Re: Variable length fields question

On 29-Jul-2014 16:26 -0500, John Smith wrote:

On Jul 29, 2014, at 17:18, Jon Paris wrote:

<<SNIP>> There is an overhead associated with a VARLEN (can't
recall how big but certainly likely to be at least 16 bytes) plus
the Varlen field has a 2 byte length header. <<SNIP>>

I would be very interested in hearing if someone can confirm /
correct the additional 16 bytes of overhead.
I already knew about the 2 bytes that proceed the field but this is
the first I have heard of the additional 16.

The actual storage being taken can be /seen/ for any example, by use of the Start Service Tools (STRSST) Display Alter Dump (D/A/D) feature to obtain a formatted dump of the dataspace for some variety of record formats, with some variety of data that includes rows that will overflow the allocated length. Dumping the aux SID from the pointer recorded in the dump of the dataspace for such an example file.mbr would reveal apparent implementation, about how that data is stored; again, for the particular example, which may not be directly indicative of what would be seen in another example. Best to include examples where there are more than one varying length column that would exceed any minimums for which the implementation might be fixed-length storage within the dataspace; though of course, that effect would be conspicuous for all of the column data appearing in the dataspace for values that knowingly should have overflowed. I have no access to gather any [on any release], and so even assisting someone with how to navigate to obtain such dumps is not even an option.