currently have any better strategy for this query than re-running the
sub-select over and over; it seems unlikely that doing so 10000 times
is a more useful test than doing it a few dozen times.
entries for the victim database go away sooner rather than later. We already
did the equivalent thing at the per-relation level, not sure why it's not
been done for whole databases. With this change, pgstat_vacuum_tabstat
should usually not find anything to do; though we still need it as a backstop
in case DROPDB or TABPURGE messages get lost under load.
keeping private state in each backend that has inserted and deleted the same
tuple during its current top-level transaction. This is sufficient since
there is no need to be able to determine the cmin/cmax from any other
transaction. This gets us back down to 23-byte headers, removing a penalty
paid in 8.0 to support subtransactions. Patch by Heikki Linnakangas, with
minor revisions by moi, following a design hashed out awhile back on the
pghackers list.
get away with not (re)initializing a local variable if the variable is marked
"isconst" and not "isnull". Unfortunately it makes this decision after having
already freed the old value, meaning that something like
for i in 1..10 loop
declare c constant text := 'hi there';
leads to subsequent accesses to freed memory, and hence probably crashes.
(In particular, this is why Asif Ali Rehman's bug leads to crash and not
just an unexpectedly-NULL value for SQLERRM: SQLERRM is marked CONSTANT
and so triggers this error.)
The whole thing seems wrong on its face anyway: CONSTANT means that you can't
change the variable inside the block, not that the initializer expression is
guaranteed not to change value across successive block entries. Hence,
remove the "optimization" instead of trying to fix it.
DECLARE section needs to know about it. Formerly, everyplace besides DECLARE
that created variables needed to do "plpgsql_add_initdatums(NULL)" to prevent
those variables from being sucked up as part of a subsequent DECLARE block.
This is obviously error-prone, and in fact the SQLSTATE/SQLERRM patch had
failed to do it for those two variables, leading to the bug recently exhibited
by Asif Ali Rehman: a DECLARE within an exception handler tried to reinitialize
SQLERRM.
Although the SQLSTATE/SQLERRM patch isn't in any pre-8.1 branches, and so
I can't point to a demonstrable failure there, it seems wise to back-patch
this into the older branches anyway, just to keep the logic similar to HEAD.
For win32 in general, this makes it possible to run the regression tests
as an admin user by using the same restricted token method that's used
by pg_ctl and initdb.
For vc++, it adds building of pg_regress.exe, adds a resultmap, and
fixes how it runs the install.
Magnus Hagander
where possible, and fix some sites that apparently thought that fgets()
will overwrite the buffer by one byte.
Also add some strlcpy() to eliminate some weird memory handling.
> Currently, an index split writes all the data on the split page to
> WAL. That's a lot of WAL traffic. The tuples that are copied to the
> right page need to be WAL logged, but the tuples that stay on the
> original page don't.
Heikki Linnakangas
already collected in the current transaction; this allows plpgsql functions to
watch for stats updates even though they are confined to a single transaction.
Use this instead of the previous kluge involving pg_stat_file() to wait for
the stats collector to update in the stats regression test. Internally,
decouple storage of stats snapshots from transaction boundaries; they'll
now stick around until someone calls pgstat_clear_snapshot --- which xact.c
still does at transaction end, to maintain the previous behavior. This makes
the logic a lot cleaner, at the price of a couple dozen cycles per transaction
exit.
changes (with an upper limit of 30 seconds), and record the delay time in
the postmaster log. This should give us some info about what's happening
with the intermittent stats failures in buildfarm. After an idea of
Andrew Dunstan's.
"database system is ready to accept connections", which is issued by the
postmaster when it really is ready to accept connections. Per proposal from
Markus Schiltknecht and subsequent discussion.
thought that it didn't have to reposition the underlying tuplestore if the
portal is atEnd. But this is not so, because tuplestores have separate read
and write cursors ... and the read cursor hasn't moved from the start.
This mistake explains bug #2970 from William Zhang.
Note: the coding here is pretty inefficient, but given that no one has noticed
this bug until now, I'd say hardly anyone uses the case where the cursor has
been advanced before being persisted. So maybe it's not worth worrying about.
out that ExecEvalVar and friends don't necessarily have access to a tuple
descriptor with correct typmod: it definitely can contain -1, and possibly
might contain other values that are different from the Var's value.
Arguably this should be cleaned up someday, but it's not a simple change,
and in any case typmod discrepancies don't pose a security hazard.
Per reports from numerous people :-(
I'm not entirely sure whether the failure can occur in 8.0 --- the simple
test cases reported so far don't trigger it there. But back-patch the
change all the way anyway.
had stopped working for tables buried inside views or sub-selects. This is
because I had gotten rid of the simplify_jointree() preprocessing step, and
optimize_minmax_aggregates() wasn't smart enough to deal with a non-canonical
FromExpr. Per gripe from Bill Howe.
that aren't turned into true joins). Since this is the last missing bit of
infrastructure, go ahead and fill out the hash integer_ops and float_ops
opfamilies with cross-type operators. The operator family project is now
DONE ... er, except for documentation ...
describe the maximum size of index tuples (which is typically AM-dependent
anyway); and consequently remove the bogus deduction for "special space"
that was built into it.
Adjust TOAST_TUPLE_THRESHOLD and TOAST_MAX_CHUNK_SIZE to avoid wasting two
bytes per toast chunk, and to ensure that the calculation correctly tracks any
future changes in page header size. The computation had been inaccurate in a
way that didn't cause any harm except space wastage, but future changes could
have broken it more drastically.
Fix the calculation of BTMaxItemSize, which was formerly computed as 1 byte
more than it could safely be. This didn't cause any harm in practice because
it's only compared against maxalign'd lengths, but future changes in the size
of page headers or btree special space could have exposed the problem.
initdb forced because of change in TOAST_MAX_CHUNK_SIZE, which alters the
storage of toast tables.
threshold for tuple length. On 4-byte-MAXALIGN machines, the toast code
creates tuples that have t_len exactly TOAST_TUPLE_THRESHOLD ... but this
number is not itself maxaligned, so if heap_insert maxaligns t_len before
comparing to TOAST_TUPLE_THRESHOLD, it'll uselessly recurse back to
tuptoaster.c, wasting cycles. (It turns out that this does not happen on
8-byte-MAXALIGN machines, because for them the outer MAXALIGN in the
TOAST_MAX_CHUNK_SIZE macro reduces TOAST_MAX_CHUNK_SIZE so that toast tuples
will be less than TOAST_TUPLE_THRESHOLD in size. That MAXALIGN is really
incorrect, but we can't remove it now, see below.) There isn't any particular
value in maxaligning before comparing to the thresholds, so just don't do
that, which saves a small number of cycles in itself.
These numbers should be rejiggered to minimize wasted space on toast-relation
pages, but we can't do that in the back branches because changing
TOAST_MAX_CHUNK_SIZE would force an initdb (by changing the contents of toast
tables). We can move the toast decision thresholds a bit, though, which is
what this patch effectively does.
Thanks to Pavan Deolasee for discovering the unintended recursion.
Back-patch into 8.2, but not further, pending more testing. (HEAD is about
to get a further patch modifying the thresholds, so it won't help much
for testing this form of the patch.)
observe the xmloption.
Reorganize the representation of the XML option in the parse tree and the
API to make it easier to manage and understand.
Add regression tests for parsing back XML expressions.
generated solution files for what to install, instead of blindly copying
everything as it previously did. With the previous quick-n-dirty
version, it would copy old DLLs if you reconfigured in a way that didn't
include subprojects like a PL for example.
Magnus Hagander.
made query plan. Use of ALTER COLUMN TYPE creates a hazard for cached
query plans: they could contain Vars that claim a column has a different
type than it now has. Fix this by checking during plan startup that Vars
at relation scan level match the current relation tuple descriptor. Since
at that point we already have at least AccessShareLock, we can be sure the
column type will not change underneath us later in the query. However,
since a backend's locks do not conflict against itself, there is still a
hole for an attacker to exploit: he could try to execute ALTER COLUMN TYPE
while a query is in progress in the current backend. Seal that hole by
rejecting ALTER TABLE whenever the target relation is already open in
the current backend.
This is a significant security hole: not only can one trivially crash the
backend, but with appropriate misuse of pass-by-reference datatypes it is
possible to read out arbitrary locations in the server process's memory,
which could allow retrieving database content the user should not be able
to see. Our thanks to Jeff Trout for the initial report.
Security: CVE-2007-0556
we should check that the function code returns the claimed result datatype
every time we parse the function for execution. Formerly, for simple
scalar result types we assumed the creation-time check was sufficient, but
this fails if the function selects from a table that's been redefined since
then, and even more obviously fails if check_function_bodies had been OFF.
This is a significant security hole: not only can one trivially crash the
backend, but with appropriate misuse of pass-by-reference datatypes it is
possible to read out arbitrary locations in the server process's memory,
which could allow retrieving database content the user should not be able
to see. Our thanks to Jeff Trout for the initial report.
Security: CVE-2007-0555
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
Tom Lane
Peter Eisentraut
Bruce Momjian
Alvaro Herrera
Andrew Dunstan
Neil Conway
Michael Meskes