These are unnecessary and probably dangerous. I don't see any immediate
risk situations in the core XML support or contrib/xml2 itself, but there
could be issues with external uses of libxml2, and in any case it's an
accident waiting to happen.
Get rid of the code that attempted to funnel libxml2's memory allocations
into palloc. We already knew from experience with the core xml datatype
that trying to do this is simply not reliable. Unlike the core code, I
did not bother adding a lot of PG_TRY/PG_CATCH logic to try to ensure that
everything is cleaned up on error exit. Hence, we might leak some memory
if one of these functions fails partway through. Given the deprecated
status of this contrib module and the fact that errors partway through
the functions shouldn't be too common, it doesn't seem worth worrying about.
Also fix a separate bug in xpath_table, that it did the wrong things
if given a result tuple descriptor with less than 2 columns. While
such a case isn't very useful in practice, we shouldn't fail or stomp
memory when it occurs.
Add some simple regression tests based on all the reported crash cases
that I have on hand.
This should be back-patched, but let's see if the buildfarm likes it first.
the fact that NetBSD/mips is currently broken, as per buildfarm member pika.
Also add regression tests to ensure that get_float8_nan and get_float4_nan
are exercised even on platforms where they are not needed by
float8in/float4in.
Zoltán Böszörményi and Tom Lane
We had originally made the stronger assumption that NOT A refutes any B
if B implies A, but this fails in three-valued logic, because we need to
prove B is false not just that it's not true. However the logic does
go through if B is equal to A.
Recognizing this limited case is enough to handle examples that arise when
we have simplified "bool_var = true" or "bool_var = false" to just "bool_var"
or "NOT bool_var". If we had not done that simplification then the
btree-operator proof logic would have been able to prove that the expressions
were contradictory, but only for identical expressions being compared to the
constants; so handling identical A and B covers all the same cases.
The motivation for doing this is to avoid unexpected asymmetrical behavior
when a partitioned table uses a boolean partitioning column, as in today's
gripe from Dominik Sander.
Back-patch to 8.2, which is as far back as predicate_refuted_by attempts to
do anything at all with NOTs.
how often we do SSL session key renegotiation. Can be set to
0 to disable renegotiation completely, which is required if
a broken SSL library is used (broken patches to CVE-2009-3555
a known cause) or when using a client library that can't do
renegotiation.
The main motivation for changing this is bug #4921, in which it's pointed out
that it's no longer safe to apply ltree operations to the result of
ARRAY(SELECT ...) if the sub-select might return no rows. Before 8.3,
the ARRAY() construct would return NULL, which might or might not be helpful
but at least it wouldn't result in an error. Now it returns an empty array
which results in a failure for no good reason, since the ltree operations
are all perfectly capable of dealing with zero-element arrays.
As far as I can find, these ltree functions are the only places where zero
array dimensionality is rejected unnecessarily.
Back-patch to 8.3 to prevent behavioral regression of queries that worked
in older releases.
