calculating a page's initial free space was fine, and should not have been
"improved" by letting PageGetHeapFreeSpace do it. VACUUM FULL is going to
reclaim LP_DEAD line pointers later, so there is no need for a guard
against the page being too full of line pointers, and having one risks
rejecting pages that are perfectly good move destinations.
This also exposed a second bug, which is that the empty_end_pages logic
assumed that any page with no live tuples would get entered into the
fraged_pages list automatically (by virtue of having more free space than
the threshold in the do_frag calculation). This assumption certainly
seems risky when a low fillfactor has been chosen, and even without
tunable fillfactor I think it could conceivably fail on a page with many
unused line pointers. So fix the code to force do_frag true when notup
is true, and patch this part of the fix all the way back.
Per report from Tomas Szepe.
issue a helpful error message instead of sending unparsable garbage.
(It is clearly a design error that this doesn't work, but fixing it
is not worth the trouble at this point.) Per discussion.
the parser supplies a default typmod that can result in data loss (ie,
truncation). Currently that appears to be only CHARACTER and BIT.
We can avoid the problem by specifying the type's internal name instead
of using SQL-spec syntax. Since the queries generated here are only used
internally, there's no need to worry about portability. This problem is
new in 8.3; before we just let the parser do whatever it wanted to resolve
the operator, but 8.3 is trying to be sure that the semantics of FK checks
are consistent. Per report from Harald Fuchs.
statement be a list of bare C strings, rather than String nodes, which is
what they need to be for copyfuncs/equalfuncs to work. Fortunately these
node types never go out to disk (if they did, we'd likely have noticed the
problem sooner), so we can just fix it without creating a need for initdb.
This bug has been there since 8.0, but 8.3 exposes it in a more common
code path (Parse messages) than prior releases did. Per bug #3940 from
Vladimir Kokovic.
AlterTSConfigurationStmt. All utility statement node types are expected
to be supported here, though they do not have to have outfuncs/readfuncs
support. Found by running regression tests with COPY_PARSE_PLAN_TREES
enabled.
tablespace permissions failures when copying an index that is in the
database's default tablespace. A side-effect of the change is that explicitly
specifying the default tablespace no longer triggers a permissions check;
this is not how it was done in pre-8.3 releases but is argued to be more
consistent. Per bug #3921 from Andrew Gilligan. (Note: I argued in the
subsequent discussion that maybe LIKE shouldn't copy index tablespaces
at all, but since no one indicated agreement with that idea, I've refrained
from doing it.)
erroring out of a wait. We can use a PG_TRY block for this, but add a comment
explaining why it'd be a bad idea to use it for any other state cleanup.
Back-patch to 8.2. Prior releases had the same issue, but only with respect
to the process title, which is likely to get reset almost immediately anyway
after the transaction aborts, so it seems not worth changing them. In 8.2
and HEAD, the pg_stat_activity "waiting" flag could remain set incorrectly
for a long time.
Per report from Gurjeet Singh.
Should fix a problem where two clusters are running under
two different service accounts and get colliding names,
causing only the first cluster to contain the pgident
event description.
Per report from Stephen Denne.
operations when the current transaction has any open references to the
target relation or index (implying it has an active query using the relation).
The need for this was previously recognized in connection with ALTER TABLE,
but anything that summarily eliminates tuples or moves them around would
confuse an active scan.
While this patch does not in itself fix bug #3883 (the deadlock would happen
before the new check fires), it will discourage people from attempting the
sequence of operations that creates a deadlock risk, so it's at least a
partial response to that problem.
In passing, add a previously-missing check to REINDEX to prevent trying to
reindex another backend's temp table. This isn't a security problem since
only a superuser would get past the schema permission checks, but if we are
testing for this in other utility commands then surely REINDEX should too.
whether to execute an immediate interrupt, rather than testing whether
LockWaitCancel() cancelled a lock wait. The old way misclassified the case
where we were blocked in ProcWaitForSignal(), and arguably would misclassify
any other future additions of new ImmediateInterruptOK states too. This
allows reverting the old kluge that gave LockWaitCancel() a return value,
since no callers care anymore. Improve comments in the various
implementations of PGSemaphoreLock() to explain that on some platforms, the
assumption that semop() exits after a signal is wrong, and so we must ensure
that the signal handler itself throws elog if we want cancel or die interrupts
to be effective. Per testing related to bug #3883, though this patch doesn't
solve those problems fully.
Perhaps this change should be back-patched, but since pre-8.3 branches aren't
really relying on autovacuum to respond to SIGINT, it doesn't seem critical
for them.
a double-pfree crash and another that effectively disabled size-based rotation
for CSV logs. Also suppress a memory leak and make some trivial cosmetic
improvements. Per bug #3901 from Chris Hoover and additional code-reading.
ri_FetchConstraintInfo, to avoid a query-duration memory leak when that
routine is called by RI_FKey_keyequal_upd_fk (which isn't executed in a
short-lived context). This problem was latent when the routine was added
in February, but it didn't become serious until the varvarlena patch made
it quite likely that the fields being examined would be "toasted" (ie, have
short headers). Per report from Stephen Denne.
regis. Correct the latter's oversight that a bracket-expression needs to be
terminated. Reduce the ereports to elogs, since they are now not expected to
ever be hit (thus addressing Alvaro's original complaint).
In passing, const-ify the string argument to RS_compile.
subquery output column exactly once left-to-right. Although this is the case
in the original parser output, it might not be so after rewriting and
constant-folding, as illustrated by bug #3882 from Jan Mate. Instead
scan the subquery's target list to obtain needed per-column information;
this is duplicative of what the parser did, but only a couple dozen lines
need be copied, and we can clean up a couple of notational uglinesses.
Bug was introduced in 8.2 as part of revision of SubLink representation.
constraint, the constraint is renamed as well. This avoids inconsistent
situations that could confuse pg_dump (not to mention humans). We might at
some point provide ALTER TABLE RENAME CONSTRAINT as a more general solution,
but there seems no reason not to allow doing it this way too. Per bug #3854
and related discussions.
in whichever context happens to be current during a call of an xml.c function,
use a dedicated context that will not go away until we explicitly delete it
(which we do at transaction end or subtransaction abort). This makes recovery
after an error much simpler --- we don't have to individually delete the data
structures created by libxml. Also, we need to initialize and cleanup libxml
only once per transaction (if there's no error) instead of once per function
call, so it should be a bit faster. We'll need to keep an eye out for
intra-transaction memory leaks, though. Alvaro and Tom.
its second pass over the table. It has to start at block zero, else the
"merge join" logic for detecting which TIDs are already in the index
doesn't work. Hence, extend heapam.c's API so that callers can enable or
disable syncscan. (I put in an option to disable buffer access strategy,
too, just in case somebody needs it.) Per report from Hannes Dorbath.
Therefore we must xmlCleanupParser(), or we risk leaving behind
dangling pointers to whatever memory context is current when xml_init()
is called. This seems to fix bug #3860, though we might still want
the more invasive solution being worked on by Alvaro.
constraint yields TRUE for every row of its table, only that it does not
yield FALSE (a NULL result isn't disallowed). This breaks a couple of
implications that would be true in two-valued logic. I had put in one such
mistake in an 8.2.5 patch: foo IS NULL doesn't refute a strict operator
on foo. But there was another in the original 8.2 release: NOT foo doesn't
refute an expression whose truth would imply the truth of foo.
Per report from Rajesh Kumar Mallah.
To preserve the ability to do constraint exclusion with one partition
holding NULL values, extend relation_excluded_by_constraints() to check
for attnotnull flags, and add col IS NOT NULL expressions to the set of
constraints we hope to refute.
checking of argument compatibility right; although the problem is only exposed
with multiple-input aggregates in which some arguments are polymorphic and
some are not. Per bug #3852 from Sokolov Yura.
for unhandled clause types ought to be 0.5, not 1.0. I fear I introduced
this silliness due to misreading the intent of the very-poorly-structured
code that was there when we inherited the file from Berkeley. The lack
of sanity in this behavior was exposed by an example from Sim Zacks.
(Arguably this is a bug fix and should be back-patched, but I'm a bit
hesitant to introduce a possible planner behavior change in the back
branches; it might detune queries that worked acceptably in the past.)
While at it, make estimation for DistinctExpr do something marginally
realistic, rather than just defaulting.
clauseless joins of relations that have unexploited join clauses. Rather
than looking at every other base relation in the query, the correct thing is
to examine the other relations in the "initial_rels" list of the current
make_rel_from_joinlist() invocation, because those are what we actually have
the ability to join against. This might be a subset of the whole query in
cases where join_collapse_limit or from_collapse_limit or full joins have
prevented merging the whole query into a single join problem. This is a bit
untidy because we have to pass those rels down through a new PlannerInfo
field, but it's necessary. Per bug #3865 from Oleg Kharin.
finish archiving everything (when there's no error), and to eliminate various
hazards as best we can. This fixes a previous 8.3 patch that caused the
postmaster to kill and then restart the archiver during shutdown (!?).
The new behavior is that the archiver is allowed to run unmolested until
the bgwriter has exited; then it is sent SIGUSR2 to tell it to do a final
archiving cycle and quit. We only SIGQUIT the archiver if we want a panic
stop; this is important since SIGQUIT will also be sent to any active
archive_command. The postmaster also now doesn't SIGQUIT the stats collector
until the bgwriter is done, since the bgwriter can send stats messages in 8.3.
The postmaster will not exit until both the archiver and stats collector are
gone; this provides some defense (not too bulletproof) against conflicting
archiver or stats collector processes being started by a new postmaster
instance. We continue the prior practice that the archiver will check
for postmaster death immediately before issuing any archive_command; that
gives some additional protection against conflicting archivers.
Also, modify the archiver process to notice SIGTERM and refuse to issue any
more archive commands if it gets it. The postmaster doesn't ever send it
SIGTERM; we assume that any such signal came from init and is a notice of
impending whole-system shutdown. In this situation it seems imprudent to try
to start new archive commands --- if they aren't extremely quick they're
likely to get SIGKILL'd by init.
All per discussion.
of poorer planning in 8.3 than 8.2:
1. After pushing a constant across an outer join --- ie, given
"a LEFT JOIN b ON (a.x = b.y) WHERE a.x = 42", we can deduce that b.y is
sort of equal to 42, in the sense that we needn't fetch any b rows where
it isn't 42 --- loop to see if any additional deductions can be made.
Previous releases did that by recursing, but I had mistakenly thought that
this was no longer necessary given the EquivalenceClass machinery.
2. Allow pushing constants across outer join conditions even if the
condition is outerjoin_delayed due to a lower outer join. This is safe
as long as the condition is strict and we re-test it at the upper join.
3. Keep the outer-join clause even if we successfully push a constant
across it. This is *necessary* in the outerjoin_delayed case, but
even in the simple case, it seems better to do this to ensure that the
join search order heuristics will consider the join as reasonable to
make. Mark such a clause as having selectivity 1.0, though, since it's
not going to eliminate very many rows after application of the constant
condition.
4. Tweak have_relevant_eclass_joinclause to report that two relations
are joinable when they have vars that are equated to the same constant.
We won't actually generate any joinclause from such an EquivalenceClass,
but again it seems that in such a case it's a good idea to consider
the join as worth costing out.
5. Fix a bug in select_mergejoin_clauses that was exposed by these
changes: we have to reject candidate mergejoin clauses if either side was
equated to a constant, because we can't construct a canonical pathkey list
for such a clause. This is an implementation restriction that might be
worth fixing someday, but it doesn't seem critical to get it done for 8.3.
constant ORDER/GROUP BY entries properly:
http://archives.postgresql.org/pgsql-hackers/2001-04/msg00457.php
The original solution to that was in fact no good, as demonstrated by
today's report from Martin Pitt:
http://archives.postgresql.org/pgsql-bugs/2008-01/msg00027.php
We can't use the column-number-reference format for a constant that is
a resjunk targetlist entry, a case that was unfortunately not thought of
in the original discussion. What we can do instead (which did not work
at the time, but does work in 7.3 and up) is to emit the constant with
explicit ::typename decoration, even if it otherwise wouldn't need it.
This is sufficient to keep the parser from thinking it's a column number
reference, and indeed is probably what the user must have done to get
such a thing into the querytree in the first place.
