Re: Reusing deleted records

[John Hall <jhall@xxxxxxxxxxx>]

Al Barsa, Jr. wrote:
> 
> At 12:26 AM 9/23/98 -0700, you wrote:
> >
> >I don't believe that this could be correct from what I understand the
> >relationship is between job ODP's and the underlying RDBMS.
> 
> Sorry.  I spent a great deal of time testing and researching this function
> when it was added in V2R1M1.  At the time, we beta tested the release, and
> were (re) writing an application for a client where the outage caused by
> RGZPFM was intolerable.
> >

Is it possible that IBM has since corrected this in subsequent releases
?
If not how do you access this deleted records map from your program ?


> >In a layered OS like OS/400, any program can, through the feed back DS,
> know how
> >many other programs are using a particular file.  So I have to conclude
> that the
> >OS is aware of multi job interaction with a particular file.
> 
> True, but not true for the deleted record map which is a function of any
> individual ODP's file open.
> >
> >I missed the original post so I'm going out on a limb here .... Does the
> program
> >perform record deletes and block adds?  The reason I ask is that if the disk
> >controller receives a record delete it will do so immediately (or appears
> to) but
> >blocked writes would be delayed and possibly be treated as a group that the
> >controller may attempt to search for a contiguous block write area.
> 
> The function has to do with using the REUSEDLT parameter on the creation of
> the physical file.  Writes to the LF are ultimately reflected in the PF.
> >
> >So although the program may delete x records then write x records, if the
> delete
> >was through a logical, and the writes through a physical there is no
> relationship
> >to the deleted space (record numbers) and the attempted block write.
> 
> Different ODP, different deleted records map.
> >
> 
> Al
> 

Back to the original problem with the system not using deleted records -
is it possible that when another job opens the file it copies the
existing deleted records map and does not create a new one?  Therefore
the deleted records map would never be recreated until All applications
that had opened the file ended.  This could have the effect of the
deleted records never being reused.

John Hall
Home Sales Co.
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