Remove bogus dependencies on NUMERIC_MAX_PRECISION.

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>

diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index b99b6f58010be595eccb68fa70d193991c6eb300..143bc1f9c7f4f90d1876c30529c66148a22a4da6 100644 (file)
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -650,10 +650,6 @@ numeric_recv(PG_FUNCTION_ARGS)
    init_var(&value);
 
    len = (uint16) pq_getmsgint(buf, sizeof(uint16));
-   if (len < 0 || len > NUMERIC_MAX_PRECISION + NUMERIC_MAX_RESULT_SCALE)
-       ereport(ERROR,
-               (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
-                errmsg("invalid length in external \"numeric\" value")));
 
    alloc_var(&value, len);
 
@@ -3316,12 +3312,19 @@ set_var_from_str(const char *str, const char *cp, NumericVar *dest)
                     errmsg("invalid input syntax for type numeric: \"%s\"",
                            str)));
        cp = endptr;
-       if (exponent > NUMERIC_MAX_PRECISION ||
-           exponent < -NUMERIC_MAX_PRECISION)
+
+       /*
+        * At this point, dweight and dscale can't be more than about
+        * INT_MAX/2 due to the MaxAllocSize limit on string length, so
+        * constraining the exponent similarly should be enough to prevent
+        * integer overflow in this function.  If the value is too large to
+        * fit in storage format, make_result() will complain about it later;
+        * for consistency use the same ereport errcode/text as make_result().
+        */
+       if (exponent >= INT_MAX / 2 || exponent <= -(INT_MAX / 2))
            ereport(ERROR,
-                   (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
-                    errmsg("invalid input syntax for type numeric: \"%s\"",
-                           str)));
+                   (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+                    errmsg("value overflows numeric format")));
        dweight += (int) exponent;
        dscale -= (int) exponent;
        if (dscale < 0)

diff --git a/src/include/utils/numeric.h b/src/include/utils/numeric.h
index 6f68bfab2f796f43b48dc5ef987ed05fc29d67cc..48d5186d47cef204864b005286bb471694aa2d2c 100644 (file)
--- a/src/include/utils/numeric.h
+++ b/src/include/utils/numeric.h
@@ -17,8 +17,9 @@
 #include "fmgr.h"
 
 /*
- * Hardcoded precision limit - arbitrary, but must be small enough that
- * dscale values will fit in 14 bits.
+ * Limit on the precision (and hence scale) specifiable in a NUMERIC typmod.
+ * Note that the implementation limit on the length of a numeric value is
+ * much larger --- beware of what you use this for!
  */
 #define NUMERIC_MAX_PRECISION      1000
 

diff --git a/src/interfaces/ecpg/pgtypeslib/numeric.c b/src/interfaces/ecpg/pgtypeslib/numeric.c
index 35eacf86503c64511ae0d78d173ce51ad66b92b5..d29170dffa0c1903ecbc49d3802ead7b2ae8e205 100644 (file)
--- a/src/interfaces/ecpg/pgtypeslib/numeric.c
+++ b/src/interfaces/ecpg/pgtypeslib/numeric.c
@@ -263,8 +263,7 @@ set_var_from_str(char *str, char **ptr, numeric *dest)
            return -1;
        }
        (*ptr) = endptr;
-       if (exponent > NUMERIC_MAX_PRECISION ||
-           exponent < -NUMERIC_MAX_PRECISION)
+       if (exponent >= INT_MAX / 2 || exponent <= -(INT_MAX / 2))
        {
            errno = PGTYPES_NUM_BAD_NUMERIC;
            return -1;