This patch adjusts the core statistics views to match the decision already
taken for pg_stat_statements, that values representing elapsed time should
be represented as float8 and measured in milliseconds. By using float8,
we are no longer tied to a specific maximum precision of timing data.
(Internally, it's still microseconds, but we could now change that without
needing changes at the SQL level.)
The columns affected are
pg_stat_bgwriter.checkpoint_write_time
pg_stat_bgwriter.checkpoint_sync_time
pg_stat_database.blk_read_time
pg_stat_database.blk_write_time
pg_stat_user_functions.total_time
pg_stat_user_functions.self_time
pg_stat_xact_user_functions.total_time
pg_stat_xact_user_functions.self_time
The first four of these are new in 9.2, so there is no compatibility issue
from changing them. The others require a release note comment that they
are now double precision (and can show a fractional part) rather than
bigint as before; also their underlying statistics functions now match
the column definitions, instead of returning bigint microseconds.
The original syntax wasn't universally loved, and it didn't allow its
usage in CREATE TABLE, only ALTER TABLE. It now works everywhere, and
it also allows using ALTER TABLE ONLY to add an uninherited CHECK
constraint, per discussion.
The pg_constraint column has accordingly been renamed connoinherit.
This commit partly reverts some of the changes in
61d81bd28d, particularly some pg_dump and
psql bits, because now pg_get_constraintdef includes the necessary NO
INHERIT within the constraint definition.
Author: Nikhil Sontakke
Some tweaks by me
Previously we attempted to throw an error or at least warning for missing
schemas, but this was done inconsistently because of implementation
restrictions (in many cases, GUC settings are applied outside transactions
so that we can't do system catalog lookups). Furthermore, there were
exceptions to the rule even in the beginning, and we'd been poking more
and more holes in it as time went on, because it turns out that there are
lots of use-cases for having some irrelevant items in a common search_path
value. It seems better to just adopt a philosophy similar to what's always
been done with Unix PATH settings, wherein nonexistent or unreadable
directories are silently ignored.
This commit also fixes the documentation to point out that schemas for
which the user lacks USAGE privilege are silently ignored. That's always
been true but was previously not documented.
This is mostly in response to Robert Haas' complaint that 9.1 started to
throw errors or warnings for missing schemas in cases where prior releases
had not. We won't adopt such a significant behavioral change in a back
branch, so something different will be needed in 9.1.
Ants Aasma's original patch to add timing information for buffer I/O
requests exposed this data at the relation level, which was judged too
costly. I've here exposed it at the database level instead.
We have always created a whole-table dependency for the target relation,
but that's not really good enough, as it doesn't prevent scenarios such
as dropping an individual target column or altering its type. So we
have to create an individual dependency for each target column, as well.
Per report from Bill MacArthur of a rule containing UPDATE breaking
after such an alteration. Note that this patch doesn't try to make
such cases work, only to ensure that the attempted ALTER TABLE throws
an error telling you it can't cope with adjusting the rule.
This is a long-standing bug, but given the lack of prior reports
I'm not going to risk back-patching it. A back-patch wouldn't do
anything to fix existing rules' dependency lists, anyway.
This allows loadable modules to get control at drop time, perhaps for the
purpose of performing additional security checks or to log the event.
The initial purpose of this code is to support sepgsql, but other
applications should be possible as well.
KaiGai Kohei, reviewed by me.
Phil Sorber reported that a rewriting ALTER TABLE within an extension
update script failed, because it creates and then drops a placeholder
table; the drop was being disallowed because the table was marked as an
extension member. We could hack that specific case but it seems likely
that there might be related cases now or in the future, so the most
practical solution seems to be to create an exception to the general rule
that extension member objects can only be dropped by dropping the owning
extension. To wit: if the DROP is issued within the extension's own
creation or update scripts, we'll allow it, implicitly performing an
"ALTER EXTENSION DROP object" first. This will simplify cases such as
extension downgrade scripts anyway.
No docs change since we don't seem to have documented the idea that you
would need ALTER EXTENSION DROP for such an action to begin with.
Also, arrange for explicitly temporary tables to not get linked as
extension members in the first place, and the same for the magic
pg_temp_nnn schemas that are created to hold them. This prevents assorted
unpleasant results if an extension script creates a temp table: the forced
drop at session end would either fail or remove the entire extension, and
neither of those outcomes is desirable. Note that this doesn't fix the
ALTER TABLE scenario, since the placeholder table is not temp (unless the
table being rewritten is).
Back-patch to 9.1.
This patch improves selectivity estimation for the array <@, &&, and @>
(containment and overlaps) operators. It enables collection of statistics
about individual array element values by ANALYZE, and introduces
operator-specific estimators that use these stats. In addition,
ScalarArrayOpExpr constructs of the forms "const = ANY/ALL (array_column)"
and "const <> ANY/ALL (array_column)" are estimated by treating them as
variants of the containment operators.
Since we still collect scalar-style stats about the array values as a
whole, the pg_stats view is expanded to show both these stats and the
array-style stats in separate columns. This creates an incompatible change
in how stats for tsvector columns are displayed in pg_stats: the stats
about lexemes are now displayed in the array-related columns instead of the
original scalar-related columns.
There are a few loose ends here, notably that it'd be nice to be able to
suppress either the scalar-style stats or the array-element stats for
columns for which they're not useful. But the patch is in good enough
shape to commit for wider testing.
Alexander Korotkov, reviewed by Noah Misch and Nathan Boley
The only toastable column now is datacl, but we don't really support
long ACLs anyway. The TOAST table should have been removed when the
pg_db_role_setting catalog was introduced in commit
2eda8dfb52, but I forgot to do that.
Per -hackers discussion on March 2011.
We don't normally allow quals to be pushed down into a view created
with the security_barrier option, but functions without side effects
are an exception: they're OK. This allows much better performance in
common cases, such as when using an equality operator (that might
even be indexable).
There is an outstanding issue here with the CREATE FUNCTION / ALTER
FUNCTION syntax: there's no way to use ALTER FUNCTION to unset the
leakproof flag. But I'm committing this as-is so that it doesn't
have to be rebased again; we can fix up the grammar in a future
commit.
KaiGai Kohei, with some wordsmithing by me.
The sequence USAGE privilege is sufficiently similar to the SQL
standard that it seems reasonable to show in the information schema.
Also add some compatibility notes about it on the GRANT reference
page.
Hitherto, the information schema only showed explicitly granted
privileges that were visible in the *acl catalog columns. If no
privileges had been granted, the implicit privileges were not shown.
To fix that, add an SQL-accessible version of the acldefault()
function, and use that inside the aclexplode() calls to substitute the
catalog-specific default privilege set for null values.
reviewed by Abhijit Menon-Sen
Those fields only appear in the structs so that genbki.pl can create
the BKI bootstrap files for the catalogs. But they are not actually
usable from C. So hiding them can prevent coding mistakes, saves
stack space, and can help the compiler.
In certain catalogs, the first variable-length field has been kept
visible after manual inspection. These exceptions are noted in C
comments.
reviewed by Tom Lane
This doesn't do anything useful just yet, but is intended as supporting
infrastructure for allowing sepgsql to sensibly check DROP permissions.
KaiGai Kohei and Robert Haas
Add counters for number and size of temporary files used
for spill-to-disk queries for each database to the
pg_stat_database view.
Tomas Vondra, review by Magnus Hagander
This separates the state (running/idle/idleintransaction etc) into
it's own field ("state"), and leaves the query field containing just
query text.
The query text will now mean "current query" when a query is running
and "last query" in other states. Accordingly,the field has been
renamed from current_query to query.
Since backwards compatibility was broken anyway to make that, the procpid
field has also been renamed to pid - along with the same field in
pg_stat_replication for consistency.
Scott Mead and Magnus Hagander, review work from Greg Smith
When creating a child table, or when attaching an existing table as
child of another, we must not allow inheritable constraints to be
merged with non-inheritable ones, because then grandchildren would not
properly get the constraint. This would violate the grandparent's
expectations.
Bugs noted by Robert Haas.
Author: Nikhil Sontakke
In the previous coding, it was possible for a relation to be created
via CREATE TABLE, CREATE VIEW, CREATE SEQUENCE, CREATE FOREIGN TABLE,
etc. in a schema while that schema was meanwhile being concurrently
dropped. This led to a pg_class entry with an invalid relnamespace
value. The same problem could occur if a relation was moved using
ALTER .. SET SCHEMA while the target schema was being concurrently
dropped. This patch prevents both of those scenarios by locking the
schema to which the relation is being added using AccessShareLock,
which conflicts with the AccessExclusiveLock taken by DROP.
As a desirable side effect, this also prevents the use of CREATE OR
REPLACE VIEW to queue for an AccessExclusiveLock on a relation on which
you have no rights: that will now fail immediately with a permissions
error, before trying to obtain a lock.
We need similar protection for all other object types, but as everything
other than relations uses a slightly different set of code paths, I'm
leaving that for a separate commit.
Original complaint (as far as I could find) about CREATE by Nikhil
Sontakke; risk for ALTER .. SET SCHEMA pointed out by Tom Lane;
further details by Dan Farina; patch by me; review by Hitoshi Harada.
smgrdounlink takes care to not throw an ERROR if it fails to unlink
something, but that caution was rendered useless by commit
3396000684, which put an smgrexists call in
front of it; smgrexists *does* throw error if anything looks funny, such
as getting a permissions error from trying to open the file. If that
happens post-commit, you get a PANIC, and what's worse the same logic
appears in the WAL replay code, so the database even fails to restart.
Restore the intended behavior by removing the smgrexists call --- it isn't
accomplishing anything that we can't do better by adjusting mdunlink's
ideas of whether it ought to warn about ENOENT or not.
Per report from Joseph Shraibman of unrecoverable crash after trying to
drop a table whose FSM fork had somehow gotten chmod'd to 000 permissions.
Backpatch to 8.4, where the bogus coding was introduced.
This adds support for the more or less SQL-conforming USAGE privilege
on types and domains. The intent is to be able restrict which users
can create dependencies on types, which restricts the way in which
owners can alter types.
reviewed by Yeb Havinga
This makes them enforceable only on the parent table, not on children
tables. This is useful in various situations, per discussion involving
people bitten by the restrictive behavior introduced in 8.4.
Message-Id:
8762mp93iw.fsf@comcast.netCAFaPBrSMMpubkGf4zcRL_YL-AERUbYF_-ZNNYfb3CVwwEqc9TQ@mail.gmail.com
Authors: Nikhil Sontakke, Alex Hunsaker
Reviewed by Robert Haas and myself
In the previous coding, callers were faced with an awkward choice:
look up the name, do permissions checks, and then lock the table; or
look up the name, lock the table, and then do permissions checks.
The first choice was wrong because the results of the name lookup
and permissions checks might be out-of-date by the time the table
lock was acquired, while the second allowed a user with no privileges
to interfere with access to a table by users who do have privileges
(e.g. if a malicious backend queues up for an AccessExclusiveLock on
a table on which AccessShareLock is already held, further attempts
to access the table will be blocked until the AccessExclusiveLock
is obtained and the malicious backend's transaction rolls back).
To fix, allow callers of RangeVarGetRelid() to pass a callback which
gets executed after performing the name lookup but before acquiring
the relation lock. If the name lookup is retried (because
invalidation messages are received), the callback will be re-executed
as well, so we get the best of both worlds. RangeVarGetRelid() is
renamed to RangeVarGetRelidExtended(); callers not wishing to supply
a callback can continue to invoke it as RangeVarGetRelid(), which is
now a macro. Since the only one caller that uses nowait = true now
passes a callback anyway, the RangeVarGetRelid() macro defaults nowait
as well. The callback can also be used for supplemental locking - for
example, REINDEX INDEX needs to acquire the table lock before the index
lock to reduce deadlock possibilities.
There's a lot more work to be done here to fix all the cases where this
can be a problem, but this commit provides the general infrastructure
and fixes the following specific cases: REINDEX INDEX, REINDEX TABLE,
LOCK TABLE, and and DROP TABLE/INDEX/SEQUENCE/VIEW/FOREIGN TABLE.
Per discussion with Noah Misch and Alvaro Herrera.
This gives a much better error message when the object of interest is
concurrently dropped and avoids needlessly failing when the object of
interest is concurrently dropped and recreated. It also improves the
behavior of two concurrent DROP IF EXISTS operations targeted at the
same object; as before, one will drop the object, but now the other
will emit the usual NOTICE indicating that the object does not exist,
instead of rolling back. As a fringe benefit, it's also slightly
less code.
No functional changes in this commit (except I could not resist the
temptation to re-word a couple of error messages). This is just manual
cleanup after pgindent to make the code look reasonably like other PG
code, in preparation for more detailed code review to come.
If it turns out we've locked the wrong OID, release the old lock. In
most cases, it's pretty harmless to retain the extra lock, but this
seems tidier and avoids using lock table slots unnecessarily.
Per discussion with Tom Lane.
Turns out that use of ShareUpdateExclusiveLock or ShareRowExclusiveLock
to protect DDL changes had gotten copied into several places that were
not touched by either of Simon's original patches for the feature, and
thus neither he nor I thought to revert them. (Indeed, it appears that
two of these uses were committed *after* the reversion, which just goes
to show that git merging is no panacea.) Change these places to use
AccessExclusiveLock again. If we ever manage to resurrect that feature,
we're going to have to think a bit harder about how to keep lock level
usage in sync for DDL operations that aren't within the AlterTable
infrastructure.
Two of these bugs are only in HEAD, but one is in the 9.1 branch too.
Alvaro found one of them, I found the other two.
extnamespace means something altogether different in this context.
Mostly by accident, this coding error (introduced in my commit
82a4a777d9) broke the buildfarm instead
of just silently doing the wrong thing.
This gets rid of a significant amount of duplicative code.
KaiGai Kohei, reviewed in earlier versions by Dimitri Fontaine, with
further review and cleanup by me.
This view was being insufficiently careful about matching the FK constraint
to the depended-on primary or unique key constraint. That could result in
failure to show an FK constraint at all, or showing it multiple times, or
claiming that it depended on a different constraint than the one it really
does. Fix by joining via pg_depend to ensure that we find only the correct
dependency.
Back-patch, but don't bump catversion because we can't force initdb in back
branches. The next minor-version release notes should explain that if you
need to fix this in an existing installation, you can drop the
information_schema schema then re-create it by sourcing
$SHAREDIR/information_schema.sql in each database (as a superuser of
course).
Add a column pg_class.relallvisible to remember the number of pages that
were all-visible according to the visibility map as of the last VACUUM
(or ANALYZE, or some other operations that update pg_class.relpages).
Use relallvisible/relpages, instead of an arbitrary constant, to estimate
how many heap page fetches can be avoided during an index-only scan.
This is pretty primitive and will no doubt see refinements once we've
acquired more field experience with the index-only scan mechanism, but
it's way better than using a constant.
Note: I had to adjust an underspecified query in the window.sql regression
test, because it was changing answers when the plan changed to use an
index-only scan. Some of the adjacent tests perhaps should be adjusted
as well, but I didn't do that here.
Nobody using the missing_ok flag yet, but let's speculate that this will
be a better interface for future callers.
KaiGai Kohei, with some adjustments by me.
Relation rowtypes and automatically-generated array types do not need to
have their own extension membership dependency entries. If we create such
then it becomes more difficult to remove items from an extension, and it's
also harder for an extension upgrade script to make sure it duplicates the
dependencies created by the extension's regular installation script.
I changed the code in such a way that this happened in commit
988cccc620, I think because of worries about
the shell-type-replacement case; but that cure was worse than the disease.
It would only matter if one extension created a shell type that was
replaced with an auto-generated type in another extension, which seems
pretty far-fetched. Better to make this work unsurprisingly in normal
cases.
Report and patch by Robert Haas, comment adjustments by me.
There's no particular advantage to this change on its face; indeed,
it's possible that this might be slightly slower than the old way.
But it makes this information more easily accessible to other
functions, and therefore paves the way for future code consolidation.
Performance isn't critical here, so there's no need to be smart about
how we do the search.
This is a heavily cut-down version of a patch from KaiGai Kohei,
with several fixes by me. Additional review from Dimitri Fontaine.
Thus, an object referenced in a default expression could be dropped while
the function remained present. This was unaccountably missed in the
original patch to add default parameters for functions. Reported by
Pavel Stehule.
Per bug #6205, reported by Abel Abraham Camarillo Ojeda. This isn't a
particularly elegant fix, but I'm trying to minimize the chances of
causing yet another round of breakage.
Adjust regression tests to exercise this case.
Rewrite plancache.c so that a "cached plan" (which is rather a misnomer
at this point) can support generation of custom, parameter-value-dependent
plans, and can make an intelligent choice between using custom plans and
the traditional generic-plan approach. The specific choice algorithm
implemented here can probably be improved in future, but this commit is
all about getting the mechanism in place, not the policy.
In addition, restructure the API to greatly reduce the amount of extraneous
data copying needed. The main compromise needed to make that possible was
to split the initial creation of a CachedPlanSource into two steps. It's
worth noting in particular that SPI_saveplan is now deprecated in favor of
SPI_keepplan, which accomplishes the same end result with zero data
copying, and no need to then spend even more cycles throwing away the
original SPIPlan. The risk of long-term memory leaks while manipulating
SPIPlans has also been greatly reduced. Most of this improvement is based
on use of the recently-added MemoryContextSetParent primitive.
walsender.h should depend on xlog.h, not vice versa. (Actually, the
inclusion was circular until a couple hours ago, which was even sillier;
but Bruce broke it in the expedient rather than logically correct
direction.) Because of that poor decision, plus blind application of
pgrminclude, we had a situation where half the system was depending on
xlog.h to include such unrelated stuff as array.h and guc.h. Clean up
the header inclusion, and manually revert a lot of what pgrminclude had
done so things build again.
This episode reinforces my feeling that pgrminclude should not be run
without adult supervision. Inclusion changes in header files in particular
need to be reviewed with great care. More generally, it'd be good if we
had a clearer notion of module layering to dictate which headers can sanely
include which others ... but that's a big task for another day.
In the past, relhassubclass always remained true if a relation had ever had
child relations, even if the last subclass was long gone. While this had
only marginal performance implications in most cases, it was annoying, and
I'm now considering some planner changes that would raise the cost of a
false positive. It was previously impractical to fix this because of race
condition concerns. However, given the recent change that made tablecmds.c
take ShareExclusiveLock on relations that are gaining a child (commit
fbcf4b92aa), we can now allow ANALYZE to
clear the flag when it's no longer relevant. There is no additional
locking cost to do so, since ANALYZE takes ShareExclusiveLock anyway.
When we implemented extensions, we made findDependentObjects() treat
EXTENSION dependency links similarly to INTERNAL links. However, that
logic contained an implicit assumption that an object could have at most
one INTERNAL dependency, so it did not work correctly for objects having
both INTERNAL and DEPENDENCY links. This led to failure to drop some
extension member objects when dropping the extension. Furthermore, we'd
never actually exercised the case of recursing to an internally-referenced
(owning) object from anything other than a NORMAL dependency, and it turns
out that passing the incoming dependency's flags to the owning object is
the Wrong Thing. This led to sometimes dropping a whole extension silently
when we should have rejected the drop command for lack of CASCADE.
Since we obviously were under-testing extension drop scenarios, add some
regression test cases. Unfortunately, such test cases require some
extensions (duh), so we can't test for problems in the core regression
tests. I chose to add them to the earthdistance contrib module, which is
a good test case because it has a dependency on the cube contrib module.
Back-patch to 9.1. Arguably these are pre-existing bugs in INTERNAL
dependency handling, but since it appears that the cases can never arise
pre-9.1, I'll refrain from back-patching the logic changes further than
that.
The previous coding would result in deleting and not re-creating the
extension membership pg_depend rows, since there was no
CommandCounterIncrement that would allow recordDependencyOnCurrentExtension
to see that the deletion had happened. Make it work like the shell type
case, ie, keep the existing entries (and then throw an error if they're for
the wrong extension).
Per bug #6172 from Hitoshi Harada. Investigation and fix by Dimitri
Fontaine.
This requires adjusting the API for syscache callback functions: they now
get a hash value, not a TID, to identify the target tuple. Most of them
weren't paying any attention to that argument anyway, but plancache did
require a small amount of fixing.
Also, improve performance a trifle by avoiding sending duplicate inval
messages when a heap_update isn't changing the catcache lookup columns.
The original implementation simply did nothing when replacing an existing
object during CREATE EXTENSION. The folly of this was exposed by a report
from Marc Munro: if the existing object belongs to another extension, we
are left in an inconsistent state. We should insist that the object does
not belong to another extension, and then add it to the current extension
if not already a member.
I broke this in commit 5da79169d3, which
was obviously insufficiently well tested. Add some regression tests
in the hope of making future slip-ups more likely to be noticed.
This requires a new shared catalog, pg_shseclabel.
Along the way, fix the security_label regression tests so that they
don't monkey with the labels of any pre-existing objects. This is
unlikely to matter in practice, since only the label for the "dummy"
provider was being manipulated. But this way still seems cleaner.
KaiGai Kohei, with fairly extensive hacking by me.
We already have similar functions for many other object types, including
operator classes, so it seems like we should have this one, too.
Extracted from a larger patch by Josh Kupershmidt
The commit action of temporary tables is currently not cataloged, so
we can't easily show it. The previous value was outdated from before
we had different commit actions.
Regular aggregate functions in combination with, or within the arguments
of, window functions are OK per spec; they have the semantics that the
aggregate output rows are computed and then we run the window functions
over that row set. (Thus, this combination is not really useful unless
there's a GROUP BY so that more than one aggregate output row is possible.)
The case without GROUP BY could fail, as recently reported by Jeff Davis,
because sloppy construction of the Agg node's targetlist resulted in extra
references to possibly-ungrouped Vars appearing outside the aggregate
function calls themselves. See the added regression test case for an
example.
Fixing this requires modifying the API of flatten_tlist and its underlying
function pull_var_clause. I chose to make pull_var_clause's API for
aggregates identical to what it was already doing for placeholders, since
the useful behaviors turn out to be the same (error, report node as-is, or
recurse into it). I also tightened the error checking in this area a bit:
if it was ever valid to see an uplevel Var, Aggref, or PlaceHolderVar here,
that was a long time ago, so complain instead of ignoring them.
Backpatch into 9.1. The failure exists in 8.4 and 9.0 as well, but seeing
that it only occurs in a basically-useless corner case, it doesn't seem
worth the risks of changing a function API in a minor release. There might
be third-party code using pull_var_clause.
The fields were previously wrongly typed as character_data; change to
cardinal_number. Update the documentation and the implementation to
show more clearly that this applies to a feature not available in
PostgreSQL, rather than just not yet being implemented in the
information schema.
In the previous coding, we would look up a relation in RangeVarGetRelid,
lock the resulting OID, and then AcceptInvalidationMessages(). While
this was sufficient to ensure that we noticed any changes to the
relation definition before building the relcache entry, it didn't
handle the possibility that the name we looked up no longer referenced
the same OID. This was particularly problematic in the case where a
table had been dropped and recreated: we'd latch on to the entry for
the old relation and fail later on. Now, we acquire the relation lock
inside RangeVarGetRelid, and retry the name lookup if we notice that
invalidation messages have been processed meanwhile. Many operations
that would previously have failed with an error in the presence of
concurrent DDL will now succeed.
There is a good deal of work remaining to be done here: many callers
of RangeVarGetRelid still pass NoLock for one reason or another. In
addition, nothing in this patch guards against the possibility that
the meaning of an unqualified name might change due to the creation
of a relation in a schema earlier in the user's search path than the
one where it was previously found. Furthermore, there's nothing at
all here to guard against similar race conditions for non-relations.
For all that, it's a start.
Noah Misch and Robert Haas
Unlike the relistemp field which it replaced, relpersistence must be
set correctly quite early during the table creation process, as we
rely on it quite early on for a number of purposes, including security
checks. Normally, this is set based on whether the user enters CREATE
TABLE, CREATE UNLOGGED TABLE, or CREATE TEMPORARY TABLE, but a
relation may also be made implicitly temporary by creating it in
pg_temp. This patch fixes the handling of that case, and also
disables creation of unlogged tables in temporary tablespace (such
table indeed skip WAL-logging, but we reject an explicit
specification) and creation of relations in the temporary schemas of
other sessions (which is not very sensible, and didn't work right
anyway).
Report by Amit Khandekar.
This means that they can initially be added to a large existing table
without checking its initial contents, but new tuples must comply to
them; a separate pass invoked by ALTER TABLE / VALIDATE can verify
existing data and ensure it complies with the constraint, at which point
it is marked validated and becomes a normal part of the table ecosystem.
An non-validated CHECK constraint is ignored in the planner for
constraint_exclusion purposes; when validated, cached plans are
recomputed so that partitioning starts working right away.
This patch also enables domains to have unvalidated CHECK constraints
attached to them as well by way of ALTER DOMAIN / ADD CONSTRAINT / NOT
VALID, which can later be validated with ALTER DOMAIN / VALIDATE
CONSTRAINT.
Thanks to Thom Brown, Dean Rasheed and Jaime Casanova for the various
reviews, and Robert Hass for documentation wording improvement
suggestions.
This patch was sponsored by Enova Financial.
Fill in the collation columns of the views attributes, columns,
domains, and element_types. Also update collation information in
sql_implementation_info.
Initially, we use this only to eliminate calls to the varchar()
function in cases where the length is not being reduced and, therefore,
the function call is equivalent to a RelabelType operation. The most
significant effect of this is that we can avoid a table rewrite when
changing a varchar(X) column to a varchar(Y) column, where Y > X.
Noah Misch, reviewed by me and Alexey Klyukin
The code that created the init fork neglected to make sure that the
relation was open at the smgr level before attempting to invoke smgr.
This didn't happen every time; only when the relcache entry was rebuilt
along the way.
Per report from Garick Hamlin.
We had already converted most places to this style, but this patch gets the
last few that were still doing it the old way. The main advantage is that
this exposes a greppable name for each target column, rather than having
to rely on comments (which a couple of places failed to provide anyhow).
Richard Hopkins, additional work by me to clean up update_attstats() too
Truncating or dropping a table is treated like deletion of all tuples, and
check for conflicts accordingly. If a table is clustered or rewritten by
ALTER TABLE, all predicate locks on the heap are promoted to relation-level
locks, because the tuple or page ids of any existing tuples will change and
won't be valid after rewriting the table. Arguably ALTER TABLE should be
treated like a mass-UPDATE of every row, but if you e.g change the datatype
of a column, you could also argue that it's just a change to the physical
layout, not a logical change. Reindexing promotes all locks on the index to
relation-level lock on the heap.
Kevin Grittner, with a lot of cosmetic changes by me.
This avoids an Assert failure when we try to use ordinary index fetches
while checking for exclusion conflicts. Per report from Noah Misch.
No need for back-patch because the Assert wasn't there before 9.1.
We need this now because we allow domains over arrays, and we'll probably
allow domains over composites pretty soon, which makes the problem even
more obvious.
Although domains over arrays also exist in previous versions, this does not
need to be back-patched, because the coding used in older versions
successfully "looked through" domains over arrays. The problem is exposed
by not treating a domain as having a typelem.
Problem identified by Noah Misch, though I did not use his patch, since
it would require additional work to handle domains over composites that
way. This approach is more future-proof.
This commit fixes psql, pg_dump, and the information schema to be
consistent with the backend changes which I made as part of commit
be90032e0d, and also includes a
related documentation tweak.
Shigeru Hanada, with slight adjustment.
Per bug #5988, reported by Marko Tiikkaja, and further analyzed by Tom
Lane, the previous coding was broken in several respects: even if the
target table already existed, a subsequent CREATE TABLE IF NOT EXISTS
might try to add additional constraints or sequences-for-serial
specified in the new CREATE TABLE statement.
In passing, this also fixes a minor information leak: it's no longer
possible to figure out whether a schema to which you don't have CREATE
access contains a sequence named like "x_y_seq" by attempting to create a
table in that schema called "x" with a serial column called "y".
Some more refactoring of this code in the future might be warranted,
but that will need to wait for a later major release.
Instead, foreign tables are treated just like views: permissions can
be granted using GRANT privilege ON [TABLE] foreign_table_name TO role,
and revoked similarly. GRANT/REVOKE .. FOREIGN TABLE is no longer
supported, just as we don't support GRANT/REVOKE .. VIEW. The set of
accepted permissions for foreign tables is now identical to the set for
regular tables, and views.
Per report from Thom Brown, and subsequent discussion.
This option turns off autovacuum, prevents non-super-user connections,
and enables oid setting hooks in the backend. The code continues to use
the old autoavacuum disable settings for servers with earlier catalog
versions.
This includes a catalog version bump to identify servers that support
the -b option.
This patch is almost entirely cosmetic --- mostly cleaning up a lot of
neglected comments, and fixing code layout problems in places where the
patch made lines too long and then pgindent did weird things with that.
I did find a bug-of-omission in equalTupleDescs().
If we find a DELETE_IN_PROGRESS HOT-updated tuple, it is impossible to know
whether to index it or not except by waiting to see if the deleting
transaction commits. If it doesn't, the tuple might again be LIVE, meaning
we have to index it. So wait and recheck in that case.
Also, we must not rely on ii_BrokenHotChain to decide that it's possible to
omit tuples from the index. That could result in omitting tuples that we
need, particularly in view of yesterday's fixes to not necessarily set
indcheckxmin (but it's broken even without that, as per my analysis today).
Since this is just an extremely marginal performance optimization, dropping
the test shouldn't hurt.
These cases are only expected to happen in system catalogs (they're
possible there due to early release of RowExclusiveLock in most
catalog-update code paths). Since reindexing of a system catalog isn't a
particularly performance-critical operation anyway, there's no real need to
be concerned about possible performance degradation from these changes.
The worst aspects of this bug were introduced in 9.0 --- 8.x will always
wait out a DELETE_IN_PROGRESS tuple. But I think dropping index entries
on the strength of ii_BrokenHotChain is dangerous even without that, so
back-patch removal of that optimization to 8.3 and 8.4.
Per comment from Greg Stark, it's less clear that HOT chains don't conflict
with the index than it would be for a valid index. So, let's preserve the
former behavior that indcheckxmin does get set when there are
potentially-broken HOT chains in this case. This change does not cause any
pg_index update that wouldn't have happened anyway, so we're not
re-introducing the previous bug with pg_index updates, and surely the case
is not significant from a performance standpoint; so let's be as
conservative as possible.
There can never be a need to push the indcheckxmin horizon forward, since
any HOT chains that are actually broken with respect to the index must
pre-date its original creation. So we can just avoid changing pg_index
altogether during a REINDEX operation.
This offers a cleaner solution than my previous patch for the problem
found a few days ago that we mustn't try to update pg_index while we are
reindexing it. System catalog indexes will always be created with
indcheckxmin = false during initdb, and with this modified code we should
never try to change their pg_index entries. This avoids special-casing
system catalogs as the former patch did, and should provide a performance
benefit for many cases where REINDEX formerly caused an index to be
considered unusable for a short time.
Back-patch to 8.3 to cover all versions containing HOT. Note that this
patch changes the API for index_build(), but I believe it is unlikely that
any add-on code is calling that directly.
Per spec we ought to apply select_common_collation() across the expressions
in each column of the VALUES table. The original coding was just taking
the first row and assuming it was representative.
This patch adds a field to struct RangeTblEntry to carry the resolved
collations, so initdb is forced for changes in stored rule representation.
For what seem entirely historical reasons, a bitmask "flags" argument was
recently added to reindex_relation without subsuming its existing boolean
argument into that bitmask. This seems a bit bizarre, so fold them
together.
The places that attempt to change pg_index.indcheckxmin during a reindexing
operation cannot be executed safely if pg_index itself is the subject of
the operation. This is the explanation for a couple of recent reports of
VACUUM FULL failing with
ERROR: duplicate key value violates unique constraint "pg_index_indexrelid_index"
DETAIL: Key (indexrelid)=(2678) already exists.
However, there isn't any real need to update indcheckxmin in such a
situation, if we assume that pg_index can never contain a truly broken HOT
chain. This assumption holds if new indexes are never created on it during
concurrent operations, which is something we don't consider safe for any
system catalog, not just pg_index. Accordingly, modify the code to not
manipulate indcheckxmin when reindexing any system catalog.
Back-patch to 8.3, where HOT was introduced. The known failure scenarios
involve 9.0-style VACUUM FULL, so there might not be any real risk before
9.0, but let's not assume that.
Instead of using slightly-too-clever heuristics to decide when we must
create a TOAST table, just check whether one is needed every time the
table is altered. Checking whether a toast table is needed is cheap
enough that we needn't worry about doing it on every ALTER TABLE command,
and the previous coding is apparently prone to accidental breakage:
commit 04e17bae50 broken ALTER TABLE ..
SET STORAGE, which moved some actions from AT_PASS_COL_ATTRS to
AT_PASS_MISC, and commit 6c57239985 broke
ALTER TABLE .. ADD COLUMN by changing the way that adding columns
recurses into child tables.
Noah Misch, with one comment change by me
This warning is new in gcc 4.6 and part of -Wall. This patch cleans
up most of the noise, but there are some still warnings that are
trickier to remove.
The previous functions of assign hooks are now split between check hooks
and assign hooks, where the former can fail but the latter shouldn't.
Aside from being conceptually clearer, this approach exposes the
"canonicalized" form of the variable value to guc.c without having to do
an actual assignment. And that lets us fix the problem recently noted by
Bernd Helmle that the auto-tune patch for wal_buffers resulted in bogus
log messages about "parameter "wal_buffers" cannot be changed without
restarting the server". There may be some speed advantage too, because
this design lets hook functions avoid re-parsing variable values when
restoring a previous state after a rollback (they can store a pre-parsed
representation of the value instead). This patch also resolves a
longstanding annoyance about custom error messages from variable assign
hooks: they should modify, not appear separately from, guc.c's own message
about "invalid parameter value".
This mostly involves making it work with the objectaddress.c framework,
which does most of the heavy lifting. In that vein, change
GetForeignDataWrapperOidByName to get_foreign_data_wrapper_oid and
GetForeignServerOidByName to get_foreign_server_oid, to match the
pattern we use for other object types.
Robert Haas and Shigeru Hanada
Feature F692 "Extended collation support" is now also supported. This
refers to allowing the COLLATE clause anywhere in a column or domain
definition instead of just directly after the type.
Also correct the name of the feature in accordance with the latest SQL
standard.
Eventually we might be able to allow that, but it's not clear how many
places need to be fixed to prevent infinite recursion when there's a direct
or indirect inclusion of a rowtype in itself. One such place is
CheckAttributeType(), which will recurse to stack overflow in cases such as
those exhibited in bug #5950 from Alex Perepelica. If we were sure it was
the only such place, we could easily modify the code added by this patch to
stop the recursion without a complaint ... but it probably isn't the only
such place. Hence, throw error until such time as someone is excited
enough about this type of usage to put work into making it safe.
Back-patch as far as 8.3. 8.2 doesn't have the recursive call in
CheckAttributeType in the first place, so I see no need to add code there
in the absence of clear evidence of a problem elsewhere.
Ensure that parameter symbols receive collation from the function's
resolved input collation, and fix inlining to behave properly.
BTW, this commit lays about 90% of the infrastructure needed to support
use of argument names in SQL functions. Parsing of parameters is now
done via the parser-hook infrastructure ... we'd just need to supply
a column-ref hook ...
All expression nodes now have an explicit output-collation field, unless
they are known to only return a noncollatable data type (such as boolean
or record). Also, nodes that can invoke collation-aware functions store
a separate field that is the collation value to pass to the function.
This avoids confusion that arises when a function has collatable inputs
and noncollatable output type, or vice versa.
Also, replace the parser's on-the-fly collation assignment method with
a post-pass over the completed expression tree. This allows us to use
a more complex (and hopefully more nearly spec-compliant) assignment
rule without paying for it in extra storage in every expression node.
Fix assorted bugs in the planner's handling of collations by making
collation one of the defining properties of an EquivalenceClass and
by converting CollateExprs into discardable RelabelType nodes during
expression preprocessing.
CollateClause is now used only in raw grammar output, and CollateExpr after
parse analysis. This is for clarity and to avoid carrying collation names
in post-analysis parse trees: that's both wasteful and possibly misleading,
since the collation's name could be changed while the parsetree still
exists.
Also, clean up assorted infelicities and omissions in processing of the
node type.
Use collencoding = -1 to represent such a collation in pg_collation.
We need this to make the "default" entry work sanely, and a later
patch will fix the C/POSIX entries to be represented this way instead
of duplicating them across all encodings. All lookup operations now
search first for an entry that's database-encoding-specific, and then
for the same name with collencoding = -1.
Also some incidental code cleanup in collationcmds.c and pg_collation.c.
Including collation in the behavior of that function promotes a world view
we do not want. Moreover, it was producing the wrong behavior for pg_dump
anyway: what we want is to dump a COLLATE clause on attributes whose
attcollation is different from the underlying type, and likewise for
domains, and the function cannot do that for us. Doing it the hard way
in pg_dump is a bit more tedious but produces more correct output.
In passing, fix initdb so that the initial entry in pg_collation is
properly pinned. It was droppable before :-(
Formerly, any member of a role could change the role's comment, as of
course could superusers; but holders of CREATEROLE privilege could not,
unless they were also members. This led to the odd situation that a
CREATEROLE holder could create a role but then could not comment on it.
It also seems a bit dubious to let an unprivileged user change his own
comment, let alone those of group roles he belongs to. So, change the
rule to be "you must be superuser to comment on a superuser role, or
hold CREATEROLE to comment on non-superuser roles". This is the same
as the privilege check for creating/dropping roles, and thus fits much
better with the rule for other object types, namely that only the owner
of an object can comment on it.
In passing, clean up the documentation for COMMENT a little bit.
Per complaint from Owen Jacobson and subsequent discussion.
If a standby is broadcasting reply messages and we have named
one or more standbys in synchronous_standby_names then allow
users who set synchronous_replication to wait for commit, which
then provides strict data integrity guarantees. Design avoids
sending and receiving transaction state information so minimises
bookkeeping overheads. We synchronize with the highest priority
standby that is connected and ready to synchronize. Other standbys
can be defined to takeover in case of standby failure.
This version has very strict behaviour; more relaxed options
may be added at a later date.
Simon Riggs and Fujii Masao, with reviews by Yeb Havinga, Jaime
Casanova, Heikki Linnakangas and Robert Haas, plus the assistance
of many other design reviewers.
It is possible that an expression ends up with a collatable type but
without a collation. CREATE TABLE AS could then create a table based
on that. But such a column cannot be dumped with valid SQL syntax, so
we disallow creating such a column.
per test report from Noah Misch
Remove the unconditional superuser permissions check in CREATE EXTENSION,
and instead define a "superuser" extension property, which when false
(not the default) skips the superuser permissions check. In this case
the calling user only needs enough permissions to execute the commands
in the extension's installation script. The superuser property is also
enforced in the same way for ALTER EXTENSION UPDATE cases.
In other ALTER EXTENSION cases and DROP EXTENSION, test ownership of
the extension rather than superuserness. ALTER EXTENSION ADD/DROP needs
to insist on ownership of the target object as well; to do that without
duplicating code, refactor comment.c's big switch for permissions checks
into a separate function in objectaddress.c.
I also removed the superuserness checks in pg_available_extensions and
related functions; there's no strong reason why everybody shouldn't
be able to see that info.
Also invent an IF NOT EXISTS variant of CREATE EXTENSION, and use that
in pg_dump, so that dumps won't fail for installed-by-default extensions.
We don't have any of those yet, but we will soon.
This is all per discussion of wrapping the standard procedural languages
into extensions. I'll make those changes in a separate commit; this is
just putting the core infrastructure in place.
With this patch, portals, SQL functions, and SPI all agree that there
should be only a CommandCounterIncrement between the queries that are
generated from a single SQL command by rule expansion. Fetching a whole
new snapshot now happens only between original queries. This is equivalent
to the existing behavior of EXPLAIN ANALYZE, and it was judged to be the
best choice since it eliminates one source of concurrency hazards for
rules. The patch should also make things marginally faster by reducing the
number of snapshot push/pop operations.
The patch removes pg_parse_and_rewrite(), which is no longer used anywhere.
There was considerable discussion about more aggressive refactoring of the
query-processing functions exported by postgres.c, but for the moment
nothing more has been done there.
I also took the opportunity to refactor snapmgr.c's API slightly: the
former PushUpdatedSnapshot() has been split into two functions.
Marko Tiikkaja, reviewed by Steve Singer and Tom Lane
The recent additions for FDW support required checking foreign-table-ness
in several places in the parse/plan chain. While it's not clear whether
that would really result in a noticeable slowdown, it seems best to avoid
any performance risk by keeping a copy of the relation's relkind in
RangeTblEntry. That might have some other uses later, anyway.
Per discussion.
Recent releases had a check on rel->rd_refcnt in heap_drop_with_catalog,
but failed to cover the possibility of pending trigger events at DROP time.
(Before 8.4 we didn't even check the refcnt.) When the trigger events were
eventually fired, you'd get "could not open relation with OID nnn" errors,
as in recent report from strk. Better to throw a suitable error when the
DROP is attempted.
Also add a similar check in DROP INDEX.
Back-patch to all supported branches.
The original design of pg_available_extensions did not consider the
possibility of version-specific control files. Split it into two views:
pg_available_extensions shows information that is generic about an
extension, while pg_available_extension_versions shows all available
versions together with information that could be version-dependent.
Also, add an SRF pg_extension_update_paths() to assist in checking that
a collection of update scripts provide sane update path sequences.
- collowner field
- CREATE COLLATION
- ALTER COLLATION
- DROP COLLATION
- COMMENT ON COLLATION
- integration with extensions
- pg_dump support for the above
- dependency management
- psql tab completion
- psql \dO command
When the old type is binary coercible to the new type and the using
clause does not change the column contents, we can avoid a full table
rewrite, though any indexes on the affected columns will still need
to be rebuilt. This applies, for example, when changing a varchar
column to be of type text.
The prior coding assumed that the set of operations that force a
rewrite is identical to the set of operations that must be propagated
to tables making use of the affected table's rowtype. This is
no longer true: even though the tuples in those tables wouldn't
need to be modified, the data type change invalidate indexes built
using those composite type columns. Indexes on the table we're
actually modifying can be invalidated too, of course, but the
existing machinery is sufficient to handle that case.
Along the way, add some debugging messages that make it possible
to understand what operations ALTER TABLE is actually performing
in these cases.
Noah Misch and Robert Haas
the standby has written, flushed, and applied the WAL. At the moment, this
is for informational purposes only, the values are only shown in
pg_stat_replication system view, but in the future they will also be needed
for synchronous replication.
Extracted from Simon riggs' synchronous replication patch by Robert Haas, with
some tweaking by me.
Tracks one counter for each database, which is reset whenever
the statistics for any individual object inside the database is
reset, and one counter for the background writer.
Tomas Vondra, reviewed by Greg Smith
This follows my proposal of yesterday, namely that we try to recreate the
previous state of the extension exactly, instead of allowing CREATE
EXTENSION to run a SQL script that might create some entirely-incompatible
on-disk state. In --binary-upgrade mode, pg_dump won't issue CREATE
EXTENSION at all, but instead uses a kluge function provided by
pg_upgrade_support to recreate the pg_extension row (and extension-level
pg_depend entries) without creating any member objects. The member objects
are then restored in the same way as if they weren't members, in particular
using pg_upgrade's normal hacks to preserve OIDs that need to be preserved.
Then, for each member object, ALTER EXTENSION ADD is issued to recreate the
pg_depend entry that marks it as an extension member.
In passing, fix breakage in pg_upgrade's enum-type support: somebody didn't
fix it when the noise word VALUE got added to ALTER TYPE ADD. Also,
rationalize parsetree representation of COMMENT ON DOMAIN and fix
get_object_address() to allow OBJECT_DOMAIN.
This patch adds the server infrastructure to support extensions.
There is still one significant loose end, namely how to make it play nice
with pg_upgrade, so I am not yet committing the changes that would make
all the contrib modules depend on this feature.
In passing, fix a disturbingly large amount of breakage in
AlterObjectNamespace() and callers.
Dimitri Fontaine, reviewed by Anssi Kääriäinen,
Itagaki Takahiro, Tom Lane, and numerous others
This adds collation support for columns and domains, a COLLATE clause
to override it per expression, and B-tree index support.
Peter Eisentraut
reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch
FK constraints that are marked NOT VALID may later be VALIDATED, which uses an
ShareUpdateExclusiveLock on constraint table and RowShareLock on referenced
table. Significantly reduces lock strength and duration when adding FKs.
New state visible from psql.
Simon Riggs, with reviews from Marko Tiikkaja and Robert Haas
There isn't any need to track this state on a table-wide basis, and trying
to do so introduces undesirable semantic fuzziness. Move the flag to
pg_index, where it clearly describes just a single index and can be
immutable after index creation.
This feature allows a unique or pkey constraint to be created using an
already-existing unique index. While the constraint isn't very
functionally different from the bare index, it's nice to be able to do that
for documentation purposes. The main advantage over just issuing a plain
ALTER TABLE ADD UNIQUE/PRIMARY KEY is that the index can be created with
CREATE INDEX CONCURRENTLY, so that there is not a long interval where the
table is locked against updates.
On the way, refactor some of the code in DefineIndex() and index_create()
so that we don't have to pass through those functions in order to create
the index constraint's catalog entries. Also, in parse_utilcmd.c, pass
around the ParseState pointer in struct CreateStmtContext to save on
notation, and add error location pointers to some error reports that didn't
have one before.
Gurjeet Singh, reviewed by Steve Singer and Tom Lane
Include the lefttype/righttype columns explicitly (instead of assuming
the reader can deduce them from the operator or function description),
and move the operator or function description to the end of the string,
to make it clearer that it's a referenced object and not the amop or
amproc item itself. Per extensive discussion of Andreas Karlsson's
original patch.
Andreas Karlsson, Tom Lane
Failure to do so can lead to constraint violations. This was broken by
commit 1ddc2703a9 on 2010-02-07, so
back-patch to 9.0.
Noah Misch. Regression test by me.
Toast tables have identical pg_class.oid and pg_class.relfilenode, but
for clarity it is good to preserve the pg_class.oid.
Update comments regarding what is preserved, and do some
variable/function renaming for clarity.
Tom Lane
Robert Haas
Alvaro Herrera
Simon Riggs
Peter Eisentraut
Magnus Hagander
Bruce Momjian
Heikki Linnakangas
Itagaki Takahiro