One would have needed out-of-tree code to observe the defects. Remove
unreferenced fields instead of completing their support functions.
Since in-tree code can't reach _readIntoClause(), no catversion bump.
This is still using the 2.0 version of pg_bsd_indent.
I thought it would be good to commit this separately,
so as to document the differences between 2.0 and 2.1 behavior.
Discussion: https://postgr.es/m/16296.1558103386@sss.pgh.pa.us
Commit 41b54ba78e allowed existing VACUUM options to take a boolean
argument. It's documented that valid boolean values that VACUUM can
accept are true, false, on, off, 1, and 0. But previously the parser
failed to accept 1 and 0 as a boolean value in VACUUM syntax because
of a lack of NumericOnly clause for vac_analyze_option_arg in gram.y.
This commit adds such NumericOnly clause so that VACUUM options
can take also 1 and 0 as a boolean value.
Discussion: https://postgr.es/m/CAHGQGwGYg82A8UCQxZe7Zn9MnyUBGdyB=1CNpKF3jBny+RbyfA@mail.gmail.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
Up to now, DefineIndex() was responsible for adding attnotnull constraints
to the columns of a primary key, in any case where it hadn't been
convenient for transformIndexConstraint() to mark those columns as
is_not_null. It (or rather its minion index_check_primary_key) did this
by executing an ALTER TABLE SET NOT NULL command for the target table.
The trouble with this solution is that if we're creating the index due
to ALTER TABLE ADD PRIMARY KEY, and the outer ALTER TABLE has additional
sub-commands, the inner ALTER TABLE's operations executed at the wrong
time with respect to the outer ALTER TABLE's operations. In particular,
the inner ALTER would perform a validation scan at a point where the
table's storage might be inconsistent with its catalog entries. (This is
on the hairy edge of being a security problem, but AFAICS it isn't one
because the inner scan would only be interested in the tuples' null
bitmaps.) This can result in unexpected failures, such as the one seen
in bug #15580 from Allison Kaptur.
To fix, let's remove the attempt to do SET NOT NULL from DefineIndex(),
reducing index_check_primary_key's role to verifying that the columns are
already not null. (It shouldn't ever see such a case, but it seems wise
to keep the check for safety.) Instead, make transformIndexConstraint()
generate ALTER TABLE SET NOT NULL subcommands to be executed ahead of
the ADD PRIMARY KEY operation in every case where it can't force the
column to be created already-not-null. This requires only minor surgery
in parse_utilcmd.c, and it makes for a much more satisfying spec for
transformIndexConstraint(): it's no longer having to take it on faith
that someone else will handle addition of NOT NULL constraints.
To make that work, we have to move the execution of AT_SetNotNull into
an ALTER pass that executes ahead of AT_PASS_ADD_INDEX. I moved it to
AT_PASS_COL_ATTRS, and put that after AT_PASS_ADD_COL to avoid failure
when the column is being added in the same command. This incidentally
fixes a bug in the only previous usage of AT_PASS_COL_ATTRS, for
AT_SetIdentity: it didn't work either for a newly-added column.
Playing around with this exposed a separate bug in ALTER TABLE ONLY ...
ADD PRIMARY KEY for partitioned tables. The intent of the ONLY modifier
in that context is to prevent doing anything that would require holding
lock for a long time --- but the implied SET NOT NULL would recurse to
the child partitions, and do an expensive validation scan for any child
where the column(s) were not already NOT NULL. To fix that, invent a
new ALTER subcommand AT_CheckNotNull that just insists that a child
column be already NOT NULL, and apply that, not AT_SetNotNull, when
recursing to children in this scenario. This results in a slightly laxer
definition of ALTER TABLE ONLY ... SET NOT NULL for partitioned tables,
too: that command will now work as long as all children are already NOT
NULL, whereas before it just threw up its hands if there were any
partitions.
In passing, clean up the API of generateClonedIndexStmt(): remove a
useless argument, ensure that the output argument is not left undefined,
update the header comment.
A small side effect of this change is that no-such-column errors in ALTER
TABLE ADD PRIMARY KEY now produce a different message that includes the
table name, because they are now detected by the SET NOT NULL step which
has historically worded its error that way. That seems fine to me, so
I didn't make any effort to avoid the wording change.
The basic bug #15580 is of very long standing, and these other bugs
aren't new in v12 either. However, this is a pretty significant change
in the way ALTER TABLE ADD PRIMARY KEY works. On balance it seems best
not to back-patch, at least not till we get some more confidence that
this patch has no new bugs.
Patch by me, but thanks to Jie Zhang for a preliminary version.
Discussion: https://postgr.es/m/15580-d1a6de5a3d65da51@postgresql.org
Discussion: https://postgr.es/m/1396E95157071C4EBBA51892C5368521017F2E6E63@G08CNEXMBPEKD02.g08.fujitsu.local
The syntax
GENERATED BY DEFAULT AS (expr)
is not allowed but we have to accept it in the grammar to avoid
shift/reduce conflicts because of the similar syntax for identity
columns. The existing code just ignored this, incorrectly. Add an
explicit error check and a bespoke error message.
Reported-by: Justin Pryzby <pryzby@telsasoft.com>
This is an SQL-standard feature that allows creating columns that are
computed from expressions rather than assigned, similar to a view or
materialized view but on a column basis.
This implements one kind of generated column: stored (computed on
write). Another kind, virtual (computed on read), is planned for the
future, and some room is left for it.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com
This adds the CONCURRENTLY option to the REINDEX command. A REINDEX
CONCURRENTLY on a specific index creates a new index (like CREATE
INDEX CONCURRENTLY), then renames the old index away and the new index
in place and adjusts the dependencies, and then drops the old
index (like DROP INDEX CONCURRENTLY). The REINDEX command also has
the capability to run its other variants (TABLE, DATABASE) with the
CONCURRENTLY option (but not SYSTEM).
The reindexdb command gets the --concurrently option.
Author: Michael Paquier, Andreas Karlsson, Peter Eisentraut
Reviewed-by: Andres Freund, Fujii Masao, Jim Nasby, Sergei Kornilov
Discussion: https://www.postgresql.org/message-id/flat/60052986-956b-4478-45ed-8bd119e9b9cf%402ndquadrant.com#74948a1044c56c5e817a5050f554ddee
Introduce a third extended statistic type, supported by the CREATE
STATISTICS command - MCV lists, a generalization of the statistic
already built and used for individual columns.
Compared to the already supported types (n-distinct coefficients and
functional dependencies), MCV lists are more complex, include column
values and allow estimation of much wider range of common clauses
(equality and inequality conditions, IS NULL, IS NOT NULL etc.).
Similarly to the other types, a new pseudo-type (pg_mcv_list) is used.
Author: Tomas Vondra
Reviewed-by: Dean Rasheed, David Rowley, Mark Dilger, Alvaro Herrera
Discussion: https://postgr.es/m/dfdac334-9cf2-2597-fb27-f0fb3753f435@2ndquadrant.com
Column references are not allowed in default expressions and partition
bound expressions, and are restricted as such once the transformation of
their expressions is done. However, trying to use more complex column
references can lead to confusing error messages. For example, trying to
use a two-field column reference name for default expressions and
partition bounds leads to "missing FROM-clause entry for table", which
makes no sense in their respective context.
In order to make the errors generated more useful, this commit adds more
verbose messages when transforming column references depending on the
context. This has a little consequence though: for example an
expression using an aggregate with a column reference as argument would
cause an error to be generated for the column reference, while the
aggregate was the problem reported before this commit because column
references get transformed first.
The confusion exists for default expressions for a long time, and the
problem is new as of v12 for partition bounds. Still per the lack of
complaints on the matter no backpatch is done.
The patch has been written by Amit Langote and me, and Tom Lane has
provided the improvement of the documentation for default expressions on
the CREATE TABLE page.
Author: Amit Langote, Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20190326020853.GM2558@paquier.xyz
Since 7c079d7, partition bounds are able to use generalized expression
syntax when processed, treating "minvalue" and "maxvalue" as specific
cases as they get passed down for transformation as a column references.
The checks for infinite bounds in range expressions have been lax
though, causing crashes when trying to use column reference names with
more than one field. Here is an example causing a crash:
CREATE TABLE list_parted (a int) PARTITION BY LIST (a);
CREATE TABLE part_list_crash PARTITION OF list_parted
FOR VALUES IN (somename.somename);
Note that the creation of the second relation should fail as partition
bounds cannot have column references in their expressions, so when
finding an expression which does not match the expected infinite bounds,
then this commit lets the generic transformation machinery check after
it. The error message generated in this case references as well a
missing RTE, which is confusing. This problem will be treated
separately as it impacts as well default expressions for some time, and
for now only the cases where a crash can happen are fixed.
While on it, extend the set of regression tests in place for list
partition bounds and add an extra set for range partition bounds.
Reported-by: Alexander Lakhin
Author: Michael Paquier
Reviewed-by: Amit Langote
Discussion: https://postgr.es/m/15668-0377b1981aa1a393@postgresql.org
Add command variants COMMIT AND CHAIN and ROLLBACK AND CHAIN, which
start new transactions with the same transaction characteristics as the
just finished one, per SQL standard.
Support for transaction chaining in PL/pgSQL is also added. This
functionality is especially useful when running COMMIT in a loop in
PL/pgSQL.
Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>
Discussion: https://www.postgresql.org/message-id/flat/28536681-324b-10dc-ade8-ab46f7645a5a@2ndquadrant.com
These commands allow the argument type list to be omitted if there is
just one object that matches by name. However, if that syntax was
used with DROP IF EXISTS and there was more than one match, you got
a "function ... does not exist, skipping" notice message rather than a
truthful complaint about the ambiguity. This was basically due to
poor factorization and a rats-nest of logic, so refactor the relevant
lookup code to make it cleaner.
Note that this amounts to narrowing the scope of which sorts of
error conditions IF EXISTS will bypass. Per discussion, we only
intend it to skip no-such-object cases, not multiple-possible-matches
cases.
Per bug #15572 from Ash Marath. Although this definitely seems like
a bug, it's not clear that people would thank us for changing the
behavior in minor releases, so no back-patch.
David Rowley, reviewed by Julien Rouhaud and Pavel Stehule
Discussion: https://postgr.es/m/15572-ed1b9ed09503de8a@postgresql.org
Aggregates have acquired a dozen or so optional attributes in recent
years for things like parallel query and moving-aggregate mode; the
lack of an OR REPLACE option to add or change these for an existing
agg makes extension upgrades gratuitously hard. Rectify.
Like commit f41551f61f, this aims
to make it easier to add non-Boolean options to VACUUM (or, in
this case, to ANALYZE). Instead of building up a bitmap of
options directly in the parser, build up a list of DefElem
objects and let ExecVacuum() sort it out; right now, we make
no use of the fact that a DefElem can carry an associated value,
but it will be easy to make that change in the future.
Masahiko Sawada
Discussion: http://postgr.es/m/CAD21AoATE4sn0jFFH3NcfUZXkU2BMbjBWB_kDj-XWYA-LXDcQA@mail.gmail.com
This clause is used to indicate the passing mode of a XML document, but
we were doing it wrong: we accepted BY REF and ignored it, and rejected
BY VALUE as a syntax error. The reality, however, is that documents are
always passed BY VALUE, so rejecting that clause was silly. Change
things so that we accept BY VALUE.
BY REF continues to be accepted, and continues to be ignored.
Author: Chapman Flack
Reviewed-by: Pavel Stehule
Discussion: https://postgr.es/m/5C297BB7.9070509@anastigmatix.net
This introduces the concept of table access methods, i.e. CREATE
ACCESS METHOD ... TYPE TABLE and
CREATE TABLE ... USING (storage-engine).
No table access functionality is delegated to table AMs as of this
commit, that'll be done in following commits.
Subsequent commits will incrementally abstract table access
functionality to be routed through table access methods. That change
is too large to be reviewed & committed at once, so it'll be done
incrementally.
Docs will be updated at the end, as adding them incrementally would
likely make them less coherent, and definitely is a lot more work,
without a lot of benefit.
Table access methods are specified similar to index access methods,
i.e. pg_am.amhandler returns, as INTERNAL, a pointer to a struct with
callbacks. In contrast to index AMs that struct needs to live as long
as a backend, typically that's achieved by just returning a pointer to
a constant struct.
Psql's \d+ now displays a table's access method. That can be disabled
with HIDE_TABLEAM=true, which is mainly useful so regression tests can
be run against different AMs. It's quite possible that this behaviour
still needs to be fine tuned.
For now it's not allowed to set a table AM for a partitioned table, as
we've not resolved how partitions would inherit that. Disallowing
allows us to introduce, if we decide that's the way forward, such a
behaviour without a compatibility break.
Catversion bumped, to add the heap table AM and references to it.
Author: Haribabu Kommi, Andres Freund, Alvaro Herrera, Dimitri Golgov and others
Discussion:
https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.dehttps://postgr.es/m/20160812231527.GA690404@alvherre.pgsqlhttps://postgr.es/m/20190107235616.6lur25ph22u5u5av@alap3.anarazel.dehttps://postgr.es/m/20190304234700.w5tmhducs5wxgzls@alap3.anarazel.de
We have forboth() and forthree() macros that simplify iterating
through several parallel lists, but not everyplace that could
reasonably use those was doing so. Also invent forfour() and
forfive() macros to do the same for four or five parallel lists,
and use those where applicable.
The immediate motivation for doing this is to reduce the number
of ad-hoc lnext() calls, to reduce the footprint of a WIP patch.
However, it seems like good cleanup and error-proofing anyway;
the places that were combining forthree() with a manually iterated
loop seem particularly illegible and bug-prone.
There was some speculation about restructuring related parsetree
representations to reduce the need for parallel list chasing of
this sort. Perhaps that's a win, or perhaps not, but in any case
it would be considerably more invasive than this patch; and it's
not particularly related to my immediate goal of improving the
List infrastructure. So I'll leave that question for another day.
Patch by me; thanks to David Rowley for review.
Discussion: https://postgr.es/m/11587.1550975080@sss.pgh.pa.us
The Bison documentation clearly states that a semicolon is required
after every grammar rule, and our scripts that generate ecpg's
grammar from the backend's implicitly assumed this is true. But it
turns out that only ancient versions of Bison actually enforce that.
There have been a couple of rules without trailing semicolons in
gram.y for some time, and as a consequence, ecpg's grammar was faulty
and produced wrong output for the affected statements.
To fix, add the missing semis, and add some cross-checks to ecpg's
scripts so that they'll bleat if we mess this up again.
The cases that were broken were:
* "SET variable = DEFAULT" (but not "SET variable TO DEFAULT"),
as well as allied syntaxes such as ALTER SYSTEM SET ... DEFAULT.
These produced syntactically invalid output that the server
would reject.
* Multiple type names in DROP TYPE/DOMAIN commands. Only the
first type name would be listed in the emitted command.
Per report from Daisuke Higuchi. Back-patch to all supported versions.
Discussion: https://postgr.es/m/1803D792815FC24D871C00D17AE95905DB51CE@g01jpexmbkw24
Historically we've always materialized the full output of a CTE query,
treating WITH as an optimization fence (so that, for example, restrictions
from the outer query cannot be pushed into it). This is appropriate when
the CTE query is INSERT/UPDATE/DELETE, or is recursive; but when the CTE
query is non-recursive and side-effect-free, there's no hazard of changing
the query results by pushing restrictions down.
Another argument for materialization is that it can avoid duplicate
computation of an expensive WITH query --- but that only applies if
the WITH query is called more than once in the outer query. Even then
it could still be a net loss, if each call has restrictions that
would allow just a small part of the WITH query to be computed.
Hence, let's change the behavior for WITH queries that are non-recursive
and side-effect-free. By default, we will inline them into the outer
query (removing the optimization fence) if they are called just once.
If they are called more than once, we will keep the old behavior by
default, but the user can override this and force inlining by specifying
NOT MATERIALIZED. Lastly, the user can force the old behavior by
specifying MATERIALIZED; this would mainly be useful when the query had
deliberately been employing WITH as an optimization fence to prevent a
poor choice of plan.
Andreas Karlsson, Andrew Gierth, David Fetter
Discussion: https://postgr.es/m/87sh48ffhb.fsf@news-spur.riddles.org.uk
The grammar IF NOT EXISTS for CTAS is supported since 9.5 and documented
as such, however the case of using EXECUTE as query has never been
covered as EXECUTE CTAS statements and normal CTAS statements are parsed
separately.
Author: Andreas Karlsson
Discussion: https://postgr.es/m/2ddcc188-e37c-a0be-32bf-a56b07c3559e@proxel.se
Backpatch-through: 9.5
Rename/repurpose pg_proc.protransform as "prosupport". The idea is
still that it names an internal function that provides knowledge to
the planner about the behavior of the function it's attached to;
but redesign the API specification so that it's not limited to doing
just one thing, but can support an extensible set of requests.
The original purpose of simplifying a function call is handled by
the first request type to be invented, SupportRequestSimplify.
Adjust all the existing transform functions to handle this API,
and rename them fron "xxx_transform" to "xxx_support" to reflect
the potential generalization of what they do. (Since we never
previously provided any way for extensions to add transform functions,
this change doesn't create an API break for them.)
Also add DDL and pg_dump support for attaching a support function to a
user-defined function. Unfortunately, DDL access has to be restricted
to superusers, at least for now; but seeing that support functions
will pretty much have to be written in C, that limitation is just
theoretical. (This support is untested in this patch, but a follow-on
patch will add cases that exercise it.)
Discussion: https://postgr.es/m/15193.1548028093@sss.pgh.pa.us
We can't allow these pseudo-types to be used as table column types,
because storing an anonymous record value in a table would result
in data that couldn't be understood by other sessions. However,
it seems like there's no harm in allowing the case in a column
definition list that's specifying what a function-returning-record
returns. The data involved is all local to the current session,
so we should be just as able to resolve its actual tuple type as
we are for the function-returning-record's top-level tuple output.
Elvis Pranskevichus, with cosmetic changes by me
Discussion: https://postgr.es/m/11038447.kQ5A9Uj5xi@hammer.magicstack.net
Create a new header optimizer/optimizer.h, which exposes just the
planner functions that can be used "at arm's length", without need
to access Paths or the other planner-internal data structures defined
in nodes/relation.h. This is intended to provide the whole planner
API seen by most of the rest of the system; although FDWs still need
to use additional stuff, and more thought is also needed about just
what selfuncs.c should rely on.
The main point of doing this now is to limit the amount of new
#include baggage that will be needed by "planner support functions",
which I expect to introduce later, and which will be in relevant
datatype modules rather than anywhere near the planner.
This commit just moves relevant declarations into optimizer.h from
other header files (a couple of which go away because everything
got moved), and adjusts #include lists to match. There's further
cleanup that could be done if we want to decide that some stuff
being exposed by optimizer.h doesn't belong in the planner at all,
but I'll leave that for another day.
Discussion: https://postgr.es/m/11460.1548706639@sss.pgh.pa.us
Move a few very simple node-creation and node-type-testing functions
from the planner's clauses.c to nodes/makefuncs and nodes/nodeFuncs.
There's nothing planner-specific about them, as evidenced by the
number of other places that were using them.
While at it, rename and_clause() etc to is_andclause() etc, to clarify
that they are node-type-testing functions not node-creation functions.
And use "static inline" implementations for the shortest ones.
Also, modify flatten_join_alias_vars() and some subsidiary functions
to take a Query not a PlannerInfo to define the join structure that
Vars should be translated according to. They were only using the
"parse" field of the PlannerInfo anyway, so this just requires removing
one level of indirection. The advantage is that now parse_agg.c can
use flatten_join_alias_vars() without the horrid kluge of creating an
incomplete PlannerInfo, which will allow that file to be decoupled from
relation.h in a subsequent patch.
Discussion: https://postgr.es/m/11460.1548706639@sss.pgh.pa.us
The fact that "SELECT expression" has no base relations has long been a
thorn in the side of the planner. It makes it hard to flatten a sub-query
that looks like that, or is a trivial VALUES() item, because the planner
generally uses relid sets to identify sub-relations, and such a sub-query
would have an empty relid set if we flattened it. prepjointree.c contains
some baroque logic that works around this in certain special cases --- but
there is a much better answer. We can replace an empty FROM clause with a
dummy RTE that acts like a table of one row and no columns, and then there
are no such corner cases to worry about. Instead we need some logic to
get rid of useless dummy RTEs, but that's simpler and covers more cases
than what was there before.
For really trivial cases, where the query is just "SELECT expression" and
nothing else, there's a hazard that adding the extra RTE makes for a
noticeable slowdown; even though it's not much processing, there's not
that much for the planner to do overall. However testing says that the
penalty is very small, close to the noise level. In more complex queries,
this is able to find optimizations that we could not find before.
The new RTE type is called RTE_RESULT, since the "scan" plan type it
gives rise to is a Result node (the same plan we produced for a "SELECT
expression" query before). To avoid confusion, rename the old ResultPath
path type to GroupResultPath, reflecting that it's only used in degenerate
grouping cases where we know the query produces just one grouped row.
(It wouldn't work to unify the two cases, because there are different
rules about where the associated quals live during query_planner.)
Note: although this touches readfuncs.c, I don't think a catversion
bump is required, because the added case can't occur in stored rules,
only plans.
Patch by me, reviewed by David Rowley and Mark Dilger
Discussion: https://postgr.es/m/15944.1521127664@sss.pgh.pa.us
Previously, only literals were allowed. This change allows general
expressions, including functions calls, which are evaluated at the
time the DDL command is executed.
Besides offering some more functionality, it simplifies the parser
structures and removes some inconsistencies in how the literals were
handled.
Author: Kyotaro Horiguchi, Tom Lane, Amit Langote
Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/9f88b5e0-6da2-5227-20d0-0d7012beaa1c@lab.ntt.co.jp/
Extends the COPY FROM command with a WHERE condition, which allows doing
various types of filtering while importing the data (random sampling,
condition on a data column, etc.). Until now such filtering required
either preprocessing of the input data, or importing all data and then
filtering in the database. COPY FROM ... WHERE is an easy-to-use and
low-overhead alternative for most simple cases.
Author: Surafel Temesgen
Reviewed-by: Tomas Vondra, Masahiko Sawada, Lim Myungkyu
Discussion: https://www.postgresql.org/message-id/flat/CALAY4q_DdpWDuB5-Zyi-oTtO2uSk8pmy+dupiRe3AvAc++1imA@mail.gmail.com
Previously, parseCheckAggregates was run before
assign_query_collations, but this causes problems if any expression
has already had a collation assigned by some transform function (e.g.
transformCaseExpr) before parseCheckAggregates runs. The differing
collations would cause expressions not to be recognized as equal to
the ones in the GROUP BY clause, leading to spurious errors about
unaggregated column references.
The result was that CASE expr WHEN val ... would fail when "expr"
contained a GROUPING() expression or matched one of the group by
expressions, and where collatable types were involved; whereas the
supposedly identical CASE WHEN expr = val ... would succeed.
Backpatch all the way; this appears to have been wrong ever since
collations were introduced.
Per report from Guillaume Lelarge, analysis and patch by me.
Discussion: https://postgr.es/m/CAECtzeVSO_US8C2Khgfv54ZMUOBR4sWq+6_bLrETnWExHT=rFg@mail.gmail.com
Discussion: https://postgr.es/m/87muo0k0c7.fsf@news-spur.riddles.org.uk
heapam.h previously was included in a number of widely used
headers (e.g. execnodes.h, indirectly in executor.h, ...). That's
problematic on its own, as heapam.h contains a lot of low-level
details that don't need to be exposed that widely, but becomes more
problematic with the upcoming introduction of pluggable table storage
- it seems inappropriate for heapam.h to be included that widely
afterwards.
heapam.h was largely only included in other headers to get the
HeapScanDesc typedef (which was defined in heapam.h, even though
HeapScanDescData is defined in relscan.h). The better solution here
seems to be to just use the underlying struct (forward declared where
necessary). Similar for BulkInsertState.
Another problem was that LockTupleMode was used in executor.h - parts
of the file tried to cope without heapam.h, but due to the fact that
it indirectly included it, several subsequent violations of that goal
were not not noticed. We could just reuse the approach of declaring
parameters as int, but it seems nicer to move LockTupleMode to
lockoptions.h - that's not a perfect location, but also doesn't seem
bad.
As a number of files relied on implicitly included heapam.h, a
significant number of files grew an explicit include. It's quite
probably that a few external projects will need to do the same.
Author: Andres Freund
Reviewed-By: Alvaro Herrera
Discussion: https://postgr.es/m/20190114000701.y4ttcb74jpskkcfb@alap3.anarazel.de
Previously, ScanKeywordLookup was passed an array of string pointers.
This had some performance deficiencies: the strings themselves might
be scattered all over the place depending on the compiler (and some
quick checking shows that at least with gcc-on-Linux, they indeed
weren't reliably close together). That led to very cache-unfriendly
behavior as the binary search touched strings in many different pages.
Also, depending on the platform, the string pointers might need to
be adjusted at program start, so that they couldn't be simple constant
data. And the ScanKeyword struct had been designed with an eye to
32-bit machines originally; on 64-bit it requires 16 bytes per
keyword, making it even more cache-unfriendly.
Redesign so that the keyword strings themselves are allocated
consecutively (as part of one big char-string constant), thereby
eliminating the touch-lots-of-unrelated-pages syndrome. And get
rid of the ScanKeyword array in favor of three separate arrays:
uint16 offsets into the keyword array, uint16 token codes, and
uint8 keyword categories. That reduces the overhead per keyword
to 5 bytes instead of 16 (even less in programs that only need
one of the token codes and categories); moreover, the binary search
only touches the offsets array, further reducing its cache footprint.
This also lets us put the token codes somewhere else than the
keyword strings are, which avoids some unpleasant build dependencies.
While we're at it, wrap the data used by ScanKeywordLookup into
a struct that can be treated as an opaque type by most callers.
That doesn't change things much right now, but it will make it
less painful to switch to a hash-based lookup method, as is being
discussed in the mailing list thread.
Most of the change here is associated with adding a generator
script that can build the new data structure from the same
list-of-PG_KEYWORD header representation we used before.
The PG_KEYWORD lists that plpgsql and ecpg used to embed in
their scanner .c files have to be moved into headers, and the
Makefiles have to be taught to invoke the generator script.
This work is also necessary if we're to consider hash-based lookup,
since the generator script is what would be responsible for
constructing a hash table.
Aside from saving a few kilobytes in each program that includes
the keyword table, this seems to speed up raw parsing (flex+bison)
by a few percent. So it's worth doing even as it stands, though
we think we can gain even more with a follow-on patch to switch
to hash-based lookup.
John Naylor, with further hacking by me
Discussion: https://postgr.es/m/CAJVSVGXdFVU2sgym89XPL=Lv1zOS5=EHHQ8XWNzFL=mTXkKMLw@mail.gmail.com
In commit 8b08f7d482 I added member relationId to IndexStmt struct.
I'm now not sure why; DefineIndex doesn't need it, since the relation
OID is passed as a separate argument anyway. Remove it.
Also remove a redundant assignment to the relationId argument (it wasn't
redundant when added by commit e093dcdd28, but should have been removed
in commit 5f173040e3), and use relationId instead of stmt->relation when
locking the relation in the second phase of CREATE INDEX CONCURRENTLY,
which is not only confusing but it means we resolve the name twice for
no reason.
The "name" comparison operators now all support collations, making them
functionally equivalent to "text" comparisons, except for the different
physical representation of the datatype. They do, in fact, mostly share
the varstr_cmp and varstr_sortsupport infrastructure, which has been
slightly enlarged to handle the case.
To avoid changes in the default behavior of the datatype, set name's
typcollation to C_COLLATION_OID not DEFAULT_COLLATION_OID, so that
by default comparisons to a name value will continue to use strcmp
semantics. (This would have been the case for system catalog columns
anyway, because of commit 6b0faf723, but doing this makes it true for
user-created name columns as well. In particular, this avoids
locale-dependent changes in our regression test results.)
In consequence, tweak a couple of places that made assumptions about
collatable base types always having typcollation DEFAULT_COLLATION_OID.
I have not, however, attempted to relax the restriction that user-
defined collatable types must have that. Hence, "name" doesn't
behave quite like a user-defined type; it acts more like a domain
with COLLATE "C". (Conceivably, if we ever get rid of the need for
catalog name columns to be fixed-length, "name" could actually become
such a domain over text. But that'd be a pretty massive undertaking,
and I'm not volunteering.)
Discussion: https://postgr.es/m/15938.1544377821@sss.pgh.pa.us
Previously tables declared WITH OIDS, including a significant fraction
of the catalog tables, stored the oid column not as a normal column,
but as part of the tuple header.
This special column was not shown by default, which was somewhat odd,
as it's often (consider e.g. pg_class.oid) one of the more important
parts of a row. Neither pg_dump nor COPY included the contents of the
oid column by default.
The fact that the oid column was not an ordinary column necessitated a
significant amount of special case code to support oid columns. That
already was painful for the existing, but upcoming work aiming to make
table storage pluggable, would have required expanding and duplicating
that "specialness" significantly.
WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0).
Remove it.
Removing includes:
- CREATE TABLE and ALTER TABLE syntax for declaring the table to be
WITH OIDS has been removed (WITH (oids[ = true]) will error out)
- pg_dump does not support dumping tables declared WITH OIDS and will
issue a warning when dumping one (and ignore the oid column).
- restoring an pg_dump archive with pg_restore will warn when
restoring a table with oid contents (and ignore the oid column)
- COPY will refuse to load binary dump that includes oids.
- pg_upgrade will error out when encountering tables declared WITH
OIDS, they have to be altered to remove the oid column first.
- Functionality to access the oid of the last inserted row (like
plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed.
The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false)
for CREATE TABLE) is still supported. While that requires a bit of
support code, it seems unnecessary to break applications / dumps that
do not use oids, and are explicit about not using them.
The biggest user of WITH OID columns was postgres' catalog. This
commit changes all 'magic' oid columns to be columns that are normally
declared and stored. To reduce unnecessary query breakage all the
newly added columns are still named 'oid', even if a table's column
naming scheme would indicate 'reloid' or such. This obviously
requires adapting a lot code, mostly replacing oid access via
HeapTupleGetOid() with access to the underlying Form_pg_*->oid column.
The bootstrap process now assigns oids for all oid columns in
genbki.pl that do not have an explicit value (starting at the largest
oid previously used), only oids assigned later by oids will be above
FirstBootstrapObjectId. As the oid column now is a normal column the
special bootstrap syntax for oids has been removed.
Oids are not automatically assigned during insertion anymore, all
backend code explicitly assigns oids with GetNewOidWithIndex(). For
the rare case that insertions into the catalog via SQL are called for
the new pg_nextoid() function can be used (which only works on catalog
tables).
The fact that oid columns on system tables are now normal columns
means that they will be included in the set of columns expanded
by * (i.e. SELECT * FROM pg_class will now include the table's oid,
previously it did not). It'd not technically be hard to hide oid
column by default, but that'd mean confusing behavior would either
have to be carried forward forever, or it'd cause breakage down the
line.
While it's not unlikely that further adjustments are needed, the
scope/invasiveness of the patch makes it worthwhile to get merge this
now. It's painful to maintain externally, too complicated to commit
after the code code freeze, and a dependency of a number of other
patches.
Catversion bump, for obvious reasons.
Author: Andres Freund, with contributions by John Naylor
Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
The realfail1 and realfail2 backup-prevention rules always returned
token type FCONST, ignoring the possibility that what we've scanned
is more appropriately described as ICONST. I think that at the
time that code was added, it might actually have been safe to not
distinguish; but since we started allowing AS-less aliases in SELECT
target lists, it's definitely legal to have a number immediately
followed by an identifier.
In the SELECT case, it seems there's no visible consequence because
make_const() will change the type back to integer anyway. But I'm
worried that there are other contexts, or will be in future, where
it's more important to get the constant's type right.
Hence, use process_integer_literal to correctly determine which
token type to return.
Arguably this is a bug fix, but given the lack of evidence of
user-visible problems, I'll refrain from back-patching.
Discussion: https://postgr.es/m/21364.1542136808@sss.pgh.pa.us
Michael Paquier
Noah Misch
Tom Lane
Fujii Masao
Alvaro Herrera
Peter Eisentraut
Robert Haas
Tomas Vondra
Andrew Gierth
Andres Freund
Heikki Linnakangas
Bruce Momjian
Peter Eisentraut