Here are patches which should help fix timezone problems in the
datetime and abstime code. Also, I repatched varlena.c to add in
some comments and a little error checking on top of Vadim's earlier
repairs. There are slight mods to the circle data type to have the
distance operator between circles measure the distance between
closest points rather than between centers.
Subject: Re: [PATCHES] SET DateStyle patches
On Tue, 22 Apr 1997, Thomas Lockhart wrote:
> Some more patches! These (try to) finish implementing SET variable TO value
> for "DateStyle" (changed the name from simply "date" to be more descriptive).
> This is based on code from Martin and Bruce (?), which was easy to modify.
> The syntax is
>
> SET DateStyle TO 'iso'
> SET DateStyle TO 'postgres'
> SET DateStyle TO 'sql'
> SET DateStyle TO 'european'
> SET DateStyle TO 'noneuropean'
> SET DateStyle TO 'us' (same as "noneuropean")
> SET DateStyle TO 'default' (current same as "postgres,us")
>
> ("european" is just compared for the first 4 characters, and "noneuropean"
> is compared for the first 7 to allow less typing).
>
> Multiple arguments are allowed, so SET datestyle TO 'sql,euro' is valid.
>
> My mods also try to implement "SHOW variable" and "RESET variable", but
> that part just core dumps at the moment. I would guess that my errors
> are obvious to someone who knows what they are doing with the parser stuff,
> so if someone (Bruce and/or Martin??) could have it do the right thing
> we will have a more complete set of what we need.
>
> Also, I would like to have a floating point precision global variable to
> implement "SET precision TO 10" and perhaps "SET precision TO 10,2" for
> float8 and float4, but I don't know how to do that for integer types rather
> than strings. If someone is fixing the SHOW and RESET code, perhaps they can
> add some hooks for me to do the floats while they are at it.
>
> I've left some remnants of variable structures in the source code which
> I did not use in the interests of getting something working for v6.1.
> We'll have time to clean things up for the next release...
OK, here are a passel of patches for the geometric data types.
These add a "circle" data type, new operators and functions
for the existing data types, and change the default formats
for some of the existing types to make them consistant with
each other. Current formatting conventions (e.g. compatible
with v6.0 to allow dump/reload) are supported, but the new
conventions should be an improvement and we can eventually
drop the old conventions entirely.
For example, there are two kinds of paths (connected line segments),
open and closed, and the old format was
'(1,2,1,2,3,4)' for a closed path with two points (1,2) and (3,4)
'(0,2,1,2,3,4)' for an open path with two points (1,2) and (3,4)
Pretty arcane, huh? The new format for paths is
'((1,2),(3,4))' for a closed path with two points (1,2) and (3,4)
'[(1,2),(3,4)]' for an open path with two points (1,2) and (3,4)
For polygons, the old convention is
'(0,4,2,0,4,3)' for a triangle with points at (0,0),(4,4), and (2,3)
and the new convention is
'((0,0),(4,4),(2,3))' for a triangle with points at (0,0),(4,4), and (2,3)
Other data types which are also represented as lists of points
(e.g. boxes, line segments, and polygons) have similar representations
(they surround each point with parens).
For v6.1, any format which can be interpreted as the old style format
is decoded as such; we can remove that backwards compatibility but ugly
convention for v7.0. This will allow dump/reloads from v6.0.
These include some updates to the regression test files to change the test
for creating a data type from "circle" to "widget" to keep the test from
trashing the new builtin circle type.
Subject: [HACKERS] Patch: set date to euro/us postgres/iso/sql
Here a patch that implements a SET date for use by the datetime
stuff. The syntax is
SET date TO 'val[,val,...]'
where val is us (us dates), euro (european dates), postgres,
iso or sql.
Thomas is working on the integration in his datetime module.
I just needed to get the patch out before it went stale :)
Subject: [HACKERS] Money integration patches
Here are patches to integrate the money data type. I have included
some math and aggregate functions and have made the locale support optional
by #ifdef USE_LOCALE bracketing of functions.
Modules affected are:
builtins.h.patch
cash.c.patch
cash.h.patch
main.c.patch
pg_aggregate.h.patch
pg_operator.h.patch
pg_proc.h.patch
pg_type.h.patch
I changed the data type to be pass-by-reference rather than by-value
to pave the way for a larger internal representation (64-bit ints?).
Also, I changed the tabbing of cash.c and cash.h to match most of
the other Postgres source code files (4 space indent, 8 spaces == 1 tab).
The locale stuff should be tested under another convention (Russian?)
but I don't know what the correct results should be so perhaps someone
else can give them a try. Will update docs and regression tests in
the next few days.
pg_proc.h still needs modifying, but this gets it in there so that we can
get around any compiler bugs. Will try and get the pg_proc.h entries done
up later tonight...
Remove USE_LOCALE from Makefile.global.in
Add USE_LOCALE to build/configure/config.h
Add check for BUILDRUN in configure to make sure that build is run before
configure
Subject: [HACKERS] Aggregate function patches
Here are the aggregate function patches I originally sent in last December.
They fix sum() and avg() behavior for ints and floats when NULL values are
involved.
I was waiting to resubmit these until I had a chance to write a v6.0->v6.1
database upgrade script to ensure that existing v6.0 databases which have
not been reloaded for v6.1 do no break with the new aggregate behavior.
These scripts are included below. It's OK with me if someone wants to do
something different with the upgrade strategy, but something like this
was discussed a few weeks ago.
Also, there were a couple of small items which cropped up in doing a clean
install of 970403 (actually 970402 + 970403 changes since the full 970403
tar file appears to be damaged or at least suspect). They are the first
two patches below and can be omitted if desired (although I think they
aren't dangerous :).
Subject: [HACKERS] More date time functions
Here are some additional patches mostly related to the date and time
data types. It includes some type conversion routines to move between
the different date types and some other date manipulation routines such
as date_part(units,datetime).
I noticed Edmund Mergl et al's neat trick for getting function overloading
for builtin functions, so started to use that for the date and time stuff.
Later, if someone figures out how to get function overloading directly
for internal C code, then we can move to that technique.
These patches include documentation updates (don't faint!) for the built-in
man page. Doesn't yet include mention of timestamp, since I don't know
much about it and since it may change a bit to become a _real_ ANSI timestamp
which would include parser support for the declaration syntax (what do you
think, Dan?).
The patches were developed on the 970330 release, but have been rebuilt
off of the 970402 release. The first patch below is to get libpq to compile,
on my Linux box, but is not related to the rest of the patches and you can
choose not to apply that one at this time. Thanks in advance, scrappy!
Subject: [HACKERS] Patch: SET var TO 'val'
Here is a patch that adds a "SET variable TO 'somevalue'" capability
to the parser, and then calls the SetPGVariable() function (which does
just issue a elog(NOTICE) to see whether it works).
That's the framework for adding timezone/date format/language/...
stuff.
Subject: Re: [HACKERS] abstime "now" broken
Yes, I broke 'now' :( with an attempt at a bug fix involving
servers running in the UTC/GMT timezone. These patches fix
the problem, and have been tested in GMT (+00 hours),
PST (-08), and NZT (+12) timezones which exercized the code for
various cases including across day boundaries. btw, this code
fixes the same type of problem for 'today', 'yesterday', 'tomorrow',
for DATETIME, ABSTIME, DATE and TIME types.
The bugfix itself is quite small, but I have accumulated other
changes in the datetime data type and include them here also.
One set of changes involves printing ISO-formatted dates and
is in response to the helpful information from Kurt Lidl regarding
ANSI SQL dates. I'll send another e-mail sometime soon discussing
more issues he has raised...
Reply-To: hackers@hub.org, Dan McGuirk <mcguirk@indirect.com>
To: hackers@hub.org
Subject: [HACKERS] tmin writeback optimization
I was doing some profiling of the backend, and noticed that during a certain
benchmark I was running somewhere between 30% and 75% of the backend's CPU
time was being spent in calls to TransactionIdDidCommit() from
HeapTupleSatisfiesNow() or HeapTupleSatisfiesItself() to determine that
changed rows' transactions had in fact been committed even though the rows'
tmin values had not yet been set.
When a query looks at a given row, it needs to figure out whether the
transaction that changed the row has been committed and hence it should pay
attention to the row, or whether on the other hand the transaction is still
in progress or has been aborted and hence the row should be ignored. If
a tmin value is set, it is known definitively that the row's transaction
has been committed. However, if tmin is not set, the transaction
referred to in xmin must be looked up in pg_log, and this is what the
backend was spending a lot of time doing during my benchmark.
So, implementing a method suggested by Vadim, I created the following
patch that, the first time a query finds a committed row whose tmin value
is not set, sets it, and marks the buffer where the row is stored as
dirty. (It works for tmax, too.) This doesn't result in the boost in
real time performance I was hoping for, however it does decrease backend
CPU usage by up to two-thirds in certain situations, so it could be
rather beneficial in high-concurrency settings.
Subject: [HACKERS] backend/utils/adt/timestamp.c
Back to this timezone stuff. The struct tm has a field (tm_gmtoff) which
is the offset from UTC (GMT is archaic BTW) in seconds. Is this the
value you are looking for when you use timezone? Note that this applies
to NetBSD but it does not appear to be in either ANSI C or POSIX. This
looks like one of those things that is just going to have to be hand
coded for each platform.
Why not just store the values in UTC and use localtime instead of
gmtime when retrieving the value?
Also, you assume the time is returned as a 4 byte integer. In fact,
there is not even any requirement that time be an integral value. You
should use time_t here.
The input function seems unduly restrictive. Somewhere in the sources
there is an input function that allows words for months. Can't we do
the same here?
There is a standard function, difftime, for subtracting two times. It
deals with cases where time_t is not integral. There is, however, a
small performance hit since it returns a double and I don't believe
there is any system currently which uses anything but an integral for
time_t. Still, this is technically the correct and portable thing to do.
The returns from the various comparisons should probably be a bool.
of endian.h. I figure that if it exists it's pretty sure that it has
the byte order information and we may catch some other ports without
any further testing.
From: "D'Arcy J.M. Cain" <darcy@druid.net>
Subject: [HACKERS] More patches for date/time
I have accumulated several patches to add functionality to the datetime
and timespan data types as well as to fix reported porting bugs on non-BSD
machines. These patches are:
dt.c.patch - add datetime_part(), fix bugs
dt.h.patch - add quarter and timezone support, add prototypes
globals.c.patch - add time and timezone variables
miscadmin.h.patch - add time and timezone variables
nabstime.c.patch - add datetime conversion routine
nabstime.h.patch - add prototypes
pg_operator.h.patch - add datetime operators, clean up formatting
pg_proc.h.patch - add datetime functions, reassign conflicting date OIDs
pg_type.h.patch - add datetime and timespan data types
The dt.c and pg_proc.h patches are fairly large; the latter mostly because I tried
to get some columns for existing entries to line up.
Subject: [HACKERS] libpq/pqcomm stuff and Solaris byte order
I decided to go ahead with the required changes since no one else seems
to. I don't guarantee that it is perfect but with these changes the
package actually compiles. While I was at it I added to the Sparc
Solaris header to define the byte order. Note that NetBSD sets this
in the system headers so it wasn't required there.
In particular, someone may want to check whether I removed the correct
84 lines from backend/libpq/pqcomprim.c.
of common routines in pqcomprim.c (pq communication primitives).
Not all adapted to it yet, but it's a start.
- Rewritten some of those routines, to write/read bigger chunks of
data, precomputing stuff in buffers instead of sending out byte
by byte.
- As a consequence, I need to know the endianness of the machine.
Currently I rely on getting it from machine/endian.h, but this
may not be available everywhere? (Who the hell thought it was
a good idea to pass integers to the backend the other way around
than the normal network byte order? *argl*)
- Libpq looks in the environment for magic variables, and upon
establishing a connection to the backend, sends it queries
of the form "SET var_name TO 'var_value'". This needs a change
in the backend parser (Mr. Parser, are you there? :)
- Currently it looks for two Env-Vars, namely PG_DATEFORMAT
and PG_FLOATFORMAT. What else makes sense? PG_TIMEFORMAT?
PG_TIMEZONE?
From: "Martin J. Laubach" <mjl@wwx.vip.at>
