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CPI4338 - &1 Access path(s) used for bitmap processing of file &2. ( OS/400 )

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Message : CPI4338
&1 Access path(s) used for bitmap processing of file &2.

Message Long Text :

Cause . . . . . : Bitmap processing was used to access records from member &4 of file &2 in library &3.
Bitmap processing is a method of allowing one or more access path(s) to be used to access the selected records from a file. Using bitmap processing, record selection is applied against each access path, similar to key row positioning, to create a bitmap. The bitmap has marked in it only the records of the file that are to be selected. If more than one access path is used, the resulting bitmaps are merged together using boolean logic. The resulting bitmap is then used to reduce access to just those records actually selected from the file.
Bitmap processing is used in conjunction with the two primary access methods: arrival sequence (CPI4327 or CPI4329) or keyed access (CPI4326 or CPI4328). The message that describes the primary access method immediately precedes this message.
When the bitmap is used with the keyed access method then it is used to further reduce the number of records selected by the primary access path before retrieving the selected records from the file.
When the bitmap is used with arrival sequence then it allows the sequential scan of the file to skip records which are not selected by the bitmap. This is called skip sequential processing.
The list below shows the names of the access paths used in the bitmap processing:
&8
If file &2 in library &3 is a logical file then member &7 of physical file &5 in library &6 is the actual file being accessed.
Recovery . . . : Refer to the DB2 for i - Database Performance and Query Optimization topic collection in the Database category in the IBM i Information Center for more information on bitmap processing.

Message File : QCPFMSG
Library Message File : QSYS2924


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