NUMERIC_MAX_PRECISION is a purely arbitrary constraint on the precision
and scale you can write in a numeric typmod. It might once have had
something to do with the allowed range of a typmod-less numeric value,
but at least since 9.1 we've allowed, and documented that we allowed,
any value that would physically fit in the numeric storage format;
which is something over 100000 decimal digits, not 1000.
Hence, get rid of numeric_in()'s use of NUMERIC_MAX_PRECISION as a limit
on the allowed range of the exponent in scientific-format input. That was
especially silly in view of the fact that you can enter larger numbers as
long as you don't use 'e' to do it. Just constrain the value enough to
avoid localized overflow, and let make_result be the final arbiter of what
is too large. Likewise adjust ecpg's equivalent of this code.
Also get rid of numeric_recv()'s use of NUMERIC_MAX_PRECISION to limit the
number of base-NBASE digits it would accept. That created a dump/restore
hazard for binary COPY without doing anything useful; the wire-format
limit on number of digits (65535) is about as tight as we would want.
In HEAD, also get rid of pg_size_bytes()'s unnecessary intimacy with what
the numeric range limit is. That code doesn't exist in the back branches.
Per gripe from Aravind Kumar. Back-patch to all supported branches,
since they all contain the documentation claim about allowed range of
NUMERIC (cf commit cabf5d84b).
Discussion: <2895.1471195721@sss.pgh.pa.us>
div_var_fast() postpones propagating carries in the same way as mul_var(),
so it has the same corner-case overflow risk we fixed in 246693e5ae,
namely that the size of the carries has to be accounted for when setting
the threshold for executing a carry propagation step. We've not devised
a test case illustrating the brokenness, but the required fix seems clear
enough. Like the previous fix, back-patch to all active branches.
Dean Rasheed
mul_var() postpones propagating carries until it risks overflow in its
internal digit array. However, the logic failed to account for the
possibility of overflow in the carry propagation step, allowing wrong
results to be generated in corner cases. We must slightly reduce the
when-to-propagate-carries threshold to avoid that.
Discovered and fixed by Dean Rasheed, with small adjustments by me.
This has been wrong since commit d72f6c7503,
so back-patch to all supported branches.
Commit 145343534c arranged to store numeric
NaN values as short-header numerics, but the field access macros did not
get the memo: they thought only "SHORT" numerics have short headers.
Most of the time this makes no difference because we don't access the
weight or dscale of a NaN; but numeric_send does that. As pointed out
by Andrew Gierth, this led to fetching uninitialized bytes.
AFAICS this could not have any worse consequences than that; in particular,
an unaligned stored numeric would have been detoasted by PG_GETARG_NUMERIC,
so that there's no risk of a fetch off the end of memory. Still, the code
is wrong on its own terms, and it's not hard to foresee future changes that
might expose us to real risks. So back-patch to all affected branches.
We were not checking to see if the supplied dscale was valid for the given
digit array when receiving binary-format numeric values. While dscale can
validly be more than the number of nonzero fractional digits, it shouldn't
be less; that case causes fractional digits to be hidden on display even
though they're there and participate in arithmetic.
Bug #12053 from Tommaso Sala indicates that there's at least one broken
client library out there that sometimes supplies an incorrect dscale value,
leading to strange behavior. This suggests that simply throwing an error
might not be the best response; it would lead to failures in applications
that might seem to be working fine today. What seems the least risky fix
is to truncate away any digits that would be hidden by dscale. This
preserves the existing behavior in terms of what will be printed for the
transmitted value, while preventing subsequent arithmetic from producing
results inconsistent with that.
In passing, throw a specific error for the case of dscale being outside
the range that will fit into a numeric's header. Before you got "value
overflows numeric format", which is a bit misleading.
Back-patch to all supported branches.
The code for raising a NUMERIC value to an integer power wasn't very
careful about large powers. It got an outright wrong answer for an
exponent of INT_MIN, due to failure to consider overflow of the Abs(exp)
operation; which is fixable by using an unsigned rather than signed
exponent value after that point. Also, even though the number of
iterations of the power-computation loop is pretty limited, it's easy for
the repeated squarings to result in ridiculously enormous intermediate
values, which can take unreasonable amounts of time/memory to process,
or even overflow the internal "weight" field and so produce a wrong answer.
We can forestall misbehaviors of that sort by bailing out as soon as the
weight value exceeds what will fit in int16, since then the final answer
must overflow (if exp > 0) or underflow (if exp < 0) the packed numeric
format.
Per off-list report from Pavel Stehule. Back-patch to all supported
branches.
This was not changed in HEAD, but will be done later as part of a
pgindent run. Future pgindent runs will also do this.
Report by Tom Lane
Backpatch through all supported branches, but not HEAD
In most cases, these were just references to the SQL standard in
general. In a few cases, a contrast was made between SQL92 and later
standards -- those have been kept unchanged.
In many functions, a NumericVar was initialized from an input Numeric, to be
passed as input to a calculation function. When the NumericVar is not
modified, the digits array of the NumericVar can point directly to the digits
array in the original Numeric, and we can avoid a palloc() and memcpy(). Add
init_var_from_num() function to initialize a var like that.
Remove dscale argument from get_str_from_var(), as all the callers just
passed the dscale of the variable. That means that the rounding it used to
do was not actually necessary, and get_str_from_var() no longer scribbles on
its input. That makes it safer in general, and allows us to use the new
init_var_from_num() function in e.g numeric_out().
Also modified numericvar_to_int8() to no scribble on its input either. It
creates a temporary copy to avoid that. To compensate, the callers no longer
need to create a temporary copy, so the net # of pallocs is the same, but this
is nicer.
In the passing, use a constant for the number 10 in get_str_from_var_sci(),
when calculating 10^exponent. Saves a palloc() and some cycles to convert
integer 10 to numeric.
Original patch by Kyotaro HORIGUCHI, with further changes by me. Reviewed
by Pavel Stehule.
Fix loss of previous expression-simplification work when a transform
function fires: we must not simply revert to untransformed input tree.
Instead build a dummy FuncExpr node to pass to the transform function.
This has the additional advantage of providing a simpler, more uniform
API for transform functions.
Move documentation to a somewhat less buried spot, relocate some
poorly-placed code, be more wary of null constants and invalid typmod
values, add an opr_sanity check on protransform function signatures,
and some other minor cosmetic adjustments.
Note: although this patch touches pg_proc.h, no need for catversion
bump, because the changes are cosmetic and don't actually change the
intended catalog contents.
This enables ALTER TABLE to skip table and index rebuilds when a column
is changed to an unconstrained numeric, or when the scale is unchanged
and the precision does not decrease.
Noah Misch, with a few stylistic changes and a fix for an OID
collision by me.
The old computation can sometimes underestimate the necessary space
by 2 bytes; however we're not back-patching this, because this result
isn't used for anything critical. Per discussion with Tom Lane,
make the typmod test in this function match the ones in numeric()
and apply_typmod() exactly.
being called as aggregates, and to get the aggregate transition state memory
context if needed. Use it instead of poking directly into AggState and
WindowAggState in places that shouldn't know so much.
We should have done this in 8.4, probably, but better late than never.
Revised version of a patch by Hitoshi Harada.
we're not going to support that anymore.
I did keep the 64-bit-CRC-with-32-bit-arithmetic code, since it has a
performance excuse to live. It's a bit moot since that's all ifdef'd
out, of course.
where Datum is 8 bytes wide. Since this will break old-style C functions
(those still using version 0 calling convention) that have arguments or
results of these types, provide a configure option to disable it and retain
the old pass-by-reference behavior. Likewise, provide a configure option
to disable the recently-committed float4 pass-by-value change.
Zoltan Boszormenyi, plus configurability stuff by me.
algorithm. This is a good deal slower than our old roundoff-error-prone
code for long inputs, so we keep the old code for use in the transcendental
functions, where everything is approximate anyway. Also create a
user-accessible function div(numeric, numeric) to provide access to the
exact result of trunc(x/y) --- since the regular numeric / operator will
round off its result, simply computing that expression in SQL doesn't
reliably give the desired answer. This fixes bug #3387 and various related
corner cases, and improves the usefulness of PG for high-precision integer
arithmetic.
an array of strings rather than an array of integers, and allow any simple
constant or identifier to be used in typmods; for example
create table foo (f1 widget(42,'23skidoo',point));
Of course the typmodin function has still got to pack this info into a
non-negative int32 for storage, but it's still a useful improvement in
flexibility, especially considering that you can do nearly anything if you
are willing to keep the info in a side table. We can get away with this
change since we have not yet released a version providing user-definable
typmods. Per discussion.
large inputs. Also cause it to error out immediately if the result will
overflow, instead of grinding through a lot of calculation first.
Per gripe from Jim Nasby.
from the other string-category types; this eliminates a lot of surprising
interpretations that the parser could formerly make when there was no directly
applicable operator.
Create a general mechanism that supports casts to and from the standard string
types (text,varchar,bpchar) for *every* datatype, by invoking the datatype's
I/O functions. These new casts are assignment-only in the to-string direction,
explicit-only in the other, and therefore should create no surprising behavior.
Remove a bunch of thereby-obsoleted datatype-specific casting functions.
The "general mechanism" is a new expression node type CoerceViaIO that can
actually convert between *any* two datatypes if their external text
representations are compatible. This is more general than needed for the
immediate feature, but might be useful in plpgsql or other places in future.
This commit does nothing about the issue that applying the concatenation
operator || to non-text types will now fail, often with strange error messages
due to misinterpreting the operator as array concatenation. Since it often
(not always) worked before, we should either make it succeed or at least give
a more user-friendly error; but details are still under debate.
Peter Eisentraut and Tom Lane
numerics as "oprcanhash", and make the corresponding system catalog
updates. As a result, hash indexes, hashed aggregation, and hash
joins can now be used with the numeric type. Bump the catversion.
The only tricky aspect to doing this is writing a correct hash
function: it's possible for two Numerics to be equal according to
their equality operator, but have different in-memory bit patterns.
To cope with this, the hash function doesn't consider the Numeric's
"scale" or "sign", and explictly skips any leading or trailing
zeros in the Numeric's digit buffer (the current implementation
should suppress any such zeros, but it seems unwise to rely upon
this). See discussion on pgsql-patches for more details.
Get rid of VARATT_SIZE and VARATT_DATA, which were simply redundant with
VARSIZE and VARDATA, and as a consequence almost no code was using the
longer names. Rename the length fields of struct varlena and various
derived structures to catch anyplace that was accessing them directly;
and clean up various places so caught. In itself this patch doesn't
change any behavior at all, but it is necessary infrastructure if we hope
to play any games with the representation of varlena headers.
Greg Stark and Tom Lane
The implementation is somewhat ugly logic-wise, but I don't see an
easy way to make it more concise.
When writing this, I noticed that my previous implementation of
width_bucket() doesn't handle NaN correctly:
postgres=# select width_bucket('NaN', 1, 5, 5);
width_bucket
--------------
6
(1 row)
AFAICS SQL:2003 does not define a NaN value, so it doesn't address how
width_bucket() should behave here. The patch changes width_bucket() so
that ereport(ERROR) is raised if NaN is specified for the operand or the
lower or upper bounds to width_bucket(). For float8, NaN is disallowed
for any of the floating-point inputs, and +/- infinity is disallowed
for the histogram bounds (but allowed for the operand).
Update docs and regression tests, bump the catversion.
