get_op_btree_interpretation assumed this in order to save some duplication
of code, but it's not true in general anymore because we added <> support
to btree_gist. (We still assume it for btree opclasses, though.)
Also, essentially the same logic was baked into predtest.c. Get rid of
that duplication by generalizing get_op_btree_interpretation so that it
can be used by predtest.c.
Per bug report from Denis de Bernardy and investigation by Jeff Davis,
though I didn't use Jeff's patch exactly as-is.
Back-patch to 9.1; we do not support this usage before that.
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 existence of a btree opclass accepting composite types caused us to
assume that every composite type is sortable. This isn't true of course;
we need to check if the column types are all sortable. There was logic
for this for the case of array comparison (ie, check that the element
type is sortable), but we missed the point for rowtypes. Per Teodor's
report of an ANALYZE failure for an unsortable composite type.
Rather than just add some more ad-hoc logic for this, I moved knowledge of
the issue into typcache.c. The typcache will now only report out array_eq,
record_cmp, and friends as usable operators if the array or composite type
will work with those functions.
Unfortunately we don't have enough info to do this for anonymous RECORD
types; in that case, just assume it will work, and take the runtime failure
as before if it doesn't.
This patch might be a candidate for back-patching at some point, but
given the lack of complaints from the field, I'd rather just test it in
HEAD for now.
Note: most of the places touched in this patch will need further work
when we get around to supporting hashing of record types.
Failure to distinguish these cases is the real cause behind the recent
reports of Windows builds crashing on 'infinity'::timestamp, which was
directly due to failure to establish a value of timezone_abbreviations
in postmaster child processes. The postmaster had the desired value,
but write_one_nondefault_variable() didn't transmit it to backends.
To fix that, invent a new value PGC_S_DYNAMIC_DEFAULT, and be sure to use
that or PGC_S_ENV_VAR (as appropriate) for "default" settings that are
computed during initialization. (We need both because there's at least
one variable that could receive a value from either source.)
This commit also fixes ProcessConfigFile's failure to restore the correct
default value for certain GUC variables if they are set in postgresql.conf
and then removed/commented out of the file. We have to recompute and
reinstall the value for any GUC variable that could have received a value
from PGC_S_DYNAMIC_DEFAULT or PGC_S_ENV_VAR sources, and there were a
number of oversights. (That whole thing is a crock that needs to be
redesigned, but not today.)
However, I intentionally didn't make it work "exactly right" for the cases
of timezone and log_timezone. The exactly right behavior would involve
running select_default_timezone, which we'd have to do independently in
each postgres process, causing the whole database to become entirely
unresponsive for as much as several seconds. That didn't seem like a good
idea, especially since the variable's removal from postgresql.conf might be
just an accidental edit. Instead the behavior is to adopt the previously
active setting as if it were default.
Note that this patch creates an ABI break for extensions that use any of
the PGC_S_XXX constants; they'll need to be recompiled.
The style is set to "printf" for backwards compatibility everywhere except
on Windows, where it is set to "gnu_printf", which eliminates hundreds of
false error messages from modern versions of gcc arising from %m and %ll{d,u}
formats.
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.
These functions should take a pg_locale_t, not a collation OID, and should
call mbstowcs_l/wcstombs_l where available. Where those functions are not
available, temporarily select the correct locale with uselocale().
This change removes the bogus assumption that all locales selectable in
a given database have the same wide-character conversion method; in
particular, the collate.linux.utf8 regression test now passes with
LC_CTYPE=C, so long as the database encoding is UTF8.
I decided to move the char2wchar/wchar2char functions out of mbutils.c and
into pg_locale.c, because they work on wchar_t not pg_wchar_t and thus
don't really belong with the mbutils.c functions. Keeping them where they
were would have required importing pg_locale_t into pg_wchar.h somehow,
which did not seem like a good plan.
Since collation is effectively an argument, not a property of the function,
FmgrInfo is really the wrong place for it; and this becomes critical in
cases where a cached FmgrInfo is used for varying purposes that might need
different collation settings. Fix by passing it in FunctionCallInfoData
instead. In particular this allows a clean fix for bug #5970 (record_cmp
not working). This requires touching a bit more code than the original
method, but nobody ever thought that collations would not be an invasive
patch...
This is necessary, not optional, now that ILIKE and regexes are collation
aware --- else we might derive a wrong comparison constant for index
optimized pattern matches.
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
I'm not sure these have any non-cosmetic implications, but I'm not sure
they don't, either. In particular, ensure the CaseTestExpr generated
by transformAssignmentIndirection to represent the base target column
carries the correct collation, because parse_collate.c won't fix that.
Tweak lsyscache.c API so that we can get the appropriate collation
without an extra syscache lookup.
While this will give wrong answers when estimating selectivity for a
comparison operator that's using a non-default collation, the estimation
error probably won't be large; and anyway the former approach created
estimation errors of its own by trying to use a histogram that might have
been computed with some other collation. So we'll adopt this simplified
approach for now and perhaps improve it sometime in the future.
This patch incorporates changes from Andres Freund to make sure that
selfuncs.c passes a valid collation OID to any datatype-specific function
it calls, in case that function wants collation information. Said OID will
now always be DEFAULT_COLLATION_OID, but at least we won't get errors.
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.
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.
This works around the problem noted by Yamamoto Takashi in bug #5906,
that there were code paths whereby we could reach AtCleanup_Portals
with a portal's cleanup hook still unexecuted. The changes I made
a few days ago were intended to prevent that from happening, and
I think that on balance it's still a good thing to avoid, so I don't
want to remove the Assert in AtCleanup_Portals. Hence do this instead.
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 originally committed patch for modifying CTEs didn't interact well
with EXPLAIN, as noted by myself, and also had corner-case problems with
triggers, as noted by Dean Rasheed. Those problems show it is really not
practical for ExecutorEnd to call any user-defined code; so split the
cleanup duties out into a new function ExecutorFinish, which must be called
between the last ExecutorRun call and ExecutorEnd. Some Asserts have been
added to these functions to help verify correct usage.
It is no longer necessary for callers of the executor to call
AfterTriggerBeginQuery/AfterTriggerEndQuery for themselves, as this is now
done by ExecutorStart/ExecutorFinish respectively. If you really need to
suppress that and do it for yourself, pass EXEC_FLAG_SKIP_TRIGGERS to
ExecutorStart.
Also, refactor portal commit processing to allow for the possibility that
PortalDrop will invoke user-defined code. I think this is not actually
necessary just yet, since the portal-execution-strategy logic forces any
non-pure-SELECT query to be run to completion before we will consider
committing. But it seems like good future-proofing.
This patch implements data-modifying WITH queries according to the
semantics that the updates all happen with the same command counter value,
and in an unspecified order. Therefore one WITH clause can't see the
effects of another, nor can the outer query see the effects other than
through the RETURNING values. And attempts to do conflicting updates will
have unpredictable results. We'll need to document all that.
This commit just fixes the code; documentation updates are waiting on
author.
Marko Tiikkaja and Hitoshi Harada
Add functions plpy.quote_ident, plpy.quote_literal,
plpy.quote_nullable, which wrap the equivalent SQL functions.
To be able to propagate char * constness properly, make the argument
of quote_literal_cstr() const char *. This also makes it more
consistent with quote_identifier().
Jan Urbański, reviewed by Hitoshi Harada, some refinements by Peter
Eisentraut
void_send is useful for the same reason that void_out doesn't throw error,
namely that someone might do "select void_returning_func(...)" from a
client that prefers to operate in binary mode. The void_recv function may
or may not have any practical use, but we provide it for symmetry.
Radosław Smogura
Add a fdwhandler column to pg_foreign_data_wrapper, plus HANDLER options
in the CREATE FOREIGN DATA WRAPPER and ALTER FOREIGN DATA WRAPPER commands,
plus pg_dump support for same. Also invent a new pseudotype fdw_handler
with properties similar to language_handler.
This is split out of the "FDW API" patch for ease of review; it's all stuff
we will certainly need, regardless of any other details of the FDW API.
FDW handler functions will not actually get called yet.
In passing, fix some omissions and infelicities in foreigncmds.c.
Shigeru Hanada, Jan Urbanski, Heikki Linnakangas
They share the same locking namespace with the existing session-level
advisory locks, but they are automatically released at the end of the
current transaction and cannot be released explicitly via unlock
functions.
Marko Tiikkaja, reviewed by me.
These are needed to support reloading dumps of 9.0 installations containing
contrib/intarray or contrib/tsearch2. Since not only regular dump/reload
but binary upgrade would fail, it seems worth the trouble to carry these
stubs for awhile. Note that the contrib opclasses referencing these
functions will still work fine, since GIN doesn't actually pay any
attention to the declared signature of a support function.
(I'm not entirely sure that we've finished bikeshedding the syntax details,
but the functionality seems OK.)
Pavel Stehule, reviewed by Stephen Frost and Tom Lane
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
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
src/pl/plpgsql/src/plerrcodes.h, src/include/utils/errcodes.h, and a
big chunk of errcodes.sgml are now automatically generated from a single
file, src/backend/utils/errcodes.txt.
Jan Urbański, reviewed by Tom Lane.
Previously reported as ERRCODE_ADMIN_SHUTDOWN, this case is now
reported as ERRCODE_T_R_DATABASE_DROPPED. No message text change.
Unlikely to happen on most servers, so low impact change to allow
session poolers to correctly handle this situation.
Tatsuo Ishii, edits by me, review by Robert Haas
The new coding avoids a spurious debug message when a transaction
that has changed the isolation level has been rolled back. It also
allows the property to be freely changed to the current value within
a subtransaction.
Kevin Grittner, with one small change by me.
This will support fixing contrib/intarray (and probably other places)
so that they don't have to fail on arrays that contain a null bitmap
but no live null entries.
Per my recent proposal(s). Null key datums can now be returned by
extractValue and extractQuery functions, and will be stored in the index.
Also, placeholder entries are made for indexable items that are NULL or
contain no keys according to extractValue. This means that the index is
now always complete, having at least one entry for every indexed heap TID,
and so we can get rid of the prohibition on full-index scans. A full-index
scan is implemented much the same way as partial-match scans were already:
we build a bitmap representing all the TIDs found in the index, and then
drive the results off that.
Also, introduce a concept of a "search mode" that can be requested by
extractQuery when the operator requires matching to empty items (this is
just as cheap as matching to a single key) or requires a full index scan
(which is not so cheap, but it sure beats failing or giving wrong answers).
The behavior remains backward compatible for opclasses that don't return
any null keys or request a non-default search mode.
Using these features, we can now make the GIN index opclass for anyarray
behave in a way that matches the actual anyarray operators for &&, <@, @>,
and = ... which it failed to do before in assorted corner cases.
This commit fixes the core GIN code and ginarrayprocs.c, updates the
documentation, and adds some simple regression test cases for the new
behaviors using the array operators. The tsearch and contrib GIN opclass
support functions still need to be looked over and probably fixed.
Another thing I intend to fix separately is that this is pretty inefficient
for cases where more than one scan condition needs a full-index search:
we'll run duplicate GinScanEntrys, each one of which builds a large bitmap.
There is some existing logic to merge duplicate GinScanEntrys but it needs
refactoring to make it work for entries belonging to different scan keys.
Note that most of gin.h has been split out into a new file gin_private.h,
so that gin.h doesn't export anything that's not supposed to be used by GIN
opclasses or the rest of the backend. I did quite a bit of other code
beautification work as well, mostly fixing comments and choosing more
appropriate names for things.
Foreign tables are a core component of SQL/MED. This commit does
not provide a working SQL/MED infrastructure, because foreign tables
cannot yet be queried. Support for foreign table scans will need to
be added in a future patch. However, this patch creates the necessary
system catalog structure, syntax support, and support for ancillary
operations such as COMMENT and SECURITY LABEL.
Shigeru Hanada, heavily revised by Robert Haas
The contents of an unlogged table are WAL-logged; thus, they are not
available on standby servers and are truncated whenever the database
system enters recovery. Indexes on unlogged tables are also unlogged.
Unlogged GiST indexes are not currently supported.
The "date" type supports a wider range of dates than int64 timestamps do.
However, there is pre-int64-timestamp code in the planner that assumes that
all date values can be converted to timestamp with impunity. Fortunately,
what we really need out of the conversion is always a double (float8)
value; so even when the date is out of timestamp's range it's possible to
produce a sane answer. All we need is a code path that doesn't try to
force the result into int64. Per trouble report from David Rericha.
Back-patch to all supported versions. Although this is surely a corner
case, there's not much point in advertising a date range wider than
timestamp's if we will choke on such values in unexpected places.
This is to avoid use of the C++ keywords "bitand" and "bitor" in
the header file utils/varbit.h. Note the functions' SQL-level
names are not changed, only their C-level names.
In passing, make some comments in varbit.c conform to project-standard
layout.
My previous commit, 85cff3ce7f on
2010-12-25, failed to update errcodes.sgml or plerrcodes.h. This patch
corrects that oversight, per a gripe from Tom Lane, and also corrects
a typographical error.
This commit replaces pg_class.relistemp with pg_class.relpersistence;
and also modifies the RangeVar node type to carry relpersistence rather
than istemp. It also removes removes rd_istemp from RelationData and
instead performs the correct computation based on relpersistence.
For clarity, we add three new macros: RelationNeedsWAL(),
RelationUsesLocalBuffers(), and RelationUsesTempNamespace(), so that we
can clarify the purpose of each check that previous depended on
rd_istemp.
This is intended as infrastructure for the upcoming unlogged tables
patch, as well as for future possible work on global temporary tables.
This commit represents a rather heavily editorialized version of
Teodor's builtin_knngist_itself-0.8.2 and builtin_knngist_proc-0.8.1
patches. I redid the opclass API to add a separate Distance method
instead of turning the Consistent method into an illogical mess,
fixed some bit-rot in the rbtree interfaces, and generally worked over
the code style and comments.
There's still no non-code documentation to speak of, but I'll work on
that separately. Some contrib-module changes are also yet to come
(right now, point <-> point is the only KNN-ified operator).
Teodor Sigaev and Tom Lane
This eliminates some crufty, special-purpose code and, as a non-trivial
side benefit, allows recovery.conf parameters to be unquoted.
Dimitri Fontaine, with review and cleanup by Alvaro Herrera, Itagaki
Takahiro, and me.
This is a heavily revised version of builtin_knngist_core-0.9. The
ordering operators are no longer mixed in with actual quals, which would
have confused not only humans but significant parts of the planner.
Instead, ordering operators are carried separately throughout planning and
execution.
Since the API for ambeginscan and amrescan functions had to be changed
anyway, this commit takes the opportunity to rationalize that a bit.
RelationGetIndexScan no longer forces a premature index_rescan call;
instead, callers of index_beginscan must call index_rescan too. Aside from
making the AM-side initialization logic a bit less peculiar, this has the
advantage that we do not make a useless extra am_rescan call when there are
runtime key values. AMs formerly could not assume that the key values
passed to amrescan were actually valid; now they can.
Teodor Sigaev and Tom Lane
Formerly we looked up the operators associated with each index (caching
them in relcache) and then the planner looked up the btree opfamily
containing such operators in order to build the btree-centric pathkey
representation that describes the index's sort order. This is quite
pointless for btree indexes: we might as well just use the index's opfamily
information directly. That saves syscache lookup cycles during planning,
and furthermore allows us to eliminate the relcache's caching of operators
altogether, which may help in reducing backend startup time.
I added code to plancat.c to perform the same type of double lookup
on-the-fly if it's ever faced with a non-btree amcanorder index AM.
If such a thing actually becomes interesting for production, we should
replace that logic with some more-direct method for identifying the
corresponding btree opfamily; but it's not worth spending effort on now.
There is considerably more to do pursuant to my recent proposal to get rid
of sort-operator-based representations of sort orderings, but this patch
grabs some of the low-hanging fruit. I'll look at the remainder of that
work after the current commitfest.
supplied, also print the IP address. This allows IPv4 and IPv6 failures
to be distinguished. Also useful when a hostname resolves to multiple
IP addresses.
Also, remove use of inet_ntoa() and use our own inet_net_ntop() in all
places, including in libpq, because it is thread-safe.
Currently, three conversion format specifiers are supported: %s for a
string, %L for an SQL literal, and %I for an SQL identifier. The latter
two are deliberately designed not to overlap with what sprintf() already
supports, in case we want to add more of sprintf()'s functionality here
later.
Patch by Pavel Stehule, heavily revised by me. Reviewed by Jeff Janes
and, in earlier versions, by Itagaki Takahiro and Tom Lane.
This eliminates the need for inefficient implementions of this
functionality in both contrib/dblink and contrib/tablefunc, so remove
them. The upcoming patch implementing an in-core format() function
will also require this functionality.
In passing, add some regression tests.
A hand-coded implementation turns out to be much faster than calling
printf(). In passing, add a few more regresion tests.
Andres Freund, with assorted, mostly cosmetic changes.
The core of this patch is hash_array() and associated typcache
infrastructure, which works just about exactly like the existing support
for array comparison.
In addition I did some work to ensure that the planner won't think that an
array type is hashable unless its element type is hashable, and similarly
for sorting. This includes adding a datatype parameter to op_hashjoinable
and op_mergejoinable, and adding an explicit "hashable" flag to
SortGroupClause. The lack of a cross-check on the element type was a
pre-existing bug in mergejoin support --- but it didn't matter so much
before, because if you couldn't sort the element type there wasn't any good
alternative to failing anyhow. Now that we have the alternative of hashing
the array type, there are cases where we can avoid a failure by being picky
at the planner stage, so it's time to be picky.
The issue of exactly how to combine the per-element hash values to produce
an array hash is still open for discussion, but the rest of this is pretty
solid, so I'll commit it as-is.
After much expenditure of effort, we've got this to the point where the
performance penalty is pretty minimal in typical cases.
Andrew Dunstan, reviewed by Brendan Jurd, Dean Rasheed, and Tom Lane
This patch eliminates various bizarre behaviors caused by sloppy thinking
about the difference between a domain type and its underlying array type.
In particular, the operation of updating one element of such an array
has to be considered as yielding a value of the underlying array type,
*not* a value of the domain, because there's no assurance that the
domain's CHECK constraints are still satisfied. If we're intending to
store the result back into a domain column, we have to re-cast to the
domain type so that constraints are re-checked.
For similar reasons, such a domain can't be blindly matched to an ANYARRAY
polymorphic parameter, because the polymorphic function is likely to apply
array-ish operations that could invalidate the domain constraints. For the
moment, we just forbid such matching. We might later wish to insert an
automatic downcast to the underlying array type, but such a change should
also change matching of domains to ANYELEMENT for consistency.
To ensure that all such logic is rechecked, this patch removes the original
hack of setting a domain's pg_type.typelem field to match its base type;
the typelem will always be zero instead. In those places where it's really
okay to look through the domain type with no other logic changes, use the
newly added get_base_element_type function in place of get_element_type.
catversion bumped due to change in pg_type contents.
Per bug #5717 from Richard Huxton and subsequent discussion.
This patch adds the SQL-standard concept of an INSTEAD OF trigger, which
is fired instead of performing a physical insert/update/delete. The
trigger function is passed the entire old and/or new rows of the view,
and must figure out what to do to the underlying tables to implement
the update. So this feature can be used to implement updatable views
using trigger programming style rather than rule hacking.
In passing, this patch corrects the names of some columns in the
information_schema.triggers view. It seems the SQL committee renamed
them somewhere between SQL:99 and SQL:2003.
Dean Rasheed, reviewed by Bernd Helmle; some additional hacking by me.
Since the code underlying pg_get_expr() is not secure against malformed
input, and can't practically be made so, we need to prevent miscreants
from feeding arbitrary data to it. We can do this securely by declaring
pg_get_expr() to take a new datatype "pg_node_tree" and declaring the
system catalog columns that hold nodeToString output to be of that type.
There is no way at SQL level to create a non-null value of type pg_node_tree.
Since the backend-internal operations that fill those catalog columns
operate below the SQL level, they are oblivious to the datatype relabeling
and don't need any changes.
SI invalidation events, rather than indirectly through the relcache.
In the previous coding, we had to flush a composite-type typcache entry
whenever we discarded the corresponding relcache entry. This caused problems
at least when testing with RELCACHE_FORCE_RELEASE, as shown in recent report
from Jeff Davis, and might result in real-world problems given the kind of
unexpected relcache flush that that test mechanism is intended to model.
The new coding decouples relcache and typcache management, which is a good
thing anyway from a structural perspective. The cost is that we have to
search the typcache linearly to find entries that need to be flushed. There
are a couple of ways we could avoid that, but at the moment it's not clear
it's worth any extra trouble, because the typcache contains very few entries
in typical operation.
Back-patch to 8.2, the same as some other recent fixes in this general area.
The patch could be carried back to 8.0 with some additional work, but given
that it's only hypothetical whether we're fixing any problem observable in
the field, it doesn't seem worth the work now.
This allows us to reliably remove all leftover temporary relation
files on cluster startup without reference to system catalogs or WAL;
therefore, we no longer include temporary relations in XLOG_XACT_COMMIT
and XLOG_XACT_ABORT WAL records.
Since these changes require including a backend ID in each
SharedInvalSmgrMsg, the size of the SharedInvalidationMessage.id
field has been reduced from two bytes to one, and the maximum number
of connections has been reduced from INT_MAX / 4 to 2^23-1. It would
be possible to remove these restrictions by increasing the size of
SharedInvalidationMessage by 4 bytes, but right now that doesn't seem
like a good trade-off.
Review by Jaime Casanova and Tom Lane.
functions to the core XML code. Per discussion, the former depends on
XMLOPTION while the others do not. These supersede a version previously
offered by contrib/xml2.
Mike Fowler, reviewed by Pavel Stehule
better handling of NULL elements within the arrays. The third parameter
is a string that should be used to represent a NULL element, or should
be translated into a NULL element, respectively. If the third parameter
is NULL it behaves the same as the two-parameter form.
There are two incompatible changes in the behavior of the two-parameter form
of string_to_array. First, it will return an empty (zero-element) array
rather than NULL when the input string is of zero length. Second, if the
field separator is NULL, the function splits the string into individual
characters, rather than returning NULL as before. These two changes make
this form fully compatible with the behavior of the new three-parameter form.
Pavel Stehule, reviewed by Brendan Jurd
functionality, while creating an ambiguity in usage with ORDER BY that at
least two people have already gotten seriously confused by. Also, add an
opr_sanity test to check that we don't in future violate the newly minted
policy of not having built-in aggregates with the same name and different
numbers of parameters. Per discussion of a complaint from Thom Brown.
unqualified names.
- Add a missing_ok parameter to get_tablespace_oid.
- Avoid duplicating get_tablespace_od guts in objectNamesToOids.
- Add a missing_ok parameter to get_database_oid.
- Replace get_roleid and get_role_checked with get_role_oid.
- Add get_namespace_oid, get_language_oid, get_am_oid.
- Refactor existing code to use new interfaces.
Thanks to KaiGai Kohei for the review.
struct representing a tree entry, rather than being a separately allocated
piece of storage. This API is at least as clean as the old one (if not
more so --- there were some bizarre choices in there) and it permits a
very substantial memory savings, on the order of 2X in ginbulk.c's usage.
Also, fix minor memory leaks in code called by ginEntryInsert, in
particular in ginInsertValue and entryFillRoot, as well as ginEntryInsert
itself. These leaks resulted in the GIN index build context continuing
to bloat even after we'd filled it to maintenance_work_mem and started
to dump data out to the index.
In combination these fixes restore the GIN index build code to honoring
the maintenance_work_mem limit about as well as it did in 8.4. Speed
seems on par with 8.4 too, maybe even a bit faster, for a non-pathological
case in which HEAD was formerly slower.
Back-patch to 9.0 so we don't have a performance regression from 8.4.
I've added a quote_all_identifiers GUC which affects the behavior
of the backend, and a --quote-all-identifiers argument to pg_dump
and pg_dumpall which sets the GUC and also affects the quoting done
internally by those applications.
Design by Tom Lane; review by Alex Hunsaker; in response to bug #5488
filed by Hartmut Goebel.
Normally, we automatically restart after a backend crash, but in some
cases when PostgreSQL is invoked by clusterware it may be desirable to
suppress this behavior, so we provide an option which does this.
Since no existing GUC group quite fits, create a new group called
"error handling options" for this and the previously undocumented GUC
exit_on_error, which is now documented.
Review by Fujii Masao.
rather than just $N. This brings the display of nestloop-inner-indexscan
plans back to where it's been, and incidentally improves the display of
SubPlan parameters as well. In passing, simplify the EXPLAIN code by
having it deal primarily in the PlanState tree rather than separately
searching Plan and PlanState trees. This is noticeably cleaner for
subplans, and about a wash elsewhere.
One small difference from previous behavior is that EXPLAIN will no longer
qualify local variable references in inner-indexscan plan nodes, since it
no longer sees such nodes as possibly referencing multiple tables. Vars
referenced through PARAM_EXEC Params are still forcibly qualified, though,
so I don't think the display is any more confusing than before. Adjust a
couple of examples in the documentation to match this behavior.
being used in a PL/pgSQL FOR loop is closed was inadequate, as Tom Lane
pointed out. The bug affects FOR statement variants too, because you can
close an implicitly created cursor too by guessing the "<unnamed portal X>"
name created for it.
To fix that, "pin" the portal to prevent it from being dropped while it's
being used in a PL/pgSQL FOR loop. Backpatch all the way to 7.4 which is
the oldest supported version.
description for vacuum_defer_cleanup_age to the correct category.
Sections in postgresql.conf are also sorted in the same order with docs.
Per gripe by Fujii Masao, suggestion by Heikki Linnakangas, and patch by me.
by a superuser -- "ALTER USER f RESET setting" already disallows removing such a
setting.
Apply the same treatment to ALTER DATABASE d RESET ALL when run by a database
owner that's not superuser.
too, instead of duplicating the functionality (badly).
I renamed xml_init to pg_xml_init, because the former seemed just a bit too
generic to be safe as a global symbol. I considered likewise renaming
xml_ereport to pg_xml_ereport, but felt that the reference to ereport probably
made it sufficiently PG-centric already.
The purpose of this change is to eliminate the need for every caller
of SearchSysCache, SearchSysCacheCopy, SearchSysCacheExists,
GetSysCacheOid, and SearchSysCacheList to know the maximum number
of allowable keys for a syscache entry (currently 4). This will
make it far easier to increase the maximum number of keys in a
future release should we choose to do so, and it makes the code
shorter, too.
Design and review by Tom Lane.
defined. Its reference to CurrentMemoryContext causes link failures on some
platforms, evidently because the inline function gets compiled despite lack of
use. Per buildfarm member warthog.
compilers, by applying a configure check to see if the compiler will accept
an unreferenced "static inline foo ..." function without warnings. It is
believed that such warnings are the only reason not to declare inlined
functions in headers, if the compiler understands "inline" at all.
Kurt Harriman
several places, but for now only GIN uses it during index creation.
Using self-balanced tree greatly speeds up index creation in corner cases
with preordered data.
Move rd_targblock, rd_fsm_nblocks, and rd_vm_nblocks from relcache to the smgr
relation entries, so that they will get reset to InvalidBlockNumber whenever
an smgr-level flush happens. Because we now send smgr invalidation messages
immediately (not at end of transaction) when a relation truncation occurs,
this ensures that other backends will reset their values before they next
access the relation. We no longer need the unreliable assumption that a
VACUUM that's doing a truncation will hold its AccessExclusive lock until
commit --- in fact, we can intentionally release that lock as soon as we've
completed the truncation. This patch therefore reverts (most of) Alvaro's
patch of 2009-11-10, as well as my marginal hacking on it yesterday. We can
also get rid of assorted no-longer-needed relcache flushes, which are far more
expensive than an smgr flush because they kill a lot more state.
In passing this patch fixes smgr_redo's failure to perform visibility-map
truncation, and cleans up some rather dubious assumptions in freespace.c and
visibilitymap.c about when rd_fsm_nblocks and rd_vm_nblocks can be out of
date.
needed by nothing else.
The restructuring I just finished doing on cache management exposed to me how
silly this routine was. Its function was to go into the catcache and blow
away all entries related to a given relation when there was a relcache flush
on that relation. However, there is no point in removing a catcache entry
if the catalog row it represents is still valid --- and if it isn't valid,
there must have been a catcache entry flush on it, because that's triggered
directly by heap_update or heap_delete on the catalog row. So this routine
accomplished nothing except to blow away valid cache entries that we'd very
likely be wanting in the near future to help reconstruct the relcache entry.
Dumb.
On top of which, it required a subtle and easy-to-get-wrong attribute in
syscache definitions, ie, the column containing the OID of the related
relation if any. Removing that is a very useful maintenance simplification.
VACUUM FULL INPLACE), along with a boatload of subsidiary code and complexity.
Per discussion, the use case for this method of vacuuming is no longer large
enough to justify maintaining it; not to mention that we don't wish to invest
the work that would be needed to make it play nicely with Hot Standby.
Aside from the code directly related to old-style VACUUM FULL, this commit
removes support for certain WAL record types that could only be generated
within VACUUM FULL, redirect-pointer removal in heap_page_prune, and
nontransactional generation of cache invalidation sinval messages (the last
being the sticking point for Hot Standby).
We still have to retain all code that copes with finding HEAP_MOVED_OFF and
HEAP_MOVED_IN flag bits on existing tuples. This can't be removed as long
as we want to support in-place update from pre-9.0 databases.
of shared or nailed system catalogs. This has two key benefits:
* The new CLUSTER-based VACUUM FULL can be applied safely to all catalogs.
* We no longer have to use an unsafe reindex-in-place approach for reindexing
shared catalogs.
CLUSTER on nailed catalogs now works too, although I left it disabled on
shared catalogs because the resulting pg_index.indisclustered update would
only be visible in one database.
Since reindexing shared system catalogs is now fully transactional and
crash-safe, the former special cases in REINDEX behavior have been removed;
shared catalogs are treated the same as non-shared.
This commit does not do anything about the recently-discussed problem of
deadlocks between VACUUM FULL/CLUSTER on a system catalog and other
concurrent queries; will address that in a separate patch. As a stopgap,
parallel_schedule has been tweaked to run vacuum.sql by itself, to avoid
such failures during the regression tests.
of old and new toast tables can be done either at the logical level (by
swapping the heaps' reltoastrelid links) or at the physical level (by swapping
the relfilenodes of the toast tables and their indexes). This is necessary
infrastructure for upcoming changes to support CLUSTER/VAC FULL on shared
system catalogs, where we cannot change reltoastrelid. The physical swap
saves a few catalog updates too.
We unfortunately have to keep the logical-level swap logic because in some
cases we will be adding or deleting a toast table, so there's no possibility
of a physical swap. However, that only happens as a consequence of schema
changes in the table, which we do not need to support for system catalogs,
so such cases aren't an obstacle for that.
In passing, refactor the cluster support functions a little bit to eliminate
unnecessarily-duplicated code; and fix the problem that while CLUSTER had
been taught to rename the final toast table at need, ALTER TABLE had not.
the relfilenode of currently-not-relocatable system catalogs.
1. Get rid of inval.c's dependency on relfilenode, by not having it emit
smgr invalidations as a result of relcache flushes. Instead, smgr sinval
messages are sent directly from smgr.c when an actual relation delete or
truncate is done. This makes considerably more structural sense and allows
elimination of a large number of useless smgr inval messages that were
formerly sent even in cases where nothing was changing at the
physical-relation level. Note that this reintroduces the concept of
nontransactional inval messages, but that's okay --- because the messages
are sent by smgr.c, they will be sent in Hot Standby slaves, just from a
lower logical level than before.
2. Move setNewRelfilenode out of catalog/index.c, where it never logically
belonged, into relcache.c; which is a somewhat debatable choice as well but
better than before. (I considered catalog/storage.c, but that seemed too
low level.) Rename to RelationSetNewRelfilenode.
3. Cosmetic cleanups of some other relfilenode manipulations.
the input values into a string. The two argument version also does the same
thing, but inserts delimiters between elements.
Original patch by Pavel Stehule, reviewed by David E. Wheeler and me.
default of "plpgsql". This is more reasonable than it was when the DO patch
was written, because we have since decided that plpgsql should be installed
by default. Per discussion, having a parameter for this doesn't seem useful
enough to justify the risk of application breakage if the value is changed
unexpectedly.
and implement OVERLAY() for bit strings and bytea.
In passing also convert text OVERLAY() to a true built-in, instead of
relying on a SQL function.
Leonardo F, reviewed by Kevin Grittner
pg_constraint before searching pg_trigger. This allows saner handling of
corner cases; in particular we now say "constraint is not deferrable"
rather than "constraint does not exist" when the command is applied to
a constraint that's inherently non-deferrable. Per a gripe several months
ago from hubert depesz lubaczewski.
To make this work without breaking user-defined constraint triggers,
we have to add entries for them to pg_constraint. However, in return
we can remove the pgconstrname column from pg_constraint, which represents
a fairly sizable space savings. I also replaced the tgisconstraint column
with tgisinternal; the old meaning of tgisconstraint can now be had by
testing for nonzero tgconstraint, while there is no other way to get
the old meaning of nonzero tgconstraint, namely that the trigger was
internally generated rather than being user-created.
In passing, fix an old misstatement in the docs and comments, namely that
pg_trigger.tgdeferrable is exactly redundant with pg_constraint.condeferrable.
Actually, we mark RI action triggers as nondeferrable even when they belong to
a nominally deferrable FK constraint. The SET CONSTRAINTS code now relies on
that instead of hard-coding a list of exception OIDs.
This includes two new kinds of postmaster processes, walsenders and
walreceiver. Walreceiver is responsible for connecting to the primary server
and streaming WAL to disk, while walsender runs in the primary server and
streams WAL from disk to the client.
Documentation still needs work, but the basics are there. We will probably
pull the replication section to a new chapter later on, as well as the
sections describing file-based replication. But let's do that as a separate
patch, so that it's easier to see what has been added/changed. This patch
also adds a new section to the chapter about FE/BE protocol, documenting the
protocol used by walsender/walreceivxer.
Bump catalog version because of two new functions,
pg_last_xlog_receive_location() and pg_last_xlog_replay_location(), for
monitoring the progress of replication.
Fujii Masao, with additional hacking by me
we're not going to support that anymore.
I did keep the 64-bit-CRC-with-32-bit-arithmetic code, since it has a
performance excuse to live. It's a bit moot since that's all ifdef'd
out, of course.
This patch only supports seq_page_cost and random_page_cost as parameters,
but it provides the infrastructure to scalably support many more.
In particular, we may want to add support for effective_io_concurrency,
but I'm leaving that as future work for now.
Thanks to Tom Lane for design help and Alvaro Herrera for the review.
"column < constant", and the comparison value is in the first or last
histogram bin or outside the histogram entirely, try to fetch the actual
column min or max value using an index scan (if there is an index on the
column). If successful, replace the lower or upper histogram bound with
that value before carrying on with the estimate. This limits the
estimation error caused by moving min/max values when the comparison
value is close to the min or max. Per a complaint from Josh Berkus.
It is tempting to consider using this mechanism for mergejoinscansel as well,
but that would inject index fetches into main-line join estimation not just
endpoint cases. I'm refraining from that until we can get a better handle
on the costs of doing this type of lookup.
and teach ANALYZE to compute such stats for tables that have subclasses.
Per my proposal of yesterday.
autovacuum still needs to be taught about running ANALYZE on parent tables
when their subclasses change, but the feature is useful even without that.
Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record.
New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far.
This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required.
Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit.
Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
an allegedly immutable index function. It was previously recognized that
we had to prevent such a function from executing SET/RESET ROLE/SESSION
AUTHORIZATION, or it could trivially obtain the privileges of the session
user. However, since there is in general no privilege checking for changes
of session-local state, it is also possible for such a function to change
settings in a way that might subvert later operations in the same session.
Examples include changing search_path to cause an unexpected function to
be called, or replacing an existing prepared statement with another one
that will execute a function of the attacker's choosing.
The present patch secures VACUUM, ANALYZE, and CREATE INDEX/REINDEX against
these threats, which are the same places previously deemed to need protection
against the SET ROLE issue. GUC changes are still allowed, since there are
many useful cases for that, but we prevent security problems by forcing a
rollback of any GUC change after completing the operation. Other cases are
handled by throwing an error if any change is attempted; these include temp
table creation, closing a cursor, and creating or deleting a prepared
statement. (In 7.4, the infrastructure to roll back GUC changes doesn't
exist, so we settle for rejecting changes of "search_path" in these contexts.)
Original report and patch by Gurjeet Singh, additional analysis by
Tom Lane.
Security: CVE-2009-4136
support any indexable commutative operator, not just equality. Two rows
violate the exclusion constraint if "row1.col OP row2.col" is TRUE for
each of the columns in the constraint.
Jeff Davis, reviewed by Robert Haas
Instead of expensive cross joins to resolve the ACL, add table-returning
function aclexplode() that expands the ACL into a useful form, and join
against that.
Also, implement the role_*_grants views as a thin layer over the respective
*_privileges views instead of essentially repeating the same code twice.
fixes bug #4596
by Joachim Wieland, with cleanup by me
in a subtransaction stays open even if the subtransaction is aborted, so
any temporary files related to it must stay alive as well. With the patch,
we use ResourceOwners to track open temporary files and don't automatically
close them at subtransaction end (though in the normal case temporary files
are registered with the subtransaction resource owner and will therefore be
closed).
At end of top transaction, we still check that there's no temporary files
marked as close-at-end-of-transaction open, but that's now just a debugging
cross-check as the resource owner cleanup should've closed them already.
checked to determine whether the trigger should be fired.
For BEFORE triggers this is mostly a matter of spec compliance; but for AFTER
triggers it can provide a noticeable performance improvement, since queuing of
a deferred trigger event and re-fetching of the row(s) at end of statement can
be short-circuited if the trigger does not need to be fired.
Takahiro Itagaki, reviewed by KaiGai Kohei.
As proof of concept, modify plpgsql to use the hooks. plpgsql is still
inserting $n symbols textually, but the "back end" of the parsing process now
goes through the ParamRef hook instead of using a fixed parameter-type array,
and then execution only fetches actually-referenced parameters, using a hook
added to ParamListInfo.
Although there's a lot left to be done in plpgsql, this already cures the
"if (TG_OP = 'INSERT' and NEW.foo ...)" problem, as illustrated by the
changed regression test.
those accepted by date_in(). I confused julian day numbers and number of
days since the postgres epoch 2000-01-01 in the original patch.
I just noticed that it's still easy to get such out-of-range values into
the database using to_date or +- operators, but this patch doesn't do
anything about those functions.
Per report from James Pye.
style by default. Per discussion, there seems to be hardly anything that
really relies on being able to change the regex flavor, so the ability to
select it via embedded options ought to be enough for any stragglers.
Also, if we didn't remove the GUC, we'd really be morally obligated to
mark the regex functions non-immutable, which'd possibly create performance
issues.
Add a variant of pg_get_triggerdef with a second argument "pretty" that
causes the output to be formatted in the way pg_dump used to do. Use this
variant in pg_dump with server versions >= 8.5.
This insulates pg_dump from most future trigger feature additions, such as
the upcoming column triggers patch.
Author: Itagaki Takahiro <itagaki.takahiro@oss.ntt.co.jp>
Create a new catalog pg_db_role_setting where they are now stored, and better
encapsulate the code that deals with settings into its realm. The old
datconfig and rolconfig columns are removed.
psql has gained a \drds command to display the settings.
Backwards compatibility warning: while the backwards-compatible system views
still have the config columns, they no longer completely represent the
configuration for a user or database.
Catalog version bumped.
Partially revert the previous patch I installed and replace it with a more
general fix: any time a snapshot is pushed as Active, we need to ensure that it
will not be modified in the future. This means that if the same snapshot is
used as CurrentSnapshot, it needs to be copied separately. This affects
serializable transactions only, because CurrentSnapshot has already been copied
by RegisterSnapshot and so PushActiveSnapshot does not think it needs another
copy. However, CommandCounterIncrement would modify CurrentSnapshot, whereas
ActiveSnapshots must not have their command counters incremented.
I say "partially" because the regression test I added for the previous bug
has been kept.
(This restores 8.3 behavior, because before snapmgr.c existed, any snapshot set
as Active was copied.)
Per bug report from Stuart Bishop in
6bc73d4c0910042358k3d1adff3qa36f8df75198ecea@mail.gmail.com
the privileges that will be applied to subsequently-created objects.
Such adjustments are always per owning role, and can be restricted to objects
created in particular schemas too. A notable benefit is that users can
override the traditional default privilege settings, eg, the PUBLIC EXECUTE
privilege traditionally granted by default for functions.
Petr Jelinek
settings: avoid calling superuser() in contexts where it's not defined,
don't leak the transient copies of GetConfigOption output, and avoid the
whole exercise in postmaster child processes.
I found that actually no current caller of GetConfigOption has any use for
its internal check of GUC_SUPERUSER_ONLY. But rather than just remove
that entirely, it seemed better to add a parameter indicating whether to
enforce the check.
Per report from Simon and subsequent testing.
The old coding was using a regular snapshot, referenced elsewhere, that was
subject to having its command counter updated. Fix by creating a private copy
of the snapshot exclusively for the cursor.
Backpatch to 8.4, which is when the bug was introduced during the snapshot
management rewrite.
to create a function for it.
Procedural languages now have an additional entry point, namely a function
to execute an inline code block. This seemed a better design than trying
to hide the transient-ness of the code from the PL. As of this patch, only
plpgsql has an inline handler, but probably people will soon write handlers
for the other standard PLs.
In passing, remove the long-dead LANCOMPILER option of CREATE LANGUAGE.
Petr Jelinek
Before, PL/Python converted data between SQL and Python by going
through a C string representation. This broke for bytea in two ways:
- On input (function parameters), you would get a Python string that
contains bytea's particular external representation with backslashes
etc., instead of a sequence of bytes, which is what you would expect
in a Python environment. This problem is exacerbated by the new
bytea output format.
- On output (function return value), null bytes in the Python string
would cause truncation before the data gets stored into a bytea
datum.
This is now fixed by converting directly between the PostgreSQL datum
and the Python representation.
The required generalized infrastructure also allows for other
improvements in passing:
- When returning a boolean value, the SQL datum is now true if and
only if Python considers the value that was passed out of the
PL/Python function to be true. Previously, this determination was
left to the boolean data type input function. So, now returning
'foo' results in true, because Python considers it true, rather than
false because PostgreSQL considers it false.
- On input, we can convert the integer and float types directly to
their Python equivalents without having to go through an
intermediate string representation.
original patch by Caleb Welton, with updates by myself
input functions don't accept either. While the backend can handle such
values fine, they can cause trouble in clients and in pg_dump/restore.
This is followup to the original issue on time datatype reported by Andrew
McNamara a while ago. Like that one, none of these seem worth
back-patching.
functions.
This extends the previous patch that forbade SETting these variables inside
security-definer functions. RESET is equally a security hole, since it
would allow regaining privileges of the caller; furthermore it can trigger
Assert failures and perhaps other internal errors, since the code is not
expecting these variables to change in such contexts. The previous patch
did not cover this case because assign hooks don't really have enough
information, so move the responsibility for preventing this into guc.c.
Problem discovered by Heikki Linnakangas.
Security: no CVE assigned yet, extends CVE-2007-6600
Recent commits have removed the various uses it was supporting. It was a
performance bottleneck, according to bug report #4919 by Lauris Ulmanis; seems
it slowed down user creation after a billion users.
(That flat file is now completely useless, but removal will come later.)
To do this, postpone client authentication into the startup transaction
that's run by InitPostgres. We still collect the startup packet and do
SSL initialization (if needed) at the same time we did before. The
AuthenticationTimeout is applied separately to startup packet collection
and the actual authentication cycle. (This is a bit annoying, since it
means a couple extra syscalls; but the signal handling requirements inside
and outside a transaction are sufficiently different that it seems best
to treat the timeouts as completely independent.)
A small security disadvantage is that if the given database name is invalid,
this will be reported to the client before any authentication happens.
We could work around that by connecting to database "postgres" instead,
but consensus seems to be that it's not worth introducing such surprising
behavior.
Processing of all command-line switches and GUC options received from the
client is now postponed until after authentication. This means that
PostAuthDelay is much less useful than it used to be --- if you need to
investigate problems during InitPostgres you'll have to set PreAuthDelay
instead. However, allowing an unauthenticated user to set any GUC options
whatever seems a bit too risky, so we'll live with that.
To make this work in the base case, pg_database now has a nailed-in-cache
relation descriptor that is initialized using hardwired knowledge in
relcache.c. This means pg_database is added to the set of relations that
need to have a Schema_pg_xxx macro maintained in pg_attribute.h. When this
path is taken, we'll have to do a seqscan of pg_database to find the row
we need.
In the normal case, we are able to do an indexscan to find the database's row
by name. This is made possible by storing a global relcache init file that
describes only the shared catalogs and their indexes (and therefore is usable
by all backends in any database). A new backend loads this cache file,
finds its database OID after an indexscan on pg_database, and then loads
the local relcache init file for that database.
This change should effectively eliminate number of databases as a factor
in backend startup time, even with large numbers of databases. However,
the real reason for doing it is as a first step towards getting rid of
the flat files altogether. There are still several other sub-projects
to be tackled before that can happen.
