Originally, we treated memory context names as potentially variable in
all cases, and therefore always copied them into the context header.
Commit 9fa6f00b1 rethought this a little bit and invented a distinction
between fixed and variable names, skipping the copy step for the former.
But we can make things both simpler and more useful by instead allowing
there to be two parts to a context's identification, a fixed "name" and
an optional, variable "ident". The name supplied in the context create
call is now required to be a compile-time-constant string in all cases,
as it is never copied but just pointed to. The "ident" string, if
wanted, is supplied later. This is needed because typically we want
the ident to be stored inside the context so that it's cleaned up
automatically on context deletion; that means it has to be copied into
the context before we can set the pointer.
The cost of this approach is basically just an additional pointer field
in struct MemoryContextData, which isn't much overhead, and is bought
back entirely in the AllocSet case by not needing a headerSize field
anymore, since we no longer have to cope with variable header length.
In addition, we can simplify the internal interfaces for memory context
creation still further, saving a few cycles there. And it's no longer
true that a custom identifier disqualifies a context from participating
in aset.c's freelist scheme, so possibly there's some win on that end.
All the places that were using non-compile-time-constant context names
are adjusted to put the variable info into the "ident" instead. This
allows more effective identification of those contexts in many cases;
for example, subsidary contexts of relcache entries are now identified
by both type (e.g. "index info") and relname, where before you got only
one or the other. Contexts associated with PL function cache entries
are now identified more fully and uniformly, too.
I also arranged for plancache contexts to use the query source string
as their identifier. This is basically free for CachedPlanSources, as
they contained a copy of that string already. We pay an extra pstrdup
to do it for CachedPlans. That could perhaps be avoided, but it would
make things more fragile (since the CachedPlanSource is sometimes
destroyed first). I suspect future improvements in error reporting will
require CachedPlans to have a copy of that string anyway, so it's not
clear that it's worth moving mountains to avoid it now.
This also changes the APIs for context statistics routines so that the
context-specific routines no longer assume that output goes straight
to stderr, nor do they know all details of the output format. This
is useful immediately to reduce code duplication, and it also allows
for external code to do something with stats output that's different
from printing to stderr.
The reason for pushing this now rather than waiting for v12 is that
it rethinks some of the API changes made by commit 9fa6f00b1. Seems
better for extension authors to endure just one round of API changes
not two.
Discussion: https://postgr.es/m/CAB=Je-FdtmFZ9y9REHD7VsSrnCkiBhsA4mdsLKSPauwXtQBeNA@mail.gmail.com
Commit eb7ed3f306 enabled unique constraints on partitioned tables,
but one thing that was not working properly is INSERT/ON CONFLICT.
This commit introduces a new node keeps state related to the ON CONFLICT
clause per partition, and fills it when that partition is about to be
used for tuple routing.
Author: Amit Langote, Álvaro Herrera
Reviewed-by: Etsuro Fujita, Pavan Deolasee
Discussion: https://postgr.es/m/20180228004602.cwdyralmg5ejdqkq@alvherre.pgsql
My commit 4dba331cb3 that moved around CommandCounterIncrement calls
in partitioning DDL code unearthed a problem with the relcache handling
for the 'default' partition: the construction of a correct relcache
entry for the partitioned table was at the mercy of lack of CCI calls in
non-trivial amounts of code. This was prone to creating problems later
on, as the code develops. This was visible as a test failure in a
compile with RELCACHE_FORCE_RELASE (buildfarm member prion).
The problem is that after the mentioned commit it was possible to create
a relcache entry that had incomplete information regarding the default
partition because I introduced a CCI between adding the catalog entries
for the default partition (StorePartitionBound) and the update of
pg_partitioned_table entry for its parent partitioned table
(update_default_partition_oid). It seems the best fix is to move the
latter so that it occurs inside the former; the purposeful lack of
intervening CCI should be more obvious, and harder to break.
I also remove a check in RelationBuildPartitionDesc that returns NULL if
the key is not set. I couldn't find any place that needs this hack
anymore; probably it was required because of bugs that have since been
fixed.
Fix a few typos I noticed while reviewing the code involved.
Discussion: https://postgr.es/m/20180320182659.nyzn3vqtjbbtfgwq@alvherre.pgsql
One of the things canonicalize_qual() does is to remove constant-NULL
subexpressions of top-level AND/OR clauses. It does that on the assumption
that what it's given is a top-level WHERE clause, so that NULL can be
treated like FALSE. Although this is documented down inside a subroutine
of canonicalize_qual(), it wasn't mentioned in the documentation of that
function itself, and some callers hadn't gotten that memo.
Notably, commit d007a9505 caused get_relation_constraints() to apply
canonicalize_qual() to CHECK constraints. That allowed constraint
exclusion to misoptimize situations in which a CHECK constraint had a
provably-NULL subclause, as seen in the regression test case added here,
in which a child table that should be scanned is not. (Although this
thinko is ancient, the test case doesn't fail before 9.2, for reasons
I've not bothered to track down in detail. There may be related cases
that do fail before that.)
More recently, commit f0e44751d added an independent bug by applying
canonicalize_qual() to index expressions, which is even sillier since
those might not even be boolean. If they are, though, I think this
could lead to making incorrect index entries for affected index
expressions in v10. I haven't attempted to prove that though.
To fix, add an "is_check" parameter to canonicalize_qual() to specify
whether it should assume WHERE or CHECK semantics, and make it perform
NULL-elimination accordingly. Adjust the callers to apply the right
semantics, or remove the call entirely in cases where it's not known
that the expression has one or the other semantics. I also removed
the call in some cases involving partition expressions, where it should
be a no-op because such expressions should be canonical already ...
and was a no-op, independently of whether it could in principle have
done something, because it was being handed the qual in implicit-AND
format which isn't what it expects. In HEAD, add an Assert to catch
that type of mistake in future.
This represents an API break for external callers of canonicalize_qual().
While that's intentional in HEAD to make such callers think about which
case applies to them, it seems like something we probably wouldn't be
thanked for in released branches. Hence, in released branches, the
extra parameter is added to a new function canonicalize_qual_ext(),
and canonicalize_qual() is a wrapper that retains its old behavior.
Patch by me with suggestions from Dean Rasheed. Back-patch to all
supported branches.
Discussion: https://postgr.es/m/24475.1520635069@sss.pgh.pa.us
Similar to what commit b022923556 for a
different set of functions, pass the required bits of the PartitionKey
instead of the whole thing. This allows these functions to be used
without needing the PartitionKey to be available.
Amit Langote. The larger patch series of which this patch is a part
has been reviewed and tested by Ashutosh Bapat, David Rowley, Dilip
Kumar, Jesper Pedersen, Rajkumar Raghuwanshi, Beena Emerson, Kyotaro
Horiguchi, Álvaro Herrera, and me, but especially and in great detail
by David Rowley.
Discussion: http://postgr.es/m/098b9c71-1915-1a2a-8d52-1a7a50ce79e8@lab.ntt.co.jp
Discussion: http://postgr.es/m/1f6498e8-377f-d077-e791-5dc84dba2c00@lab.ntt.co.jp
Remove partition_bound_cmp() and partition_bound_bsearch(), whose
void * argument could be, depending on the situation, of any of
three different types: PartitionBoundSpec *, PartitionRangeBound *,
Datum *.
Instead, introduce separate bound-searching functions for each
situation: partition_list_bsearch, partition_range_bsearch,
partition_range_datum_bsearch, and partition_hash_bsearch. This
requires duplicating the code for binary search, but it makes the
code much more type safe, involves fewer branches at runtime, and
at least in my opinion, is much easier to understand.
Along the way, add an option to partition_range_datum_bsearch
allowing the number of keys to be specified, so that we can search
for partitions based on a prefix of the full list of partition
keys. This is important for pending work to improve partition
pruning.
Amit Langote, per a suggestion from me.
Discussion: http://postgr.es/m/CA+TgmoaVLDLc8=YESRwD32gPhodU_ELmXyKs77gveiYp+JE4vQ@mail.gmail.com
The old code generated always generated a constraint of the form
col = ANY(ARRAY[val1, val2, ...]), but that's invalid when col is an
array type. Instead, generate col = val when there's only one value,
col = val1 OR col = val2 OR ... when there are multiple values and
col is of array type, and the old form when there are multiple values
and col is not of an array type.
As a side benefit, this makes constraint exclusion able to prune
a list partition declared to accept a single Boolean value, which
didn't work before.
Amit Langote, reviewed by Etsuro Fujita
Discussion: http://postgr.es/m/97267195-e235-89d1-a41a-c110198dfce9@lab.ntt.co.jp
Generalize is_partition_attr to has_partition_attrs and make it
accessible from outside tablecmds.c. Change map_partition_varattnos
to clarify that it can be used for mapping between any two relations
in a partitioning hierarchy, not just parent -> child.
Amit Khandekar, reviewed by Amit Langote, David Rowley, and me.
Some comment changes by me.
Discussion: http://postgr.es/m/CAJ3gD9fWfxgKC+PfJZF3hkgAcNOy-LpfPxVYitDEXKHjeieWQQ@mail.gmail.com
This patch makes a number of interrelated changes to reduce the overhead
involved in creating/deleting memory contexts. The key ideas are:
* Include the AllocSetContext header of an aset.c context in its first
malloc request, rather than allocating it separately in TopMemoryContext.
This means that we now always create an initial or "keeper" block in an
aset, even if it never receives any allocation requests.
* Create freelists in which we can save and recycle recently-destroyed
asets (this idea is due to Robert Haas).
* In the common case where the name of a context is a constant string,
just store a pointer to it in the context header, rather than copying
the string.
The first change eliminates a palloc/pfree cycle per context, and
also avoids bloat in TopMemoryContext, at the price that creating
a context now involves a malloc/free cycle even if the context never
receives any allocations. That would be a loser for some common
usage patterns, but recycling short-lived contexts via the freelist
eliminates that pain.
Avoiding copying constant strings not only saves strlen() and strcpy()
overhead, but is an essential part of the freelist optimization because
it makes the context header size constant. Currently we make no
attempt to use the freelist for contexts with non-constant names.
(Perhaps someday we'll need to think harder about that, but in current
usage, most contexts with custom names are long-lived anyway.)
The freelist management in this initial commit is pretty simplistic,
and we might want to refine it later --- but in common workloads that
will never matter because the freelists will never get full anyway.
To create a context with a non-constant name, one is now required to
call AllocSetContextCreateExtended and specify the MEMCONTEXT_COPY_NAME
option. AllocSetContextCreate becomes a wrapper macro, and it includes
a test that will complain about non-string-literal context name
parameters on gcc and similar compilers.
An unfortunate side effect of making AllocSetContextCreate a macro is
that one is now *required* to use the size parameter abstraction macros
(ALLOCSET_DEFAULT_SIZES and friends) with it; the pre-9.6 habit of
writing out individual size parameters no longer works unless you
switch to AllocSetContextCreateExtended.
Internally to the memory-context-related modules, the context creation
APIs are simplified, removing the rather baroque original design whereby
a context-type module called mcxt.c which then called back into the
context-type module. That saved a bit of code duplication, but not much,
and it prevented context-type modules from exercising control over the
allocation of context headers.
In passing, I converted the test-and-elog validation of aset size
parameters into Asserts to save a few more cycles. The original thought
was that callers might compute size parameters on the fly, but in practice
nobody does that, so it's useless to expend cycles on checking those
numbers in production builds.
Also, mark the memory context method-pointer structs "const",
just for cleanliness.
Discussion: https://postgr.es/m/2264.1512870796@sss.pgh.pa.us
Non-default range partitions have a constraint which include null
tests, and both default and non-default list partitions also have a
constraint which includes null tests, but for some reason this was
missed for default range partitions. This could cause the partition
constraint to evaluate to false for rows that were (correctly) routed
to that partition by insert tuple routing, which could in turn
cause constraint exclusion to prune the default partition in cases
where it should not.
Amit Langote, reviewed by Kyotaro Horiguchi
Discussion: http://postgr.es/m/ba7aaeb1-4399-220e-70b4-62eade1522d0@lab.ntt.co.jp
Fix the function header comment to describe the actual behavior.
Check that table OID, modulus, and remainder arguments are not NULL
before accessing them. Check that the modulus and remainder are
sensible. If the table OID doesn't exist, return NULL instead of
emitting an internal error, similar to what we do elsewhere. Check
that the actual argument types match, or at least are binary coercible
to, the expected argument types. Correctly handle invocation of this
function using the VARIADIC syntax. Add regression tests.
Robert Haas and Amul Sul, per a report by Andreas Seltenreich and
subsequent followup investigation.
Discussion: http://postgr.es/m/871sl4sdrv.fsf@ansel.ydns.eu
Some code is moved from partition.c, which has grown very quickly lately;
splitting the executor parts out might help to keep it from getting
totally out of control. Other code is moved from execMain.c. All is
moved to a new file execPartition.c. get_partition_for_tuple now has
a new interface that more clearly separates executor concerns from
generic concerns.
Amit Langote. A slight comment tweak by me.
Discussion: http://postgr.es/m/1f0985f8-3b61-8bc4-4350-baa6d804cb6d@lab.ntt.co.jp
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
With this change, the order of leaf partitions as returned by
RelationGetPartitionDispatchInfo should now be the same as the
order used by expand_inherited_rtentry. This will make it simpler
for future patches to match up the partition dispatch information
with the planner data structures. The new code is also, in my
opinion anyway, simpler and easier to understand.
Amit Langote, reviewed by Amit Khandekar. I also reviewed and
made a few cosmetic revisions.
Discussion: http://postgr.es/m/d98d4761-5071-1762-501e-0e15047c714b@lab.ntt.co.jp
The previous coding of get_qual_for_list() was careful to copy everything
it was using from the input data structure. The new version missed
making a copy of pass-by-ref datum values that it's inserting into Consts.
This is not optional, however, as revealed by buildfarm failures on
machines running -DRELCACHE_FORCE_RELEASE: we're copying from a relcache
entry that could go away before the required lifespan of our output
expression. I'm pretty sure -DCLOBBER_CACHE_ALWAYS machines won't like
this either, but none of them have reported in yet.
map_partition_varattnos() failed to set its found_whole_row output
parameter if the given expression list was NIL. This seems to be
a pre-existing bug that chanced to be exposed by commit 6f6b99d13.
It might be unreachable in v10, but I have little faith in that
proposition, so back-patch.
Per buildfarm.
Instead, lock them in the caller using find_all_inheritors so that
they get locked in the standard order, minimizing deadlock risks.
Also in RelationGetPartitionDispatchInfo, avoid opening tables which
are not partitioned; there's no need.
Amit Langote, reviewed by Ashutosh Bapat and Amit Khandekar
Discussion: http://postgr.es/m/91b36fa1-c197-b72f-ca6e-56c593bae68c@lab.ntt.co.jp
Instead of duplicating the logic to search for a matching
ParamPathInfo in multiple places, factor it out into a separate
function.
Pass only the relevant bits of the PartitionKey to
partition_bounds_equal instead of the whole thing, because
partition-wise join will want to call this without having a
PartitionKey available.
Adjust allow_star_schema_join and calc_nestloop_required_outer
to take relevant Relids rather than the entire Path, because
partition-wise join will want to call it with the top-parent
relids to determine whether a child join is allowable.
Ashutosh Bapat. Review and testing of the larger patch set of which
this is a part by Amit Langote, Rajkumar Raghuwanshi, Rafia Sabih,
Thomas Munro, Dilip Kumar, and me.
Discussion: http://postgr.es/m/CA+TgmobQK80vtXjAsPZWWXd7c8u13G86gmuLupN+uUJjA+i4nA@mail.gmail.com
The previous message didn't mention the name of the table or the
bounds. Put the table name in the primary error message and the
bounds in the detail message.
Amit Langote, changed slightly by me. Suggestions on the exac
phrasing from Tom Lane, David G. Johnston, and Dean Rasheed.
Discussion: http://postgr.es/m/CA+Tgmoae6bpwVa-1BMaVcwvCCeOoJ5B9Q9-RHWo-1gJxfPBZ5Q@mail.gmail.com
Otherwise, partitioned tables with RETURNING expressions or subject
to a WITH CHECK OPTION do not work properly.
Amit Langote, reviewed by Amit Khandekar and Etsuro Fujita. A few
comment changes by me.
Discussion: http://postgr.es/m/9a39df80-871e-6212-0684-f93c83be4097@lab.ntt.co.jp
Add error checks in some places that were calling get_opfamily_member
or get_opfamily_proc and just assuming that the call could never fail.
Also, standardize the wording for such errors in some other places.
None of these errors are expected in normal use, hence they're just
elog not ereport. But they may be handy for diagnosing omissions in
custom opclasses.
Rushabh Lathia found the oversight in RelationBuildPartitionKey();
I found the others by grepping for all callers of these functions.
Discussion: https://postgr.es/m/CAGPqQf2R9Nk8htpv0FFi+FP776EwMyGuORpc9zYkZKC8sFQE3g@mail.gmail.com
Previously, UNBOUNDED meant no lower bound when used in the FROM list,
and no upper bound when used in the TO list, which was OK for
single-column range partitioning, but problematic with multiple
columns. For example, an upper bound of (10.0, UNBOUNDED) would not be
collocated with a lower bound of (10.0, UNBOUNDED), thus making it
difficult or impossible to define contiguous multi-column range
partitions in some cases.
Fix this by using MINVALUE and MAXVALUE instead of UNBOUNDED to
represent a partition column that is unbounded below or above
respectively. This syntax removes any ambiguity, and ensures that if
one partition's lower bound equals another partition's upper bound,
then the partitions are contiguous.
Also drop the constraint prohibiting finite values after an unbounded
column, and just document the fact that any values after MINVALUE or
MAXVALUE are ignored. Previously it was necessary to repeat UNBOUNDED
multiple times, which was needlessly verbose.
Note: Forces a post-PG 10 beta2 initdb.
Report by Amul Sul, original patch by Amit Langote with some
additional hacking by me.
Discussion: https://postgr.es/m/CAAJ_b947mowpLdxL3jo3YLKngRjrq9+Ej4ymduQTfYR+8=YAYQ@mail.gmail.com
partition_rbound_cmp() is intended to compare range partition bounds
in a way such that if all the bound values are equal but one is an
upper bound and one is a lower bound, the upper bound is treated as
smaller than the lower bound. This particular ordering is required by
RelationBuildPartitionDesc() when building the PartitionBoundInfoData,
so that it can consistently keep only the upper bounds when upper and
lower bounds coincide.
Update the function comment to make that clearer.
Also, fix a (currently unreachable) corner-case bug -- if the bound
values coincide and they contain unbounded values, fall through to the
lower-vs-upper comparison code, rather than immediately returning
0. Currently it is not possible to define coincident upper and lower
bounds containing unbounded columns, but that may change in the
future, so code defensively.
Discussion: https://postgr.es/m/CAAJ_b947mowpLdxL3jo3YLKngRjrq9+Ej4ymduQTfYR+8=YAYQ@mail.gmail.com
The previous logic, whilst not actually wrong, was overly complex and
involved doing two binary searches, where only one was really
necessary. This simplifies that logic and improves the comments.
One visible change is that if the new partition overlaps multiple
existing partitions, the error message now always reports the overlap
with the first existing partition (the one with the lowest
bounds). The old code would sometimes report the clash with the first
partition and sometimes with the last one.
Original patch idea from Amit Langote, substantially rewritten by me.
Discussion: https://postgr.es/m/CAAJ_b947mowpLdxL3jo3YLKngRjrq9+Ej4ymduQTfYR+8=YAYQ@mail.gmail.com
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.
By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis. However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent. That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.
This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
Tom Lane
Alvaro Herrera
Robert Haas
Peter Eisentraut
Bruce Momjian
Magnus Hagander
Dean Rasheed