RDBPROD: How to identify fragmented rows in a table
(Doc ID 283203.1)
Last updated on JANUARY 03, 2019
Applies to:Oracle Rdb Server on OpenVMS - Version 7.1.3 and later
HP OpenVMS Alpha
HP OpenVMS Itanium
The purpose of this article is to explain how to identify rows in a table that are fragmented, causing extra IO and CPU to fetch data.
Fragmentation occurs when either the row is too large to fit entirely on a page or an existing row was updated to a larger size and no space existed at that time for the expanded row. The first case requires that the page size be changed for the area. However, for the second case a DELETE and INSERT of the row might remove the fragmentation. In that case, the RDB$$IS_ROW_FRAGMENTED function, introduced in Oracle Rdb version 7.1.3, allows the DBA to identify candidate fragmented rows.
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