functions. This patch optimizes int2_sum(), int4_sum(), float4_accum()
and float8_accum() to avoid needing to copy the transition function's
state for each input tuple of the aggregate. In an extreme case
(e.g. SELECT sum(int2_col) FROM table where table has a single column),
it improves performance by about 20%. For more complex queries or tables
with wider rows, the relative performance improvement will not be as
significant.
performance hack Tom introduced recently. This means we can avoid
copying the transition array for each input tuple if these functions
are invoked as aggregate transition functions.
To test the performance improvement, I created a 1 million row table
with a single int4 column. Without the patch, SELECT avg(col) FROM
table took about 4.2 seconds (after the data was cached); with the
patch, it took about 3.2 seconds. Naturally, the performance
improvement for a less trivial query (or a table with wider rows)
would be relatively smaller.
bigint variants). Clean up some inconsistencies in error message wording.
Fix scanint8 to allow trailing whitespace in INT64_MIN case. Update
int8-exp-three-digits.out, which seems to have been ignored by the last
couple of people to modify the int8 regression test, and remove
int8-exp-three-digits-win32.out which is thereby exposed as redundant.
a variant of the function for the 'numeric' datatype; it would be possible
to add additional variants for other datatypes, but I haven't done so yet.
This commit includes regression tests and minimal documentation; if we
want developers to actually use this function in applications, we'll
probably need to document what it does more fully.
conversion of basic ASCII letters. Remove all uses of strcasecmp and
strncasecmp in favor of new functions pg_strcasecmp and pg_strncasecmp;
remove most but not all direct uses of toupper and tolower in favor of
pg_toupper and pg_tolower. These functions use the same notions of
case folding already developed for identifier case conversion. I left
the straight locale-based folding in place for situations where we are
just manipulating user data and not trying to match it to built-in
strings --- for example, the SQL upper() function is still locale
dependent. Perhaps this will prove not to be what's wanted, but at
the moment we can initdb and pass regression tests in Turkish locale.
is asked to assign a variable to itself, it will result in doing a
memcpy() on an entirely-overlapping memory range, which results in
undefined behavior according to ANSI C. That said, it is unlikely to
actually do anything bad on any sane libc, but this keeps valgrind quiet.
to note:
1) arttype is numeric. I thought this was the best way of allowing
arbitarily large factorials, even though factorial(2^63) is a large
number. Happy to change to integers if this is overkill.
2) since we're accepting numeric arguments, the patch tests for floats.
If a numeric is passed with non-zero decimal portion, an error is raised
since (from memory) they are undefined.
Gavin Sherry
float8smaller, float8larger (and thereby the MIN/MAX aggregates on these
datatypes) to agree with the datatypes' comparison operations as
regards NaN handling. In all these datatypes, NaN is arbitrarily
considered larger than any normal value ... but MIN/MAX had not gotten
the word. Per recent discussion on pgsql-sql.
some of the algorithms for higher functions. I see about a factor of ten
speedup on the 'numeric' regression test, but it's unlikely that that test
is representative of real-world applications.
initdb forced due to change of on-disk representation for NUMERIC.
division and modulo functions, to avoid problems on OS X (which fails to
trap 0 divide at all) and Windows (which traps it in some bizarre
nonstandard fashion). Standardize on 'division by zero' as the one true
spelling of this error message. Add regression tests as suggested by
Neil Conway.
specifically ceil(), floor(), and sign(). There may be other functions
that need to be added, but this is a start. I've included some simple
regression tests.
Neil Conway
so that precision of result is always at least as good as you'd get from
float8 arithmetic (ie, always at least 16 digits of accuracy). Per
pg_hackers discussion a few days ago.
to be flexible about assignment casts without introducing ambiguity in
operator/function resolution. Introduce a well-defined promotion hierarchy
for numeric datatypes (int2->int4->int8->numeric->float4->float8).
Change make_const to initially label numeric literals as int4, int8, or
numeric (never float8 anymore).
Explicitly mark Func and RelabelType nodes to indicate whether they came
from a function call, explicit cast, or implicit cast; use this to do
reverse-listing more accurately and without so many heuristics.
Explicit casts to char, varchar, bit, varbit will truncate or pad without
raising an error (the pre-7.2 behavior), while assigning to a column without
any explicit cast will still raise an error for wrong-length data like 7.3.
This more nearly follows the SQL spec than 7.2 behavior (we should be
reporting a 'completion condition' in the explicit-cast cases, but we have
no mechanism for that, so just do silent truncation).
Fix some problems with enforcement of typmod for array elements;
it didn't work at all in 'UPDATE ... SET array[n] = foo', for example.
Provide a generalized array_length_coerce() function to replace the
specialized per-array-type functions that used to be needed (and were
missing for NUMERIC as well as all the datetime types).
Add missing conversions int8<->float4, text<->numeric, oid<->int8.
initdb forced.
array header, and to compute sizing and alignment of array elements
the same way normal tuple access operations do --- viz, using the
tupmacs.h macros att_addlength and att_align. This makes the world
safe for arrays of cstrings or intervals, and should make it much
easier to write array-type-polymorphic functions; as examples see
the cleanups of array_out and contrib/array_iterator. By Joe Conway
and Tom Lane.
time zones.
SQL99 spec requires a default of zero (round to seconds) which is set
in gram.y as typmod is set in the parse tree. We *could* change to a
default of either 6 (for internal compatibility with previous versions)
or 2 (for external compatibility with previous versions).
Evaluate entries in pg_proc wrt the iscachable attribute for timestamp and
other date/time types. Try to recognize cases where side effects like the
current time zone setting may have an effect on results to decide whether
something is cachable or not.
for speed reasons; its result type also changes to int8. avg() on these
datatypes now accumulates the running sum in int8 for speed; but we still
deliver the final result as numeric, so that fractional accuracy is
preserved.
count() now counts and returns in int8, not int4. I am a little nervous
about this possibly breaking users' code, but there didn't seem to be
a strong sentiment for avoiding the problem. If we get complaints during
beta, we can change count back to int4 and add a "count8" aggregate.
For that matter, users can do it for themselves with a simple CREATE
AGGREGATE command; the int4inc function is still present, so no C hacking
is needed.
Also added max() and min() aggregates for OID that do proper unsigned
comparison, instead of piggybacking on int4 aggregates.
initdb forced.
give consistent results for all datatypes. Types float4, float8, and
numeric were broken for NaN values; abstime, timestamp, and interval
were broken for INVALID values; timetz was just plain broken (some
possible pairs of values were neither < nor = nor >). Also clean up
text, bpchar, varchar, and bit/varbit to eliminate duplicate code and
thereby reduce the probability of similar inconsistencies arising in
the future.
Although it was now using the right equation, it was making bogus choices
of the precision to compute intermediate results to. I'm not sure this
is really right even yet, but it's better than before ...
At this point I think it'd be possible to make float4 be pass-by-value
without too much work --- and float8 too on machines where Datum is
8 bytes. Something to try when the mood strikes, anyway.
I did not force. I marked numeric as compressable-but-not-move-off-able,
partly to test that storage mode and partly because I've got doubts
that numerics are large enough to need external storage.
There's now only one transition value and transition function.
NULL handling in aggregates is a lot cleaner. Also, use Numeric
accumulators instead of integer accumulators for sum/avg on integer
datatypes --- this avoids overflow at the cost of being a little slower.
Implement VARIANCE() and STDDEV() aggregates in the standard backend.
Also, enable new LIKE selectivity estimators by default. Unrelated
change, but as long as I had to force initdb anyway...
we'll get there one day.
Use `cat' to create aclocal.m4, not `aclocal'. Some people don't
have automake installed.
Only run the autoconf rule in the top-level GNUmakefile if the
invoker specified `make configure', don't run it automatically
because of CVS timestamp skew.
inputs have been converted to newstyle. This should go a long way towards
fixing our portability problems with platforms where char and short
parameters are passed differently from int-width parameters. Still
more to do for the Alpha port however.
(ie, allow rounding to occur at a digit position left of the decimal
point). Apparently this is how Oracle handles it, and there are
precedents in other programming languages as well.
as a unary minus operator for numeric. Now that long numeric constants
will get converted to NUMERIC in early parsing, it's essential to have
numeric->int8 conversion to avoid 'can't convert' errors on undecorated
int8 constants. Threw in the rest for completeness while I was in the
area.
I did not force an initdb for this, since the system will still run
without the new pg_proc/pg_operator entries. Possibly I should've.
is considerably more robust and accurate than it used to be.
Also, get rid of numeric's private allocation freelist, which is no longer
a win since Jan rewrote palloc.
Bruce Momjian
Neil Conway
Tom Lane
PostgreSQL Daemon
Peter Eisentraut
Thomas G. Lockhart
Jan Wieck