarm member rover_firefly.
We can only support a lossy distance function when the distance function's
datatype is comparable with the original ordering operator's datatype.
The distance function always returns a float8, so we are limited to float8,
and float4 (by a hard-coded cast of the float8 to float4).
In light of this limitation, it seems like a good idea to have a separate
'recheck' flag for the ORDER BY expressions, so that if you have a non-lossy
distance function, it still works with lossy quals. There are cases like
that with the build-in or contrib opclasses, but it's plausible.
There was a hidden assumption that the ORDER BY values returned by GiST
match the original ordering operator's return type, but there are plenty
of examples where that's not true, e.g. in btree_gist and pg_trgm. As long
as the distance function is not lossy, we can tolerate that and just not
return the distance to the executor (or rather, always return NULL). The
executor doesn't need the distances if there are no lossy results.
There was another little bug: the recheck variable was not initialized
before calling the distance function. That revealed the bigger issue,
as the executor tried to reorder tuples that didn't need reordering, and
that failed because of the datatype mismatch.
The previous coding effectively only verified that the second byte of a
multibyte character was in the expected range; moreover, it wasn't careful
to make sure that the second byte even exists in the buffer before touching
it. The latter seems unlikely to cause any real problems in the field
(in particular, it could never be a problem with null-terminated input),
but it's still a bug.
Since GB18030 is not a supported backend encoding, the only thing we'd
really be doing with GB18030 text is converting it to UTF8 in LocalToUtf,
which would fail anyway on any invalid character for lack of a match in
its lookup table. So the only user-visible consequence of this change
should be that you'll get "invalid byte sequence for encoding" rather than
"character has no equivalent" for malformed GB18030 input. However,
impending changes to the GB18030 conversion code will require these tighter
up-front checks to avoid producing bogus results.
No need to have pg_audit.conf any longer since the regression tests are
just loading the module at the start of each session (to simulate being
in shared_preload_libraries, which isn't something we can actually make
happen on the buildfarm itself, it seems).
Pointed out by Tom
The distance function can now set *recheck = false, like index quals. The
executor will then re-check the ORDER BY expressions, and use a queue to
reorder the results on the fly.
This makes it possible to do kNN-searches on polygons and circles, which
don't store the exact value in the index, but just a bounding box.
Alexander Korotkov and me
When this option is specified, a progress report is printed as each index
is reindexed.
Per discussion, we agreed on the following syntax for the extensibility of
the options.
REINDEX (flexible options) { INDEX | ... } name
Sawada Masahiko.
Reviewed by Robert Haas, Fabrízio Mello, Alvaro Herrera, Kyotaro Horiguchi,
Jim Nasby and me.
Discussion: CAD21AoA0pK3YcOZAFzMae+2fcc3oGp5zoRggDyMNg5zoaWDhdQ@mail.gmail.com
Until now, these functions have only supported encoding conversions using
lookup tables, which is fine as long as there's not too many code points
to convert. However, GB18030 expects all 1.1 million Unicode code points
to be convertible, which would require a ridiculously-sized lookup table.
Fortunately, a large fraction of those conversions can be expressed through
arithmetic, ie the conversions are one-to-one in certain defined ranges.
To support that, provide a callback function that is used after consulting
the lookup tables. (This patch doesn't actually change anything about the
GB18030 conversion behavior, just provide infrastructure for fixing it.)
Since this requires changing the APIs of UtfToLocal/LocalToUtf anyway,
take the opportunity to rearrange their argument lists into what seems
to me a saner order. And beautify the call sites by using lengthof()
instead of error-prone sizeof() arithmetic.
In passing, also mark all the lookup tables used by these calls "const".
This moves an impressive amount of stuff into the text segment, at least
on my machine, and is safer anyhow.
In pg_audit, set client_min_messages up to warning, then reset the role
attributes, to completely reset the session while not making the
regression tests depend on being run by any particular user.
Instead of creating a new superuser role, extract out what the current
user is and use that user instead. Further, clean up and drop all
objects created by the regression test.
Pointed out by Tom.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
Also, use a function to load the extension ahead of all other calls,
simulating load from shared_libraries_preload, to make sure the
hooks are in place before logging start.
Remove the check that pg_audit be installed by
shared_preload_libraries as that's not going to work when running the
regressions tests in the buildfarm. That check was primairly a nice to
have and isn't required anyway.
This extension provides detailed logging classes, ability to control
logging at a per-object level, and includes fully-qualified object
names for logged statements (DML and DDL) in independent fields of the
log output.
Authors: Ian Barwick, Abhijit Menon-Sen, David Steele
Reviews by: Robert Haas, Tatsuo Ishii, Sawada Masahiko, Fujii Masao,
Simon Riggs
Discussion with: Josh Berkus, Jaime Casanova, Peter Eisentraut,
David Fetter, Yeb Havinga, Alvaro Herrera, Petr Jelinek, Tom Lane,
MauMau, Bruce Momjian, Jim Nasby, Michael Paquier,
Fabrízio de Royes Mello, Neil Tiffin
The top-level makefile removes tmp_install in its "clean" target, but the
distclean and maintainer-clean targets overlooked that (and they don't
simply invoke clean, because that would result in an extra tree traversal).
While at it, let's just make sure that removing GNUmakefile itself is the
very last step of the recipe.
Tom Lane