Surprising bug in sort

[Tim_Ryan]

Hi there,

I ran into a very surprising bug in the Windows cygwin sort routine:

I'm running GNU coreutils 6.9.92.4-f088d-dirtJanuary 2008  on  Windows XP 
Service Pack 2.

Using the source data:
2008-08-17 14:09:13,816 [RMI TCP Connection(5)-10.67.16.134] INFO 
bnz.ib.util.logging.MethodEntryExitLogger - Starting
2008-08-17 14:09:15,676 [RMI TCP Connection(5)-10.67.16.134] INFO 
bnz.ib.util.logging.MethodEntryExitLogger - Exiting
2008-08-17 14:09:16,806 [RMI TCP Connection(4)-10.67.16.134] INFO 
bnz.ib.util.logging.MethodEntryExitLogger - Starting
2008-08-17 14:09:16,806 [RMI TCP Connection(4)-10.67.16.134] INFO 
bnz.ib.util.logging.MethodEntryExitLogger - Exiting
2008-08-17 14:09:16,949 [RMI TCP Connection(5)-10.67.16.134] INFO 
bnz.ib.util.logging.MethodEntryExitLogger - Starting
2008-08-17 14:09:16,955 [RMI TCP Connection(5)-10.67.16.134] INFO 
bnz.ib.util.logging.MethodEntryExitLogger - Exiting
2008-08-17 14:09:17,141 [RMI TCP Connection(5)-10.67.16.134] INFO 
bnz.ib.util.logging.MethodEntryExitLogger - Starting
2008-08-17 14:09:17,141 [RMI TCP Connection(5)-10.67.16.134] INFO 
bnz.ib.util.logging.MethodEntryExitLogger - Exiting

If I use the sort command: 
        sort --stable -k2 -k9r 
the data is not sorted correctly - the two pairs of lines containing the 
same timestamp (14:09:16,806, and 14:09:17,141) are incorrectly reversed 
in order so that the Exiting line comes before the Starting line - despite 
the -k9r sort key. 

In fact I shouldn't even need the -k9r key as I am using --stable, but the 
sort reverses the two pairs of lines regardless.


I found a workaround... if I make no changes to the data, but use the sort 
command: 
        sort --stable -k1,2 -k9r
then the data is sorted correctly - adding the date as the high-order part 
of the time key somehow corrects the behaviour.


Regards,
Tim

Tim Ryan
Technical Consultant
Development Centre, Business Technology Services
Bank of New Zealand

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