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Re: Beta release of LDM version 5.1.2 available

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  • Subject: Re: Beta release of LDM version 5.1.2 available
  • Date: Fri, 04 Aug 2000 14:19:12 -0600
>To: address@hidden
>From: David Wojtowicz <address@hidden>
>Subject: Re: 20000804: Beta release of LDM version 5.1.2 available
>Organization: UIUC
>Keywords: LDM beta release

Hi David,

> I just finished putting up 5.1.1 on my systems yesterday.
> Should I worry about going to 5.1.2b right away?

No, if you've got 5.1.1 you already have most of the improvements in
the new version.  There's no hurry to go to 5.1.2.  The main advantage
should be better performance in (possibly rare) cases where the pq
free list gets long (over 1000 elements).  You can see if this is
happening with your LDM by running pqmon and looking at the output, to
see what the current free list length is and how large it has ever
gotten.

For example, on motherlode currently:

 % pqmon
 Aug 04 20:09:26 pqmon: Starting Up (21165)
 Aug 04 20:09:26 pqmon: nprods nfree  nempty      nbytes  maxprods  maxfree  
minempty    maxext  age
 Aug 04 20:09:26 pqmon:  99317   450  376307  1816749320    143682     1790    
332391  10949216 7049
 Aug 04 20:09:26 pqmon: Exiting

the "nfree" entry is 450, meaning there are currently 450 free regions
in the product queue available for use by new products coming in.
Under "maxfree", the 1790 means that this list has gotten as long as
1790 elements.  In version 5.1.1, when a product comes in a "best fit"
is attempted to match it to an existing free region in the queue,
which in the worst case means a linear search through the whole free
list to get the best match.  In 5.1.2, the free list is indexed by
extent, which makes it very fast to find the best fit without
searching, but making it slower to update the free list when it is
short.

So the bottom line is, 5.1.2 might even be somewhat slower than 5.1.1
in the typical case of a short free list, but will be significantly
faster in the possibly rare case of a long free list.

If I were you, I'd wait until the 5.1.2 release.

But you still might want to check whether you are running pqexpire and
turn it off in ldmd.conf, since you may not need it ...

--Russ