Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (S)
Guardian Procedure Calls Reference Manual—522629-013
14-86
SETMODE Procedure
91 Disk: Set cache and sequential option (function 91 is not applicable for
alternate-key
files).
param1 = 0 system managed (default). DP2 will detect sequential
access;
when detected, it will set LRU access to sequential and
perform key-sequenced sequential splits.
= 1 direct I/O, bypass disk cache
= 2 random access, LRU-chain buffer
= 3 sequential access, reuse buffer. Directs DP2 to set
cache
LRU access to sequential and perform key-sequenced
sequential splits.
param2 is not used with function 91.
Sequential LRU access results in “random” LRU chaining that provides an
approximate half-life within the LRU cache chain.
Key-sequenced sequential splits attempt to leave the inserted record as the
last in the old block, in contrast to a 50/50 split. This helps to ensure a
compact key-sequenced structure when multiple sequential records are
inserted.
92 Disk: Set maximum number of extents for a nonpartitioned file. (Function 92
is invalid for audit-trail files and for partitioned non-key-sequenced files.)
param1 = new maximum number of extents value. There is no
guarantee of success if you specify a value greater than
500. The default is 16 extents.
param2 is not used with function 92.
This SETMODE operation returns ERROR 12 (file in use) if:
•
the file is a format 2 file, non-keysequenced and non-partitioned
•
the new values for maxextents would cause the maximum size of the file
to exceed 4 GB
•
the maximum size of the file before the SETMODE is less than 4 GB
•
the file is currently opened by the process issuing the SETMODE and the
open did not specify the "use 64-bit primary keys" election to
FILE_OPEN_
Table 14-4. SETMODE Functions (page 19 of 34)
function Parameters and Effect