transaction snapshots, i.e. a snapshot registered at the beginning of
a transaction. Change variable naming and comments to reflect this reality
in preparation for a future, truly serializable mode, e.g.
Serializable Snapshot Isolation (SSI).
For the moment transaction snapshots are still used to implement
SERIALIZABLE, but hopefully not for too much longer. Patch by Kevin
Grittner and Dan Ports with review and some minor wording changes by me.
returning "record" actually do have the same rowtype. This is needed because
the parser can't realistically enforce that they will all have the same typmod,
as seen in a recent example from David Wheeler.
Back-patch to 8.0, which is as far back as we have the notion of RECORD
subtypes being distinguished by typmod. Wheeler's example depends on
8.4-and-up features, but I suspect there may be ways to provoke similar
failures before 8.4.
ExecModifyTable(). This avoids memory leakage when trigger functions leave
junk behind in that context (as they more or less must). Problem and solution
identified by Dean Rasheed.
I'm a bit concerned about the longevity of this solution --- once a plan can
have multiple ModifyTable nodes, we are very possibly going to have to do
something different. But it should hold up for 9.0.
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.
list in ExecLockRows() forgot to allow for the possibility that some of the
rowmarks are for child tables that aren't relevant to the current row.
Per report from Kenichiro Tanaka.
a pass-by-reference datatype with a nontrivial projection step.
We were using the same memory context for the projection operation as for
the temporary context used by the hashtable routines in execGrouping.c.
However, the hashtable routines feel free to reset their temp context at
any time, which'd lead to destroying input data that was still needed.
Report and diagnosis by Tao Ma.
Back-patch to 8.1, where the problem was introduced by the changes that
allowed us to work with "virtual" tuples instead of materializing intermediate
tuple values everywhere. The earlier code looks quite similar, but it doesn't
suffer the problem because the data gets copied into another context as a
result of having to materialize ExecProject's output tuple.
Remove bespoke code in DoCopy and RI_Initial_Check, which now instead
fabricate call ExecCheckRTPerms with a manufactured RangeTblEntry.
This is intended to make it feasible for an enhanced security provider
to actually make use of ExecutorCheckPerms_hook, but also has the
advantage that RI_Initial_Check can allow use of the fast-path when
column-level but not table-level permissions are present.
KaiGai Kohei. Reviewed (in an earlier version) by Stephen Frost, and by me.
Some further changes to the comments by me.
from defining non-self-conflicting constraints.
Jeff Davis
Note: I (tgl) objected to removing this check in 9.0 on the grounds that it
was an important sanity check in new, poorly tested code. However, it should
be all right to remove it for 9.1, since we'll get field testing from the
9.0 branch.
relation using the general PARAM_EXEC executor parameter mechanism, rather
than the ad-hoc kluge of passing the outer tuple down through ExecReScan.
The previous method was hard to understand and could never be extended to
handle parameters coming from multiple join levels. This patch doesn't
change the set of possible plans nor have any significant performance effect,
but it's necessary infrastructure for future generalization of the concept
of an inner indexscan plan.
ExecReScan's second parameter is now unused, so it's removed.
This hook allows a loadable module to gain control when table permissions
are checked. It is expected to be used by an eventual SE-PostgreSQL
implementation, but there are other possible applications as well. A
sample contrib module can be found in the archives at:
http://archives.postgresql.org/pgsql-hackers/2010-05/msg01095.php
Robert Haas and Stephen Frost
is treated like end-of-input, if nulls sort last in that column and we are not
doing outer-join filling for that input. In such a case, the tuple cannot
join to anything from the other input (because we assume mergejoinable
operators are strict), and neither can any tuple following it in the sort
order. If we're not interested in doing outer-join filling we can just
pretend the tuple and its successors aren't there at all. This can save a
great deal of time in situations where there are many nulls in the join
column, as in a recent example from Scott Marlowe. Also, since the planner
tends to not count nulls in its mergejoin scan selectivity estimates, this
is an important fix to make the runtime behavior more like the estimate.
I regard this as an omission in the patch I wrote years ago to teach mergejoin
that tuples containing nulls aren't joinable, so I'm back-patching it. But
only to 8.3 --- in older versions, we didn't have a solid notion of whether
nulls sort high or low, so attempting to apply this optimization could break
things.
archival or hot standby should be WAL-logged, instead of deducing that from
other options like archive_mode. This replaces recovery_connections GUC in
the primary, where it now has no effect, but it's still used in the standby
to enable/disable hot standby.
Remove the WAL-logging of "unlogged operations", like creating an index
without WAL-logging and fsyncing it at the end. Instead, we keep a copy of
the wal_mode setting and the settings that affect how much shared memory a
hot standby server needs to track master transactions (max_connections,
max_prepared_xacts, max_locks_per_xact) in pg_control. Whenever the settings
change, at server restart, write a WAL record noting the new settings and
update pg_control. This allows us to notice the change in those settings in
the standby at the right moment, they used to be included in checkpoint
records, but that meant that a changed value was not reflected in the
standby until the first checkpoint after the change.
Bump PG_CONTROL_VERSION and XLOG_PAGE_MAGIC. Whack XLOG_PAGE_MAGIC back to
the sequence it used to follow, before hot standby and subsequent patches
changed it to 0x9003.
catalog entries via SearchSysCache and related operations. Although, at the
time that these callbacks are called by elog.c, we have not officially aborted
the current transaction, it still seems rather risky to initiate any new
catalog fetches. In all these cases the needed information is readily
available in the caller and so it's just a matter of a bit of extra notation
to pass it to the callback.
Per crash report from Dennis Koegel. I've concluded that the real fix for
his problem is to clear the error context stack at entry to proc_exit, but
it still seems like a good idea to make the callbacks a bit less fragile
for other cases.
Backpatch to 8.4. We could go further back, but the patch doesn't apply
cleanly. In the absence of proof that this fixes something and isn't just
paranoia, I'm not going to expend the effort.
Add some checks that seem logically necessary, in particular let's make
real sure that HS slave sessions cannot create temp tables. (If they did
they would think that temp tables belonging to the master's session with
the same BackendId were theirs. We *must* not allow myTempNamespace to
become set in a slave session.)
Change setval() and nextval() so that they are only allowed on temp sequences
in a read-only transaction. This seems consistent with what we allow for
table modifications in read-only transactions. Since an HS slave can't have a
temp sequence, this also provides a nicer cure for the setval PANIC reported
by Erik Rijkers.
Make the error messages more uniform, and have them mention the specific
command being complained of. This seems worth the trifling amount of extra
code, since people are likely to see such messages a lot more than before.
being assigned to, in case the expression to be assigned is a FieldStore that
would need to modify that value. The need for this was foreseen some time
ago, but not implemented then because we did not have arrays of composites.
Now we do, but the point evidently got overlooked in that patch. Net result
is that updating a field of an array element doesn't work right, as
illustrated if you try the new regression test on an unpatched backend.
Noted while experimenting with EXPLAIN VERBOSE, which has also got some issues
in this area.
Backpatch to 8.3, where arrays of composites were introduced.
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.
This patch allows the frame to start from CURRENT ROW (in either RANGE or
ROWS mode), and it also adds support for ROWS n PRECEDING and ROWS n FOLLOWING
start and end points. (RANGE value PRECEDING/FOLLOWING isn't there yet ---
the grammar works, but that's all.)
Hitoshi Harada, reviewed by Pavel Stehule
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.
being called as aggregates, and to get the aggregate transition state memory
context if needed. Use it instead of poking directly into AggState and
WindowAggState in places that shouldn't know so much.
We should have done this in 8.4, probably, but better late than never.
Revised version of a patch by Hitoshi Harada.
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.
heap_sync() to the callers, because heap_sync() is sometimes called even
if the operation itself is WAL-logged. This eliminates the bogus unlogged
records from CLUSTER that Simon Riggs reported, patch by Fujii Masao.
We show the number of buckets, the number of batches (and also the original
number if it has changed), and the peak space used by the hash table. Minor
executor changes to track peak space used.
We need to free the OID list returned by ExecInsertIndexTuples to avoid
a query-lifespan memory leak. When many rows require rechecking, this
can be a significant leak --- it's even more than the space used for the
queued trigger events.
Dean Rasheed
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
rowtype contains dropped columns. Sometimes the input tuple will be formed
from a select targetlist in which dropped columns are filled with a NULL
of an arbitrary type (the planner typically uses INT4, since it can't tell
what type the dropped column really was). So we need to relax the rowtype
compatibility check to not insist on physical compatibility if the actual
column value is NULL.
In principle we might need to do this for functions returning composite
types, too (see tupledesc_match()). In practice there doesn't seem to be
a bug there, probably because the function will be using the same cached
rowtype descriptor as the caller. Fixing that code path would require
significant rearrangement, so I left it alone for now.
Per complaint from Filip Rembialkowski.
extract a system column, and remove a couple of lines that are useless
in light of the fact that we aren't ever going to support this case. There
isn't much point in trying to make this work because a tuple Datum does
not carry many of the system columns. Per experimentation with a case
reported by Dean Rasheed; we'll have to fix his problem somewhere else.
someone else has just updated it, we have to set priorXmax to that tuple's
xmax (ie, the XID of the other xact that updated it) before looping back to
examine the next tuple. Obviously, the next tuple in the update chain should
have that XID as its xmin, not the same xmin as the preceding tuple that we
had been trying to lock. The mismatch would cause the EvalPlanQual logic to
decide that the tuple chain ended in a deletion, when actually there was a
live tuple that should have been found.
I inserted this error when recently adding logic to EvalPlanQual to make it
lock tuples before returning them (as opposed to the old method in which the
lock would occur much later, causing a great deal of work to be wasted if we
only then discover someone else updated it). Sigh. Per today's report from
Takahiro Itagaki of inconsistent results during pgbench runs.
peculiar variant of UNION ALL, and so wouldn't likely get written directly
as-is, it's possible for it to arise as a result of simplification of
less-obviously-silly queries. In particular, now that we can do flattening
of subqueries that have constant outputs and are underneath an outer join,
it's possible for the case to result from simplification of queries of the
type exhibited in bug #5263. Back-patch to 8.4 to avoid a functionality
regression for this type of query.
"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.
expressions: FormIndexDatum requires the estate's scantuple to already point
at the tuple the values are supposedly being extracted from. Adjust test
case so that this type of confusion will be exposed.
Per report from hubert depesz lubaczewski.
8.2beta but never carried out. This avoids repetitive tests of whether the
argument is of scalar or composite type. Also, be a bit more paranoid about
composite arguments in some places where we previously weren't checking.
to be just a minor extension of the previous patch that made "x IS NULL"
indexable, because we can treat the IS NOT NULL condition as if it were
"x < NULL" or "x > NULL" (depending on the index's NULLS FIRST/LAST option),
just like IS NULL is treated like "x = NULL". Aside from any possible
usefulness in its own right, this is an important improvement for
index-optimized MAX/MIN aggregates: it is now reliably possible to get
a column's min or max value cheaply, even when there are a lot of nulls
cluttering the interesting end of the index.
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.
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.
Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.
Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.
non-kluge method for controlling the order in which values are fed to an
aggregate function. At the same time eliminate the old implementation
restriction that DISTINCT was only supported for single-argument aggregates.
Possibly release-notable behavioral change: formerly, agg(DISTINCT x)
dropped null values of x unconditionally. Now, it does so only if the
agg transition function is strict; otherwise nulls are treated as DISTINCT
normally would, ie, you get one copy.
Andrew Gierth, reviewed by Hitoshi Harada
This patch also removes buffer-usage statistics from the track_counts
output, since this (or the global server statistics) is deemed to be a better
interface to this information.
Itagaki Takahiro, reviewed by Euler Taveira de Oliveira.
we have to cope with the possibility that the declared result rowtype contains
dropped columns. This fails in 8.4, as per bug #5240.
While at it, be more paranoid about inserting binary coercions when inlining.
The pre-8.4 code did not really need to worry about that because it could not
inline at all in any case where an added coercion could change the behavior
of the function's statement. However, when inlining a SRF we allow sorting,
grouping, and set-ops such as UNION. In these cases, modifying one of the
targetlist entries that the sort/group/setop depends on could conceivably
change the behavior of the function's statement --- so don't inline when
such a case applies.
before we zap the input tuple. Otherwise, pass-by-reference columns of
the result slot are likely to contain just references to the input
tuple, leading to big trouble if the pfree'd space is reused. Per
trouble report from Jaime Casanova. This is a new bug in the recent
rewrite of EvalPlanQual, so nothing to back-patch.
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
Magnus Hagander