How to avoid most reorgs of DOL tables in Sybase ASE (Jeff Tallman)

On the sybase-l mailing list,

Sybase

Jeff Tallman replied to a question on how to avoid unnecessary reorgs. He graciously agreed to let me post his response here 🙂

You can avoid most (if not all) of the reorgs by doing:

  1. setting the exp_row_size to something that covers about 90% of the space each row takes up
  2. changing enable housekeeper GC to a 4 or 5

Both of these are a *MUST* do for DOL (datapages or datarows). See manuals on ‘enable housekeeper GC’ for correct setting of 4 or 5 (refers to whether deletes are batch or OLTP).

You can also watch for housekeeper overflows in monEngine/monOpenObjectActivity……and if you see any HKGC pending – wait a few before shutting down.

Jeff wrote up an excellent article, Locking Redux – APL vs. DOL and Tuning, that goes into detail why this is the case.

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