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.
This patch creates an API whereby a btree index opclass can optionally
provide non-SQL-callable support functions for sorting. In the initial
patch, we only use this to provide a directly-callable comparator function,
which can be invoked with a bit less overhead than the traditional
SQL-callable comparator. While that should be of value in itself, the real
reason for doing this is to provide a datatype-extensible framework for
more aggressive optimizations, as in Peter Geoghegan's recent work.
Robert Haas and Tom Lane
The "date" type supports a wider range of dates than int64 timestamps do.
However, there is pre-int64-timestamp code in the planner that assumes that
all date values can be converted to timestamp with impunity. Fortunately,
what we really need out of the conversion is always a double (float8)
value; so even when the date is out of timestamp's range it's possible to
produce a sane answer. All we need is a code path that doesn't try to
force the result into int64. Per trouble report from David Rericha.
Back-patch to all supported versions. Although this is surely a corner
case, there's not much point in advertising a date range wider than
timestamp's if we will choke on such values in unexpected places.
the timestamp types. Turns out this doesn't even reduce the available
range of dates, since the restriction to dates that work for Julian-date
arithmetic is much tighter than the int32 range anyway. Per a longstanding
TODO item.
a new typedef TimeOffset to represent an intermediate time value. It's
either int64 or double as appropriate, and in most usages will be measured
in microseconds or seconds the same as Timestamp. We don't call it
Timestamp, though, since the value doesn't necessarily represent an absolute
time instant.
Warren Turkal
unwarranted liberties with int8 vs float8 values for these types.
Specifically, be sure to apply either hashint8 or hashfloat8 depending
on HAVE_INT64_TIMESTAMP. Per my gripe of even date.
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
like '23:59:60' because of fractional-second roundoff problems. Trying
to control this upstream of the actual display code was hopeless; the right
way is to explicitly round fractional seconds in the display code and then
refigure the results if the fraction rounds up to 1. Per bug #1927.
better SQL compliance in this area, per recent discussion. Mark related
operators as commutators where possible. (The system doesn't actually care
about commutator marking for operators not returning boolean, at the moment,
but this seems forward-thinking and besides it made it easier to verify
that we hadn't missed any.)
Also, remove interval-minus-time and interval-minus-timetz operators.
I'm not sure how these got in, but they are nonstandard and had very
obviously broken behavior. (minus is not commutative in anyone's book.)
I doubt anyone had ever used 'em, because we'd surely have gotten a bug
report about it if so.
vs. timestamptz. This allows use of indexes for expressions like
datecol >= date 'today' - interval '1 month'
which were formerly not indexable without casting the righthand side
down from timestamp to date.
value of MAX_TIME_PRECISION in floating-point-timestamp-storage case
from 13 to 10, which is as much as time_out is actually willing to print.
(The alternative of increasing the number of digits we are willing to
print looks risky; we might find ourselves printing roundoff garbage.)
Use "--enable-integer-datetimes" in configuration to use this rather
than the original float8 storage. I would recommend the integer-based
storage for any platform on which it is available. We perhaps should
make this the default for the production release.
Change timezone(timestamptz) results to return timestamp rather than
a character string. Formerly, we didn't have a way to represent
timestamps with an explicit time zone other than freezing the info into
a string. Now, we can reasonably omit the explicit time zone from the
result and return a timestamp with values appropriate for the specified
time zone. Much cleaner, and if you need the time zone in the result
you can put it into a character string pretty easily anyway.
Allow fractional seconds in date/time types even for dates prior to 1BC.
Limit timestamp data types to 6 decimal places of precision. Just right
for a micro-second storage of int8 date/time types, and reduces the
number of places ad-hoc rounding was occuring for the float8-based types.
Use lookup tables for precision/rounding calculations for timestamp and
interval types. Formerly used pow() to calculate the desired value but
with a more limited range there is no reason to not type in a lookup
table. Should be *much* better performance, though formerly there were
some optimizations to help minimize the number of times pow() was called.
Define a HAVE_INT64_TIMESTAMP variable. Based on the configure option
"--enable-integer-datetimes" and the existing internal INT64_IS_BUSTED.
Add explicit date/interval operators and functions for addition and
subtraction. Formerly relied on implicit type promotion from date to
timestamp with time zone.
Change timezone conversion functions for the timetz type from "timetz()"
to "timezone()". This is consistant with other time zone coersion
functions for other types.
Bump the catalog version to 200204201.
Fix up regression tests to reflect changes in fractional seconds
representation for date/times in BC eras.
All regression tests pass on my Linux box.
Modified the parser and the SET handlers to use full Node structures
rather than simply a character string argument.
Implement INTERVAL() YEAR TO MONTH (etc) syntax per SQL99.
Does not yet accept the goofy string format that goes along with, but
this should be fairly straight forward to fix now as a bug or later
as a feature.
Implement precision for the INTERVAL() type.
Use the typmod mechanism for both of INTERVAL features.
Fix the INTERVAL syntax in the parser:
opt_interval was in the wrong place.
INTERVAL is now a reserved word, otherwise we get reduce/reduce errors.
Implement an explicit date_part() function for TIMETZ.
Should fix coersion problem with INTERVAL reported by Peter E.
Fix up some error messages for date/time types.
Use all caps for type names within message.
Fix recently introduced side-effect bug disabling 'epoch' as a recognized
field for date_part() etc. Reported by Peter E. (??)
Bump catalog version number.
Rename "microseconds" current transaction time field
from ...Msec to ...Usec. Duh!
date/time regression tests updated for reference platform, but a few
changes will be necessary for others.
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.
Define a new function, GetCurrentTransactionStartTimeUsec() to get the time
to this precision.
Allow now() and timestamp 'now' to use this higher precision result so
we now have fractional seconds in this "constant".
Add timestamp without time zone type.
Move previous timestamp type to timestamp with time zone.
Accept another ISO variant for date/time values: yyyy-mm-ddThh:mm:ss
(note the "T" separating the day from hours information).
Remove 'current' from date/time types; convert to 'now' in input.
Separate time and timetz regression tests.
Separate timestamp and timestamptz regression test.
Allow some operator-like tokens to be used as function names.
Flesh out support for time, timetz, and interval operators
and interactions.
Regression tests pass, but non-reference-platform horology test results
will need to be updated.
Bruce Momjian