Object difference DSPFD vs qsys2.systables

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I have a strange observation, that's I'd like to share.

There's an object (it's a logical file) on my system that when displayed on 5250 shows following characteristic:

  • Maximum record length . . . . . . . . . . . : 3120

  • and then when SQL qsys2.SYSTABLES it states: Row_length: 32120

Where does that (may) come from?

The PF that this LF is based on have row lenght < 3120.

On top of that I can say that if I transfer (SAVF over FTP) this view (and its dependencies) to mirrored (QuickEDD) system then:

  • DSPFD which states: Maximum record length . . . . . . . . . . . : 3120

  • and qsys2.SYSTABLES which states: 3120

*same thing happens with QuickEDD - it eventually throws an error (file is synchronised but different :) )

Any idea ?

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WStanzl On

Here is an excerpt from IBMs documentation

https://www.ibm.com/docs/en/i/7.3?topic=views-systables#rbafzcatsystbls__recln

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1) The length is the number of bytes passed in database buffers, not the internal storage length.

It seems like Data Management decided to buffer ten records at a time, plus a few control bytes on the primary system, where there is read activity on the file. On the mirrored system, Data Management decided not to buffer.