Re: JDBC, Timestamps, and Fractions of a Second - Mailing list pgsql-interfaces
From | Nissim |
---|---|
Subject | Re: JDBC, Timestamps, and Fractions of a Second |
Date | |
Msg-id | 3948DD3F.B0324DE7@nksystems.com Whole thread Raw |
In response to | RE: JDBC, Timestamps, and Fractions of a Second (Peter Mount <petermount@it.maidstone.gov.uk>) |
List | pgsql-interfaces |
I know I mentioned this before, and the suggestion wasn't looked upon favorably on the pg-hackers list, but this problem stems from the fact that the server returns the timestamp in a different format if the number of "centiseconds" is 0 or other than 0. Even if you insert with the "centiseconds" value there, but it is zero (e.g. set timestamp_col = '2000-06-03 11:47:47.00-04') when you select it out, it willl come out without the .00 There is a whole bunch of code in backend/utils/adt/datetime.c that formats the timestamp in this way. I think that the timestamp should be returned from the database in the same format no matter whether it has millisecond or not. Isn't that how other databases work? -Nissim Peter Mount wrote: > > Two things: First, Timestamps in the JDBC driver have always had one problem > or another, but so far no patch that's been passed on to me has worked for > everyone - normally it's time zones that have problems. > > I'll check today (as there's been two reports over night) and see how this > one works. > > Second, the only valid retep.org.uk address is peter@retep.org.uk. The > others haven't existed for some time now. Also for the next few weeks, it > will be better to email me here than at home as I'm moving home next week so > it will take a while to get comms working again. > > Peter > > -- > Peter Mount > Enterprise Support > Maidstone Borough Council > Any views stated are my own, and not those of Maidstone Borough Council > > -----Original Message----- > From: Jim Caley [mailto:caley@chesco.com] > Sent: Wednesday, June 14, 2000 10:27 PM > To: pgsql-interfaces@postgresql.org > Cc: patches@postgres.retep.org.uk > Subject: [INTERFACES] JDBC, Timestamps, and Fractions of a Second > > I'm using the JDBC2 driver in the PostgreSQL 7.0.1 distribution to both > INSERT and SELECT (the same) records with timestamp columns. The > ResultSet.getTimestamp method is choking, because it's looking for a > "yyyy-MM-dd HH:mm:sszzz" format, while the default in 7.0 now seems to > be "yyyy-MM-dd HH:mm:ss.SSzzz", where "SS" is centiseconds. (The Java 2 > SDK javadoc for SimpleDateFormat actually defines 'S' to represent a > millisecond digit in a time pattern string, but I'm using it here for > centiseconds since they define no character for that. :-/ ) > > Here's part of the stack trace: > > Bad Timestamp Format at 19 in 2000-06-14 15:37:11.67-04 > at > org.postgresql.jdbc2.ResultSet.getTimestamp(ResultSet.java:447) > at > org.postgresql.jdbc2.ResultSet.getTimestamp(ResultSet.java:595) > > Aleksey Demakov wrote about a similar problem in 1998, (see > http://www.postgresql.org/mhonarc/pgsql-interfaces/1998-10/msg00183.html), > and he rewrote the code to account for milliseconds. > > Likewise, I've rewritten the current code to account for both the "no > fractions" format and the "centiseconds" format. The patch is below. > > This is solving my immediate problem, but I don't know what other > formats may need to be taken into consideration to make the patch an > acceptably robust solution. > > I'd appreciate any comments (e.g. could this patch -- or a more robust > version -- be applied to the next version of the driver? -- I am CCing > this to patches@postgres.retep.org.uk). > > (As an aside, in the way of trivia, a search of > http://www.dictionary.com turned up no legitimate word "centiseconds." > However, a search on Google confirmed that, correctly or not, others do > use it. :) > > Platform info: > -Red Hat Linux 6.2 > -Blackdown JDK 1.2.2 RC4 > > Regards, > Jim Caley > E-mail: caley@chesco.com > -- > > *** ResultSet.java.orig Fri May 12 16:54:22 2000 > --- ResultSet.java Tue Jun 13 16:46:21 2000 > *************** > *** 439,445 **** > if(s==null) > return null; > > ! SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd > HH:mm:sszzz"); > > try { > return new Timestamp(df.parse(s).getTime()); > --- 439,447 ---- > if(s==null) > return null; > > ! SimpleDateFormat df = (s.charAt(19) == '.') ? > ! new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSzzz") : > ! new SimpleDateFormat("yyyy-MM-dd HH:mm:sszzz"); > > try { > return new Timestamp(df.parse(s).getTime());
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