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Message Posted: Mon, 12 Aug 2003 @ 01:57:11 GMT

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Note, the formal name for the Teradata feautere is SyncScan and it must be "turned on". If the query processing loads are different enough such that one query's processing trails the other, the "piggy back" can be broken as only a limited range of blocks are are temporarily cached part of a piggy back arrangement. At that point the slow query starts to initiate its own physical reads and not piggy backing on the first queries reads. (Note, the second query could move through faster also, and in that case would start to initiate its own reads). With V2R5, Full Cylinder Reads can also help to share I/Os on full table scans.

Regards,

Andrew Schroter

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