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* TECH NOTE CE703.T03                             DECEMBER 1994

*

* KEYWORDS: DB-IMAGE FLUSH BUFFERS INITIALISE VSAM

*

* DB-90S RELEASE 4.1 TAPES : C41201

*

* DB-Image:

* This Technical note contains advice to sites using DB-Image

*

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Users of DB-Image, who initialise the DB-Image VSAM files while CV

is still active may, after successful initialisation, still find

they pick up copies of the old image pages.



This is due to the image pages still being in the CA-IDMS buffers.



To prevent unwanted image records being retrieved, users should ensure

that the CA-IDMS buffers are purged of the image pages. This can be

done in one of two ways;



Use DCMT to vary the DB-Image database area offline then online. This

will flush any pages from the buffers.



Alternatively you can issue a DCMT VARY AREA PURGE command for each

DB-Image area. This will temporarily stop IO for the area, flush any

pages from the database buffers, then resume IO.



It is recommended that the DB-Image areas are varied offline before

the VSAM file initialisation is performed, then after successful

initialisation vary the areas back online. This will prevent any

IO being attempted while the VSAM file is being initialised, as well

as flushing the buffers.