Re: [GENERAL] Daylight savings time confusion

2010-03-22 Thread Rob Richardson
Tom, You said, It seems to me that you're not entirely understanding how timestamps work in Postgres. That is an understatement! Thank you very much for your explanation. I have forwarded it to the other members of my development group, with my suggestion that we follow your ideas for future

Re: [GENERAL] Daylight savings time confusion

2010-03-22 Thread Alban Hertroys
On 22 Mar 2010, at 14:08, Rob Richardson wrote: One question: We have customers all over the world. It would be best if we could rely on the operating system (usually Windows Server 2003) to tell us what time zone we're in, rather than asking for a specific timezone when we want to know a

Re: [GENERAL] Daylight savings time confusion

2010-03-16 Thread Alvaro Herrera
Tom Lane wrote: If my guesses are correct, then the minimum change to avoid this type of problem in the future is to change UTCTimestamp to be declared as timestamp WITHOUT time zone, so that you don't get two extra zone rotations in there. However, I would strongly suggest that you rethink

[GENERAL] Daylight savings time confusion

2010-03-15 Thread Rob Richardson
Greetings! Our database monitors the progression of steel coils through the annealing process. The times for each step are recorded in wallclock time (US eastern time zone for this customer) and in UTC time. During standard time, the difference will be 5 hours, and during daylight savings time

Re: [GENERAL] Daylight savings time confusion

2010-03-15 Thread Justin Graf
On 3/15/2010 2:40 PM, Rob Richardson wrote: Greetings! Our database monitors the progression of steel coils through the annealing process. The times for each step are recorded in wallclock time (US eastern time zone for this customer) and in UTC time. During standard time, the difference

Re: [GENERAL] Daylight savings time confusion

2010-03-15 Thread Rob Richardson
Thanks for the try, Justin, but that doesn't seem to be the problem. The query generates the same results on my customer's machine. Besides, I think your theory would only hold up if there were two machines involved. There aren't. RobR -- Sent via pgsql-general mailing list

Re: [GENERAL] Daylight savings time confusion

2010-03-15 Thread Steve Crawford
Rob Richardson wrote: Greetings! ... I just looked at the record for a charge for which heating started just after 9:00 Saturday night, less than 3 hours before the change to daylight savings time. The UTC time stored for this event is six hours later! The function that writes these times

Re: [GENERAL] Daylight savings time confusion

2010-03-15 Thread Adrian Klaver
On 03/15/2010 12:40 PM, Rob Richardson wrote: Greetings! Our database monitors the progression of steel coils through the annealing process. The times for each step are recorded in wallclock time (US eastern time zone for this customer) and in UTC time. During standard time, the difference

Re: [GENERAL] Daylight savings time confusion

2010-03-15 Thread Tom Lane
Rob Richardson rob.richard...@rad-con.com writes: Our database monitors the progression of steel coils through the annealing process. The times for each step are recorded in wallclock time (US eastern time zone for this customer) and in UTC time. During standard time, the difference will be

[GENERAL] Daylight Savings Time

2006-04-21 Thread Terry Lee Tucker
Hello List: I need to know if there is a convienient way of establishing whether DST is active within a function dealing with adjusting timestamps to other time zones. The problem is that if I have the following timestamp: '04/21/2006 17:05 EDT' and I use the timezone() function in the

Re: [GENERAL] Daylight Savings Time

2006-04-21 Thread Tom Lane
Terry Lee Tucker [EMAIL PROTECTED] writes: I need to know if there is a convienient way of establishing whether DST is active within a function dealing with adjusting timestamps to other time zones. The problem is that if I have the following timestamp: '04/21/2006 17:05 EDT' and I use the

Re: [GENERAL] Daylight Savings Time

2006-04-21 Thread Terry Lee Tucker
On Friday 21 April 2006 05:47 pm, Tom Lane [EMAIL PROTECTED] thus communicated: -- Terry Lee Tucker [EMAIL PROTECTED] writes: -- I need to know if there is a convienient way of establishing whether DST is -- active within a function dealing with adjusting timestamps to other time -- zones.

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-11-02 Thread Steve Crawford
On Sunday 31 October 2004 11:44 am, Tom Lane wrote: Randall Nortman [EMAIL PROTECTED] writes: Ah, I see now. PostgreSQL is behaving a bit differently than I expected. The timestamp string above is ambiguous in the timezone US/Eastern -- it could be EST or EDT. I was expecting

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-11-01 Thread Vinko Vrsalovic
On Sun, Oct 31, 2004 at 05:55:23PM -0500, Tom Lane wrote: [...] I'm inclined to think that rejecting impossible or ambiguous input without a zone is reasonable (and it would go along with the changes we made in 7.4 to tighten up datetime field order assumptions). But I don't want to take away

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-11-01 Thread Martijn van Oosterhout
On Mon, Nov 01, 2004 at 01:57:38PM -0300, Vinko Vrsalovic wrote: On Sun, Oct 31, 2004 at 05:55:23PM -0500, Tom Lane wrote: One point here is that timestamp-to-timestamptz datatype conversion will be affected by whatever we choose. While it's easy to say reject it for data coming into a

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-11-01 Thread Vinko Vrsalovic
On Mon, Nov 01, 2004 at 07:08:39PM +0100, Martijn van Oosterhout wrote: For the parsing integer issue it may have worked, but this is another kettle of fish. I don't think you can do this as a simple switch, it would have to set during the initdb and not allowed to be changed afterwards. I

[GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Randall Nortman
I assume I'm not the first person to have encountered this, but I couldn't find anything in the FAQ or on the mailing lists recently. My apologies if this is already documented somewhere... My application logs data to a Postgres table continuously (once every 15 seconds), maintaining a persistent

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Tom Lane
Randall Nortman [EMAIL PROTECTED] writes: My suspicion is that Postgres calculates the local offset from UTC only once per session, during session initialization. This is demonstrably not so. We might be able to figure out what actually went wrong, if you would show us the exact commands your

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Randall Nortman
On Sun, Oct 31, 2004 at 11:52:03AM -0500, Tom Lane wrote: Randall Nortman [EMAIL PROTECTED] writes: My suspicion is that Postgres calculates the local offset from UTC only once per session, during session initialization. This is demonstrably not so. We might be able to figure out what

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Tom Lane
Randall Nortman [EMAIL PROTECTED] writes: I can't reproduce the error without messing up my clock, but from my logs, here's the text of the SQL sent to the server: insert into sensor_readings_numeric (sensor_id, reading_ts, reading, min, max) values (3, '2004-10-31 01:00:00', 0.540602,

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Randall Nortman
On Sun, Oct 31, 2004 at 12:47:31PM -0500, Tom Lane wrote: Randall Nortman [EMAIL PROTECTED] writes: I can't reproduce the error without messing up my clock, but from my logs, here's the text of the SQL sent to the server: insert into sensor_readings_numeric (sensor_id, reading_ts,

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Tom Lane
Randall Nortman [EMAIL PROTECTED] writes: Ah, I see now. PostgreSQL is behaving a bit differently than I expected. The timestamp string above is ambiguous in the timezone US/Eastern -- it could be EST or EDT. I was expecting PostgreSQL to resolve this ambiguity based on the current time

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Randall Nortman
On Sun, Oct 31, 2004 at 02:44:51PM -0500, Tom Lane wrote: Randall Nortman [EMAIL PROTECTED] writes: Ah, I see now. PostgreSQL is behaving a bit differently than I expected. The timestamp string above is ambiguous in the timezone US/Eastern -- it could be EST or EDT. I was expecting

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Tom Lane
Randall Nortman [EMAIL PROTECTED] writes: On Sun, Oct 31, 2004 at 02:44:51PM -0500, Tom Lane wrote: Actually, the intended and documented behavior is that it should interpret an ambiguous time as local standard time (e.g., EST not EDT). I'm finding it hard to see how either way is likely to

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Martijn van Oosterhout
On Sun, Oct 31, 2004 at 04:14:52PM -0500, Tom Lane wrote: That line of argument leads directly to the conclusion that we shouldn't allow timezone-less input strings at all, since it's unlikely that anyone would code their app to append a timezone spec only during the two hours a year when it

Re: [GENERAL] Daylight Savings Time handling on persistent connections

2004-10-31 Thread Tom Lane
Martijn van Oosterhout [EMAIL PROTECTED] writes: On Sun, Oct 31, 2004 at 04:14:52PM -0500, Tom Lane wrote: That line of argument leads directly to the conclusion that we shouldn't allow timezone-less input strings at all, since it's unlikely that anyone would code their app to append a