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From André Bögge (Commented) (JIRA) <j...@apache.org>
Subject [jira] [Commented] (COUCHDB-1405) error generating document id with utc_random
Date Thu, 09 Feb 2012 10:08:59 GMT

    [ https://issues.apache.org/jira/browse/COUCHDB-1405?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13204417#comment-13204417
] 

André Bögge commented on COUCHDB-1405:
--------------------------------------

We use a time server to synchronize all the PCs in our domain. I checked the system time of
both computers and the system time of the physical pc hosting the VM. They were identical.
The problem is, that the db generates a document id that differs from local system time on
server by calculating back the timestamp. Here is the used algorithm in Tcl (http://www.activestate.com/activetcl/downloads):

      public method ID2Time {docID {timeFormat "%d.%m.%Y %H:%M:%S"}} {
            set docID      [string range $docID 0 13];                                   
                             # Getting the first 14 characters
            set docTime  [expr 0x$docID];                                                
                              # Converting hex to decimal
            set docTime  [expr {$docTime / 1000000}];                                    
                        # Calculate seconds out of microseconds
            set docDate  [clock format $docTime -format $timeFormat]                     
                # Formating the time
      
            return $docDate
    }


I will now check if the problem occurs within a local installation of CouchDB on my physical
pc and will post the result here. Perhaps we really have a problem using a virtual machine.

                
> error generating document id with utc_random
> --------------------------------------------
>
>                 Key: COUCHDB-1405
>                 URL: https://issues.apache.org/jira/browse/COUCHDB-1405
>             Project: CouchDB
>          Issue Type: Bug
>          Components: Database Core
>    Affects Versions: 1.1.1
>         Environment: Windows 7, 64-bit, running as virtual pc in hyper-v
>            Reporter: André Bögge
>
> I use the utc_random algorithm for generating document ids. So it's possible for me to
calculate time and date out of the id in my client application. After running CouchDB for
about a month i got a difference between system time and calculated time of id of about half
an hour. I restarted the database and even then i got a difference about 1 minute.

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