Commit Graph

602 Commits

Author SHA1 Message Date
Robert Haas
fd1843ff89 Standardize get_whatever_oid functions for other object types.
- Rename TSParserGetPrsid to get_ts_parser_oid.
- Rename TSDictionaryGetDictid to get_ts_dict_oid.
- Rename TSTemplateGetTmplid to get_ts_template_oid.
- Rename TSConfigGetCfgid to get_ts_config_oid.
- Rename FindConversionByName to get_conversion_oid.
- Rename GetConstraintName to get_constraint_oid.
- Add new functions get_opclass_oid, get_opfamily_oid, get_rewrite_oid,
  get_rewrite_oid_without_relid, get_trigger_oid, and get_cast_oid.

The name of each function matches the corresponding catalog.

Thanks to KaiGai Kohei for the review.
2010-08-05 15:25:36 +00:00
Robert Haas
2a6ef3445c Standardize get_whatever_oid functions for object types with
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.
2010-08-05 14:45:09 +00:00
Tom Lane
5ce63f480b Avoid an Assert failure in deconstruct_array() by making get_attstatsslot()
use the actual element type of the array it's disassembling, rather than
trusting the type OID passed in by its caller.  This is needed because
sometimes the planner passes in a type OID that's only binary-compatible
with the target column's type, rather than being an exact match.  Per an
example from Bernd Helmle.

Possibly we should refactor get_attstatsslot/free_attstatsslot to not expect
the caller to supply type ID data at all, but for now I'll just do the
minimum-change fix.

Back-patch to 7.4.  Bernd's test case only crashes back to 8.0, but since
these subroutines are the same in 7.4, I suspect there may be variant
cases that would crash 7.4 as well.
2010-07-09 22:57:39 +00:00
Bruce Momjian
239d769e7e pgindent run for 9.0, second run 2010-07-06 19:19:02 +00:00
Simon Riggs
90e04bab39 Patch revoked because of objections. 2010-04-24 16:20:32 +00:00
Simon Riggs
473af39737 Add missing optimizer hooks for function cost and number of rows.
Closely follow design of other optimizer hooks: if hook exists
retrieve value from plugin; if still not set then get from cache.
2010-04-23 22:23:39 +00:00
Tom Lane
ea46000a40 Arrange for client authentication to occur before we select a specific
database to connect to. This is necessary for the walsender code to work
properly (it was previously using an untenable assumption that template1 would
always be available to connect to).  This also gets rid of a small security
shortcoming that was introduced in the original patch to eliminate the flat
authentication files: before, you could find out whether or not the requested
database existed even if you couldn't pass the authentication checks.

The changes needed to support this are mainly just to treat pg_authid and
pg_auth_members as nailed relations, so that we can read them without having
to be able to locate real pg_class entries for them.  This mechanism was
already debugged for pg_database, but we hadn't recognized the value of
applying it to those catalogs too.

Since the current code doesn't have support for accessing toast tables before
we've brought up all of the relcache, remove pg_authid's toast table to ensure
that no one can store an out-of-line toasted value of rolpassword.  The case
seems quite unlikely to occur in practice, and was effectively unsupported
anyway in the old "flatfiles" implementation.

Update genbki.pl to actually implement the same rules as bootstrap.c does for
not-nullability of catalog columns.  The previous coding was a bit cheesy but
worked all right for the previous set of bootstrap catalogs.  It does not work
for pg_authid, where rolvaliduntil needs to be nullable.

Initdb forced due to minor catalog changes (mainly the toast table removal).
2010-04-20 23:48:47 +00:00
Tom Lane
73981cb451 Fix a problem introduced by my patch of 2010-01-12 that revised the way
relcache reload works.  In the patched code, a relcache entry in process of
being rebuilt doesn't get unhooked from the relcache hash table; which means
that if a cache flush occurs due to sinval queue overrun while we're
rebuilding it, the entry could get blown away by RelationCacheInvalidate,
resulting in crash or misbehavior.  Fix by ensuring that an entry being
rebuilt has positive refcount, so it won't be seen as a target for removal
if a cache flush occurs.  (This will mean that the entry gets rebuilt twice
in such a scenario, but that's okay.)  It appears that the problem can only
arise within a transaction that has previously reassigned the relfilenode of
a pre-existing table, via TRUNCATE or a similar operation.  Per bug #5412
from Rusty Conover.

Back-patch to 8.2, same as the patch that introduced the problem.
I think that the failure can't actually occur in 8.2, since it lacks the
rd_newRelfilenodeSubid optimization, but let's make it work like the later
branches anyway.

Patch by Heikki, slightly editorialized on by me.
2010-04-14 21:31:11 +00:00
Bruce Momjian
65e806cba1 pgindent run for 9.0 2010-02-26 02:01:40 +00:00
Tom Lane
50a90fac40 Stamp HEAD as 9.0devel, and update various places that were referring to 8.5
(hope I got 'em all).  Per discussion, this release will be 9.0 not 8.5.
2010-02-17 04:19:41 +00:00
Robert Haas
e26c539e9f Wrap calls to SearchSysCache and related functions using macros.
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.
2010-02-14 18:42:19 +00:00
Simon Riggs
dd428c79a4 Fix relcache init file invalidation during Hot Standby for the case
where a database has a non-default tablespaceid. Pass thru MyDatabaseId
and MyDatabaseTableSpace to allow file path to be re-created in
standby and correct invalidation to take place in all cases.
Update and rework xact_commit_desc() debug messages.
Bug report from Tom by code inspection. Fix by me.
2010-02-13 16:15:48 +00:00
Tom Lane
cbe9d6beb4 Fix up rickety handling of relation-truncation interlocks.
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.
2010-02-09 21:43:30 +00:00
Tom Lane
9a75803b1a Remove CatalogCacheFlushRelation, and the reloidattr infrastructure that was
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.
2010-02-08 05:53:55 +00:00
Tom Lane
0a469c8769 Remove old-style VACUUM FULL (which was known for a little while as
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.
2010-02-08 04:33:55 +00:00
Tom Lane
1c05b0b4ea Looks like we need #include <sys/stat.h> here on some
platforms.  Per buildfarm.
2010-02-07 22:00:53 +00:00
Tom Lane
b9b8831ad6 Create a "relation mapping" infrastructure to support changing the relfilenodes
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.
2010-02-07 20:48:13 +00:00
Tom Lane
9727c583fe Restructure CLUSTER/newstyle VACUUM FULL/ALTER TABLE support so that swapping
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.
2010-02-04 00:09:14 +00:00
Tom Lane
70a2b05a59 Assorted cleanups in preparation for using a map file to support altering
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.
2010-02-03 01:14:17 +00:00
Robert Haas
d779199175 Fix several oversights in previous commit - attribute options patch.
I failed to 'cvs add' the new files and also neglected to bump catversion.
2010-01-22 16:42:31 +00:00
Robert Haas
76a47c0e74 Replace ALTER TABLE ... SET STATISTICS DISTINCT with a more general mechanism.
Attributes can now have options, just as relations and tablespaces do, and
the reloptions code is used to parse, validate, and store them.  For
simplicity and because these options are not performance critical, we store
them in a separate cache rather than the main relcache.

Thanks to Alex Hunsaker for the review.
2010-01-22 16:40:19 +00:00
Tom Lane
08f8d478eb Do parse analysis of an EXPLAIN's contained statement during the normal
parse analysis phase, rather than at execution time.  This makes parameter
handling work the same as it does in ordinary plannable queries, and in
particular fixes the incompatibility that Pavel pointed out with plpgsql's
new handling of variable references.  plancache.c gets a little bit
grottier, but the alternatives seem worse.
2010-01-15 22:36:35 +00:00
Tom Lane
715120e7ac When loading critical system indexes into the relcache, ensure we lock the
underlying catalog not only the index itself.  Otherwise, if the cache
load process touches the catalog (which will happen for many though not
all of these indexes), we are locking index before parent table, which can
result in a deadlock against processes that are trying to lock them in the
normal order.  Per today's failure on buildfarm member gothic_moth; it's
surprising the problem hadn't been identified before.

Back-patch to 8.2.  Earlier releases didn't have the issue because they
didn't try to lock these indexes during load (instead assuming that they
couldn't change schema at all during multiuser operation).
2010-01-13 23:07:08 +00:00
Tom Lane
dbba3a1465 Fix bug #5269: ResetPlanCache mustn't invalidate cached utility statements,
especially not ROLLBACK.  ROLLBACK might need to be executed in an already
aborted transaction, when there is no safe way to revalidate the plan.  But
in general there's no point in marking utility statements invalid, since
they have no plans in the normal sense of the word; so we might as well
work a bit harder here to avoid future revalidation cycles.

Back-patch to 8.4, where the bug was introduced.
2010-01-13 16:56:56 +00:00
Tom Lane
491dd4a97d Fix relcache reload mechanism to be more robust in the face of errors
occurring during a reload, such as query-cancel.  Instead of zeroing out
an existing relcache entry and rebuilding it in place, build a new relcache
entry, then swap its contents with the old one, then free the new entry.
This avoids problems with code believing that a previously obtained pointer
to a cache entry must still reference a valid entry, as seen in recent
failures on buildfarm member jaguar.  (jaguar is using CLOBBER_CACHE_ALWAYS
which raises the probability of failure substantially, but the problem
could occur in the field without that.)  The previous design was okay
when it was made, but subtransactions and the ResourceOwner mechanism
make it unsafe now.

Also, make more use of the already existing rd_isvalid flag, so that we
remember that the entry requires rebuilding even if the first attempt fails.

Back-patch as far as 8.2.  Prior versions have enough issues around relcache
reload anyway (due to inadequate locking) that fixing this one doesn't seem
worthwhile.
2010-01-12 18:12:18 +00:00
Bruce Momjian
228170410d Please tablespace directories in their own subdirectory so pg_migrator
can upgrade clusters without renaming the tablespace directories.  New
directory structure format is, e.g.:

	$PGDATA/pg_tblspc/20981/PG_8.5_201001061/719849/83292814
2010-01-12 02:42:52 +00:00
Simon Riggs
42edbd16fb During Hot Standby, set DatabasePath correctly during relcache init file
deletion, so that we attempt to unlink the correct filepath. unlink()
errors are ignorable there, so lack of a DatabasePath initialization step
did not cause visible problems until a related bug showed up on Solaris.

Code refactored from xact_redo_commit() to
ProcessCommittedInvalidationMessages() in inval.c. Recovery may replay
shared invalidation messages for many databases, so we cannot
SetDatabasePath() once as we do in normal backends. Read the databaseid
from the shared invalidation messages, then set DatabasePath
temporarily before calling RelationCacheInitFileInvalidate().

Problem report by Robert Treat, analysis and fix by me.
2010-01-09 16:49:27 +00:00
Robert Haas
b1ee6daf2f Document why we copy reloptions into CacheMemoryContext after-the-fact. 2010-01-07 20:39:45 +00:00
Robert Haas
814c8a03ba Further fixes for per-tablespace options patch.
Add missing varlena header to TableSpaceOpts structure.  And, per
Tom Lane, instead of calling tablespace_reloptions in CacheMemoryContext,
call it in the caller's memory context and copy the value over
afterwards, to reduce the chances of a session-lifetime memory leak.
2010-01-07 03:53:08 +00:00
Tom Lane
9261b19fb5 Fix spccache.c to not suppose that a cache entry will live across database
access, per testing with CLOBBER_CACHE_ALWAYS.  Minor other editorialization.
2010-01-06 23:00:02 +00:00
Tom Lane
64b9c850e9 Access hash entry before freeing it, not after. 2010-01-06 22:27:09 +00:00
Robert Haas
d86d51a958 Support ALTER TABLESPACE name SET/RESET ( tablespace_options ).
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.
2010-01-05 21:54:00 +00:00
Tom Lane
64737e9313 Get rid of the need for manual maintenance of the initial contents of
pg_attribute, by having genbki.pl derive the information from the various
catalog header files.  This greatly simplifies modification of the
"bootstrapped" catalogs.

This patch finally kills genbki.sh and Gen_fmgrtab.sh; we now rely entirely on
Perl scripts for those build steps.  To avoid creating a Perl build dependency
where there was not one before, the output files generated by these scripts
are now treated as distprep targets, ie, they will be built and shipped in
tarballs.  But you will need a reasonably modern Perl (probably at least
5.6) if you want to build from a CVS pull.

The changes to the MSVC build process are untested, and may well break ---
we'll soon find out from the buildfarm.

John Naylor, based on ideas from Robert Haas and others
2010-01-05 01:06:57 +00:00
Tom Lane
40608e7f94 When estimating the selectivity of an inequality "column > constant" or
"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.
2010-01-04 02:44:40 +00:00
Bruce Momjian
0239800893 Update copyright for the year 2010. 2010-01-02 16:58:17 +00:00
Tom Lane
649b5ec7c8 Add the ability to store inheritance-tree statistics in pg_statistic,
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.
2009-12-29 20:11:45 +00:00
Tom Lane
d4d1885e42 Remove a couple of unnecessary calls of CreateCacheMemoryContext. These
probably got there via blind copy-and-paste from one of the legitimate
callers, so rearrange and comment that code a bit to make it clearer that
this isn't a necessary prerequisite to hash_create.  Per observation
from Robert Haas.
2009-12-27 18:55:52 +00:00
Simon Riggs
efc16ea520 Allow read only connections during recovery, known as Hot Standby.
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.
2009-12-19 01:32:45 +00:00
Tom Lane
0cb65564e5 Add exclusion constraints, which generalize the concept of uniqueness to
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
2009-12-07 05:22:23 +00:00
Tom Lane
9bedd128d6 Add support for invoking parser callback hooks via SPI and in cached plans.
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.
2009-11-04 22:26:08 +00:00
Tom Lane
9f2ee8f287 Re-implement EvalPlanQual processing to improve its performance and eliminate
a lot of strange behaviors that occurred in join cases.  We now identify the
"current" row for every joined relation in UPDATE, DELETE, and SELECT FOR
UPDATE/SHARE queries.  If an EvalPlanQual recheck is necessary, we jam the
appropriate row into each scan node in the rechecking plan, forcing it to emit
only that one row.  The former behavior could rescan the whole of each joined
relation for each recheck, which was terrible for performance, and what's much
worse could result in duplicated output tuples.

Also, the original implementation of EvalPlanQual could not re-use the recheck
execution tree --- it had to go through a full executor init and shutdown for
every row to be tested.  To avoid this overhead, I've associated a special
runtime Param with each LockRows or ModifyTable plan node, and arranged to
make every scan node below such a node depend on that Param.  Thus, by
signaling a change in that Param, the EPQ machinery can just rescan the
already-built test plan.

This patch also adds a prohibition on set-returning functions in the
targetlist of SELECT FOR UPDATE/SHARE.  This is needed to avoid the
duplicate-output-tuple problem.  It seems fairly reasonable since the
other restrictions on SELECT FOR UPDATE are meant to ensure that there
is a unique correspondence between source tuples and result tuples,
which an output SRF destroys as much as anything else does.
2009-10-26 02:26:45 +00:00
Tom Lane
8a5849b7ff Split the processing of INSERT/UPDATE/DELETE operations out of execMain.c.
They are now handled by a new plan node type called ModifyTable, which is
placed at the top of the plan tree.  In itself this change doesn't do much,
except perhaps make the handling of RETURNING lists and inherited UPDATEs a
tad less klugy.  But it is necessary preparation for the intended extension of
allowing RETURNING queries inside WITH.

Marko Tiikkaja
2009-10-10 01:43:50 +00:00
Tom Lane
249724cb01 Create an ALTER DEFAULT PRIVILEGES command, which allows users to adjust
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
2009-10-05 19:24:49 +00:00
Tom Lane
ca70c3cfda Revert my ill-considered change that made formrdesc not insert the correct
relation rowtype OID into the relcache entries it builds.  This ensures
that catcache copies of the relation tupdescs will be fully correct.
While the deficiency doesn't seem to have any effect in the current
sources, we have been bitten by not-quite-right catcache tupdescs before,
so it seems like a good idea to maintain the rule that they should be right.
2009-09-26 23:08:22 +00:00
Tom Lane
c2e228d44e Fix RelationCacheInitializePhase2 (Phase3, in HEAD) to cope with the
possibility of shared-inval messages causing a relcache flush while it tries
to fill in missing data in preloaded relcache entries.  There are actually
two distinct failure modes here:

1. The flush could delete the next-to-be-processed cache entry, causing
the subsequent hash_seq_search calls to go off into the weeds.  This is
the problem reported by Michael Brown, and I believe it also accounts
for bug #5074.  The simplest fix is to restart the hashtable scan after
we've read any new data from the catalogs.  It appears that pre-8.4
branches have not suffered from this failure, because by chance there were
no other catalogs sharing the same hash chains with the catalogs that
RelationCacheInitializePhase2 had work to do for.  However that's obviously
pretty fragile, and it seems possible that derivative versions with
additional system catalogs might be vulnerable, so I'm back-patching this
part of the fix anyway.

2. The flush could delete the *current* cache entry, in which case the
pointer to the newly-loaded data would end up being stored into an
already-deleted Relation struct.  As long as it was still deleted, the only
consequence would be some leaked space in CacheMemoryContext.  But it seems
possible that the Relation struct could already have been recycled, in
which case this represents a hard-to-reproduce clobber of cached data
structures, with unforeseeable consequences.  The fix here is to pin the
entry while we work on it.

In passing, also change RelationCacheInitializePhase2 to Assert that
formrdesc() set up the relation's cached TupleDesc (rd_att) with the
correct type OID and hasoids values.  This is more appropriate than
silently updating the values, because the original tupdesc might already
have been copied into the catcache.  However this part of the patch is
not in HEAD because it fails due to some questionable recent changes in
formrdesc :-(.  That will be cleaned up in a subsequent patch.
2009-09-26 18:24:49 +00:00
Tom Lane
e1cc64197b Remove some useless assignments of the result of fread(). Quiets warnings
from clang static checker, and makes the code more readable anyway IMO.
2009-08-30 17:18:52 +00:00
Tom Lane
04011cc970 Allow backends to start up without use of the flat-file copy of pg_database.
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.
2009-08-12 20:53:31 +00:00
Tom Lane
9bd27b7c9e Extend EXPLAIN to support output in XML or JSON format.
There are probably still some adjustments to be made in the details
of the output, but this gets the basic structure in place.

Robert Haas
2009-08-10 05:46:50 +00:00
Tom Lane
25d9bf2e3e Support deferrable uniqueness constraints.
The current implementation fires an AFTER ROW trigger for each tuple that
looks like it might be non-unique according to the index contents at the
time of insertion.  This works well as long as there aren't many conflicts,
but won't scale to massive unique-key reassignments.  Improving that case
is a TODO item.

Dean Rasheed
2009-07-29 20:56:21 +00:00
Tom Lane
0d4899e448 Do a conditional SPI_push/SPI_pop when replanning a query in
RevalidateCachedPlan.  This is to avoid a "SPI_ERROR_CONNECT" failure when
the planner calls a SPI-using function and we are already inside one.
The alternative fix is to expect callers of RevalidateCachedPlan to do this,
which seems likely to result in additional hard-to-detect bugs of omission.
Per reports from Frank van Vugt and Marek Lewczuk.

Back-patch to 8.3. It's much harder to trigger the bug in 8.3, due to a
smaller set of cases in which plans can be invalidated, but it could happen.
(I think perhaps only a SI reset event could make 8.3 fail here, but that's
certainly within the realm of possibility.)
2009-07-14 15:37:50 +00:00