available output buffer when presented with corrupt input. Some testing
suggests that this slows the decompression loop about 1%, which seems an
acceptable price to pay for more robustness. (Curiously, the penalty
seems to be *less* on not-very-compressible data, which I didn't expect
since the overhead per output byte ought to be more in the literal-bytes
path.)
Patch from Zdenek Kotala. I fixed a corner case and did some renaming
of variables to make the routine more readable.
were discussed last year, but we felt it was too late in the 8.3 cycle to
change the code immediately. Specifically, the patch:
* Reduces the minimum datum size to be considered for compression from
256 to 32 bytes, as suggested by Greg Stark.
* Increases the required compression rate for compressed storage from
20% to 25%, again per Greg's suggestion.
* Replaces force_input_size (size above which compression is forced)
with a maximum size to be considered for compression. It was agreed
that allowing large inputs to escape the minimum-compression-rate
requirement was not bright, and that indeed we'd rather have a knob
that acted in the other direction. I set this value to 1MB for the
moment, but it could use some performance studies to tune it.
* Adds an early-failure path to the compressor as suggested by Jan:
if it's been unable to find even one compressible substring in the
first 1KB (parameterizable), assume we're looking at incompressible
input and give up. (Possibly this logic can be improved, but I'll
commit it as-is for now.)
* Improves the toasting heuristics so that when we have very large
fields with attstorage 'x' or 'e', we will push those out to toast
storage before considering inline compression of shorter fields.
This also responds to a suggestion of Greg's, though my original
proposal for a solution was a bit off base because it didn't fix
the problem for large 'e' fields.
There was some discussion in the earlier threads of exposing some
of the compression knobs to users, perhaps even on a per-column
basis. I have not done anything about that here. It seems to me
that if we are changing around the parameters, we'd better get some
experience and be sure we are happy with the design before we set
things in stone by providing user-visible knobs.
TopMemoryContext, rather than scattered through executor per-query contexts.
This poses no danger of memory leak since the ResourceOwner mechanism
guarantees release of no-longer-needed items. It is needed because the
per-query context might already be released by the time we try to clean up
the hash scan list. Report by ykhuang, diagnosis by Heikki.
Back-patch to 8.0, where the ResourceOwner-based cleanup was introduced.
The given test case does not fail before 8.2, probably because we rearranged
transaction abort processing somehow; but this coding is undoubtedly risky
so I'll patch 8.0 and 8.1 anyway.
a unused memory holes in tsquery.
Per report by Richard Huxton <dev@archonet.com>.
It was working well because in fact tsquery->size is not used for any
kind of operation except comparing tsqueries. So, in HEAD it's enough to
fix to_tsquery function, but for previous version it's needed to
remove optimization in CompareTSQ to prevent requirement of renew all
stored tsquery.
caches that we don't actually need to touch. This saves some trivial
number of cycles and avoids certain cases of deadlock when doing concurrent
VACUUM FULL on system catalogs. Per report from Gavin Roy.
Backpatch to 8.2. In earlier versions, CatalogCacheInitializeCache didn't
lock the relation so there's no deadlock risk (though that certainly had
plenty of risks of its own).
temporary table; we can't support that because there's no way to clean up the
source backend's internal state if the eventual COMMIT PREPARED is done by
another backend. This was checked correctly in 8.1 but I broke it in 8.2 :-(.
Patch by Heikki Linnakangas, original trouble report by John Smith.
"struct varlena" would be at least word-aligned. Per buildfarm results
from gypsy_moth. I did a little bit of trawling for other instances of
this coding pattern, and didn't find any; but if we turn up any more
of them I think we'd better revert the "char [4]" patch and find another
way of making tuptoaster.c alignment-safe.
to explicitly cast the output back to char before comparing it to a char
value, else we get the wrong result for high-bit-set characters. Found by
Rolf Jentsch. Also, fix several places where <ctype.h> functions were being
called without casting the argument to unsigned char; this is likewise
unportable, but we keep making that mistake :-(. These found by buildfarm
member salamander, which I will desperately miss if it ever goes belly-up.
left in the code though it was not meant to be provided. It represents a
security hole because unprivileged users could use it to look at (at least the
first line of) any file readable by the backend. Fortunately, this is only
possible if the backend was built with XML support, so the damage is at least
mitigated; and 8.3 probably hasn't propagated into any security-critical uses
yet anyway. Per report from Sergey Burladyan.
is also licensed to put a local variable declared that way at an unaligned
address. Which will not work if the variable is then manipulated with
SET_VARSIZE or other macros that assume alignment. So the previous patch
is not an unalloyed good, but on balance I think it's still a win, since
we have very few places that do that sort of thing. Fix the one place in
tuptoaster.c that does it. Per buildfarm results from gypsy_moth
(I'm a bit surprised that only one machine showed a failure).
by explicitly adding back the user to the DACL of the new process.
This fixes the failure case when executing as the Administrator
user, which had no permissions left at all after we dropped the
Administrators group.
Dave Page with some modifications from me
"multi_call_ctx" to be a distinct sub-context of the EState's per-query
context, and delete the multi_call_ctx as soon as the SRF finishes
execution. This avoids leaking SRF memory until the end of the current
query, which is particularly egregious when the SRF is scanned
multiple times. This change also fixes a leak of the fields of the
AttInMetadata struct in shutdown_MultiFuncCall().
Also fix a leak of the SRF result TupleDesc when rescanning a
FunctionScan node. The TupleDesc is allocated in the per-query context
for every call to ExecMakeTableFunctionResult(), so we should free it
after calling that function. Since the SRF might choose to return
a non-expendable TupleDesc, we only free the TupleDesc if it is
not being reference-counted.
Backpatch to 8.3 and 8.2 stable branches.
that is shipped in the distribution, named libpq-dist.rc. This way the
build system doesn't get upset when a distributed file is forcibly
overwritten by during a normal build.
has been reinvented about four different times throughout history (aix,
cygwin, win32, darwin/linux) and a lot of the concepts are actually shared,
which the code now shows better.
So only rebuild when a makefile changes (which presumably defines the
file list somewhere), and only touch the file if an object changed. The
touch is necessary so the parent make knows something changed and
ultimately rebuilds postgres.
values into \nnn octal escape sequences. When the database encoding is
multibyte this is *necessary* to avoid generating invalidly encoded text.
Even in a single-byte encoding, the old behavior seems very hazardous ---
consider for example what happens if the text is transferred to another
database with a different encoding. Decoding would then yield some other
bytea value than what was encoded, which is surely undesirable. Per gripe
from Hernan Gonzalez.
Backpatch to 8.3, but not further. This is a bit of a judgment call, but I
make it on these grounds: pre-8.3 we don't really have much encoding safety
anyway because of the convert() function family, and we would also have much
higher risk of breaking existing apps that may not be expecting this behavior.
8.3 is still new enough that we can probably get away with making this change
in the function's behavior.
(then it means 2000 AD). Formerly we silently interpreted this as 1 BC,
which at best is unwarranted familiarity with the implementation.
It's barely possible that some app somewhere expects the old behavior,
though, so we won't back-patch this into existing release branches.
Formerly, DecodeDate attempted to verify the day-of-the-month exactly, but
it was under the misapprehension that it would know whether we were looking
at a BC year or not. In reality this check can't be made until the calling
function (eg DecodeDateTime) has processed all the fields. So, split the
BC adjustment and validity checks out into a new function ValidateDate that
is called only after processing all the fields. In passing, this patch
makes DecodeTimeOnly work for BC inputs, which it never did before.
(The historical veracity of all this is nonexistent, of course, but if
we're going to say we support proleptic Gregorian calendar then we should
do it correctly. In any case the unpatched code is broken because it could
emit dates that it would then reject on re-inputting.)
Per report from Bernd Helmle. Back-patch as far as 8.0; in 7.x we were
not using our own calendar support and so this seems a bit too risky
to put into 7.4.
SUBSYS.o step and allow for better optimization by the linker.
Instead of partial linking into SUBSYS.o, the list of object files is
assembled in objfiles.txt files that are expanded when the final
linking is done.
Because we are not yet sure how long command lines different platforms
can handle, the old way of linking is still available, by defining the
make variable PARTIAL_LINKING (e.g., make all PARTIAL_LINKING=1). If
we determine that this is necessary for some platforms, then we will
document this in a more prominent place.
represented as "char ...[4]" not "int32". Since the length word is never
supposed to be accessed via this struct member anyway, this won't break
any existing code that is following the rules. The advantage is that C
compilers will no longer assume that a pointer to struct varlena is
word-aligned, which prevents incorrect optimizations in TOAST-pointer
access and perhaps other places. gcc doesn't seem to do this (at least
not at -O2), but the problem is demonstrable on some other compilers.
I changed struct inet as well, but didn't bother to touch a lot of other
struct definitions in which it wouldn't make any difference because there
were other fields forcing int alignment anyway. Hopefully none of those
struct definitions are used for accessing unaligned Datums.
non-default settings for the postmaster's port number. The code to parse
command line options and postgresql.conf entries wasn't quite right about
whitespace or quotes, and it was coded in a not-very-readable way too.
Per bug #3969 from Itagaki Takahiro, though this is more extensive than his
proposed patch (which fixed only the whitespace problem).
This code has been broken since it was put in in 8.0, so patch all the way
back.
OID or new relfilenode. If the existing OIDs are sufficiently densely
populated, this could take a long time (perhaps even be an infinite loop),
so it seems wise to allow the system to respond to a cancel interrupt here.
Per a gripe from Jacky Leng.
Backpatch as far as 8.1. Older versions just fail on OID collision,
instead of looping.
and RI_FKey_keyequal_upd_fk, as well as no-longer-needed calls of
ri_BuildQueryKeyFull. Aside from saving a few cycles, this avoids needless
deadlock risks when an update is not changing the columns that participate
in an RI constraint. Per a gripe from Alexey Nalbat.
Back-patch to 8.3. Earlier releases did have a need to open the other
relation due to the way in which they retrieved information about the RI
constraint, so this problem unfortunately can't easily be improved pre-8.3.
Tom Lane and Stephan Szabo
- Change configure.in to use Autoconf 2.61 and update generated files.
- Update build system and documentation to support now directory variables
offered by Autoconf 2.61.
- Replace usages of PGAC_CHECK_ALIGNOF by AC_CHECK_ALIGNOF, now available
in Autoconf 2.61.
- Drop our patched version of AC_C_INLINE, as Autoconf now has the change.
data structures and backend internal APIs. This solves problems we've seen
recently with inconsistent layout of pg_control between machines that have
32-bit time_t and those that have already migrated to 64-bit time_t. Also,
we can get out from under the problem that Windows' Unix-API emulation is not
consistent about the width of time_t.
There are a few remaining places where local time_t variables are used to hold
the current or recent result of time(NULL). I didn't bother changing these
since they do not affect any cross-module APIs and surely all platforms will
have 64-bit time_t before overflow becomes an actual risk. time_t should
be avoided for anything visible to extension modules, however.
this adds support for 64-bit tzdata files, which is needed to support DST
calculations beyond 2038. Add a regression test case to give some minimal
confidence that that really works.
Heikki Linnakangas
verify_peer_name_matches_certificate(), clarify some of the function's
variables and logic, and update a comment. This should make SSL
improvements easier in the future.
(or RETURNING), but only when the output name is not any SQL keyword.
This seems as close as we can get to the standard's syntax without a
great deal of thrashing. Original patch by Hiroshi Saito, amended by me.
This was probably protecting some implementation limitation when it was
put in, but as far as I can tell the planner and executor have no such
assumption anymore; the case seems to work fine. Per a gripe from
Grzegorz Jaskiewicz.
was Tcl 8.4.8. The main changes are to remove the never-fully-implemented
code for multi-character collating elements, and to const-ify some stuff a
bit more fully. In combination with the recent security patch, this commit
brings us into line with Tcl 8.5.0.
Note that I didn't make any effort to duplicate a lot of cosmetic changes
that they made to bring their copy into line with their own style
guidelines, such as adding braces around single-line IF bodies. Most of
those we either had done already (such as ANSI-fication of function headers)
or there is no point because pgindent would undo the change anyway.
doing anything interesting, such as calling RevalidateCachedPlan(). The
necessity of this is demonstrated by an example from Willem Buitendyk:
during a replan, the planner might try to evaluate SPI-using functions,
and so we'd better be in a clean SPI context.
A small downside of this fix is that these two functions will now fail
outright if called when not inside a SPI-using procedure (ie, a
SPI_connect/SPI_finish pair). The documentation never promised or suggested
that that would work, though; and they are normally used in concert with
other functions, mainly SPI_prepare, that always have failed in such a case.
So the odds of breaking something seem pretty low.
In passing, make SPI_is_cursor_plan's error handling convention clearer,
and fix documentation's erroneous claim that SPI_cursor_open would
return NULL on error.
Before 8.3 these functions could not invoke replanning, so there is probably
no need for back-patching.
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.)
in .bat simply did not work, and it called them in the wrong order,
some several times, and some not at all. So this unrolls all subroutine
calls.
This should fix the issues with clean deleting the wrong files reported
by Dave Page.
While at it, add the "clean dist" option to act like "make distclean",
and no longer remove the flex/bison output files by default. This shuold
fix the problem reported by Pavel Golub in bug #3909.
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.
work with the PQExpBuffer code instead of fighting it. This avoids an
unnecessary limit on message length and fixes the latent bug that
errorMessage.len wasn't getting set.
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.
the patch for those features put its cleanup code into freePGconn() which is
really the wrong place. Remove redundant code from freePGconn() and add
comments in hopes of preventing similar mistakes in future.
Noticed while trying (futilely) to reproduce bug #3902.
are known to write on the socket sometimes and thus we are vulnerable to
being killed by the signal if the server happens to go away unexpectedly.
Noticed while trying (futilely) to reproduce bug #3902.
This bug has been there all along, but since the situation is usually
only of interest to developers, I chose not to back-patch the changes.
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.
TimestampTzPlusMilliseconds. An integer argument of more than INT_MAX/1000
milliseconds (ie, about 35 minutes) would provoke a wrong result, resulting
in incorrect enforcement of statement_timestamp values larger than that.
Bug was introduced in my rewrite of 2006-06-20, which fixed some other
overflow risks, but missed this one :-( Per report from Elein.
* The temporary enabling of the caller opcode here is to work around a
* bug in perl 5.10, which unkindly changed the way its Safe.pm works, without
* notice. It is quite safe, as caller is informational only, and in any case
* we only enable it while we load the 'strict' module.
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.
to format properly for the actually needed column width, instead of having
a hard-wired assumption about the longest command name length. Also make it
respond to the current screen width. In passing, const-ify the constant
table.
On other platforms it's better to let the Makefile handle it, but we want
the regression tests to be invokable without make on Windows. A batch
file would be a better solution, but no time for that before 8.3.
Per my discovery that this breaks testing under SELinux, and subsequent
discussion.
main code path for enlarging libpq's input buffer in one swoop when needing to
read a long data message. Without this, the code will double the buffer size,
read more data, notice it still hasn't got the whole message, and repeat till
it finally has a large enough buffer. Which wastes a lot of data-moving
effort and also memory (since malloc probably can't do anything very useful
with the freed-up smaller buffers). Not sure why this wasn't there already;
certainly the COPY data path is a place where we're quite likely to see long
data messages. I'm not backpatching though, since this is just a marginal
performance issue rather than a real bug.
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.
ParameterStatus message can be sent during COPY OUT: it's definitely
possible, since COPY from a SELECT subquery can trigger any user-defined
function.
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.
This is to avoid uselessly requiring superuser permissions to restore
the dump without errors. Pretty grotty, but no better alternative seems
available, at least not in the near term.
we need to be able to swallow NOTICE messages, and potentially also
ParameterStatus messages (although the latter would be a bit weird),
without exiting COPY OUT state. Fix it, and adjust the protocol documentation
to emphasize the need for this. Per off-list report from Alexander Galler.
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.
Andrew Dunstan
Tom Lane
Teodor Sigaev
Bruce Momjian
Alvaro Herrera
Magnus Hagander
Michael Meskes
Peter Eisentraut
Neil Conway