db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Oystein.Grov...@Sun.COM (Øystein Grøvlen)
Subject Re: RowLocation lifetime
Date Mon, 14 Nov 2005 20:28:29 GMT
>>>>> "MM" == Mike Matrigali <mikem_app@sbcglobal.net> writes:

    MM> Not really.
    MM> I don't think even a unique key constraint meets the requirements,
    MM> as the row can be deleted and a different row can be created.

HeapRowLocation contains a RecordHandle which if I have understood
this correctly refers to a RecordId in this case.  Looking at the
code, RecordId consists of pageId and a sequence number within each
page.  It seems to me that RecordIds should be unique and not reused.
Could not this be used as a stable handle? 

    MM> Rick Hillegas wrote:
    >> Hi Mike,
    >> It appears  that RowLocations are stable under  some combinations of
    >> isolation  levels and  lock granularities  but that,  in  general, a
    >> RowLocation isn't guaranteed to be stable even for the duration of a
    >> statement. Is there some other, more stable handle on a heap row? By
    >> "more  stable" I mean  something which  uniquely identifies  the row
    >> across statements, transactions, or connections?

    >> Thanks,

    >> -Rick
    >> 





-- 
Øystein


Mime
View raw message