In commit 9e8da0f757, I improved btree
to handle ScalarArrayOpExpr quals natively, so that constructs like
"indexedcol IN (list)" could be supported by index-only scans. Using
such a qual results in multiple scans of the index, under-the-hood.
I went to some lengths to ensure that this still produces rows in index
order ... but I failed to recognize that if a higher-order index column
is lacking an equality constraint, rescans can produce out-of-order
data from that column. Tweak the planner to not expect sorted output
in that case. Per trouble report from Robert McGehee.
Currently, we are making mangled copies of plpython/{expected,sql} to
plpython/python3/{expected,sql}, and run the tests in
plpython/python3. This has the disadvantage that the regression.diffs
file, if any, ends up in plpython/python3, which is not the normal
location. If we instead make the mangled copies in
plpython/{expected,sql}/python3/, we can run the tests from the normal
directory, regression.diffs ends up the normal place, and the
pg_regress invocation also becomes a lot simpler. It's also more
obvious at run time what's going on, because the tests end up being
named "python3/something" in the test output.
Some experimentation with examples similar to bug #7539 has convinced me
that indxpath.c's original implementation of parameterized-path generation
was several bricks shy of a load. In general, if we are relying on a
particular outer rel or set of outer rels for a parameterized path, the
path should use every indexable join clause that's available from that rel
or rels. Any join clauses that get left out of the indexqual will end up
getting applied as plain filter quals (qpquals), and that's generally a
significant loser compared to having the index AM enforce them. (This is
particularly true with btree, which can skip the index scan entirely if
it can see that the given indexquals are mutually contradictory.) The
original heuristics failed to ensure this, though, and were overly
complicated anyway. Rewrite to make the code explicitly identify each
useful set of outer rels and then select all applicable join clauses for
each one. The one plan that changes in the regression tests is in fact
for the better according to the planner's cost estimates.
(Note: this is not a correctness issue but just a matter of plan quality.
I don't yet know what is going on in bug #7539, but I don't expect this
change to fix that.)
Recovery code documents clearly that a shutdown checkpoint is executed at
end of recovery - a shutdown checkpoint WAL record is written but the buffer
manager had been altered to treat end of recovery as a normal checkpoint.
This bug exacerbates the bufmgr relpersistence bug.
Bug spotted by Andres Freund, patch by me.
Looks like the correct size of DOS-ified tenk.data is 680800 not 680801.
(I got the latter from a version of unix2dos that appends a trailing ^Z,
which evidently is not git's practice.)
The idea here is to provide a more easily diagnosable failure diff when
the problem is that tenk.data has been DOS-ified, as I believe to be
happening currently on buildfarm member hamerkop. Per suggestion from
Magnus Hagander.
Also, sync output/largeobject_1.source with current regression test.
Failure to do that in commit 3a0e4d36eb
turns out to be the real reason that hamerkop has been complaining.
Given what we now know about the cause of this bug, it seems like it'd
be a real good idea to include it in the plperl regression tests, so as
to catch any platform-specific cases where the code gets misoptimized.
This at least saves some palloc overhead, and should furthermore reduce
the risk of anything going wrong, eg somebody resetting the context the
current_call_data record was in.
In commit 1bc16a9460 I added a minor
optimization to drop the component variables of a GROUP BY expression from
the target list computed at the aggregation level of a query, if those Vars
weren't referenced elsewhere in the tlist. However, I overlooked that the
window-function planning code would deconstruct such expressions and thus
need to have access to their component variables. Fix it to not do that.
While at it, I removed the distinction between volatile and nonvolatile
window partition/order expressions: the code now computes all of them
at the aggregation level. This saves a relatively expensive check for
volatility, and it's unclear that the resulting plan isn't better anyway.
Per bug #7535 from Louis-David Mitterrand. Back-patch to 9.2.
I made multiple errors in commit 97532f7c29,
stemming mostly from failure to think about the available frequency data
as being element frequencies not value frequencies (so that occurrences of
different elements are not mutually exclusive). This led to sillinesses
such as estimating that "word" would match more rows than "word:*".
The choice to clamp to a minimum estimate of DEFAULT_TS_MATCH_SEL also
seems pretty ill-considered in hindsight, as it would frequently result in
an estimate much larger than the available data suggests. We do need some
sort of clamp, since a pattern not matching any of the MCELEMs probably
still needs a selectivity estimate of more than zero. I chose instead to
clamp to at least what a non-MCELEM word would be estimated as, preserving
the property that "word:*" doesn't get an estimate less than plain "word",
whether or not the word appears in MCELEM.
Per investigation of a gripe from Bill Martin, though I suspect that his
example case actually isn't even reaching the erroneous code.
Back-patch to 9.1 where this code was introduced.
validate_plperl_function() supposed that it could free an old
plperl_proc_desc struct immediately upon detecting that it was stale.
However, if a plperl function is called recursively, this could result
in deleting the struct out from under an outer invocation, leading to
misbehavior or crashes. Add a simple reference-count mechanism to
ensure that such structs are freed only when the last reference goes
away.
Per investigation of bug #7516 from Marko Tiikkaja. I am not certain
that this error explains his report, because he says he didn't have
any recursive calls --- but it's hard to see how else it could have
crashed right there. In any case, this definitely fixes some problems
in the area.
Back-patch to all active branches.
Investigation shows that some intermittent build failures in ecpg are the
result of a gmake bug that was reported quite some time ago:
http://savannah.gnu.org/bugs/?30653
Preventing parallel builds of the ecpg subdirectories seems to dodge the
bug. Per yesterday's pgsql-hackers discussion, there are some other things
in the subdirectory makefiles that seem rather unsafe for parallel builds
too, but there's little point in fixing them as long as we have to work
around a make bug.
Back-patch to 9.1; parallel builds weren't very well supported before
that anyway.
Commit 2cfb1c6f77 fixed some issues caused
by Python 3.3 choosing to iterate through dict entries in a different order
than before. But here's another one: the test cases adjusted here made two
bad entries in a dict and expected the one complained of would always be
the same.
Possibly this should be back-patched further than 9.2, but there seems
little point unless the earlier fix is too.
Create an internal function pqDropConnection that does the physical socket
close and cleans up closely-associated state. This removes a bunch of ad
hoc, not always consistent closure code. The ulterior motive is to have a
single place to wait for a spawned child backend to exit, but this seems
like good cleanup even if that never happens.
I went back and forth on whether to include "conn->status = CONNECTION_BAD"
in pqDropConnection's actions, but for the moment decided not to. Only a
minority of the call sites actually want that, and in any case it's
arguable that conn->status is slightly higher-level state, and thus not
part of this function's purview.
This fix removes an unnecessary incompatibility with the old behavior of
the unix_socket_directory parameter. Since pathnames with embedded spaces
are fairly popular on some platforms, the incompatibility could be
significant in practice. We'll still strip unquoted leading/trailing
spaces, however.
No docs update since the documentation already implied that it worked
like this.
Per bug #7514 from Murray Cumming.
When the startup process restores a WAL file from the archive, it deletes
any old file with the same name and renames the new file in its place. On
Windows, however, when a file is deleted, it still lingers as long as a
process holds a file handle open on it. With cascading replication, a
walsender process can hold the old file open, so the rename() in the startup
process would fail. To fix that, rename the old file to a temporary name, to
make the original file name available for reuse, before deleting the old
file.
Give the correct name of the GUC parameter being complained of.
Also, emit a more suitable SQLSTATE (INVALID_PARAMETER_VALUE,
not the default INTERNAL_ERROR).
Gurjeet Singh, errcode adjustment by me
Perl, for some unaccountable reason, believes it's a good idea to reset
SIGFPE handling to SIG_IGN. Which wouldn't be a good idea even if it
worked; but on some platforms (Linux at least) it doesn't work at all,
instead resulting in forced process termination if the signal occurs.
Given the lack of other complaints, it seems safe to assume that Perl
never actually provokes SIGFPE and so there is no value in the setting
anyway. Hence, reset it to our normal handler after initializing Perl.
Report, analysis and patch by Andres Freund.
The planner previously assumed that parameter Vars having the same absolute
query level, varno, and varattno could safely be assigned the same runtime
PARAM_EXEC slot, even though they might be different Vars appearing in
different subqueries. This was (probably) safe before the introduction of
CTEs, but the lazy-evalution mechanism used for CTEs means that a CTE can
be executed during execution of some other subquery, causing the lifespan
of Params at the same syntactic nesting level as the CTE to overlap with
use of the same slots inside the CTE. In 9.1 we created additional hazards
by using the same parameter-assignment technology for nestloop inner scan
parameters, but it was broken before that, as illustrated by the added
regression test.
To fix, restructure the planner's management of PlannerParamItems so that
items having different semantic lifespans are kept rigorously separated.
This will probably result in complex queries using more runtime PARAM_EXEC
slots than before, but the slots are cheap enough that this hardly matters.
Also, stop generating PlannerParamItems containing Params for subquery
outputs: all we really need to do is reserve the PARAM_EXEC slot number,
and that now only takes incrementing a counter. The planning code is
simpler and probably faster than before, as well as being more correct.
Per report from Vik Reykja.
These changes will mostly also need to be made in the back branches, but
I'm going to hold off on that until after 9.2.0 wraps.
The cascading replication code assumed that the current RecoveryTargetTLI
never changes, but that's not true with recovery_target_timeline='latest'.
The obvious upshot of that is that RecoveryTargetTLI in shared memory needs
to be protected by a lock. A less obvious consequence is that when a
cascading standby is connected, and the standby switches to a new target
timeline after scanning the archive, it will continue to stream WAL to the
cascading standby, but from a wrong file, ie. the file of the previous
timeline. For example, if the standby is currently streaming from the middle
of file 000000010000000000000005, and the timeline changes, the standby
will continue to stream from that file. However, the WAL on the new
timeline is in file 000000020000000000000005, so the standby sends garbage
from 000000010000000000000005 to the cascading standby, instead of the
correct WAL from file 000000020000000000000005.
This also fixes a related bug where a partial WAL segment is restored from
the archive and streamed to a cascading standby. The code assumed that when
a WAL segment is copied from the archive, it can immediately be fully
streamed to a cascading standby. However, if the segment is only partially
filled, ie. has the right size, but only N first bytes contain valid WAL,
that's not safe. That can happen if a partial WAL segment is manually copied
to the archive, or if a partial WAL segment is archived because a server is
started up on a new timeline within that segment. The cascading standby will
get confused if the WAL it received is not valid, and will get stuck until
it's restarted. This patch fixes that problem by not allowing WAL restored
from the archive to be streamed to a cascading standby until it's been
replayed, and thus validated.
Serializable Snapshot Isolation used for serializable transactions
depends on acquiring SIRead locks on all heap relation tuples which
are used to generate the query result, so that a later delete or
update of any of the tuples can flag a read-write conflict between
transactions. This is normally handled in heapam.c, with tuple level
locking. Since an index-only scan avoids heap access in many cases,
building the result from the index tuple, the necessary predicate
locks were not being acquired for all tuples in an index-only scan.
To prevent problems with tuple IDs which are vacuumed and re-used
while the transaction still matters, the xmin of the tuple is part of
the tag for the tuple lock. Since xmin is not available to the
index-only scan for result rows generated from the index tuples, it
is not possible to acquire a tuple-level predicate lock in such
cases, in spite of having the tid. If we went to the heap to get the
xmin value, it would no longer be an index-only scan. Rather than
prohibit index-only scans under serializable transaction isolation,
we acquire an SIRead lock on the page containing the tuple, when it
was not necessary to visit the heap for other reasons.
Backpatch to 9.2.
Kevin Grittner and Tom Lane
Each setup block is run as a single PQexec submission, and some
statements such as VACUUM cannot be combined with others in such a
block.
Backpatch to 9.2.
Kevin Grittner and Tom Lane
The same message is used in both pg_restore and pg_dump, and it's
confusing to output "restoring data for table xyz" when the user
is just doing a pg_dump.
This gets rid of a dangerous-looking use of the not-volatile XLogCtl
pointer in a couple of spinlock-protected sections, where the normal
coding rule is that you should only access shared memory through a
pointer-to-volatile. I think the risk is only hypothetical not actual,
since for there to be a bug the compiler would have to move the spinlock
acquire or release across the memcpy() call, which one sincerely hopes
it will not. Still, it looks cleaner this way.
Per comment from Daniel Farina and subsequent discussion.
Formerly it would only show them for relkinds 'r' and 'f' (plain tables
and foreign tables). However, as of 9.2, views can also have reloptions,
namely security_barrier. The relkind restriction seems pointless and
not at all future-proof, so just print reloptions whenever there are any.
In passing, make some cosmetic improvements to the code that pulls the
"tableinfo" fields out of the PGresult.
Noted and patched by Dean Rasheed, with adjustment for all relkinds by me.
We can detect whether the planner top level is going to care at all about
cheap startup cost (it will only do so if query_planner's tuple_fraction
argument is greater than zero). If it isn't, we might as well discard
paths immediately whose only advantage over others is cheap startup cost.
This turns out to get rid of quite a lot of paths in complex queries ---
I saw planner runtime reduction of more than a third on one large query.
Since add_path isn't currently passed the PlannerInfo "root", the easiest
way to tell it whether to do this was to add a bool flag to RelOptInfo.
That's a bit redundant, since all relations in a given query level will
have the same setting. But in the future it's possible that we'd refine
the control decision to work on a per-relation basis, so this seems like
a good arrangement anyway.
Per my suggestion of a few months ago.
If a PlaceHolderVar contains a pulled-up LATERAL reference, its minimum
possible evaluation level might be higher in the join tree than its
original syntactic location. That in turn affects the ph_needed level for
any contained PlaceHolderVars (that is, those PHVs had better propagate up
the join tree at least to the evaluation level of the outer PHV). We got
this mostly right, but mark_placeholder_maybe_needed() failed to account
for the effect, and in consequence could leave the inner PHVs with
ph_may_need less than what their ultimate ph_needed value will be. That's
bad because it could lead to failure to select a join order that will allow
evaluation of the inner PHV at a valid location. Fix that, and add an
Assert that checks that we don't ever set ph_needed to more than
ph_may_need.
Only warn when connecting to a newer server, since connecting to older
servers works pretty well nowadays. Also update the documentation a
little about current psql/server compatibility expectations.
This was removed in commit cd00406774,
we're not quite sure why, but there have been reports of crashes due
to AS Perl being built with it when we are not, and it certainly
seems like the right thing to do. There is still some uncertainty
as to why it sometimes fails and sometimes doesn't.
Original patch from Owais Khani, substantially reworked and
extended by Andrew Dunstan.
The LATERAL implementation is now basically complete, and I still don't
see a cost-effective way to make an exact qual scope cross-check in the
presence of LATERAL. However, I did add a PlannerInfo.hasLateralRTEs flag
along the way, so it's easy to make the check only when not hasLateralRTEs.
That seems to still be useful, and it beats having no check at all.
We previously supposed that any given platform would supply both or neither
of these functions, so that one configure test would be sufficient. It now
appears that at least on AIX this is not the case ... which is likely an
AIX bug, but nonetheless we need to cope with it. So use separate tests.
Per bug #6758; thanks to Andrew Hastie for doing the followup testing
needed to confirm what was happening.
Backpatch to 9.1, where we began using these functions.
This is mostly cosmetic, but it does eliminate a speculative portability
issue. The previous coding ignored the fact that sum_grow could easily
overflow (in fact, it could be summing multiple IEEE float infinities).
On a platform where that didn't guarantee to produce a positive result,
the code would misbehave. In any case, it was less than readable.
This reduces unnecessary exposure of other headers through htup.h, which
is very widely included by many files.
I have chosen to move the function prototypes to the new file as well,
because that means htup.h no longer needs to include tupdesc.h. In
itself this doesn't have much effect in indirect inclusion of tupdesc.h
throughout the tree, because it's also required by execnodes.h; but it's
something to explore in the future, and it seemed best to do the htup.h
change now while I'm busy with it.
Given a query such as
SELECT * FROM foo JOIN LATERAL (SELECT foo.var1) ss(x) ON ss.x = foo.var2
the existence of the join clause "ss.x = foo.var2" encourages indxpath.c to
build a parameterized path for foo using any index available for foo.var2.
This is completely useless activity, though, since foo has got to be on the
outside not the inside of any nestloop join with ss. It's reasonably
inexpensive to add tests that prevent creation of such paths, so let's do
that.
Every time the best-tuple-found-so-far changes, we need to reset all
the penalty values in which_grow[] to the penalties for the new best
tuple. The old code failed to do this, resulting in inferior index
quality.
The original patch from Alexander Korotkov was just two lines; I took
the liberty of fleshing that out by adding a bunch of comments that I
hope will make this logic easier for others to understand than it was
for me.
push_child_plan/pop_child_plan didn't bother to adjust the "ancestors"
list of parent plan nodes when descending to a child plan node. I think
this was okay when it was written, but it's not okay in the presence of
LATERAL references, since a subplan node could easily be returning a
LATERAL value back up to the same nestloop node that provides the value.
Per changed regression test results, the omission led to failure to
interpret Param nodes that have perfectly good interpretations.
In the initial cut at LATERAL, I kept the rule that cheapest_total_path
was always unparameterized, which meant it had to be NULL if the relation
has no unparameterized paths. It turns out to work much more nicely if
we always have *some* path nominated as cheapest-total for each relation.
In particular, let's still say it's the cheapest unparameterized path if
there is one; if not, take the cheapest-total-cost path among those of
the minimum available parameterization. (The first rule is actually
a special case of the second.)
This allows reversion of some temporary lobotomizations I'd put in place.
In particular, the planner can now consider hash and merge joins for
joins below a parameter-supplying nestloop, even if there aren't any
unparameterized paths available. This should bring planning of
LATERAL-containing queries to the same level as queries not using that
feature.
Along the way, simplify management of parameterized paths in add_path()
and friends. In the original coding for parameterized paths in 9.2,
I tried to minimize the logic changes in add_path(), so it just treated
parameterization as yet another dimension of comparison for paths.
We later made it ignore pathkeys (sort ordering) of parameterized paths,
on the grounds that ordering isn't a useful property for the path on the
inside of a nestloop, so we might as well get rid of useless parameterized
paths as quickly as possible. But we didn't take that reasoning as far as
we should have. Startup cost isn't a useful property inside a nestloop
either, so add_path() ought to discount startup cost of parameterized paths
as well. Having done that, the secondary sorting I'd implemented (in
add_parameterized_path) is no longer needed --- any parameterized path that
survives add_path() at all is worth considering at higher levels. So this
should be a bit faster as well as simpler.
This includes two micro-optimizations to the tight inner loop in descending
the SP-GiST tree: 1. avoid an extra function call to index_getprocinfo when
calling user-defined choose function, and 2. avoid a useless palloc+pfree
when node labels are not used.
The heapam XLog functions are used by other modules, not all of which
are interested in the rest of the heapam API. With this, we let them
get just the XLog stuff in which they are interested and not pollute
them with unrelated includes.
Also, since heapam.h no longer requires xlog.h, many files that do
include heapam.h no longer get xlog.h automatically, including a few
headers. This is useful because heapam.h is getting pulled in by
execnodes.h, which is in turn included by a lot of files.
This threw ERROR, not the expected NOTICE, if the index didn't exist.
The bug was actually visible in not-as-expected regression test output,
so somebody wasn't paying too close attention in commit
8cb53654db.
Per report from Brendan Byrd.
This enables selectivity estimation of the <<, >>, &<, &> and && operators,
as well as the normal inequality operators: <, <=, >=, >. "range @> element"
is also supported, but the range-variant @> and <@ operators are not,
because they cannot be sensibly estimated with lower and upper bound
histograms alone. We would need to make some assumption about the lengths of
the ranges for that. Alexander's patch included a separate histogram of
lengths for that, but I left that out of the patch for simplicity. Hopefully
that will be added as a followup patch.
The fraction of empty ranges is also calculated and used in estimation.
Alexander Korotkov, heavily modified by me.
This patch takes care of a number of problems having to do with failure
to choose valid join orders and incorrect handling of lateral references
pulled up from subqueries. Notable changes:
* Add a LateralJoinInfo data structure similar to SpecialJoinInfo, to
represent join ordering constraints created by lateral references.
(I first considered extending the SpecialJoinInfo structure, but the
semantics are different enough that a separate data structure seems
better.) Extend join_is_legal() and related functions to prevent trying
to form unworkable joins, and to ensure that we will consider joins that
satisfy lateral references even if the joins would be clauseless.
* Fill in the infrastructure needed for the last few types of relation scan
paths to support parameterization. We'd have wanted this eventually
anyway, but it is necessary now because a relation that gets pulled up out
of a UNION ALL subquery may acquire a reltargetlist containing lateral
references, meaning that its paths *have* to be parameterized whether or
not we have any code that can push join quals down into the scan.
* Compute data about lateral references early in query_planner(), and save
in RelOptInfo nodes, to avoid repetitive calculations later.
* Assorted corner-case bug fixes.
There's probably still some bugs left, but this is a lot closer to being
real than it was before.
The GUC check hooks for transaction_read_only and transaction_isolation
tried to check RecoveryInProgress(), so as to disallow setting read/write
mode or serializable isolation level (respectively) in hot standby
sessions. However, GUC check hooks can be called in many situations where
we're not connected to shared memory at all, resulting in a crash in
RecoveryInProgress(). Among other cases, this results in EXEC_BACKEND
builds crashing during child process start if default_transaction_isolation
is serializable, as reported by Heikki Linnakangas. Protect those calls
by silently allowing any setting when not inside a transaction; which is
okay anyway since these GUCs are always reset at start of transaction.
Also, add a check to GetSerializableTransactionSnapshot() to complain
if we are in hot standby. We need that check despite the one in
check_XactIsoLevel() because default_transaction_isolation could be
serializable. We don't want to complain any sooner than this in such
cases, since that would prevent running transactions at all in such a
state; but a transaction can be run, if SET TRANSACTION ISOLATION is done
before setting a snapshot. Per report some months ago from Robert Haas.
Back-patch to 9.1, since these problems were introduced by the SSI patch.
Kevin Grittner and Tom Lane, with ideas from Heikki Linnakangas
If we revoke a grant option from some role X, but X still holds the option
via another grant, we should not recursively revoke the privilege from
role(s) Y that X had granted it to. This was supposedly fixed as one
aspect of commit 4b2dafcc0b, but I must not
have tested it, because in fact that code never worked: it forgot to shift
the grant-option bits back over when masking the bits being revoked.
Per bug #6728 from Daniel German. Back-patch to all active branches,
since this has been wrong since 8.0.
This improves on commit 51fed14d73 by
eliminating the assumption that we can form <some pointer value> +
<some offset> without overflow. The entire point of those tests is that
we don't trust the offset value, so coding them in a way that could wrap
around if the buffer happens to be near the top of memory doesn't seem
sound. Instead, track the remaining space as a size_t variable and
compare offsets against that.
Also, improve comment about why we need the extra early check on
xl_tot_len.
If a view has circular dependencies, pg_dump splits it into a CREATE TABLE
and a CREATE RULE command to break the dependency loop. However, if the
view has reloptions, those options cannot be applied in the CREATE TABLE
command, because views and tables have different allowed reloptions so
CREATE TABLE would reject them. Instead apply the reloptions after the
CREATE RULE, using ALTER VIEW SET.
Move discussion of why our algorithm for taking snapshots in recovery
to a more appropriate location in the function, and delete incorrect
mention of taking a lock.
When elevel >= ERROR, we add an abort() call to the ereport() macro to
give the compiler a hint that the ereport() expansion will not return,
but the abort() isn't actually reached because the longjmp happens in
errfinish().
Because the effect of ereport() varies with the elevel, we cannot use
standard compiler attributes such as noreturn for this.
If a WAL record header was split across pages, but xl_tot_len was 0, we
would get confused and conclude that we had already read the whole record,
and proceed to CRC check it. That can lead to a crash in RecordIsValid(),
which isn't careful to not read beyond end-of-record, as defined by
xl_tot_len.
Add an explicit sanity check for xl_tot_len <= SizeOfXlogRecord. Also,
make RecordIsValid() more robust by checking in each step that it doesn't
try to access memory beyond end of record, even if a length field in the
record's or a backup block's header is bogus.
Per report and analysis by Tom Lane.
Formerly, subquery pullup had no need to examine other entries in the range
table, since they could not contain any references to the subquery being
pulled up. That's no longer true with LATERAL, so now we need to be able
to visit rangetable subexpressions to replace Vars referencing the
pulled-up subquery. Also, this means that extract_lateral_references must
be unsurprised at encountering lateral PlaceHolderVars, since such might be
created when pulling up a subquery that's underneath an outer join with
respect to the lateral reference.
We had put a test for libxml2's xmlStructuredErrorContext variable in
configure, but of course that doesn't work on Windows builds. The next
best alternative seems to be to test the LIBXML_VERSION symbol provided
by xmlversion.h.
Per report from Talha Bin Rizwan, though this fixes it in a different way
than his proposed patch.
In the initial cut at the "parameterized paths" feature, I'd simplified
create_index_paths() to the point where it would only generate a single
parameterized bitmap path per relation. Experimentation with an example
supplied by Josh Berkus convinces me that that's not good enough: we really
need to consider a bitmap path for each possible outer relation. Otherwise
we have regressions relative to pre-9.2 versions, in which the planner
picks a plain indexscan where it should have used a bitmap scan in queries
involving three or more tables. Indeed, after fixing this, several queries
in the regression tests show improved plans as a result of using bitmap not
plain indexscans.
The implementation is a quad-tree, largely copied from the quad-tree
implementation for points. The lower and upper bound of ranges are the 2d
coordinates, with some extra code to handle empty ranges.
I left out the support for adjacent operator, -|-, from the original patch.
Not because there was necessarily anything wrong with it, but it was more
complicated than the other operators, and I only have limited time for
reviewing. That will follow as a separate patch.
Alexander Korotkov, reviewed by Jeff Davis and me.
We use a hash table to track the parents of inner pages, but when inserting
to a leaf page, the caller of gistbufferinginserttuples() must pass a
correct block number of the leaf's parent page. Before gistProcessItup()
descends to a child page, it checks if the downlink needs to be adjusted to
accommodate the new tuple, and updates the downlink if necessary. However,
updating the downlink might require splitting the page, which might move the
downlink to a page to the right. gistProcessItup() doesn't realize that, so
when it descends to the leaf page, it might pass an out-of-date parent block
number as a result. Fix that by returning the block a tuple was inserted to
from gistbufferinginserttuples().
This fixes the bug reported by Zdeněk Jílovec.
The previous coding essentially assumed that nodes would be rescanned in
the same order they were initialized in; or at least that the "leader" of
a group of CTEscans would be rescanned before any others were required to
execute. Unfortunately, that isn't even a little bit true. It's possible
to devise queries in which the leader isn't rescanned until other CTEscans
on the same CTE have run to completion, or even in which the leader never
gets a rescan call at all.
The fix makes the leader specially responsible only for initial creation
and final destruction of the tuplestore; rescan resets are now a
symmetrically shared responsibility. This means that we might reset the
tuplestore multiple times when restarting a plan subtree containing
multiple CTEscans; but resetting an already-empty tuplestore is cheap
enough that that doesn't seem like a problem.
Per report from Adam Mackler; the new regression test cases are based on
his example query.
Back-patch to 8.4 where CTE scans were introduced.
This situation creates a dependency loop that confuses pg_dump and probably
other things. Moreover, since the mental model is that the extension
"contains" schemas it owns, but "is contained in" its extschema (even
though neither is strictly true), having both true at once is confusing for
people too. So prevent the situation from being set up.
Reported and patched by Thom Brown. Back-patch to 9.1 where extensions
were added.
This essentially reverts commit e54b10a62d,
in which I'd decided that the "last ditch" join logic was useless. The
folly of that is now exposed by a report from Pavel Stehule: although the
function should always find at least one join in a self-contained join
problem, it can still fail to do so in a sub-problem created by artificial
from_collapse_limit or join_collapse_limit constraints. Adjust the
comments to describe this, and simplify the code a bit to match the new
coding of the earlier loop in the function.
I'm not terribly happy about this: I still subscribe to the opinion stated
in the previous commit message that the "last ditch" code can obscure logic
bugs elsewhere. But the alternative seems to be to complicate the earlier
tests for does-this-relation-have-a-join-clause to the point where they can
tell whether the join clauses link outside the current join sub-problem.
And that looks messy, slow, and possibly a source of bugs in itself.
In any case, now is not the time to be inserting experimental code into
9.2, so let's just go back to the time-tested solution.
xml_parse() would attempt to fetch external files or URLs as needed to
resolve DTD and entity references in an XML value, thus allowing
unprivileged database users to attempt to fetch data with the privileges
of the database server. While the external data wouldn't get returned
directly to the user, portions of it could be exposed in error messages
if the data didn't parse as valid XML; and in any case the mere ability
to check existence of a file might be useful to an attacker.
The ideal solution to this would still allow fetching of references that
are listed in the host system's XML catalogs, so that documents can be
validated according to installed DTDs. However, doing that with the
available libxml2 APIs appears complex and error-prone, so we're not going
to risk it in a security patch that necessarily hasn't gotten wide review.
So this patch merely shuts off all access, causing any external fetch to
silently expand to an empty string. A future patch may improve this.
In HEAD and 9.2, also suppress warnings about undefined entities, which
would otherwise occur as a result of not loading referenced DTDs. Previous
branches don't show such warnings anyway, due to different error handling
arrangements.
Credit to Noah Misch for first reporting the problem, and for much work
towards a solution, though this simplistic approach was not his preference.
Also thanks to Daniel Veillard for consultation.
Security: CVE-2012-3489
DST law changes in Morocco; Tokelau has relocated to the other side of
the International Date Line; and apparently Olson had Tokelau's GMT
offset wrong by an hour even before that.
There are also a large number of non-significant changes in this update.
Upstream took the opportunity to remove trailing whitespace, and the
SCCS-style version numbers on the individual files are gone too.
The maximum number of parameters supported by the FE/BE protocol is 65535,
as it's transmitted as a 16-bit unsigned integer. However, the nParams
arguments to libpq functions are all of type 'int'. We can't change the
signature of libpq functions, but a simple bounds check is in order to make
it more clear what's going wrong if you try to pass more than 65535
parameters.
Per complaint from Jim Vanns.
Re-allow subquery pullup for LATERAL subqueries, except when the subquery
is below an outer join and contains lateral references to relations outside
that outer join. If we pull up in such a case, we risk introducing lateral
cross-references into outer joins' ON quals, which is something the code is
entirely unprepared to cope with right now; and I'm not sure it'll ever be
worth coping with.
Support lateral refs in VALUES (this seems to be the only additional path
type that needs such support as a consequence of re-allowing subquery
pullup).
Put in a slightly hacky fix for joinpath.c's refusal to consider
parameterized join paths even when there cannot be any unparameterized
ones. This was causing "could not devise a query plan for the given query"
failures in queries involving more than two FROM items.
Put in an even more hacky fix for distribute_qual_to_rels() being unhappy
with join quals that contain references to rels outside their syntactic
scope; which is to say, disable that test altogether. Need to think about
how to preserve some sort of debugging cross-check here, while not
expending more cycles than befits a debugging cross-check.
The LATERAL marking has to be propagated down to the UNION leaf queries
when we pull them up. Also, fix the formerly stubbed-off
set_append_rel_pathlist(). It does already have enough smarts to cope with
making a parameterized Append path at need; it just has to not assume that
there *must* be an unparameterized path.
This command generated new pg_depend entries linking the index to the
constraint and the constraint to the table, which match the entries made
when a unique or primary key constraint is built de novo. However, it did
not bother to get rid of the entries linking the index directly to the
table. We had considered the issue when the ADD CONSTRAINT USING INDEX
patch was written, and concluded that we didn't need to get rid of the
extra entries. But this is wrong: ALTER COLUMN TYPE wasn't expecting such
redundant dependencies to exist, as reported by Hubert Depesz Lubaczewski.
On reflection it seems rather likely to break other things as well, since
there are many bits of code that crawl pg_depend for one purpose or
another, and most of them are pretty naive about what relationships they're
expecting to find. Fortunately it's not that hard to get rid of the extra
dependency entries, so let's do that.
Back-patch to 9.1, where ALTER TABLE ADD CONSTRAINT USING INDEX was added.
Replace unix_socket_directory with unix_socket_directories, which is a list
of socket directories, and adjust postmaster's code to allow zero or more
Unix-domain sockets to be created.
This is mostly a straightforward change, but since the Unix sockets ought
to be created after the TCP/IP sockets for safety reasons (better chance
of detecting a port number conflict), AddToDataDirLockFile needs to be
fixed to support out-of-order updates of data directory lockfile lines.
That's a change that had been foreseen to be necessary someday anyway.
Honza Horak, reviewed and revised by Tom Lane
Formerly we relied on checking after-the-fact to see if an expression
contained aggregates, window functions, or sub-selects when it shouldn't.
This is grotty, easily forgotten (indeed, we had forgotten to teach
DefineIndex about rejecting window functions), and none too efficient
since it requires extra traversals of the parse tree. To improve matters,
define an enum type that classifies all SQL sub-expressions, store it in
ParseState to show what kind of expression we are currently parsing, and
make transformAggregateCall, transformWindowFuncCall, and transformSubLink
check the expression type and throw error if the type indicates the
construct is disallowed. This allows removal of a large number of ad-hoc
checks scattered around the code base. The enum type is sufficiently
fine-grained that we can still produce error messages of at least the
same specificity as before.
Bringing these error checks together revealed that we'd been none too
consistent about phrasing of the error messages, so standardize the wording
a bit.
Also, rewrite checking of aggregate arguments so that it requires only one
traversal of the arguments, rather than up to three as before.
In passing, clean up some more comments left over from add_missing_from
support, and annotate some tests that I think are dead code now that that's
gone. (I didn't risk actually removing said dead code, though.)
Should be limited to the maximum number of connections excluding
autovacuum workers, not including.
Add similar check for max_wal_senders, which should never be higher than
max_connections.
Previously, the -1 option was silently ignored.
Also, emit an error if -1 is used in a context where it won't be
respected, to avoid user confusion.
Original patch by Fabien COELHO, but this version is quite different
from the original submission.
Now that we are storing structs in these lists, the distinction between
the two lists can be represented with a couple of extra flags while using
only a single list. This simplifies the code and should save a little
bit of palloc traffic, since the majority of RTEs are represented in both
lists anyway.
Cascading replication copied the incoming file into pg_xlog but
didn't set path correctly, so the first attempt to open file failed
causing it to loop around and look for file in pg_xlog. So the
earlier coding worked, but accidentally rather than by design.
Spotted by Fujii Masao, fix by Fujii Masao and Simon Riggs
This was broken in commit ed0b409d22,
which revised the GlobalTransactionData struct to not include the
associated PGPROC as its first member, but overlooked one place where
a cast was used in reliance on that equivalence.
The most effective way of fixing this seems to be to create a new function
that looks up the GlobalTransactionData struct given the XID, and make
both TwoPhaseGetDummyBackendId and TwoPhaseGetDummyProc rely on that.
Per report from Robert Ross.
This patch implements the standard syntax of LATERAL attached to a
sub-SELECT in FROM, and also allows LATERAL attached to a function in FROM,
since set-returning function calls are expected to be one of the principal
use-cases.
The main change here is a rewrite of the mechanism for keeping track of
which relations are visible for column references while the FROM clause is
being scanned. The parser "namespace" lists are no longer lists of bare
RTEs, but are lists of ParseNamespaceItem structs, which carry an RTE
pointer as well as some visibility-controlling flags. Aside from
supporting LATERAL correctly, this lets us get rid of the ancient hacks
that required rechecking subqueries and JOIN/ON and function-in-FROM
expressions for invalid references after they were initially parsed.
Invalid column references are now always correctly detected on sight.
In passing, remove assorted parser error checks that are now dead code by
virtue of our having gotten rid of add_missing_from, as well as some
comments that are obsolete for the same reason. (It was mainly
add_missing_from that caused so much fudging here in the first place.)
The planner support for this feature is very minimal, and will be improved
in future patches. It works well enough for testing purposes, though.
catversion bump forced due to new field in RangeTblEntry.
We seem to have a rough policy that our Perl scripts should work with
Perl 5.8, so make this one do so. Main change is to not use the newfangled
\h character class in regexes; "[ \t]" is a serviceable replacement.
century specifications just like positive/AD centuries. Previously the
behavior was either wrong or inconsistent with positive/AD handling.
Centuries without years now always assume the first year of the century,
which is now documented.
In particular, with a controlled shutdown of the master, pg_basebackup
with streaming log could terminate without an error message, even though
the backup is not consistent.
In passing, fix a few cases where walfile wasn't properly set to -1 after
closing.
Fujii Masao
We used to convert the unicode object directly to a string in the server
encoding by calling Python's PyUnicode_AsEncodedString function. In other
words, we used Python's routines to do the encoding. However, that has a
few problems. First of all, it required keeping a mapping table of Python
encoding names and PostgreSQL encodings. But the real killer was that Python
doesn't support EUC_TW and MULE_INTERNAL encodings at all.
Instead, convert the Python unicode object to UTF-8, and use PostgreSQL's
encoding conversion functions to convert from UTF-8 to server encoding. We
were already doing the same in the other direction in PLyUnicode_FromString,
so this is more consistent, too.
Note: This makes SQL_ASCII to behave more leniently. We used to map
SQL_ASCII to Python's 'ascii', which on Python means strict 7-bit ASCII
only, so you got an error if the python string contained anything but pure
ASCII. You no longer get an error; you get the UTF-8 representation of the
string instead.
Backpatch to 9.0, where these conversions were introduced.
Jan Urbański
DecodeInterval() failed to honor the "range" parameter (the special SQL
syntax for indicating which fields appear in the literal string) if the
time was signed. This seems inappropriate, so make it work like the
not-signed case. The inconsistency was introduced in my commit
f867339c01, which as noted in its log message
was only really focused on making SQL-compliant literals work per spec.
Including a sign here is not per spec, but if we're going to allow it
then it's reasonable to expect it to work like the not-signed case.
Also, remove bogus setting of tmask, which caused subsequent processing to
think that what had been given was a timezone and not an hh:mm(:ss) field,
thus confusing checks for redundant fields. This seems to be an aboriginal
mistake in Lockhart's commit 2cf1642461.
Add regression test cases to illustrate the changed behaviors.
Back-patch as far as 8.4, where support for spec-compliant interval
literals was added.
Range problem reported and diagnosed by Amit Kapila, tmask problem by me.
As noted by Noah Misch, btree_xlog_delete_get_latestRemovedXid is
critically dependent on the assumption that it's examining a consistent
state of the database. This was undocumented though, so the
seemingly-unrelated check for no active HS sessions might be thought to be
merely an optional optimization. Improve comments, and add an explicit
check of reachedConsistency just to be sure.
This function returns InvalidTransactionId (thereby killing all HS
transactions) in several cases that are not nearly unlikely enough for my
taste. This commit doesn't attempt to fix those deficiencies, just
document them.
Back-patch to 9.2, not from any real functional need but just to keep the
branches more closely synced to simplify possible future back-patching.
In yesterday's commit 962e0cc71e, I added the
ResolveRecoveryConflictWithSnapshot call in the wrong place. I correctly
put it before spgRedoVacuumRedirect itself would modify the index page ---
but not before RestoreBkpBlocks, so replay of a record with a full-page
image would modify the page before kicking off any conflicting HS
transactions. Oops.
The correct test for whether a redirection tuple is removable is whether
tuple's xid < RecentGlobalXmin, not OldestXmin; the previous coding
failed to protect index searches being done in concurrent transactions that
have no XID. This mirrors the recent fix in btree's page recycling logic
made in commit d3abbbebe5.
Also, WAL-log the newest XID of any removed redirection tuple on an index
page, and apply ResolveRecoveryConflictWithSnapshot during InHotStandby WAL
replay. This protects against concurrent Hot Standby transactions possibly
needing to see the redirection tuple(s).
Per my query of 2012-03-12 and subsequent discussion.
After taking awhile to digest the row-processor feature that was added to
libpq in commit 92785dac2e, we've concluded
it is over-complicated and too hard to use. Leave the core infrastructure
changes in place (that is, there's still a row processor function inside
libpq), but remove the exposed API pieces, and instead provide a "single
row" mode switch that causes PQgetResult to return one row at a time in
separate PGresult objects.
This approach incurs more overhead than proper use of a row processor
callback would, since construction of a PGresult per row adds extra cycles.
However, it is far easier to use and harder to break. The single-row mode
still affords applications the primary benefit that the row processor API
was meant to provide, namely not having to accumulate large result sets in
memory before processing them. Preliminary testing suggests that we can
probably buy back most of the extra cycles by micro-optimizing construction
of the extra results, but that task will be left for another day.
Marko Kreen
Parse analysis neglected to cover the case of a WITH clause attached to an
intermediate-level set operation; it only handled WITH at the top level
or WITH attached to a leaf-level SELECT. Per report from Adam Mackler.
In HEAD, I rearranged the order of SelectStmt's fields to put withClause
with the other fields that can appear on non-leaf SelectStmts. In back
branches, leave it alone to avoid a possible ABI break for third-party
code.
Back-patch to 8.4 where WITH support was added.
In the original coding of the log rotation stuff, we did not bother to make
the truncation logic work for the very first rotation after postmaster
start (or after a syslogger crash and restart). It just always appended
in that case. It did not seem terribly important at the time, but we've
recently had two separate complaints from people who expected it to work
unsurprisingly. (Both users tend to restart the postmaster about as often
as a log rotation is configured to happen, which is maybe not typical use,
but still...) Since the initial log file is opened in the postmaster,
fixing this requires passing down some more state to the syslogger child
process.
It's always been like this, so back-patch to all supported branches.
The most user-visible part of this is to change the long options
--statusint and --noloop to --status-interval and --no-loop,
respectively, per discussion.
Also, consistently enclose file names in double quotes, per our
conventions; and consistently use the term "transaction log file" to
talk about WAL segments. (Someday we may need to go over this
terminology and make it consistent across the whole source code.)
Finally, reflow the code to better fit in 80 columns, and have pgindent
fix it up some more.
This function suppressed any stderr output from the called program, which
is unnecessary in the normal case and unhelpful in error cases. It also
gave a rather opaque message along the lines of "fgets failure: Success"
in case the called program failed to return anything on stdout. Since
we've seen multiple reports of people not understanding what's wrong when
pg_ctl reports this, improve the message.
Back-patch to all active branches.
In the original coding of the autovacuum cancel feature, commit
acac68b2bc, an autovacuum process was
considered a target for cancellation if it was found to hard-block any
process examined in the deadlock search. This patch tightens the test so
that the autovacuum must directly hard-block the current process. This
should make the behavior more predictable in general, and in particular
it ensures that an autovacuum will not be canceled with less than
deadlock_timeout grace period. In the old coding, it was possible for an
autovacuum to be canceled almost instantly, given unfortunate timing of two
or more other processes' lock attempts.
This also justifies the logging methodology in the recent commit
d7318d43d891bd63e82dcfc27948113ed7b1db80; without this restriction, that
patch isn't providing enough information to see the connection of the
canceling process to the autovacuum. Like that one, patch all the way
back.
The old message was at DEBUG2, so typically it didn't show up in the
log at all. As a result, in most cases where autovacuum was canceled,
the only information that was logged was the table being vacuumed,
with no indication as to what problem caused the cancel. Crank up
the level to LOG and add some more details to assist with debugging.
Back-patch all the way, per discussion on pgsql-hackers.
If a crash occurred immediately after the first nextval() call for a serial
column, WAL replay would restore the sequence to a state in which it
appeared that no nextval() had been done, thus allowing the first sequence
value to be returned again by the next nextval() call; as reported in
bug #6748 from Xiangming Mei.
More generally, the problem would occur if an ALTER SEQUENCE was executed
on a freshly created or reset sequence. (The manifestation with serial
columns was introduced in 8.2 when we added an ALTER SEQUENCE OWNED BY step
to serial column creation.) The cause is that sequence creation attempted
to save one WAL entry by writing out a WAL record that made it appear that
the first nextval() had already happened (viz, with is_called = true),
while marking the sequence's in-database state with log_cnt = 1 to show
that the first nextval() need not emit a WAL record. However, ALTER
SEQUENCE would emit a new WAL entry reflecting the actual in-database state
(with is_called = false). Then, nextval would allocate the first sequence
value and set is_called = true, but it would trust the log_cnt value and
not emit any WAL record. A crash at this point would thus restore the
sequence to its post-ALTER state, causing the next nextval() call to return
the first sequence value again.
To fix, get rid of the idea of logging an is_called status different from
reality. This means that the first nextval-driven WAL record will happen
at the first nextval call not the second, but the marginal cost of that is
pretty negligible. In addition, make sure that ALTER SEQUENCE resets
log_cnt to zero in any case where it touches sequence parameters that
affect future nextval results. This will result in some user-visible
changes in the contents of a sequence's log_cnt column, as reflected in the
patch's regression test changes; but no application should be depending on
that anyway, since it was already true that log_cnt changes rather
unpredictably depending on checkpoint timing.
In addition, make some basically-cosmetic improvements to get rid of
sequence.c's undesirable intimacy with page layout details. It was always
really trying to WAL-log the contents of the sequence tuple, so we should
have it do that directly using a HeapTuple's t_data and t_len, rather than
backing into it with some magic assumptions about where the tuple would be
on the sequence's page.
Back-patch to all supported branches.
The initially implemented syntax, "CHECK NO INHERIT (expr)" was not
deemed very good, so switch to "CHECK (expr) NO INHERIT" instead. This
way it looks similar to SQL-standards compliant constraint attribute.
Backport to 9.2 where the new syntax and feature was introduced.
Per discussion.
Commit f5bcd398ad introduced a test using
a table named "circles" in inherit.sql. Unfortunately, the concurrently
executed constraints test was already using that table name, so the
parallel regression tests would sometimes fail. Rename table to dodge
the problem. Per buildfarm.
We should avoid calling sync_file_range or posix_fadvise in this case,
since (a) we don't really care if the data gets synced, and might as
well save the kernel calls; (b) at least on Linux we know that the
kernel might block us until it's scheduled the write.
Also, avoid making a useless second traversal of the directory tree
if we're not actually going to call fsync(2) after all.
We left this out of commit b966dd6c42
so as to get some more buildfarm testing of the new fsync code in initdb.
But since no problems have turned up, it's probably time to save the
cycles.
Antique versions of gcc complain about vars that are initialized outside
PG_TRY and then modified within it. Rather than marking the var volatile,
expend one more line of code.
We made use of the ROWS estimate for set-returning functions used in FROM,
but not for those used in SELECT targetlists; which is a bit of an
oversight considering there are common usages that require the latter
approach. Improve that. (I had initially thought it might be worth
folding this into cost_qual_eval, but after investigation concluded that
that wouldn't be very helpful, so just do it separately.) Per complaint
from David Johnston.
Back-patch to 9.2, but not further, for fear of destabilizing plan choices
in existing releases.
Commit 3a0e4d36eb arranged to
reference stack-allocated variables after they were out of scope.
That's no good, so let's arrange to not do that after all.
There is no point in running this test when prepared transactions are disabled,
which is the default. New make targets that include the test are provided. This
will save some useless waste of cycles on buildfarm machines.
Backpatch to 9.1 where these tests were introduced.
The code was setting it true for other constraints, which is
bogus. Doing so caused bogus catalog entries for such constraints, and
in particular caused an error to be raised when trying to drop a
constraint of types other than CHECK from a table that has children,
such as reported in bug #6712.
In 9.2, additionally ignore connoinherit=true for other constraint
types, to avoid having to force initdb; existing databases might already
contain bogus catalog entries.
Includes a catversion bump (in HEAD only).
Bug report from Miroslav Šulc
Analysis from Amit Kapila and Noah Misch; Amit also contributed the patch.
When a whole-row Var is reading the result of a subquery, we need it to
ignore any "resjunk" columns that the subquery might have evaluated for
GROUP BY or ORDER BY purposes. We've hacked this area before, in commit
68e40998d0, but that fix only covered
whole-row Vars of named composite types, not those of RECORD type; and it
was mighty klugy anyway, since it just assumed without checking that any
extra columns in the result must be resjunk. A proper fix requires getting
hold of the subquery's targetlist so we can actually see which columns are
resjunk (whereupon we can use a JunkFilter to get rid of them). So bite
the bullet and add some infrastructure to make that possible.
Per report from Andrew Dunstan and additional testing by Merlin Moncure.
Back-patch to all supported branches. In 8.3, also back-patch commit
292176a118, which for some reason I had
not done at the time, but it's a prerequisite for this change.
Commit 3855968f32 added syntax, pg_dump,
psql support, and documentation, but the triggers didn't actually fire.
With this commit, they now do. This is still a pretty basic facility
overall because event triggers do not get a whole lot of information
about what the user is trying to do unless you write them in C; and
there's still no option to fire them anywhere except at the very
beginning of the execution sequence, but it's better than nothing,
and a good building block for future work.
Along the way, add a regression test for ALTER LARGE OBJECT, since
testing of event triggers reveals that we haven't got one.
Dimitri Fontaine and Robert Haas
Instead of having one hash table entry per relation/fork/segment, just have
one per relation, and use bitmapsets to represent which specific segments
need to be fsync'd. This eliminates the need to scan the whole hash table
to implement FORGET_RELATION_FSYNC, which fixes the O(N^2) behavior
recently demonstrated by Jeff Janes for cases involving lots of TRUNCATE or
DROP TABLE operations during a single checkpoint cycle. Per an idea from
Robert Haas.
(FORGET_DATABASE_FSYNC still sucks, but since dropping a database is a
pretty expensive operation anyway, we'll live with that.)
In passing, improve the delayed-unlink code: remove the pass over the list
in mdpreckpt, since it wasn't doing anything for us except supporting a
useless Assert in mdpostckpt, and fix mdpostckpt so that it will absorb
fsync requests every so often when clearing a large backlog of deletion
requests.
We were sending one per fork, but a little bit of refactoring allows us
to send just one request with forknum == InvalidForkNumber. This not only
reduces pressure on the shared-memory request queue, but saves repeated
traversals of the checkpointer's hash table.
Functions like range_eq, range_before etc. are exposed at the SQL-level, but
they're also used internally by the GiST consistent support function. The
code sharing was done by a hack, TrickFunctionCall2, which relied on the
knowledge that all the functions used fn_extra the same way. This commit
splits the functions into internal versions that take a TypeCacheEntry as
argument, and thin wrappers to expose the functions at the SQL-level. The
internal versions can then be called directly and in a less hacky way from
the GiST consistent function.
This is just cosmetic, but backpatch to 9.2 anyway, to avoid having a
different version of this code in the 9.2 branch. That would make
backpatching fixes in this area more difficult.
Alexander Korotkov
ForwardFsyncRequest() supposed that it could only be called in regular
backends, which used to be true; but since the splitup of bgwriter and
checkpointer, it is also called in the bgwriter. We do not want to count
such calls in pg_stat_bgwriter.buffers_backend statistics, so fix things
so that they aren't.
(It's worth noting here that this implies an alarmingly large increase in
the expected amount of cross-process fsync request traffic, which may well
mean that the process splitup was not such a hot idea.)
mdinit() was misusing IsBootstrapProcessingMode() to decide whether to
create an fsync pending-operations table in the current process. This led
to creating a table not only in the startup and checkpointer processes as
intended, but also in the bgwriter process, not to mention other auxiliary
processes such as walwriter and walreceiver. Creation of the table in the
bgwriter is fatal, because it absorbs fsync requests that should have gone
to the checkpointer; instead they just sit in bgwriter local memory and are
never acted on. So writes performed by the bgwriter were not being fsync'd
which could result in data loss after an OS crash. I think there is no
live bug with respect to walwriter and walreceiver because those never
perform any writes of shared buffers; but the potential is there for
future breakage in those processes too.
To fix, make AuxiliaryProcessMain() export the current process's
AuxProcType as a global variable, and then make mdinit() test directly for
the types of aux process that should have a pendingOpsTable. Having done
that, we might as well also get rid of the random bool flags such as
am_walreceiver that some of the aux processes had grown. (Note that we
could not have fixed the bug by examining those variables in mdinit(),
because it's called from BaseInit() which is run by AuxiliaryProcessMain()
before entering any of the process-type-specific code.)
Back-patch to 9.2, where the problem was introduced by the split-up of
bgwriter and checkpointer processes. The bogus pendingOpsTable exists
in walwriter and walreceiver processes in earlier branches, but absent
any evidence that it causes actual problems there, I'll leave the older
branches alone.
They don't actually do anything yet; that will get fixed in a
follow-on commit. But this gets the basic infrastructure in place,
including CREATE/ALTER/DROP EVENT TRIGGER; support for COMMENT,
SECURITY LABEL, and ALTER EXTENSION .. ADD/DROP EVENT TRIGGER;
pg_dump and psql support; and documentation for the anticipated
initial feature set.
Dimitri Fontaine, with review and a bunch of additional hacking by me.
Thom Brown extensively reviewed earlier versions of this patch set,
but there's not a whole lot of that code left in this commit, as it
turns out.
In all branches back to 8.3, this patch fixes a questionable assumption in
CompactCheckpointerRequestQueue/CompactBgwriterRequestQueue that there are
no uninitialized pad bytes in the request queue structs. This would only
cause trouble if (a) there were such pad bytes, which could happen in 8.4
and up if the compiler makes enum ForkNumber narrower than 32 bits, but
otherwise would require not-currently-planned changes in the widths of
other typedefs; and (b) the kernel has not uniformly initialized the
contents of shared memory to zeroes. Still, it seems a tad risky, and we
can easily remove any risk by pre-zeroing the request array for ourselves.
In addition to that, we need to establish a coding rule that struct
RelFileNode can't contain any padding bytes, since such structs are copied
into the request array verbatim. (There are other places that are assuming
this anyway, it turns out.)
In 9.1 and up, the risk was a bit larger because we were also effectively
assuming that struct RelFileNodeBackend contained no pad bytes, and with
fields of different types in there, that would be much easier to break.
However, there is no good reason to ever transmit fsync or delete requests
for temp files to the bgwriter/checkpointer, so we can revert the request
structs to plain RelFileNode, getting rid of the padding risk and saving
some marginal number of bytes and cycles in fsync queue manipulation while
we are at it. The savings might be more than marginal during deletion of
a temp relation, because the old code transmitted an entirely useless but
nonetheless expensive-to-process ForgetRelationFsync request to the
background process, and also had the background process perform the file
deletion even though that can safely be done immediately.
In addition, make some cleanup of nearby comments and small improvements to
the code in CompactCheckpointerRequestQueue/CompactBgwriterRequestQueue.
These only pass cleanly on UTF8 and SQL_ASCII encodings, besides the
Japanese encoding in which they were originally written, which is clearly
not good enough. Since the functionality they test has not ever been
tested from PL/Perl, the best answer seems to be to remove the new tests
completely.
Per buildfarm results and ensuing discussion.
Management of timeouts was getting a little cumbersome; what we
originally had was more than enough back when we were only concerned
about deadlocks and query cancel; however, when we added timeouts for
standby processes, the code got considerably messier. Since there are
plans to add more complex timeouts, this seems a good time to introduce
a central timeout handling module.
External modules register their timeout handlers during process
initialization, and later enable and disable them as they see fit using
a simple API; timeout.c is in charge of keeping track of which timeouts
are in effect at any time, installing a common SIGALRM signal handler,
and calling setitimer() as appropriate to ensure timely firing of
external handlers.
timeout.c additionally supports pluggable modules to add their own
timeouts, though this capability isn't exercised anywhere yet.
Additionally, as of this commit, walsender processes are aware of
timeouts; we had a preexisting bug there that made those ignore SIGALRM,
thus being subject to unhandled deadlocks, particularly during the
authentication phase. This has already been fixed in back branches in
commit 0bf8eb2a, which see for more details.
Main author: Zoltán Böszörményi
Some review and cleanup by Álvaro Herrera
Extensive reworking by Tom Lane
The Solaris Studio compiler warns about these instances, unlike more
mainstream compilers such as gcc. But manual inspection showed that
the code is clearly not reachable, and we hope no worthy compiler will
complain about removing this code.
Formerly, when trying to copy both indexes and comments, CREATE TABLE LIKE
had to pre-assign names to indexes that had comments, because it made up an
explicit CommentStmt command to apply the comment and so it had to know the
name for the index. This creates bad interactions with other indexes, as
shown in bug #6734 from Daniele Varrazzo: the preassignment logic couldn't
take any other indexes into account so it could choose a conflicting name.
To fix, add a field to IndexStmt that allows it to carry a comment to be
assigned to the new index. (This isn't a user-exposed feature of CREATE
INDEX, only an internal option.) Now we don't need preassignment of index
names in any situation.
I also took the opportunity to refactor DefineIndex to accept the IndexStmt
as such, rather than passing all its fields individually in a mile-long
parameter list.
Back-patch to 9.2, but no further, because it seems too dangerous to change
IndexStmt or DefineIndex's API in released branches. The bug exists back
to 9.0 where CREATE TABLE LIKE grew the ability to copy comments, but given
the lack of prior complaints we'll just let it go unfixed before 9.2.
rfree() failed to cope with the case that pg_regcomp() had initialized the
regex_t struct but then failed to allocate any memory for re->re_guts (ie,
the first malloc call in pg_regcomp() failed). It would try to touch the
guts struct anyway, and thus dump core. This is a sufficiently narrow
corner case that it's not surprising it's never been seen in the field;
but still a bug is a bug, so patch all active branches.
Noted while investigating whether we need to call pg_regfree after a
failure return from pg_regcomp. Other than this bug, it turns out we
don't, so adjust comments appropriately.
This was causing a compiler warning with Solaris compiler. Use 0 instead.
The variable is initialized just for the sake of tidyness and/or debugging,
it's not used for anything before setting it to a real value.
Per report and suggestion from Peter Eisentraut.
Historically we have not worried about fsync'ing anything during initdb
(in fact, initdb intentionally passes -F to each backend launch to prevent
it from fsync'ing). But with filesystems getting more aggressive about
caching data, that's not such a good plan anymore. Make initdb do a pass
over the finished data directory tree to fsync everything. For testing
purposes, the -N/--nosync flag can be used to restore the old behavior.
Also, testing shows that on Linux, sync_file_range() is much faster than
posix_fadvise() for hinting to the kernel that an fsync is coming,
apparently because the latter blocks on a rather small request queue while
the former doesn't. So use this function if available in initdb, and also
in the backend's pg_flush_data() (where it currently will affect only the
speed of CREATE DATABASE's cloning step).
We will later make pg_regress invoke initdb with the --nosync flag
to avoid slowing down cases such as "make check" in contrib. But
let's not do so until we've shaken out any portability issues in this
patch.
Jeff Davis, reviewed by Andres Freund
Make it clearer that the passed stack mustn't be empty, and that we
are not supposed to fall off the end of the stack in the main loop.
Tighten the loop that extracts the root block number, too.
Markus Wanner and Tom Lane
When reading from a text- or CSV-format file in file_fdw, the datatype
input routines can consume a significant fraction of the runtime.
Often, the query does not need all the columns, so we can get a useful
speed boost by skipping I/O conversion for unnecessary columns.
To support this, add a "convert_selectively" option to the core COPY code.
This is undocumented and not accessible from SQL (for now, anyway).
Etsuro Fujita, reviewed by KaiGai Kohei
When the internal loop mode was added, freeing memory and closing
filedescriptors before returning became important, and a few cases
in the code missed that.
Fujii Masao
These functions support removing or replacing array element value(s)
matching a given search value. Although intended mainly to support a
future array-foreign-key feature, they seem useful in their own right.
Marco Nenciarini and Gabriele Bartolini, reviewed by Alex Hunsaker
source code(lisp/international/mule-conf.el). These charsets have not
been supported up to now anyway, so this is just for adding
commentary. Also add mention that we follow emacs's implementation,
not xemacs's.
When in SQL_ASCII encoding, strings passed around are not necessarily
UTF8-safe. We had already fixed this in some places, but it looks like
we missed some.
I had to backpatch Peter Eisentraut's a8b92b60 to 9.1 in order for this
patch to cherry-pick more cleanly.
Patch from Alex Hunsaker, tweaked by Kyotaro HORIGUCHI and myself.
Some desultory cleanup and comment addition by me, during patch review.
Per bug report from Christoph Berg in
20120209102116.GA14429@msgid.df7cb.de
To generate btree-indexable conditions from regex WHERE conditions (such as
WHERE indexed_col ~ '^foo'), we need to be able to identify any fixed
prefix that a regex might have; that is, find any string that must be a
prefix of all strings satisfying the regex. We used to do that with
entirely ad-hoc code that looked at the source text of the regex. It
didn't know very much about regex syntax, which mostly meant that it would
fail to identify some optimizable cases; but Viktor Rosenfeld reported that
it would produce actively wrong answers for quantified parenthesized
subexpressions, such as '^(foo)?bar'. Rather than trying to extend the
ad-hoc code to cover this, let's get rid of it altogether in favor of
identifying prefixes by examining the compiled form of a regex.
To do this, I've added a new entry point "pg_regprefix" to the regex library;
hopefully it is defined in a sufficiently general fashion that it can remain
in the library when/if that code gets split out as a standalone project.
Since this bug has been there for a very long time, this fix needs to get
back-patched. However it depends on some other recent commits (particularly
the addition of wchar-to-database-encoding conversion), so I'll commit this
separately and then go to work on back-porting the necessary fixes.
Previously, pattern_fixed_prefix() was defined to return whatever fixed
prefix it could extract from the pattern, plus the "rest" of the pattern.
That definition was sensible for LIKE patterns, but not so much for
regexes, where reconstituting a valid pattern minus the prefix could be
quite tricky (certainly the existing code wasn't doing that correctly).
Since the only thing that callers ever did with the "rest" of the pattern
was to pass it to like_selectivity() or regex_selectivity(), let's cut out
the middle-man and just have pattern_fixed_prefix's subroutines do this
directly. Then pattern_fixed_prefix can return a simple selectivity
number, and the question of how to cope with partial patterns is removed
from its API specification.
While at it, adjust the API spec so that callers who don't actually care
about the pattern's selectivity (which is a lot of them) can pass NULL for
the selectivity pointer to skip doing the work of computing a selectivity
estimate.
This patch is only an API refactoring that doesn't actually change any
processing, other than allowing a little bit of useless work to be skipped.
However, it's necessary infrastructure for my upcoming fix to regex prefix
extraction, because after that change there won't be any simple way to
identify the "rest" of the regex, not even to the low level of fidelity
needed by regex_selectivity. We can cope with that if regex_fixed_prefix
and regex_selectivity communicate directly, but not if we have to work
within the old API. Hence, back-patch to all active branches.
We can do this without creating an API break for estimation functions
by passing the collation using the existing fmgr functionality for
passing an input collation as a hidden parameter.
The need for this was foreseen at the outset, but we didn't get around to
making it happen in 9.1 because of the decision to sort all pg_statistic
histograms according to the database's default collation. That meant that
selectivity estimators generally need to use the default collation too,
even if they're estimating for an operator that will do something
different. The reason it's suddenly become more interesting is that
regexp interpretation also uses a collation (for its LC_TYPE not LC_COLLATE
property), and we no longer want to use the wrong collation when examining
regexps during planning. It's not that the selectivity estimate is likely
to change much from this; rather that we are thinking of caching compiled
regexps during planner estimation, and we won't get the intended benefit
if we cache them with a different collation than the executor will use.
Back-patch to 9.1, both because the regexp change is likely to get
back-patched and because we might as well get this right in all
collation-supporting branches, in case any third-party code wants to
rely on getting the collation. The patch turns out to be minuscule
now that I've done it ...
The previous coding abused the first element of a cNFA state's arcs list
to hold a per-state flag bit, which was confusing, undocumented, and not
even particularly efficient. Get rid of that in favor of a separate
"stflags" vector. Since there's only one bit in use, I chose to allocate a
char per state; we could possibly replace this with a bitmap at some point,
but that would make accesses a little slower. It's already about 8X
smaller than before, so let's not get overly tense.
Also document the representation better than it was before, which is to say
not at all.
This patch is a byproduct of investigations towards extracting a "fixed
prefix" string from the compact-NFA representation of regex patterns.
Might need to back-patch it if we decide to back-patch that fix, but for
now it's just code cleanup so I'll just put it in HEAD.
join_path_components() tried to remove leading ".." components from its
tail argument, but it was not nearly bright enough to do so correctly
unless the head argument was (a) absolute and (b) canonicalized.
Rather than try to fix that logic, let's just get rid of it: there is no
correctness reason to remove "..", and cosmetic concerns can be taken
care of by a subsequent canonicalize_path() call. Per bug #6715 from
Greg Davidson.
Back-patch to all supported branches. It appears that pre-9.2, this
function is only used with absolute paths as head arguments, which is why
we'd not noticed the breakage before. However, third-party code might be
expecting this function to work in more general cases, so it seems wise
to back-patch.
In HEAD and 9.2, also make some minor cosmetic improvements to callers.
That caused the plpython_unicode regression test to fail on SQL_ASCII
encoding, as evidenced by the buildfarm. The reason is that with the patch,
you don't get the detail in the error message that you got before. That
detail is actually very informative, so rather than just adjust the expected
output, let's revert that part of the patch for now to make the buildfarm
green again, and figure out some other way to avoid the recursion of
PLy_elog() that doesn't lose the detail.
Windows encodings, "win1252" and so forth, are named differently in Python,
like "cp1252". Also, if the PyUnicode_AsEncodedString() function call fails
for some reason, use a plain ereport(), not a PLy_elog(), to report that
error. That avoids recursion and crash, if PLy_elog() tries to call
PLyUnicode_Bytes() again.
This fixes bug reported by Asif Naeem. Backpatch down to 9.0, before that
plpython didn't even try these conversions.
Jan Urbański, with minor comment improvements by me.
All Unix-oid platforms that we currently support should have waitpid(),
since it's in V2 of the Single Unix Spec. Our git history shows that
the wait3 code was added to support NextStep, which we officially dropped
support for as of 9.2. So get rid of the configure test, and simplify the
macro spaghetti in reaper(). Per suggestion from Fujii Masao.
This is infrastructure for Alexander Korotkov's work on indexing regular
expression searches.
Alexander Korotkov, with a bit of further hackery on the MULE conversion
by me
The old value of 32MB has been around for a very long time, and in the
meantime typical system memories have become vastly larger. Also, now
that we no longer depend on being able to fit the entirety of our
shared memory segment into the system's limit on System V shared
memory, there's a much better chance of the higher limit actually
proving productive.
Per recent discussion on pgsql-hackers.
This makes it possible for the master to track how much data has
actually been written my pg_receivexlog - and not just how much
has been sent towards it.
This ensures that a standby such as pg_receivexlog will not be selected
as sync standby - which would cause the master to block waiting for
a location that could never happen.
Fujii Masao
This commit improves the comments in pg_wchar.h and creates #define symbols
for some formerly hard-coded values. No substantive code changes.
Tatsuo Ishii and Tom Lane
Per bug #6593, REASSIGN OWNED fails when the affected role has created
an extension. Even though the user related to the extension is not
nominally the owner, its OID appears on pg_shdepend and thus causes
problems when the user is to be dropped.
This commit adds code to change the "ownership" of the extension itself,
not of the contained objects. This is fine because it's currently only
called from REASSIGN OWNED, which would also modify the ownership of the
contained objects. However, this is not sufficient for a working ALTER
OWNER implementation extension.
Back-patch to 9.1, where extensions were introduced.
Bug #6593 reported by Emiliano Leporati.
A thinko in commit 029dfdf115 caused the year
519 to be handled differently from either adjacent year, which was not the
intention AFAICS. Report and diagnosis by Marc Cousin.
In passing, remove redundant re-tests of year value.
Instead of letting every backend participating in a group commit wait
independently, have the first one that becomes ready to flush WAL wait
for the configured delay, and let all the others wait just long enough
for that first process to complete its flush. This greatly increases
the chances of being able to configure a commit_delay setting that
actually improves performance.
As a side consequence of this change, commit_delay now affects all WAL
flushes, rather than just commits. There was some discussion on
pgsql-hackers about whether to rename the GUC to, say, wal_flush_delay,
but in the absence of consensus I am leaving it alone for now.
Peter Geoghegan, with some changes, mostly to the documentation, by me.
Per testing by Andres Freund, this improves replication performance
and reduces replication latency and latency jitter. I was a bit
concerned about moving more work into XLogInsert, but testing seems
to show that it's not a problem in practice.
Along the way, improve comments for WaitLatchOrSocket.
Andres Freund. Review and stylistic cleanup by me.
When (re) loading the typcache comparison cache for an enum type's values,
use an up-to-date MVCC snapshot, not the transaction's existing snapshot.
This avoids problems if we encounter an enum OID that was created since our
transaction started. Per report from Andres Freund and diagnosis by Robert
Haas.
To ensure this is safe even if enum comparison manages to get invoked
before we've set a transaction snapshot, tweak GetLatestSnapshot to
redirect to GetTransactionSnapshot instead of throwing error when
FirstSnapshotSet is false. The existing uses of GetLatestSnapshot (in
ri_triggers.c) don't care since they couldn't be invoked except in a
transaction that's already done some work --- but it seems just conceivable
that this might not be true of enums, especially if we ever choose to use
enums in system catalogs.
Note that the comparable coding in enum_endpoint and enum_range_internal
remains GetTransactionSnapshot; this is perhaps debatable, but if we
changed it those functions would have to be marked volatile, which doesn't
seem attractive.
Back-patch to 9.1 where ALTER TYPE ADD VALUE was added.
Commit 7357558fc8 introduced "(void) token;"
into the READ_TEMP_LOCALS() macro, to suppress complaints from gcc 4.6
when the value of token was not used anywhere in a particular node-read
function. However, this just moved the warning around: inspection of
buildfarm results shows that some compilers are now complaining that token
is being read before it's set. Revert the READ_TEMP_LOCALS() macro change
and instead put "(void) token;" into READ_NODE_FIELD(), which is the
principal culprit for cases where the warning might occur. In principle we
might need the same in READ_BITMAPSET_FIELD() and/or READ_LOCATION_FIELD(),
but it seems unlikely that a node would consist only of such fields, so
I'll leave them alone for now.
The original coding had it as "PGShmemHeader *", but that doesn't offer any
notational benefit because we don't dereference it. And it was resulting
in compiler warnings on some platforms, notably buildfarm member
castoroides, where mmap() and munmap() are evidently declared to take and
return "char *".
If a CHECK constraint or index definition contained a whole-row Var (that
is, "table.*"), an attempt to copy that definition via CREATE TABLE LIKE or
table inheritance produced incorrect results: the copied Var still claimed
to have the rowtype of the source table, rather than the created table.
For the LIKE case, it seems reasonable to just throw error for this
situation, since the point of LIKE is that the new table is not permanently
coupled to the old, so there's no reason to assume its rowtype will stay
compatible. In the inheritance case, we should ideally allow such
constraints, but doing so will require nontrivial refactoring of CREATE
TABLE processing (because we'd need to know the OID of the new table's
rowtype before we adjust inherited CHECK constraints). In view of the lack
of previous complaints, that doesn't seem worth the risk in a back-patched
bug fix, so just make it throw error for the inheritance case as well.
Along the way, replace change_varattnos_of_a_node() with a more robust
function map_variable_attnos(), which is capable of being extended to
handle insertion of ConvertRowtypeExpr whenever we get around to fixing
the inheritance case nicely, and in the meantime it returns a failure
indication to the caller so that a helpful message with some context can be
thrown. Also, this code will do the right thing with subselects (if we
ever allow them in CHECK or indexes), and it range-checks varattnos before
using them to index into the map array.
Per report from Sergey Konoplev. Back-patch to all supported branches.
Change things so that something like initdb --auth-local=peer
--auth-host=md5 does not cause a "must specify a password" error,
like initdb -A md5 does.
If the record header is garbled, we're now quite likely to notice it before
we try to make a bogus memory allocation and run out of memory. That can
still happen, if the xlog record is split across pages (we cannot verify
the record header until reading the next page in that scenario), but this
reduces the chances. An out-of-memory is treated as a corrupt record
anyway, so this isn't a correctness issue, just a case of giving a better
error message.
Per Amit Kapila's suggestion.